High Compression and Pump Gas - Can You? Should You?? Why Quench is Important
Vložit
- čas přidán 13. 02. 2024
- Following up on my latest video of managing high compression. Covering off a few points including why quench is important.
- Auta a dopravní prostředky
This is exactly why i love this channel. He takes on direct questions being left here and takes the time to explain..
Thanks for the compliment Jesse. It encourages me to keep digging. AG
I really enjoy Ben Alamedas channel. He is letting alot of racing secrets go lol. You are very knowledgeable as well as Ben.
I agree. That is why i recommended him. AG
Ben is definitely on the money
His insights are 1st class😂
Much can be learned listening to him
Correct. AG
Ben is Full of engine knowledge, cheers from Calgary.
Glad you agree, we are all learning. AG
Thanks Allan for the video. I really appreciate you going back to cover the quench topic. An old engine builder told me that in the high performance muscle car days, engineers tried very hard to focus the quench in the combustion chamber to eliminate knock and pre-detonation. When the smog era hit, the engineers threw it out the window and started casting open chamber small valve heads. Great video and thanks again, I really enjoy the channel!!
Thanks Andy, great comments. You are right on. AG
My father was a drag racer and a very accomplished engine builder .He taught me as a general rule ,each point of compression increase over stock /starting point is on average 2HP per cylinder per point of compression increased over your starting point .
But it also means better throttle response as well right??? And the real goal is a tight quench area right? That's where the match happens 😂
Thanks Andrew. Your dad's CR advice sounds right. AG
I have a 385 SBC with a .000 deck AFR 195 using a copper head gasket.042 2 eyebrow pistons. It's a 11.25:1 . It has 185 lb of cylinder pressure.. It runs pretty good. All cam specs are done using David Vizard s 128 formula. Again GREAT videos.
Thanks for sharing your build Roger. Sounds like you did all the right things. AG
Good info! Thanks for sharing!
Thanks for commenting Ray. AG
Great channel. doing a great job. and yes can learn alot over on bens too. Another channel everyone should swing into is Uncle Tonys Garage Keep up the good work buddy love your channel. many things to learn..
Thanks for the nice comment Jesse. AG
ben is so good even talking about iron heads verse alloy
Correct!, thanks for the comment. AG
My race engine was a Chevy DZ 302 back in the early 80s. Set up for 1/8th mile drag, it was .40 over and 13 to 1. I used leaded premium and 2 bottles of 104 Octane booster to keep the detonation down. The other option was to run to the airport and get a few gallons of AV gas. I twisted my 68 Chevelles frame with it. How I kick myself for letting it go..., but that 70 Monte Carlo was a pretty car.
Even Ol flattop engine benefitted from these formulas....
Thanks for sharing your experience Medicated. AG
Deck height is affected by block material and piston CD.
An Al block will expand more as the engine warms up so cold deck height can be a bit less. A tall CD piston will expand vertically more than a short CD piston which will require more quench clearance. Of course parts will stretch a bit as the RPM goes up and more as the rev limit is increased.
All these things need to be balanced.
Good points Dale. I have never built an aluminum block engine, would have to re-calculate for that. AG
I'm really enjoying this series of compression discussions, thanks for going so deep into this subject! I'd love to hear your thoughts on an engine I'm planning, especially if you have anything to say about the functionality of water injection for preventing detonation in high-compression naturally aspirated engines (not really talking about water/methanol injection for forced induction). It's going to be an air-cooled Porsche flat six, so we're talking aluminum SOHC hemi heads with twin spark plugs, sequential port fuel injection, 4182cc (255 ci), with a MoTeC computer to handle fuel, spark, knock sensors, and (if I add it) water injection. This would likely be on a cam with 302/294 advertised duration, 282/268 at 0.050", intake closing 58 degrees after BDC. I'm considering compression ratios up into the 14:1 to 15:1 range. Fuel would be 93 octane pump gas. Do you have a method to estimate a ballpark compression limit for a setup like this to run without detonation on 93 pump gas alone? And if so, do you have any thoughts on how much additional compression would be safe with 93 + water injection (no methanol)? Some of the elements I am considering here are: (1) Hemi heads are usually found to resist detonation better than other combustion chambers; (2) Aluminum heads resist detonation better than iron heads; (3) Twin plugs should be able to make the same power at any given timing as single plugs with more advance; (4) The combination of 3D (RPM-throttle position-manifold pressure) fuel and spark mapping together with knock detection should make it possible to set up an engine that retards ignition or even cuts fuel under knock-prone conditions (such as lugging) while still running aggressively advanced timing at high RPM. I'm wondering if all of these elements would make 93 pump gas alone completely workable at 14:1 or more? On the other hand, would the carbon-cleaning and hotspot-cooling (especially in an air-cooled head) make water injection worth it to avoid developing unexpected knock over many thousands of miles?
Thanks for the question Electro. You already know more about this than I do. Sorry I don't build engines that need water injection so i don't know much about them. Thanks for watching my channel and commenting, we are learning from you. AG
Hey AG,
Tim here. What a great tech vid.....LOTS of smart thought.....my Poncho 462.....has a quench of .040, cuz i use i stock style flat top piston, yes i have 4 valve reliefs, so i have 0 deck, and .039 compressed head gasket, and 2 valve reliefs in quench area, netting a 3 cc loss, over all creatting a .040 quench......(#'s are close not exact)......my static is 10.44:1, modern heart shaped chamber, i run 31° of total.....my Kauffman guys said i can even go to 30°.....its an efficient chamber, yet i STILL have detonation symptoms on my plugs, as tiny white deposits... i was runnin 93 pump gas, i changed to 90 non ethanol, got mildly better, added 1 gal of 110 to 4 gal of 90, netting 94, and its happy... must look at camshaft.... i have no card, its a custom grind done by my brother and his dude (Larry Hansen Racing) all Pontiac nerds..... but i have a bigger cam i was gonna put in, and wanna look at the intake closing event, and see if its within ur window..... NEAT stuff, i got alot to sort out, my 11:07 shud be a 10:98......so i'm workin on it....sorry so long, i ENJOYED this vid immensly!!!!...PEACE to you sir!!
Use Marvel Mystery Oil in your gas.
Thanks Tim, we have all the parts for Joe's 400. We will be making a video today about it. AG
@@goldsgarage8236 TY sir, i'll be watchin my notifications......appreciate it for SURE!!.....
Hahaha that's a great line! You don't drive a Hot Rod, you manage it! I'm totally using that with my customers...
Thanks for the comment Badass. Glad you found it useful. AG
United Engine & Machine suggests adding 15 degrees to your intake duration @.050 when figuring static compression ratio. On "my" particular engine it's accurate when determining intake closing point.
Thanks for your comment Raging. AG
Good morning, Bob again. Building my 1964 283 I am looking at crankcase ventilation options. Of course the motor is set up with valley ventilation through a downdraft tube but I don't think that is the right option. I can purchase the adapter to PVC or use the valve cover PVC ports. If I use the PVC system I am assuming then I would old have ventilation on on valve cover and not connect two. The other option would be valve cover push in breathers. What is your opinion? And who takes care of your beautiful landscaping by your driveway! Great look. I am inspired to pick up my game a bit!
Hello Bob. My wife does most of the landscaping, I provide some of the grunt work. Thanks for the compliment, i will pass it on to her.
Adding the PCV valve is a good upgrade. As long as you have an for opening filtered air to enter the crankcase, and a port to provide vacuum via the PCV valve you are good.
If you are using a 1964 intake the oil filler tube can provide the fresh air intake. If not, usually the PCV port is on the passenger side valve cover and the inlet breather is on the driver side.
Make sure you block off the draft tube port.
Hope this helps. AG
@@goldsgarage8236
Thanks, I am running a later model Edelbrock intake so I will block the draft tube and use PCV on one side a a push in breather on the other. Keep up the good work.
Yes Allen. I was wondering about quench in your last vireo as well. Is .030 too much? I'm refreshing an 84 vette using the stock TRW forged pistons, ,022 in hole wiith.015 gaskets, That gives ,037 quench Too? much
Thanks GM. Lot's of comment from people running less than .037" I think you are ok. AG
Will flatter pistons let's say 11.5:1 not have a better flame travel and timing will be more advance and still out of detonation, and with a tighter cam will achieve the same 200psi cranking pressure and run as fast as the 13:1 with all opposite things of what I mention, plus it will be cheaper to build and last longer?
Thanks CJ, flat top pistons do work well. AG
Use Marvel Mystery Oil to wet the charge. You can also delay the timing advance curve instead limiting your total advance. If you still get detonation lower your spark plug heat range or use water/meth injection. I have a BBC 15:1 and use 91 octane +MMO, 20 degree initial (manifold vacuum so vac adv is included in initial) 36 deg total 52 degree cruise.
Wow, that is a lot of compression. Sounds like you know how to manage it.AG
What cranking cylinder pressure does your combo produce?
Question, So more and more racing engines are putting in soft chambers???? That take .020-.035 off your Quench..... But they say it helps with tuning and power adders.... Very confusing lol sure there's still Quench around the sides but you're Taking a lot away . My heads are Milled a ton so I'm putting a .060 head gaskets. We shall see if I lose power . Thanks for your information sir . Great videos keep them coming 🙏👍
Thanks FORCEFED, let me know how it works out. AG
2 stroke tuners know much more about quench, they have been using angled quench for decades.
Good information. How much cranking psi for 87 octane gas in a properly managed sbc 350 engine for a pickup truck
Good question. i think 150psi would be safe. AG
@@goldsgarage8236 thanks
My dad's geo metro ran 210psi on 87 octane brand new back in 1997
The snow is almost gone where I live, almost time to pull out the old car!!
Thanks Alleyoop. i am looking forward to it, haven't driven my Camaro since October. AG
So I don’t have a cam card with advertised information, but at .050 this card says the “INT Closes. 39* ABC“
So when you try to figure out advertised specs would you just double that # to 78. ??
Good question Doc. It is probably closer to 60 degrees ABDC. If you have the cam number try to google it or ask BING? You will be amazed at how much she knows. AG
Water injection works well with high compression as David Vizard says...
Thanks Leonard, i don't have any experience with water. AG
Minimum Quench distnce is determined by RPM range, bore diameter, piston rock at TDC & rotating assembly component weights. The benefits go up expotentely as the the gap narrows.
Thanks Darrell. I agree, its all good until the piston hits the head. AG
I have a question about quench, wouldn’t the quench height change on a hot engine vs. cold engine? Do you compensate for this?
Aluminum rods require 060-070" clearance
Thanks Rocking. The calculations assumes a cold engine. Stick to that. AG
aluminum head’s definitely not iron and lots of camshaft. Also this is why heart shape chamber works so well makes mixture go to the center
All good points Utah. Thanks AG
AG, .040" to .045" is good as the standard. Quench depends on how much piston rock you have to makesure the piston doesn't hit the head or barely touch. Rpm is involved also AG.
All good points Leonard. Thanks for your input. AG
If we could have done this back in the mid 80s we would have. Engines with too much compression detonated. We tried all the tricks. 10.5 with aluminum heads and 9.5 with cast iron heads was about all you could do. The octane wasn't high back in the day. We ran 2 head gaskets at times to reduce detonation. We tried water injection. Fuel injection. Lots of old 60s Engines has high compression and would only work today on e85. Ls6 l88 etc.
Bloodviking
Thanks for watching and commenting Paul. AG
I am thinking of a Sick week engine. Runs on pump gas to travel and then race gas at the track. If you took the cam servo setup from a 4.6 and used it on a 302 or 351w block you could lay off cam timing to keep compression low? When you want to race, advance the cam and get your compression back at high rpms. It would extend the timing gears out from the front of the because of the servo linkage. Has anyone done this ?
Great idea, but no as far as I know.AG
You need to do a 351-C build and compare it to your SBC. A 351-C with the Closed chamber 4V head. I never see any ford builds on your channel. I think you could build a monster SBF with your knowledge.
Thanks Dallas, I did participate in a Ford small block build for a stock car years ago. I would love to do another one. AG
@@goldsgarage8236 that’s awesome! Your video on vacuum advance timing is by far the best one that I’ve watched. I’ve been trying to help a friend at work with his 65 327 with double hump heads and a aftermarket camshaft. He’s having trouble with his engines vacuum advance. I’ve been trying to explain to him how to fix it, but it’s gotten to the point to where I’m going to have to get my hands on it. I think it’s the mechanical advance spring is to light and the mechanical advance is swing too fast causing the engine to lean out causing a stumble. I won’t know until I get a vacuum gauge and timing light hooked up. I just started following your CZcams channel and have been enjoying the great information.
The way to beat having high compression and management problems is to go big block, 9 to 10 CR is all you need.
You are correct! My low compression 496 big block made 565hp and 600tq.
Going big block fixes everything lol.
All good points, thanks for the input. AG
"why not keep going with the compression?" - We do!! That's why we use turbo's, blowers, super chargers, etc.! They all equal higher and higher compression, hence more and more power developed!!
Good point Anarchy. Thanks for commenting. AG
Does anyone know what the actual bore measures in a 350 ? I heard it's not actual 4.00" ...it's 4.0030?
Thanks Mario. As per the Chevrolet manual (1968), the bore of a 350 is 3.9995'-4.0025". AG
Pinion angle is also necessary to compensate for the difference in elevation of the transmission output shaft and the differential in the chassis. AG
Sorry Mario. This reply belongs to the next question. Trying to work and watch the race at the same time. AG
327 Chevy, 14:1 compression
Bp-98 octane (RON)
Pump Fuel
Thanks Brent, that is a lot of CR. You just have to manage it. AG
What is your cranking cylinder pressure?
@@bobbyoshomebuilt2544
You will have too have me build you. A motor if you want that information.
@@goldsgarage8236
Correct
common sense 10 hp will not be felt keep it happy easy on the wallet too, great advise there will always be someone quicker,
Thanks Gordon, glad that you agree. AG
A lot of this stuff has to do with resonance frequency, everything has a resonance frequency, A tube with a fixed cross sectional area will have a resonant frequency. An intake manifold will have one too and the engine will make max torque at that RPM a ( standing wave pattern) The pulse stacked behind the intake valve closing when it becomes stationary will make max torque...... but the runners are not equal so you will get a band of max torque. instead of a single value. When you have a whole series of pulses stacked behind the intake valve you will have a slight forced inducted effect
Resonant frequency is a fascinating subject. The right voice can shatter a wine glass.
Thanks Ed, lots to think about and seldom discussed. AG
that quench spec is for steel push rods only isnt it ?
Not sure if i understand your question? AG
@@goldsgarage8236 quench is more for aluminum rods , yes ?
Yes, of course because aluminum rods will stretch more. AG
Quench dimension is relative to Bore Diameter, Valve placement(ie: opening backside of cylinders or on center)... and Intake/Exhaust Flow ratio as it relates to scavenging.
Just say'ing for example.....
FAR more going on.... one size does NOT fit all... and that saying .040"/.045" or even.050" quench is optimal(maybe on a sbf or sbc 4.00" Bore) ....or that "closer is better" is erroneous as to application ?
and fails to capture the above parameters that may indeed result in over-scavenging a cylinder with a gifted Exhaust Flow blowing perfectly good incoming A/F charge right out the exhaust !
I've personally documented on the Dyno a gain of 35 hp peak(820HP TO 855 HP) by merely INCREASING the quench distance from .055" to .085" on a 4.500" Bore 540 Inch Wedge.... NO OTHER CHANGES THAN HEAD GASKET THICKNESS right on the Dyno.... which lowered Compression/Increased quench distance and resulted in the gain.
We can also run HEMI's very close to 200 psi dynamic on 91 Octane with NO quench given the design with no detonation well past 950 hp.
Thanks for sharing your knowledge and experience Dirt. AG
run off the shelf cams and they from CC and they are very low dynamic compression. and for the fun Cars wanting 13:1 compression there is GOGGLE And VP/Sunnco. etc 120 + race gas for that 38 degrees of fun time
There is also E85, and it's about $897 per gallon cheaper than race gas!!
Thanks for the comment. AG
common rail diesel use injection timing to light the fuel they can fire the injectors 7 times per stroke.. usually they do a really lean squirt of fuel so it lights up and then they fire the many charge. the actual quick way to set it to single fire and hear the pinging is to disconnect the air flow meter .. it will go into limit mode or base tune and will ping like old noncommon rail diesels. don't recommend this you'll need a scan tool to get it out of limp mode
Thanks Jackson, diesel is a different world for sure. AG
Tight quench with long duration cam n anything is possible. I run my Big block chevys at 32-35 quench
That is good information Phil. Thanks. AG
0:16 missed a couple points? compression points??
Thanks for commenting Tom. AG
I gave you all the info in your last video in the comments of how to run high compression on pump gas but you t didn't think you should have that info.🤷
Thanks for the comment, AG
It's not necessarily going to run right
Running high compression on pump gas ⛽️ is waste of time.
I dont think so and it depends .The gas of today is better than years ago .
@@andrewslagle1974 the extra power isn't worth over heating problems and detonation.
Thanks for your comment Muscle. AG