Yes, but more so what percentage of throttle you're giving it. That increases the cylinder fill with oxygen in fuel and increases the pressure. When the cylinder is at the highest pressure is when it would not, if it's going to. There's also a heat component but we'll skip that for now.
You are so lucky to have access to 93 octane! Here in California I am just waiting on the day we lose 91 octane but they are just doing it in another way just making it unaffordable! (Does your Vette run better?
As someone who is interested in saving up for a C5 corvette, this video was incredibly helpful in factoring costs for what I may need. Thankyou for this information.
It just never FAILS! Show after Show are Top quality topics done in a professional way. BY FAR the best C-5 you tube channel! "Way to go Man" ( an old 1970s term) for what it's worth I have had to use 89 octane twice in the 8 years I have owned my "99" I am still being true to the Last nice car I will ever own ! Thanks again for the great shows! Question how long have you been Broadcasting?
Nothing more fun than reading the comments on Corvette social media. :-) I have owned my '04 since new, and have enjoyed all of the 139,910 miles currently on the clock. The choice of what fuel just requires using your brain a little. Spring and fall, I run 87. Hot summer months, I run 91. I do my best to avoid ethanol, but I only "actively" avoid it on the last couple tanks before winter storage. And even during that time, it's probably not a huge issue, as I often will get a chance at least once a month to go for drive in the winter.
Been driving a 1999 C5 as a daily driver using only the cheapest gas I can get. Have put 100,000 miles on it since my ownership and bought it when it had 50,000. Yes, the car has 150,000 miles on it now and still am driving it as a daily driver and have experienced very few maintenance issues that I have not been able to take care of myself. Heck, I have never even done a break job yet (It's getting about time though) and did not bother to change the plugs until they had 112,000 miles on them. These cars are great GM products. Go run them as much as possible and enjoy. Heck, I only paid $18,000 for it 17 years ago and its still worth a solid 10 or 12! Good informational vid.
Yet another great video. Really like your content. I've had my '03 coupe now for about 5 months and have religiously put 91 ethanol-free gas in it. I'm in Montana. 91 is the highest octane rating anywhere I've been in the state, and it's the only grade offered ethanol-free. I really appreciate the break down into 3 groups. I'm definitely group 2. I'm going to try mid grade with ethanol for a while just to see if there's a difference. I'll run the last few tanks before winter storage with ethanol-free 91 to clear the lines of anything that might cause condensation. Thanks for sticking your neck out and for a fresh perspective on this issue! UPDATE: I've run a tank of mid grade with ethanol and have had NO issues. No knocking or hesitation, and acceleration sounds and feels the same. What a relief! Not just in terms of cost, but also convenience. Not many stations have ethanol free fuel. I'll be using this formula most of the time, and switching to premium ethanol-free before storing for winter. Thanks again for this video and keep the content coming, damn the risk!
I run 87 in mine all the time. I don’t race it, just drive it. Once in a while I’ll treat to 93, but not very often. It’s a 2000 roadster with 133000. On it and she runs great. 28 mpg over all on long trips.🙋♂️🖖🏻
That's good. Just know and understand that temptation to roll into the throttle is pretty easy in these cars. Additionally, low load and lugging can be just as bad at high rpm.
I have never seen 91oct in my area. All we have is 87, 89, 93. I try to only use Shell 93oct. I use one bottle of techron three times a year. Runs great. No knock. No exhaust smoke/ carbon under heavy acceleration. Exhaust tips stay clean. Only time I have seen 91oct is at a Sunoco across the street from Daytona International speedway.
The other day I was getting gas in 2000 c5 and I noticed that a guy was getting gas in his 2015 and he was putting in 85 and told him YOU CAN'T DO THAT! He chuckled A few days later, he was in the dealership with a blown motor, I chuckled 🤭 Great video
I have a 2003 C5. I usually run 91. In a few cases, I've used 89. I can't tell any difference. I don't use 87. I rarely hammer the throttle but I do enjoy an on-ramp blast now and then.
No grief here on your good video, but I would add higher octane is better for high elevations, hilly areas and very high ambient temperatures. I’m in Phoenix, AZ - when the temps are over 100F and under load, I’ve noticed a propensity to ping. Keep up the great videos!
I was wondering if you were going to mention the two different spark tables for high octane vs low octane fuel, and then bam, there it was. Great information as always. It's definitely appreciated.
Another awesome informative video Ken. One thing you need to touch on is engine temperature. I know most GM vehicles will not have the fans run until the engine is over 195degs. This can be a very bad source of knock, a hot engine and hot intake air temp. is very bad. So if you can have a tuner like yourself reduce that temp. that alone will make a very big difference.
Good point sir! The c5's ignition tables actually do retard timing on a graduated scale as engine coolant and also inlet Air temps rise. They're actually fairly aggressive so this should account for the hot temps you mentioned.
Manufacturer's Recommendation: The owner's manual for vehicles with the LS1 engine recommends the use of premium fuel for optimal performance and longevity. I learned something new.
I’m an engineer who use to work on engines and agree with your assessment. I almost always get get at Costco so 93 is just fine there. I’m a group two driver so why not. Have you ever had an issue with slow fillups at the pump. I’m a new c5 owner and both tanks I’ve filled up stopped half way. Did some reading and there is a gm tsb for this issue which requires replacing the fuel filler tube. Also love the Winchester hat. Would love to see the toys4life at the range video!
2000 Base coup. I run 87 for day to day driving (Yes it is a mostly a daily driver... ) However, I only use name brand Tier 1 fuel. If I'm going to go about my day a little more quickly.... I will run 93. Yes there IS A NOTICABLE difference in performance and fuel economy. But again, regardless of octane, Tier 1 name brand fuel only. I do believe that the additive packages of Tier 1 fuel make a real difference.
I have always noticed different grades gas. And like diesel trucks using diesel 1 or Diesel 2 I kind of ramp up the octave rating for easier winter starting.
Where I'm typically located, I can get 91/92/93 octane generally speaking depending on the fill station. One time up in Maine on a short vacation I only had access to 89. Had some 93 left in the tank and filled 80% of the tank with 89 and I got home just fine. If I was doing a track day or something I wouldn't use anything lower than premium due to copious WOT but if you go easy an LS1 should work on 89 just fine. I have a year 2000 Hardtop. Keep in mind an LS1 compression ratio is 10:1 and LS6 is 10.5:1 so I would probably advise against using 87 in a Z06, while 89 may still be ok just to get you home. With higher compression ratios on LS2/LS6/LS3 I would be very careful before using 87, while 89 might still work ok in a pinch. Also, keep in mind that "mid-grade" gas doesn't really exist the same way regular and premium do. It's a mixture of regular unleaded and premium unleaded which is done at the pump. I imagine not all pumps and stations do this mixture 100% the same so you really kinda don't know what octane you're getting when you go for mid-grade, I assume 89 octane is a garaunteed minimum or it could even be an average. Every station may have a slightly different mix percentage. If your engine has higher compression (closer to 11:1 than 10:1) I would start staying away even from mid-grade entirely unless you were desperate. The engine can pull timing but knock could still occur and its bad anyways.
The minimum octane requirement for normally aspirated (not turbo or supercharged) gasoline engines generally decreases by one point for every 2500 ft (750 meters) of elevation above sea level, so 85 octane "regular' is sold at higher elevations like around "the mile high city" of Denver CO and other places of that elevation.
@@waynemangan9925 : As minimum octane required is generally considered a function of "compression ratio" it is actually a function of peak absolute pressure, which increases with compression ratio, but also decreases with elevation as the air is thinner. Think of absolute pressure as the number of air molecules in a given volume, in the case of a piston engine, the volume of the combustion chamber with the piston at TDC. If you start with less molecules at BDC, which is the case at a higher elevation = lower air pressure, you will have less molecules at TDC which has the same effect as a lower compression ratio, thus you can get by with a lower octane fuel. BTW; The elevation numbers I gave are only a general average, with different engines the numbers could vary ± 30%. Motors with more torque per displacement will generally be slightly more sensitive to change in elevation above sea level, and those with less, less.
Mine runs just fine on the cheapest that I can buy. On a 1000 mile trip last month I got 28.3 mpg. If I'm racing (for money) and need a little more timing advance I'll buy the expensive stuff...😜
Owners manual prefers 91 and 93. However, the owners manual also says 87 is fine but will notice a slight difference in performance. I have a 2001 C5 and all i put is 93
The C5 has a couple of different tables in the ECU that it uses. When it senses lower octane it will run on a lower octane software, adjusting spark advance and air/feul mix, if you will, until it senses a full tank at a fill up and then it will switch to the 91+ octane table. Then again if it senses lower octane it will shift to the lower octane table. It does this all on it's own. So run what you like and for normal everyday driving I doubt the average Vette owner will be able to tell the difference between the lower octane and premium. Now, that being said...if you are going to the track or just want the full potential output from the engine...fill 'er up with the good stuff and ENJOY!
Great, timely video. I just got a 2002 C5 with a manual, and I’m not exactly racing it but I get up in the REVS every time I get into it- which is several times a week. I probably should play it safe with Premium?
If you keep the revs high, you can generally get away with lower octane, it is at WOT at lower RPMs (below around 3500 ) that you need the higher octane.
I would just add that anytime you're under heavy load wide open throttle is when higher octane is beneficial. Peak torque area of the curve is where there's the maximum pressure in the cylinder which would typically be the most likely area to knock and ultimately damage something if the computer wasn't so good at pulling timing out! Just my opinion.
As someone who has programmed countless c5 corvettes I will tell you the computer has two timing tables assuming people will be cheap enough to skimp on octane. You will lose quit a bit of performance with the lower timing table which the car defaults to when it detects engine knock and with low octane it will knock before you get back on the highway. I recommend running the correct octane because a few pennies saved at the pump isn't worth the risk of a $10k engine exploding.
You missed the part about the knock learning factor that interpolates between the high and the low octane table depending on multiple factors including of course detecting knock, how often it's detected, and how extreme the knock is.
@@Toys4Life No im fully aware of the lower timing table. Have you seen those timing figures? Why by a corvette if your going to kneecap the hp by that much because your to cheap to buy the correct gas. The lower timing table is there to save the engine when things go wrong not to be daily driven because you were cheap. Now you wont have a safety margin for knock anymore and risk exploding the engine if things go wrong.
Man, Your very useful for the corvette crowd. Ill share this with you and the crowd. Nobody knows exactly what the engine will need octane wise. its all about getting as close to the line as possible...avoiding detonation and pre ignition. example. My Brother ran a mustang in the 1980's--90s with a 9.0 to 1 compression 302. He ran 87 octane in it at the track, launching at 7000 . It ran fastest with the MTBE gas they ran at certain times of the year. Higher octane? it slowed the car down. the engine did not need the octane.....and it slowed combustion down--thus less efficient. You dont have to believe squat.....but certainly extra octane never HURTS an engine....but experimentation on that line will give MOST performance efficiency. I agree with everything You said here in your vid. If you putting around town...87 is right there with 10 to 1.....89 prob even safer. hammering it alot? 91---92 you can even mix it...10 gal of 87.....2 gal of 93....... worst gas is OLD gas.....
It’s so funny - I even know the exact posts and answers you mentioned at the beginning of the video.. thanks for clarifying it, breaking it down, and keeping it real!👊👏🙏
I have been running my C5 with 91 octane and adding Lucas octane booster every other fill and she runs great. I thought the 2001 LS1 was tuned for 93 octane out of the factory.
Have to admit, I was down on income during the crazy gas price hike, so I used 87 several times as my C-5 is my daily. I typically always used 91. I used to use racing fuel every 10 tankfulls. Which was 105 octane. Of course it always ran great after that, consequently, it doesn't run great after several 87 fillups.
That should run the same, but if you were at wide Open throttle a lot with 87 octane, it might be implementing your low octane tables for a while and reducing maximum full throttle power for a little while.
I'm sure of that, because, unlike many Corvette owners, and especially with this particular one, I beat the snot out of it. Very rarely am I not at upper RPMS. The greatest part of a C-5 manual trans car is it's "spirited" driving characteristics, making it night and day different from an automatic. Yet I have been able to average 28 mpg highway fairly consistently, when my foot is out of it. Of the 18 Vettes I've owned in my life, this one is the toughest, most enjoyable one, hands down.
i ran 87 in my c5 for the entirety of my ownership, zero issues whatsoever... the compression ratio isnt quite high enough to cause knock as far as i know.
I think it would knock at WOT at low elevations (1500famsl and lower) but over time the computer learns and gives it less ignition timing to prevent further knock.
Excellent video. I don’t own a C5 yet, as I mentioned on here in the past I’m saving up for an 03 or 04 (w/o F55 suspension) manual coupe. I understand the purpose of this video, but I won’t be putting anything less than 93 octane. I don’t want to risk damaging any piston rings or any other internal engine parts. I like how you broke it down to 3 types of C5 drivers, I’m definitely in category two
91 and 92 octane will still work the same as 93. Only difference would be timing retardation if you got a tune (slightly lower power). ls1 is built to run 91.
@@Toymonkeyjr awesome thanks for your input. I believe Sunoco is the only station that carries 91. I was using Shell 93 on my current Lexus ES300 but their prices are much higher than Mobil or BP so I’m back using Mobil or BP 93.
@Stephen DiBari - Always appreciate your comments, sir! I think car prices are starting to turn and you might be able to pick p that C5 next summer? (hopefully!)
I use to own a 2001 Corvette and always used premium fuel unless I arrived at a gas station when no premium available so would add premium fuel to the tank after 3/4
Let me explain how it works. The way the factory pcm is setup is you have a low octane and a high octane timing table. High octane is the default table and it will blend between the two depending on knock detected. So what would happen with putting 87 in you will put more stress on your motor since the knocks are reactive to what happens, eventually it will blend the tables to see no knock but that takes a bit.
0:10 I have learned that posting questions on any of the corvette facebook groups is a waste of time. I don't think I've ever had a question answered with anything helpful. It's just people posting pictures of their garage queens. The forums seem to be a little better.
Interesting - the PCM should learn and pull timing out. How many miles are on it - if it has higher miles it could have enough carbon buildup on the pistons that effectively raise the compression ration a bit...
@@Toys4Life I was just gifted the car from my mom, it has 110,000 miles, this is in FL. She had the same experience, complained it would knock with "the cheap stuff" in it.
I’m also in FL and was wondering about the heat impact. In addition to the nuclear ambient temps, traveling a couple inches above molten asphalt really ups the ante on engine heat soak. I’m going to stick with the 93 despite the extra $10.00 a month.
The c5s computer system also pulls timing as the air inlet temperatures go up and as the engine coolant temperature go up so that's already built in in addition to a high octane table and a low octane table for spark timing. GM engineer spend a couple of dialing in all of the aspects of fuel management on these cars from Alaska to death valley and everywhere in between.
Guess I'm in group two. Maybe I'll try 89. Been using 91 and sometimes put a can of boost in if I feel like it will be a speeding day. Looking at this clip, I'm in no need of the extra. I do about 80 mph on the highway on average. I've never been over 130 in it.
What a beautiful state, thanks for chimng in! The human in me would love to live in the mountains, the performance guy and me understands the performance hit.
There’s literally a “low octane” table in the tune that kicks in above a specified knock threshold. The stock tune is also designed to pull timing from BOTH tables in relation to coolant temp and intake temperatures, even if there is no knock detected. Additionally, the stock tune is also designed around running the engine at higher temperatures (I.E. 220-235 degrees is normal). Solely changing the fan on/off perimeters would net little to no knock on 87 octane more times than not, even during abusive driving. You’d just be down on some power, of which most of the folks critical about octane would never even notice.
I’ve found that I can buy 87 octane and add one bottle of Amsoil Dominator Octane Boost per tank. It raises the octane 4 numbers and with a preferred customer account, the octane boost price is low enough when added to regular to be cheaper than using premium fuel and the engine runs great😊
I wish they used some different language than four numbers. I think they're probably suggesting 87.4, and not 91. Otherwise they would say for full points? I tried to look it up but I didn't say anything that clarified it which is discouraging. Have you seen something that says it raises at 4 full points all the way up to 91?
@@Toys4Life Thank you for your question. I checked the product data sheet and they only used the word “numbers” when talking about octane increase. They used the same word when referring to octane and how it affects engine performance. I’m very sure they are referring to 4 full octane numbers to 91 from 87. They say it increases engine performance, helps stop knock and replaces lead for collector cars and older off road equipment. I don’t think that 4/10ths of an octane number would do that. I have been using it for a while and haven’t heard any knock and the engine is very responsive and revs very quickly! I believe in it. You’re welcome to give it a try. I can give you a referral number if you want to order product as a preferred customer. The price drops from $12.39 a bottle to $9.89 a bottle and p.c.’s get free shipping through March 12th with a $49 order by applying FREESHIP in the promo box. Please let me know😊
Ron Harp: Colorado, Denver & cities around Denver has 86 with lot of the stations not selling 87 at all and going right to 89. Keep up the good work. I was born in Mora Mn. in 1945.
I've been running 87 octane in my 2000 Trans Am since I bought it in 04. I will put 91 or 93 in it if I'm going to the track or autocross but other than that my car drink the cheap stuff. And I have NEVER had any problems with any of my sports car running 87. Now if I was running an engine with higher compression than stock then yes I would definitely use the higher octane. I'm 55yrs old and have played with cars my whole life. Just my opinion.
I’ve seen 85 octane all over the mountain west states. You can get by with it as long as you’re at higher elevations, because the thinner air will not compress as much.
Over the last 15 years I've owned 8 different C5's, all reconstructed totals (by me). I've never run anything but 87 octane. Why? Because I actually read the owner's manual. That said, about the only time I put the hammer down is on freeway entrance ramps. That's fun.
When id go to lawton Oklahoma which was 490 miles in my 95c4 id put in 89 and id average 34.5 mpg. No issues at all. On my c5 i run 93 simply out of habit but i know itll be fine if i ran 89. Its ny daily driver and i dont drive stupid
As a retiree who owns 2 C5's I use Shell Nitro 93 octane with Tectron. Since all my pleasure driving averages around 1,500 miles a year, the additional expense over regular is about $60 per each C5. (1500 miles / 20 mpg) * (93 octane at $4.50 gallon - 87 octane at $3.75 gallon). Depends on one's financial situation and comfort level. Thanks for another excellent video by the best C5 YT source.
Used a few times when highway traveling based on previous videos years ago stating computer's will compensate and you will get alittle less mpg. But will stick with premium since it's not worth the possible issues.
The computer should compensate and it will run on 87 most older LS truck engines run on 87 but do have slightly lower compression ratios for regular driving 87 will work on a LS1 but it's not going to give you optimum performance l went the complete opposite of this with a modified 2011 Camaro SS it takes upgrades but it runs on E85 I've been getting it for 3.10 a gallon it's at least 100 octane car runs better than on premium 93 but you don't get as many miles to the gallon as 93 octane and with a E85 tune it makes more power 20+ horsepower increase on a naturally aspirated engine 40-50 if supercharged so far my car absolutely loves running on E85 it burns cleaner the engine runs cooler on it heat is what kills most engines over time so a cooler running motor should last longer and E85 doesn't leave brown or black carbon on valves pistons or combustion chambers like gasoline does taking away power and efficiency over time E85 leaves a very slight yellow or gold color residue on valves pistons and combustion chambers but nothing like the black or brown carbon gasoline leaves over the same usage even tail pipes show no brown or black carbon using E85 over time a very slight yellow or gold color
High altitude areas like Denver have lower octane fuels because you don't need 87 octane. You never going to get high enough compression high altitude and I'm naturally aspirated car. If you get a turbo or supercharger then this discussion doesn't deploy because you still have to run the proper octane because the boost will achieve the same pressures no matter what you're altitude
I run 93 in my LS6, at least 91 in my tuned LM7, and at least 91 in the wife's SHO, she actually gets mad at me because every time I fill it up, I put in 93 and that's "not necessary" but I'd rather err on side of caution.
People just don,t understand that the engines ecm will pull back timing and reduce power output based on lower octane. I am a retired Gm tech and a Master Tech with three different factories and all my research and daily driving backs this up. It’s not like the old carb days where you had no choice , now you do. Imho
My guess it was not the size or remoteness of the towns, but their elevation above sea level, see my other post as to minimum octane requirements with elevation.
91 is gas for people that have cars that have unique throttle and fuel systems, like most German cars,it's totally fine to run 87 for emergencies, however 91 is required on specified engines like some bmw requires 89, to achieve a better mpg gotta buy 91 for Mercedes BMWs and some cars like Ford gt, viper, and Lexus lFA
It's my experience with my 98 is this it runs best and gets the best mileage where I live over 5000 ft. with 91 octane when I'm at lower altitude and 93 is available I use that and my car just loves it and let's me know it
One thing he didn't touch on is fuel mileage, with 93 I get around 30-31 mpg @ 65 mph. Running a tank of 87 it dropped to 27-28 plus I had less power. So since finding that out I only run 93 octane, sadly here in S. Nevada they don't sell ethanol-free gasoline.
Part throttle low load I cannot think of any reason the MPG would change so long as the fuels have the same percentage of ethanol. E10 does get less MPG than ethanol free in an NA car.
I don't run anything less than 93 in mine (but mine is a fully forged 6.3L 383ci Twin Turbo with 1500hp) but if the Corvette is stock, and if you put 87 in and there is no detonation, then the car can obviously handle 87 fine... I personally would never put "REGULAR" In a newer Corvette... i normally even put 94 Octane in my car at the gas station by my house that sells it at the pump... also run 108-112 Octane at the track (or E85 or a mix of both).... like he said " if you can afford to fill you tank with SUPER, ya probably shouldn't be drivin a Corvette! 🤣✌️
Yeah, I'm in the I drive way too hard for 87 camp too. But if somebody wants to put 87 in their Corvette for a road trip 350 mi to the next major city, nothing's going to happen.
IMO - If you are just cruising on the freeway on long trips - that is where I would consider 87. It takes very little HP to move a C5 along at 70mph - Unless you punch it often... Cheers!
It’s a special day today.
I just purchased a black 2004 Corvette Z06
My first corvette!
Thanks for all the excellent videos,
keep the C5 Alive!
That's 😎 awesome! You're going to need a grin-ectomy!
I've used 87 in mine, and it runs fine for granny driving but it will ping and knock if you drive aggressively. Put 91 in and it's good
Is aggressive related directly to RPM?
Yes, but more so what percentage of throttle you're giving it. That increases the cylinder fill with oxygen in fuel and increases the pressure. When the cylinder is at the highest pressure is when it would not, if it's going to. There's also a heat component but we'll skip that for now.
My area has 87-89 and 93. I normally use 93, but have used 87 in the past with no issues. Appreciate all the helpful content!👍👌
You are so lucky to have access to 93 octane! Here in California I am just waiting on the day we lose 91 octane but they are just doing it in another way just making it unaffordable! (Does your Vette run better?
@@christopherdutro168 I only used 87 when vacationing or when it wasn't available. Otherwise my vette ran fine but didn't have the extra power.
Is 87 fine on the 1998 C5
@@alexisfernandez5808 believe the reply is the same as 1997, 1999, 2000, 2001, 2002, 2003...
@@megaman4201 and 2004 which was the last year of the C5🤙🏼
As someone who is interested in saving up for a C5 corvette, this video was incredibly helpful in factoring costs for what I may need. Thankyou for this information.
You got it buddy! Picked my 02 up last week! Heck of a bargain of a drivers car :)
It just never FAILS! Show after Show are Top quality topics done in a professional way. BY FAR the best C-5 you tube channel! "Way to go Man" ( an old 1970s term) for what it's worth I have had to use 89 octane twice in the 8 years I have owned my "99" I am still being true to the Last nice car I will ever own ! Thanks again for the great shows! Question how long have you been Broadcasting?
Wow, thank you - much appreciated!!
Nothing more fun than reading the comments on Corvette social media. :-) I have owned my '04 since new, and have enjoyed all of the 139,910 miles currently on the clock. The choice of what fuel just requires using your brain a little. Spring and fall, I run 87. Hot summer months, I run 91. I do my best to avoid ethanol, but I only "actively" avoid it on the last couple tanks before winter storage. And even during that time, it's probably not a huge issue, as I often will get a chance at least once a month to go for drive in the winter.
I have been looking for this question everywhere! Thank you for posting it!
Glad it was helpful!
Been driving a 1999 C5 as a daily driver using only the cheapest gas I can get. Have put 100,000 miles on it since my ownership and bought it when it had 50,000. Yes, the car has 150,000 miles on it now and still am driving it as a daily driver and have experienced very few maintenance issues that I have not been able to take care of myself. Heck, I have never even done a break job yet (It's getting about time though) and did not bother to change the plugs until they had 112,000 miles on them. These cars are great GM products. Go run them as much as possible and enjoy. Heck, I only paid $18,000 for it 17 years ago and its still worth a solid 10 or 12! Good informational vid.
Yet another great video. Really like your content. I've had my '03 coupe now for about 5 months and have religiously put 91 ethanol-free gas in it. I'm in Montana. 91 is the highest octane rating anywhere I've been in the state, and it's the only grade offered ethanol-free. I really appreciate the break down into 3 groups. I'm definitely group 2. I'm going to try mid grade with ethanol for a while just to see if there's a difference. I'll run the last few tanks before winter storage with ethanol-free 91 to clear the lines of anything that might cause condensation. Thanks for sticking your neck out and for a fresh perspective on this issue! UPDATE: I've run a tank of mid grade with ethanol and have had NO issues. No knocking or hesitation, and acceleration sounds and feels the same. What a relief! Not just in terms of cost, but also convenience. Not many stations have ethanol free fuel. I'll be using this formula most of the time, and switching to premium ethanol-free before storing for winter. Thanks again for this video and keep the content coming, damn the risk!
I run 87 in mine all the time. I don’t race it, just drive it. Once in a while I’ll treat to 93, but not very often. It’s a 2000 roadster with 133000. On it and she runs great. 28 mpg over all on long trips.🙋♂️🖖🏻
That's good. Just know and understand that temptation to roll into the throttle is pretty easy in these cars. Additionally, low load and lugging can be just as bad at high rpm.
I have never seen 91oct in my area. All we have is 87, 89, 93. I try to only use Shell 93oct. I use one bottle of techron three times a year. Runs great. No knock. No exhaust smoke/ carbon under heavy acceleration. Exhaust tips stay clean. Only time I have seen 91oct is at a Sunoco across the street from Daytona International speedway.
91 is west coast and higher elevations
Both Shell stations went out of business in my town. 😢 shell 93 only thing I ran in my motorcycle and turbo PT Cruiser!
I usually run 93 in mine, but on long roadtrips, 87 might be just fine at a constant speed.
100% agreed!
The other day I was getting gas in 2000 c5 and I noticed that a guy was getting gas in his 2015 and he was putting in 85 and told him YOU CAN'T DO THAT! He chuckled
A few days later, he was in the dealership with a blown motor, I chuckled 🤭
Great video
Yikes - it even says on the pump not to use unless the car is flex fuel!
I've ALWAYS put 93 octane in my C5 Corvette!!!!
I have a 2003 C5. I usually run 91. In a few cases, I've used 89. I can't tell any difference. I don't use 87. I rarely hammer the throttle but I do enjoy an on-ramp blast now and then.
Thanks for sharing
So is 91 recommend and anything above its not tuned for it basically?
No grief here on your good video, but I would add higher octane is better for high elevations, hilly areas and very high ambient temperatures. I’m in Phoenix, AZ - when the temps are over 100F and under load, I’ve noticed a propensity to ping.
Keep up the great videos!
I was wondering if you were going to mention the two different spark tables for high octane vs low octane fuel, and then bam, there it was. Great information as always. It's definitely appreciated.
Best C5 YT channel out there!!! Thx!!!
Another awesome informative video Ken. One thing you need to touch on is engine temperature. I know most GM vehicles will not have the fans run until the engine is over 195degs. This can be a very bad source of knock, a hot engine and hot intake air temp. is very bad. So if you can have a tuner like yourself reduce that temp. that alone will make a very big difference.
Good point sir! The c5's ignition tables actually do retard timing on a graduated scale as engine coolant and also inlet Air temps rise. They're actually fairly aggressive so this should account for the hot temps you mentioned.
Manufacturer's Recommendation: The owner's manual for vehicles with the LS1 engine recommends the use of premium fuel for optimal performance and longevity. I learned something new.
Thank you great honest advice
I’m an engineer who use to work on engines and agree with your assessment. I almost always get get at Costco so 93 is just fine there. I’m a group two driver so why not. Have you ever had an issue with slow fillups at the pump. I’m a new c5 owner and both tanks I’ve filled up stopped half way. Did some reading and there is a gm tsb for this issue which requires replacing the fuel filler tube.
Also love the Winchester hat. Would love to see the toys4life at the range video!
2000 Base coup. I run 87 for day to day driving (Yes it is a mostly a daily driver... ) However, I only use name brand Tier 1 fuel. If I'm going to go about my day a little more quickly.... I will run 93. Yes there IS A NOTICABLE difference in performance and fuel economy. But again, regardless of octane, Tier 1 name brand fuel only. I do believe that the additive packages of Tier 1 fuel make a real difference.
I have always noticed different grades gas. And like diesel trucks using diesel 1 or Diesel 2 I kind of ramp up the octave rating for easier winter starting.
Sorry to tell you this, but higher octane gas does not start any easier in the winter versus mid or low octane.
Where I'm typically located, I can get 91/92/93 octane generally speaking depending on the fill station. One time up in Maine on a short vacation I only had access to 89. Had some 93 left in the tank and filled 80% of the tank with 89 and I got home just fine. If I was doing a track day or something I wouldn't use anything lower than premium due to copious WOT but if you go easy an LS1 should work on 89 just fine. I have a year 2000 Hardtop.
Keep in mind an LS1 compression ratio is 10:1 and LS6 is 10.5:1 so I would probably advise against using 87 in a Z06, while 89 may still be ok just to get you home. With higher compression ratios on LS2/LS6/LS3 I would be very careful before using 87, while 89 might still work ok in a pinch. Also, keep in mind that "mid-grade" gas doesn't really exist the same way regular and premium do. It's a mixture of regular unleaded and premium unleaded which is done at the pump. I imagine not all pumps and stations do this mixture 100% the same so you really kinda don't know what octane you're getting when you go for mid-grade, I assume 89 octane is a garaunteed minimum or it could even be an average. Every station may have a slightly different mix percentage.
If your engine has higher compression (closer to 11:1 than 10:1) I would start staying away even from mid-grade entirely unless you were desperate. The engine can pull timing but knock could still occur and its bad anyways.
The minimum octane requirement for normally aspirated (not turbo or supercharged) gasoline engines generally decreases by one point for every 2500 ft (750 meters) of elevation above sea level, so 85 octane "regular' is sold at higher elevations like around "the mile high city" of Denver CO and other places of that elevation.
I was probing to see if someone had explaned this before I chimed in.🍻🍻
@@waynemangan9925 : As minimum octane required is generally considered a function of "compression ratio" it is actually a function of peak absolute pressure, which increases with compression ratio, but also decreases with elevation as the air is thinner. Think of absolute pressure as the number of air molecules in a given volume, in the case of a piston engine, the volume of the combustion chamber with the piston at TDC. If you start with less molecules at BDC, which is the case at a higher elevation = lower air pressure, you will have less molecules at TDC which has the same effect as a lower compression ratio, thus you can get by with a lower octane fuel. BTW; The elevation numbers I gave are only a general average, with different engines the numbers could vary ± 30%. Motors with more torque per displacement will generally be slightly more sensitive to change in elevation above sea level, and those with less, less.
I wholeheartedly 👍
I use mid-grade in my 99 C5, and never have any issues. I don't have a heavy foot either.
Mine runs just fine on the cheapest that I can buy. On a 1000 mile trip last month I got 28.3 mpg. If I'm racing (for money) and need a little more timing advance I'll buy the expensive stuff...😜
Owners manual prefers 91 and 93. However, the owners manual also says 87 is fine but will notice a slight difference in performance. I have a 2001 C5 and all i put is 93
93 in mine also Prices are nuts !
The C5 has a couple of different tables in the ECU that it uses. When it senses lower octane it will run on a lower octane software, adjusting spark advance and air/feul mix, if you will, until it senses a full tank at a fill up and then it will switch to the 91+ octane table. Then again if it senses lower octane it will shift to the lower octane table. It does this all on it's own. So run what you like and for normal everyday driving I doubt the average Vette owner will be able to tell the difference between the lower octane and premium. Now, that being said...if you are going to the track or just want the full potential output from the engine...fill 'er up with the good stuff and ENJOY!
Great, timely video. I just got a 2002 C5 with a manual, and I’m not exactly racing it but I get up in the REVS every time I get into it- which is several times a week. I probably should play it safe with Premium?
When I had my c5 I would put 87 in it here and there especially recently. It didn’t hurt the car.
If you keep the revs high, you can generally get away with lower octane, it is at WOT at lower RPMs (below around 3500 ) that you need the higher octane.
I would just add that anytime you're under heavy load wide open throttle is when higher octane is beneficial. Peak torque area of the curve is where there's the maximum pressure in the cylinder which would typically be the most likely area to knock and ultimately damage something if the computer wasn't so good at pulling timing out! Just my opinion.
As someone who has programmed countless c5 corvettes I will tell you the computer has two timing tables assuming people will be cheap enough to skimp on octane. You will lose quit a bit of performance with the lower timing table which the car defaults to when it detects engine knock and with low octane it will knock before you get back on the highway. I recommend running the correct octane because a few pennies saved at the pump isn't worth the risk of a $10k engine exploding.
You missed the part about the knock learning factor that interpolates between the high and the low octane table depending on multiple factors including of course detecting knock, how often it's detected, and how extreme the knock is.
@@Toys4Life No im fully aware of the lower timing table. Have you seen those timing figures? Why by a corvette if your going to kneecap the hp by that much because your to cheap to buy the correct gas. The lower timing table is there to save the engine when things go wrong not to be daily driven because you were cheap. Now you wont have a safety margin for knock anymore and risk exploding the engine if things go wrong.
Red 03 coupe, great info. A&A super charger in the plan near future. You have great content on your channel.
Thanks for the feedback, I do greatly appreciate it!
Once again a lot of good, useful information. Thanks for sharing from one who probably falls into the group 1 1/2 🙂
Thank you sir, appreciate it!
My 2000 Corvette will knock on 87. If i put 89 it runs well and seems to run the same as 93. Appreciate the video tho
Appreciate the feedback
I built my 6.0 engine to have 9.6 compression so I could run cheep stuff still have 415 whp with a t56 tuned on87
Man, Your very useful for the corvette crowd.
Ill share this with you and the crowd. Nobody knows exactly what the engine will need octane wise. its all about getting as close to the line as possible...avoiding detonation and pre ignition.
example. My Brother ran a mustang in the 1980's--90s with a 9.0 to 1 compression 302. He ran 87 octane in it at the track, launching at 7000 . It ran fastest with the MTBE gas they ran at certain times of the year. Higher octane? it slowed the car down. the engine did not need the octane.....and it slowed combustion down--thus less efficient.
You dont have to believe squat.....but certainly extra octane never HURTS an engine....but experimentation on that line will give MOST performance efficiency.
I agree with everything You said here in your vid. If you putting around town...87 is right there with 10 to 1.....89 prob even safer.
hammering it alot? 91---92
you can even mix it...10 gal of 87.....2 gal of 93.......
worst gas is OLD gas.....
Thanks for sharing your first hand experiences!
I have a 91 octane tune on my C5. Mild cams and AFR heads required it.
Another great video I have a 2002 C5 Corvette I only put 93 in it have had no problem with it runs great 👍
These videos are a must for any Corvette owner or enthusiast I have learned so much valuable information from them that they are a necessity for me
Your comment means a lot sir thank you much appreciated!
It’s so funny - I even know the exact posts and answers you mentioned at the beginning of the video.. thanks for clarifying it, breaking it down, and keeping it real!👊👏🙏
Thank you!
I have been running my C5 with 91 octane and adding Lucas octane booster every other fill and she runs great. I thought the 2001 LS1 was tuned for 93 octane out of the factory.
West Texas has some areas where there’s 85, 87 and 89 as the three octanes at the pump. Saw it in Amarillo.
Have to admit, I was down on income during the crazy gas price hike, so I used 87 several times as my C-5 is my daily. I typically always used 91. I used to use racing fuel every 10 tankfulls. Which was 105 octane. Of course it always ran great after that, consequently, it doesn't run great after several 87 fillups.
That should run the same, but if you were at wide Open throttle a lot with 87 octane, it might be implementing your low octane tables for a while and reducing maximum full throttle power for a little while.
I'm sure of that, because, unlike many Corvette owners, and especially with this particular one, I beat the snot out of it. Very rarely am I not at upper RPMS. The greatest part of a C-5 manual trans car is it's "spirited" driving characteristics, making it night and day different from an automatic. Yet I have been able to average 28 mpg highway fairly consistently, when my foot is out of it. Of the 18 Vettes I've owned in my life, this one is the toughest, most enjoyable one, hands down.
Looks like I fall into group 2, guess I'll be trying the 89 next time I need fuel. Thanks for the helpful content.
i ran 87 in my c5 for the entirety of my ownership, zero issues whatsoever... the compression ratio isnt quite high enough to cause knock as far as i know.
I think it would knock at WOT at low elevations (1500famsl and lower) but over time the computer learns and gives it less ignition timing to prevent further knock.
Excellent video. I don’t own a C5 yet, as I mentioned on here in the past I’m saving up for an 03 or 04 (w/o F55 suspension) manual coupe.
I understand the purpose of this video, but I won’t be putting anything less than 93 octane. I don’t want to risk damaging any piston rings or any other internal engine parts. I like how you broke it down to 3 types of C5 drivers, I’m definitely in category two
91 and 92 octane will still work the same as 93. Only difference would be timing retardation if you got a tune (slightly lower power). ls1 is built to run 91.
@@Toymonkeyjr awesome thanks for your input. I believe Sunoco is the only station that carries 91. I was using Shell 93 on my current Lexus ES300 but their prices are much higher than Mobil or BP so I’m back using Mobil or BP 93.
@@stephendibari5010 Yep, if you ever go on a roadtrip, 91 will be perfectly fine, functioning exactly the same as 93 would on the factory tune.
@Stephen DiBari - Always appreciate your comments, sir! I think car prices are starting to turn and you might be able to pick p that C5 next summer? (hopefully!)
@ ARchie M. I concur (:-)
I use to own a 2001 Corvette and always used premium fuel unless I arrived at a gas station when no premium available so would add premium fuel to the tank after 3/4
I pretty much only e85 in my C5! Running the AFD Flex Fuel kit on my car has been great. More horsepower (+~30hp) and cheaper gas!!
very useful information, I've actually wondered this in the past myself.
Thank you
Let me explain how it works. The way the factory pcm is setup is you have a low octane and a high octane timing table. High octane is the default table and it will blend between the two depending on knock detected. So what would happen with putting 87 in you will put more stress on your motor since the knocks are reactive to what happens, eventually it will blend the tables to see no knock but that takes a bit.
So technically one could "force" the tune down to low octane table?
0:10 I have learned that posting questions on any of the corvette facebook groups is a waste of time. I don't think I've ever had a question answered with anything helpful. It's just people posting pictures of their garage queens. The forums seem to be a little better.
My 2000 will knock on 87 regularly, infrequently on 89 and not at all on 91, hot climate.
Interesting - the PCM should learn and pull timing out. How many miles are on it - if it has higher miles it could have enough carbon buildup on the pistons that effectively raise the compression ration a bit...
@@Toys4Life I was just gifted the car from my mom, it has 110,000 miles, this is in FL. She had the same experience, complained it would knock with "the cheap stuff" in it.
I’m also in FL and was wondering about the heat impact. In addition to the nuclear ambient temps, traveling a couple inches above molten asphalt really ups the ante on engine heat soak. I’m going to stick with the 93 despite the extra $10.00 a month.
The c5s computer system also pulls timing as the air inlet temperatures go up and as the engine coolant temperature go up so that's already built in in addition to a high octane table and a low octane table for spark timing. GM engineer spend a couple of dialing in all of the aspects of fuel management on these cars from Alaska to death valley and everywhere in between.
@@Toys4Life Maybe that’s why my car is such a slug. I was blaming the 3.42s, but perhaps 🤔…
Guess I'm in group two. Maybe I'll try 89. Been using 91 and sometimes put a can of boost in if I feel like it will be a speeding day. Looking at this clip, I'm in no need of the extra. I do about 80 mph on the highway on average. I've never been over 130 in it.
I only use 93 in mine because I don't wanna lose any performance of the car
As you should.Good on ya
10.4
We live in the mountains of western Colorado. 85 octane is regularl here. I have a 92 c4 and still use 91 in mine.
What a beautiful state, thanks for chimng in! The human in me would love to live in the mountains, the performance guy and me understands the performance hit.
Here in northern NM (altitude 5000 ft and up), they sell 86, 88 and 91 octane gas.
86 oh my!
There’s literally a “low octane” table in the tune that kicks in above a specified knock threshold.
The stock tune is also designed to pull timing from BOTH tables in relation to coolant temp and intake temperatures, even if there is no knock detected.
Additionally, the stock tune is also designed around running the engine at higher temperatures (I.E. 220-235 degrees is normal).
Solely changing the fan on/off perimeters would net little to no knock on 87 octane more times than not, even during abusive driving. You’d just be down on some power, of which most of the folks critical about octane would never even notice.
I 👍
I’ve found that I can buy 87 octane and add one bottle of Amsoil Dominator Octane Boost per tank. It raises the octane 4 numbers and with a preferred customer account, the octane boost price is low enough when added to regular to be cheaper than using premium fuel and the engine runs great😊
I wish they used some different language than four numbers. I think they're probably suggesting 87.4, and not 91. Otherwise they would say for full points? I tried to look it up but I didn't say anything that clarified it which is discouraging. Have you seen something that says it raises at 4 full points all the way up to 91?
@@Toys4Life Thank you for your question. I checked the product data sheet and they only used the word “numbers” when talking about octane increase. They used the same word when referring to octane and how it affects engine performance. I’m very sure they are referring to 4 full octane numbers to 91 from 87. They say it increases engine performance, helps stop knock and replaces lead for collector cars and older off road equipment. I don’t think that 4/10ths of an octane number would do that. I have been using it for a while and haven’t heard any knock and the engine is very responsive and revs very quickly! I believe in it. You’re welcome to give it a try. I can give you a referral number if you want to order product as a preferred customer. The price drops from $12.39 a bottle to $9.89 a bottle and p.c.’s get free shipping through March 12th with a $49 order by applying FREESHIP in the promo box.
Please let me know😊
93 octane cuz zoom zoom!
I could care less about what any one else uses.
Here in NM we have 86 but I always put 91 in just to be safe
Winchester hat, corvette, 1776 banner on the wall. i think i just found my people!
😂
Back in late 90s Sunoco in my area there was 86 octane they called it economy
Ron Harp: Colorado, Denver & cities around Denver has 86 with lot of the stations not selling 87 at all and going right to 89. Keep up the good work. I was born in Mora Mn. in 1945.
According to my data logging using hptuners, 87 gives my car ridiculous amounts of knock. That was when it was completely stock.
Agreed and that's not surprising. Thus if you drive and at least bit aggressive you shouldn't use it. Now you're modified, what you got going on?
They are low compression for a NA engine when compared to today's engines I would bet 87 is just fine for daily driving
I've been running 87 octane in my 2000 Trans Am since I bought it in 04. I will put 91 or 93 in it if I'm going to the track or autocross but other than that my car drink the cheap stuff. And I have NEVER had any problems with any of my sports car running 87. Now if I was running an engine with higher compression than stock then yes I would definitely use the higher octane. I'm 55yrs old and have played with cars my whole life. Just my opinion.
I’ve seen 85 octane all over the mountain west states. You can get by with it as long as you’re at higher elevations, because the thinner air will not compress as much.
And there's less oxygen.
Another great video! Thanks.
Over the last 15 years I've owned 8 different C5's, all reconstructed totals (by me). I've never run anything but 87 octane. Why? Because I actually read the owner's manual. That said, about the only time I put the hammer down is on freeway entrance ramps. That's fun.
When id go to lawton Oklahoma which was 490 miles in my 95c4 id put in 89 and id average 34.5 mpg. No issues at all. On my c5 i run 93 simply out of habit but i know itll be fine if i ran 89. Its ny daily driver and i dont drive stupid
As a retiree who owns 2 C5's I use Shell Nitro 93 octane with Tectron. Since all my pleasure driving averages around 1,500 miles a year, the additional expense over regular is about $60 per each C5. (1500 miles / 20 mpg) * (93 octane at $4.50 gallon - 87 octane at $3.75 gallon).
Depends on one's financial situation and comfort level. Thanks for another excellent video by the best C5 YT source.
I used 87 in my ls1 trans am for years w no problem
Used a few times when highway traveling based on previous videos years ago stating computer's will compensate and you will get alittle less mpg.
But will stick with premium since it's not worth the possible issues.
The computer should compensate and it will run on 87 most older LS truck engines run on 87 but do have slightly lower compression ratios for regular driving 87 will work on a LS1 but it's not going to give you optimum performance l went the complete opposite of this with a modified 2011 Camaro SS it takes upgrades but it runs on E85 I've been getting it for 3.10 a gallon it's at least 100 octane car runs better than on premium 93 but you don't get as many miles to the gallon as 93 octane and with a E85 tune it makes more power 20+ horsepower increase on a naturally aspirated engine 40-50 if supercharged so far my car absolutely loves running on E85 it burns cleaner the engine runs cooler on it heat is what kills most engines over time so a cooler running motor should last longer and E85 doesn't leave brown or black carbon on valves pistons or combustion chambers like gasoline does taking away power and efficiency over time E85 leaves a very slight yellow or gold color residue on valves pistons and combustion chambers but nothing like the black or brown carbon gasoline leaves over the same usage even tail pipes show no brown or black carbon using E85 over time a very slight yellow or gold color
Go man go! Thanks for sharing.
The computer will pull timing b4 you ever hear anything close to ping
Great info! Thanks.
In West Texas 86 Octane is sold.
Diablo sport 93 octane tune in my 02 vert. It is faster than the stock tune. Does 100 mph in 2nd gear ..auto...and sounds good doing it
Ive tan 87 in many sports cars even BMW and Benz. Yes it ran and lost milage but really is that a problem 🤷🏼♂️
High altitude areas like Denver have lower octane fuels because you don't need 87 octane. You never going to get high enough compression high altitude and I'm naturally aspirated car. If you get a turbo or supercharger then this discussion doesn't deploy because you still have to run the proper octane because the boost will achieve the same pressures no matter what you're altitude
Been running 87 on my 01 and have put 50,000 miles in the past two years it’s never knocked or giving me performance problems
Only time I would use 85 octane is on a long road trip and I wouldn’t go over 50% throttle at any time.
I run 93 in my LS6, at least 91 in my tuned LM7, and at least 91 in the wife's SHO, she actually gets mad at me because every time I fill it up, I put in 93 and that's "not necessary" but I'd rather err on side of caution.
thank you
I use Plus 89 Octane. I drive easy, mostly.
People just don,t understand that the engines ecm will pull back timing and reduce power output based on lower octane. I am a retired Gm tech and a Master Tech with three different factories and all my research and daily driving backs this up. It’s not like the old carb days where you had no choice , now you do. Imho
On some road trips I've taken I've seen in the more remote areas or small towns Gas station with 85 octane.
My guess it was not the size or remoteness of the towns, but their elevation above sea level, see my other post as to minimum octane requirements with elevation.
CORVETTES ARENT ABOUT MILES PER GALLON... THEYRE ABOUT SMILES PER GALLON! 🤘
I've had mine for 8 years. Not once have I calculated my mpg. I other words, I concur. (:-) 😁
👍🏼 agree
91 is gas for people that have cars that have unique throttle and fuel systems, like most German cars,it's totally fine to run 87 for emergencies, however 91 is required on specified engines like some bmw requires 89, to achieve a better mpg gotta buy 91 for Mercedes BMWs and some cars like Ford gt, viper, and Lexus lFA
What's a BMW? Just kidding.
I’ve had my C5 Convertable for 18 years. Always ran 93 octane.
Top tier for yours!
I always use the 93 octane my baby deserves it!
There's a lot of spoiled c5's out there!
It's my experience with my 98 is this it runs best and gets the best mileage where I live over 5000 ft. with 91 octane when I'm at lower altitude and 93 is available I use that and my car just loves it and let's me know it
Thanks for sharing
One thing he didn't touch on is fuel mileage, with 93 I get around 30-31 mpg @ 65 mph. Running a tank of 87 it dropped to 27-28 plus I had less power. So since finding that out I only run 93 octane, sadly here in S. Nevada they don't sell ethanol-free gasoline.
Part throttle low load I cannot think of any reason the MPG would change so long as the fuels have the same percentage of ethanol. E10 does get less MPG than ethanol free in an NA car.
@@Toys4Life Because the computer can advance the timing more when it detects that I'm running 93 octane.
@@hoodagooboy5981 I've scanned it and tested it, that's only at high load situations not at cruise. Not at cruise whatsoever!
I don't run anything less than 93 in mine (but mine is a fully forged 6.3L 383ci Twin Turbo with 1500hp) but if the Corvette is stock, and if you put 87 in and there is no detonation, then the car can obviously handle 87 fine... I personally would never put "REGULAR" In a newer Corvette... i normally even put 94 Octane in my car at the gas station by my house that sells it at the pump... also run 108-112 Octane at the track (or E85 or a mix of both).... like he said " if you can afford to fill you tank with SUPER, ya probably shouldn't be drivin a Corvette! 🤣✌️
Yeah, I'm in the I drive way too hard for 87 camp too. But if somebody wants to put 87 in their Corvette for a road trip 350 mi to the next major city, nothing's going to happen.
85 Octane is very common in western Colorado for whatever reason
Interesting thanks!
I have a C5 on the way. Down under we have 91, 95 and 98. 91 however is 10% ethanol which I never use.
Summer is just kicking in for you - nice!
In EU we have 95 octane. It is probably similar like yours 89-91. We have not problems with our Corvette's when we use it.
I use 87 in town and for highway 89 and for long distance highway trips 91.
IMO - If you are just cruising on the freeway on long trips - that is where I would consider 87. It takes very little HP to move a C5 along at 70mph - Unless you punch it often... Cheers!