TUNE TO WIN-A/F vs TIMING
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- čas přidán 8. 07. 2024
- HOW MUCH DOES A/F & TIMING CHANGE POWER? WE ALTER THE A/F BY GOING FROM 76 JETS TO 100 JETS (THAT'S 24 JET SIZES!). WE CHANGE TIMING BY 25 DEGREES, FROM 36-11 DEGREES (THAT'S 25 DEGREES)! HOW MUCH DOES THE CHANGE IN A/F EFFECT POWER? HOW MUCH DOES THE CHANGE IN TIMING EFFECT POWER? DOES THE CHANGE IN TIMING ALSO CHANGE A/F? CHECK OUT THESE TOP-SECRET RESULTS.
- Auta a dopravní prostředky
The Dyno run at 11° total timing demonstrates how poorly an engine runs when the distributor advance mechanism gets stuck so that it no longer provides any advance.
I had a friend that refused to fix that probably had a 80 horsepower 305.
Thank You! Since AFR gauges have become so popular, time and time again I see people trying to tune to the gauge. “ I’m too fat (@12.5 hg) at part throttle”, thinking the engine needs to be near perfect AFR throughout the entire operating range they spend hours tuning one area out and now they are fat or lean somewhere else. Round and round they go. Unless it’s too Lean or grossly fat and has drivability issues don’t sweat AFR!
People, after the initial setup of the carb spend your time dialing in the TIMING. Optimizing timing will improve drivability and maximize peak power.
This is your best one yet Richard.
Dispelling all the internet BS in a single bound 😊
I would like (at some future point) to see you do a test with either the Holley or other brand carb style EFI system and do a similar test.
Why?
I’ve only used Holley and FiTech, what I learned is that the fuel tables are ‘elastic’ because they will self learn/tune, but the timing table is a ‘hard’ parameter set by the user. I honestly thing a video in this area would be very helpful to a lot of folks.
Once again, awesome job on this video!!
Cheers
being 55, this was he most informative info i have ever seen. (carb guy) i tuned cars this way, but i had know idea that these big changes were so minimal, thanks rich!
A long time ago, I read a book about the exploits of Smokey Yunick. This is very much like the that.
Think, Test, Think again... Smokey was famous for bending rules and always looking for small advantages.
One thing he always stressed was air fuel balance between cylinders. One lean cylinder can destroy a motor.
Also timing balance, This is not as big a problem anymore, as most of the new distributors are electronic and very good.
Have you ever looked into how timing balance effects how much timing an engine will accept? How slop in the timing chain and cam gear / Distributor drive gear effects this?
I remember him talking about gear drives instead of timing chains.
One thing many people don't realize is that the oil pump being driven off the distributor gears keeps all the gears and chains tight, also keeps the distributor gear up against it's thrust washer. Minimizing these timing variations.
It also damps out the vibrations from the cam opening and closing the valves.
There is so much to this subject.....
Smokey Legend
Thanks Richard, this is 30 years of experience in under 20 min.
You've quickly become my favorite channel on CZcams.
From my experience tuning my standalone, AFR doesn't change much when you adjust timing. That's why I dial in the fuel with a safe timing first, adjust timing for best safe torque, then go back and make small adjustments to the fuel as needed.
I've been a professional mechanic for over 30 years. I used to get TBI Chevy trucks in my shop for tune ups. The factory setting for initial timing is 0 degrees but most would be at 2 to 4 degrees atdc probably due to gear or timing chain wear. I would advance the timing to 4 degrees btdc. That is about as much as you can go before you get detonation. This made my shop very popular. Almost all the owners with these trucks would either call or stop by a day or two later and exclaim how the truck had never run so good, even when it was new. I never divulged my secret tuning trick, lol!
Does the computer get cranky on those if you past 2*-4*?
This is GOLD! Its answered so many of questions, I didn't know how to ask. Gives me a better understanding on how loose I can be with timing up top and still keep a detonation barrier.
If you have screw in emulsion bleeds you can lean or richen an rpm range but it still has an effect everywhere like you said. Play with them enough and rejet to correct the overall afr you can somewhat tune out bad areas just not specific rpms. But I'm sure you know that but most don't.
Timing is about syncing up peak cylinder pressure with the mechanical sweet spot based on the geometry of the crank.... AFR is about using all the air molecules available to oxidize fuel. Carbs and fixed timing distributors are pretty blunt tools, hence their demise in the OEM car world. You can definitely tune carbs to change the shape of the AFR curve, but jetting mostly moves it up or down. Things like individual 4 corner tuning of the carb and evaluating per cylinder AFR and per cylinder fill with intake manifold alterations or even rocker arm ratio changes per cylinder - all that is the beauty of having an engine dyno. Sure not going to do that for the sunday driver, but race a 350 HP motor on a road course and the difference is dramatic when working to get the area under the curve maxed out. I am sure Richard knows all this, so i guess this comment is geared to the weekend warriors here. BTW GREAT VIDS, I just found your channel and the first half dozen vids I watched are great. Jealous of your setup! :)
💪💪👍👍 best motorhead channel.. ..
Appreciate that
Engine head! AAAHHHHH!
Thanks for clearing up this set of misconceptions . The old timers who grossly over advance Ignition timing then drill out the jets were badly mistaken.
Best video/test yet! The most usable information in one video of all of your videos that I have watched (and I've watched a lot)..... well done!
I actually have had these questions for a few years. Now that I am installing an AFR gauge to a carburated car I will benefit a lot from this. Thank you for sharing Mr. Richard.
One of best teaching videos I have seen on the subject.
So my dad was right back in the day, "90% of all carb problems are in the ignition."
Fundamentals like this are critical.
Thank you for this video. I have tried to explain this for years and you actually showed what I been preaching.💪🏻
I was literally thinking about the timing vs af ratio on my 78 blazer last night! Then this video showed up on my notifications this morning. You’re a wizard 🧙♂️ mr holdener!
You know what I think it is? I think it's that old school guys are used to idle tuning a carb/distributor car. In that scenario it feels super interactive because as you lean the idle it accelerates, as you add timing it accelerates, etc. But that's not about power, it's just about the engine running better as it gets dialed in and thus speeding up.
That was another great video Richard. I have a Moates Quarterhorse on my Fox Mustang. I have been playing with fuel and timing with good results. It is nice to know that timing doesn't mess up air fuel ratio. I always learn something in your videos.
Haha! AFR in the 9's. I've noticed that a good tune without cats has a different smell to it. Without cats, you get kind of that lawnmower smell. But when it's running very fat, it's the straight up spilled gas smell.
Great video alot of good information
Timing does not directly affect A/F and vise versa. The relation comes down to engine temperature. That is why you tune A/F for optimal volumetric efficiency, and the you tune timing for power (minimum best timing).
Something I tend to do in EFI is to put a base timing around the whole table, say 10 degrees, then tune the VE table, and then tune the time properly. That way I reduce stress from the engine in half and helps me troubleshoot anything before something breaks. That's just my method. Cheers and great video!
Been tuning for years, but it's very interesting to see it all graphed out in detail.
Lol, when I was a kid I used to attach my distributor to a choke cable so that I could retard the timing, to make the engine sound like it was cammed while circling the drive-ins.
variable timing combined with drive by wire-I like it
@@richardholdener1727 Lol.
@@michaelangelo8001
Early cars like Model T and motorcycles were like that.
@@xmo552 Yes, we used to have a Model A, and it had a retard lever on the steering column.
I think it was there for starting with the crank. Otherwise you might break your arm...
@@richardholdener1727 Early drive-by-wire technology lol
Thanks Richard! Nice to see confirmed in hard data what I was taught and what I've experienced.
Love this channel no BS just the cold hard truth. Keep them coming
Excellent info! I’m learning more from your channel then I did in school lol keep it up!
Richard, Thank You for backing up what I've been preaching for decades. I have witnessed, and I'm sure you have too, people take band new out of the box carbs that ran almost optimum and loose power fiddling around with jets/air bleeds/pump shots, ETC.... I've seen "tuners" try to prove how good they are by running shit on the ragged edge for 4 HP just to badmouth the other guy. This will shut a lot of the self proclaimed tuning Jedi's up. This old gearhead always learns a thing or two from your comparisons, BRAVO!!!!
Awesome info. These vids are top notch.
I am starting to get hooked on all the info in your videos!
sure those 100's were an eye burning experience.
Bench racers and keyboard cowboys getting shut down with basic facts never gets old... Thanks Richard. You're stuff is always entertaining and informative.
Glad you like them!
You need to wear a cape and mask and introduce yourself as Captain horsepower !!! Or Major torque !!! Another great video Sir and all the best to you and yours.
I've always wondered about the effects of timing on A/F. Great video, thanks!
Hard to argue with Facts! Love the vids!! Nice to see the Sbc making a come back ...
Thanks for this testing this! I've been curious about the timing/AF relationship for a while.
This is great stuff Richard, keep it up! Very educational.
Learning alot from this channel👍
Excellent video Richard!!
More SBC, my heads spinnin' Mr Holdener. When I bought my SBC it was straight out of a Drag Bracket car (72 Chevelle, ran 10.20s), was told by the previous owner that carb was an on/off switch (tricked out 850 DP), so I put a 750 HP DP out of the box on it---set the idle circuits, been drivin' it for 2 1/2 years, reasonable throttle response (was told it likes 36/38 total timing, runnin' 28/30 on the street) and doesn't foul plugs (Autolite R133s), and I'm a happy camper. EVERYONE says they can get way more changin' every little thing. Thanks Richard, I'll continue with mine the way it is. Oh, if I needed more I'd tighten the valves a little, bump the timing, put straight 112 in it and put the 850 back on it, it does Rock&roll like that!
Richard, your videos are the best. The best. So much information with the proof behind it. When I was in my twenties I worked in a machine shop and went to the tracks drag racing Wednesday nights and weekends. The shop I worked for had a NA sbc rail and a NA sbc Vega. The a machine shop had no dyno. We track tested everything. In my mind, I was good with carbs and since I was twenty years old at the time most everything I said was blown off. So I collected a few carbs and did the air horn clean up on the vacuum secondary 750's and the double pump 850's. I tested flow with a flow bench at a local carb shop who I met at the track. So tracks with lots of grip I gave them the 750 and tracks that had little traction I gave em the 850. The 850 was lazy on the line but would make it up on the top end and the 750's flow a lot more then 750 cfm. The first few were good and then the changes I made didn't seem to affect them much at all. I would never tell the guys what was done to the carb's, I would just give it to them and ask them to "Try this one, I did something for this track". So when one of the guys would say "The carb needs a set of 78's in the secondary's" I would say it has 78's in the secondary's because I found out it doesn't make any change as long as the carb is a good working carb. It automatically, mechanically adjusts to every application, very hot days, cold days, dry, humid, except altitude (which we never dealt with). After a while the timing never changed and the carbs were never questioned. Cam's, cam timing and valve adjusts made more of a change then either of the other two. The info in these video's you make confirm and explain why. That is one thing I never could do.
Thanks for all these videos. I don't see how they could be any better.
EDIT: I do have a complaint. The advertisements on your video. Most of us know you get paid something if we watch the advertisement without "Skipping" and if we click on the ad you get a little extra for that. It's always been my thing to leave the adds running and watch em, if there interesting and even click on them to let them play in the background. But here's the thing. Your video is a little over 17 minutes long and the first advertisement is over 38 minutes long. You're getting 38 minute ad's tacked onto your videos. I can watch a 15 second or a 30 second ad or even as much as a 3 minute ad. Even worse is the 38 minute ad that's selling something that makes a 102 year old person have the same energy as if they were 60 years old. Okay so I am 63 years old so I know first hand how 63 years old feels like. I still bang gears in my 70 427 Nova, but I don't think I want any hundred and two year olds out in the streets banging gears, just sayin. I don't know if you have control over what or how long the ad's are or if CZcams controls that but I am pretty sure that any ad over 5 minutes long is going to get skipped and some video's have more then one of these ad's.
Awesome experiment. Best video on the subject.
Thanks for the tuning knowledge Richard.
Thank you for an informative and unbiased assessment on this subject.
I suspect many have fallen for the BS given out over the years, its good to know that guys such as your good self are out there.
Hats off.... deep respect, this type of information is golden... thank you very much.
Great way to show the results of such dramatic changes.
Just think back in the day we would do this by scent of the exhaust plug reading and the sound by ear.
Still do, lol. On the carbureted stuff, at least. Only got one left.
Another great post....I'm glad to see this as my wife loves to drive my Malibu that has a 388 stroker in it and I would take 16* if timming out of it so she would stay out of the ditches..my carb buddy experts would always bring up fouling the plugs....I never hurt the plugs....be safe..
Thanks for this Rich. I had a 500hp 440 that I didn't think quite ran what it should. During a refresh, when degreeing the new cam I found the damper timing mark was off by six degrees. What I thought was 38 total was 32. I was thinking I cost myself a good bit of power. Your vid helps me think it was not such a big deal. Thanks again!
This is a REALLY GOOD informative lesson.. thanks for giving some clarity 2 something I've wondered about! This is the sort of stuff I love!
An old truism that still works "Half of carb problems are in the distributor - especially back in the day of points, dwell, aluminum posts, dual points, dead condensors and ballast resistors. Outlaw screwdrivers. Tinker with your wallet. How many times have you heard " It works great right out of the box"? Well, it worked good enough.
I've always heard it as "90% of carb problems end up being distributor related".
I've been doing my own tuning for a very long time and something I've always tried to explain to people is no two engines are identical.... even in laboratory conditions. It can be the same bore same block same piston the same valve springs.... literally everything identical and they're going to tune different . It can be really close but they will not be the same. That's why I always laugh when people say I want that identical set up and I wanted to run identical but the tuning is just a jet size different or a degree of ignition timing off or whatever but it's never literally identical and that's something people just don't understand. I'm glad you're explaining that. I love watching your videos. I always learn something. you have to be open-minded and be willing to learn. if you think you know everything you probably don't know anything. Lol remember persistence overcomes resistance every time
thousands of Corvettes roll off the production line. All are within 1%. dynos can't read within 1%. that's not going to take different tuning.
Persistence overcomes resistance 💪😁♂️
Running a 95 Chrysler Jeep 4.0 in lieu of the 72 AMC 258 in a 72 IH Scout II with a FAST EASY EFI 2.0 handling ignition and EFI. 100+ days of fiddling with it on the road says timing has way more effect than AFR’s. Thankfully I can adjust it all with the handheld controller!😉. Thanks for the excellent talk and graphs. I’ll be putting what I have learned to use!!
Wow, great information. Thanks for all your work.
Basic question
Basic car
Hypothetical old carb'd...
"If I could" what would be "ideal":
1)idle AFR
2)acceleration AFR
3)cruise AFR
4)WOT AFR
Thanks guys 🙏
Depends on the engine combination.
For fun, 14.7, 12.6, 13.6-8, 12.6.
There's too many variables to define an absolute AFR. There are some generalizations that work ok but even still, every engine is different.
@@OxBlitzkriegxO
Generalizations are ok for now. Thanks. I know I had read this somewhere a long time ago.
I appreciate the response.
Excellent video interesting thanks.
Came over here from UTG. Great information on true tuning tips. I like that shirt!
So glad you did this video. It’s almost daily that I get asked to find people 30+ HP on a car or 10+ HP on a bike that’s NA with just a tune. Now going from stock ecu programs to a custom tune can indeed net that realm of power gains, but if your vehicle is already tuned and you just changed a muffler section or changed intake filters that minute 1/2 degree or so of timing or few tenths AFR I adjust in either direction is not going to break the dyno with massive power gains lol.
Side note: I would like to see this test done on a boosted application and would be especially curious of the timing aspect and it’s effects. I say this because I really can pick up significant power on say a turbo setup with small incremental timing changes in most cases, but it would make sense to magnify NA gains on a boosted setup. I would just be curious to see if the changes follow suit to doing it NA just by way of larger gains.
Great information!
I just love your stuff... i am almost 70, have been doing stuff that basically, what all the so called experts say you cant do, and getting great results a budget $... Now you come along and prove what i have been saying and doing on paper.... Here in Australia we had in start 2 Holden V8,s one was 253 CI & 308 CI the smaller one had a 2 barrel and was well just boring, and the bigger had a Rochy Q jet quiet ok.. i used to take the 4 barrel and manifold COMPLETE, and unchanged and bolt it on the small one with amazing results, really woke it up, but much ridicule... O its two big, it will flood the motor, bla bla bla, the proof was in the driving, snappy, great economy and rev like a 2 stroke.. Again thanks,, i feel more than vindicated.. keep up the incredible site.. many people should be happy with what you are doing... Eddie C4 Australia.
A old thong slapper reving like a 2 stroke. Mate you are dreaming.
@@MJTAUTOMOTIVE yeah mate what ever you say... lololol
@@ilovethephilippines8991 . No doubt that putting a 4 barre intake and carb on a 2 barrel engine is going to make it go alot better. But to say that a 253 Holden V8 was alot quicker to rev is just plain bullshit. I have built many 253's and 308's over the years and I also had a lot to do with the Commodore Cup series that ran the 253. You had to do alot of work with heads and cam to make them even slightly better than standard to rev. The blue 253 was slightly better with a standard 4 barrel but by that stage they were getting choked by pollution crap.
Having tuned my own EFI car from scratch, and had the benefit of a "rich/lean" knob, where I could change the AFR's +/- 25% at a constant timing and load while driving, I can confirm that what Richard Holdner says in this video is the truth... super easy to "feel" how insensitive the engine is to small changes in AFR's at the same timing and load, but much easier to feel changes in timing for a constant AFR and load.
excellent vid.
Great video Richard - this kinda explained why the First Gen Z/28s came with a Holley that was almost identical to the Holley on the L- 78 396 cars of the same era
Loud and clear........and true.
very valuable. I'll probably need this to limit torque to protect the transmision on a TPI
Keep em coming Richard
Awesome video!
Damn Richard way to knock it outa the park
Thankyou
No more no than 5 tenth Im thinking
Great info. Iv found that if the power valve is close to opening a idale do to big cam and stuff timing can have a part do to incresed vacum
Yes, more sbc content! I love it Richard, you're the man! Great tuning video.
I’d love to see these AF charts in Lambda. I switched to lambda when I went to e85 and it made life easier on the gm stuff.. good stuff as always Richard!
This is a video a lot of Escuela Vieja dudes need to watch!
This was a great comparison, to see the actual figures. It lines up with my experience in that a carburetor is quite forgiving, it may be a miss match at times but it will work and work well in the top end and note that a street car will be more streetable with a carby that is not too big for bottom end and mid range driveablity. The timing is an interesting one too, I have learnt through experience the engine only needs enough timing to make it happy, no more and no less. On some high comp engines running on pump octane I have had to pull the total timing back to 25deg to stop detonation and once I found that sweet spot for the fuel one particular cleveland engine was more exciting to drive than a similar spec engine with less comp and more timing. How I think about spark timing is its all about how quick that flame front moves across the top of the piston and produces the maximum pressure to push that piston back down the bore, if there is not enough timing some of that pressure is in effect wasted and too much just slows down the piston as the pressure is made too early. I like to run a soft tune on my drag car, running race fuel with 32 total so on race day I can enjoy the racing. The engine sounds sweet and happy there and makes good power and all the comments you mentioned that others say I have heard too.
I think "I could've changed two jet sizes and picked up twenty-five horsepower" is going to be my new catch phrase. Thanks. 👍
Really it's just all about dialing it in to where the engines happy according to weather conditions
Leaned it down to 72 on a vacuum secondary 750. Went up to on the shooter! The bandage on the daily driver was great. Ran as much timing as I could get away with! It was a 306 in a foxbody Capri! The 31 shooter really helped it to catch its breath till the old 750 vacuum secondary was ready! Drove it every day! A 50cc pump and 31 shooter made it think it had a bigger carb on it!
Premium content in here: many thanks for taking the time in producing this.
Timing vs boost on a knock limited pump gas tune would be very interesting. The school or more boost/less timing versus the school of less boost/more timing. Power and egt differences as an output to be opined on.
My comment is 455. ☺ Thank YOU, Richard. U may have saved my engine. I'm in agreement: give up some horses to ride another day. I'm sending this to some buddies. 👍
Great video! I'll take facts over opinions any day!
As a former 'Pinks' lover, finding 'Mr Arm Drop' on YT was great! I do nothing now besides watch his show.
I wish I was Rich Christensen from Pinks-I'm not that cool
Great test. Great info.
Love your channel
Great video.
Awesome test !!!!
Cool thank you for this Richard! Learned a lot. I thought messing with the A/F ratio would affect the engine to a larger degree. I have no experience tuning tho unless u count changing parameters on my lil pocket plug in tuner 🤣
Hell of a good video richard!
thnx
You are the man! I can’t say enough about how much I appreciate all the work you do.
I think all the car mags people read for years and year conditioned us to think that changing timing means you need to adjust the timing as well as the other way. Thank you for clearing out the smoke.
Richard, I was blow away with your afr and timing expose. WOWWW, talk about being schooled! Thank you so much! Now can we get you to do the same on boosted engines with efi and carburetors not so much afr but timing. You know, you can't run as much timing on efi as you can with carburetors. Also look at the different heads that are on ls engines and you know how sensitive to chamber shapes timing is.....
Again really enjoyed afr timing expose.
Great video
Hey Richard, glad to see another video, you always make such great content. If there’s one thing I could request is to see a 5.4 2valve ford from a junkyard with a few bolt ons and boost, I know they aren’t the greatest engines for power, but they are super common and I havent seen much content about them ever.. thanks!
same as the 2V 4.6L-just more
Richard - this video is so valuable in terms of information and education. Thank you so much! I have always wondered how much timing changes affect air fuel ratios, and now I know! One more thing Richard - I love your tests you do with large boost numbers, can you do some testing with big big nitrous? Like 500-600hp worth of direct port nitrous? I’d love to see the low amounts of ignition timing used with that much nitrous. SBC, BBC or LS I’m sure us nitrous guys will love it!
that's a lot of nitrous
Timing was my big problem for lack of performance during RMRW. The mechanical advance wouldn't advance more than 8 degrees even at more than 4000 rpm. I had to run the initial timing at near 30 degrees in order to get 36 degrees total. My 1/4 mile times shown I was down near 100 hp.
Nice Information. - too many people have opinions and internet access. - and feel they need to share. ( i really hate - “my friend’s 289” - “my Dad did this” - “heard this is the ultimate” -
I wasn’t there, so it’s irrelevant to me. But, I am glad you “shared”.
* NEXT!
Another fantastic information video! But you do a lot of power adder videos, so it would be cool to see how the timing curves might vary between nitrous, turbos, and centrifugal blowers? Like does nitrous work best with a flat timing "curve?" Does a turbo need more timing at higher rpm? Is a centrifugal blower "curve" linear or curved? Keep up the great work!
Cool video
Excellent video! One thing I've noticed in my car WRT timing, We run 40 degrees in first gear, 37 in second and 34 in third gear and the car does ET better.
Thanks. So ignition timing has a bigger effect in HP TQ.