How much compression can YOU run on pump gas?? How you can manage it for the most HORSEPOWER!

In this video I describe how you can use high compression in your engine and have a greatest chance at success.

[@joejones4296]

Thank you for your calm and polite demeanor.

[@goldsgarage8236]

Thanks you Joe, I haven't heard that before, nice compliment. AG

[@stuckinmygarage6220]

Kudos to your upbringing. 👍

[@racerd9669]

Another great video. The major problem with factory engine cooling system design. Is the coolant flows from the water pump into the lower part of the engine and then to the rear of the block and then up into the cylinder heads and then works its way to the front of the cylinder heads where it returns to the rad. So what you are doing w this design is you are putting the hot water from the block into the heads and the intake manifold. This is why you will have detonation problems. So What I did on my race car in the mid 80s was to reverse the entire system. So the coolest water enters the rear of the heads and flows down into the block and forward and then out at the water pump inlets, back to the rad. I had this system on my EMC entries. We could run 220 PSI cranking on 87 octane, and when we would run 92 it would lose power. No Stat. let the engine run the temp it wanted to, and that was in the car around 160 to 170 deg. NEVER put hot water in the intake manifold. I ran this system on my street n/a 406 SBC. I could drive 100 miles to the race track, on 87 and thru the mufflers run 9.90s at 131 and then drive it home again. So what I have learned is COOL the hot part of the engine first. Oh yes it was an aluminum head engine.

[@488ci]

That would certainly solve the burnt exhaust valve problem. Excellent thinking.

[@bobbyoshomebuilt2544]

220 psi, awesome, I remember Joe Sherman saying he would go there on pump gas too. I love the idea of running the water through the heads first. I'll try at some point.

[@rayowens4355]

Very interesting. I will have to do some research on this! Can you recommend any good resources on this subject?

[@racerd9669]

@@rayowens4355 2002 engine masters challange

[@racerd9669]

@@bobbyoshomebuilt2544 You do know that Scott Parkhurst let Joe cheat. Letting him run his cold and not at the 160 degs as the rules stated.

[@larryburns4605]

Glad you said octane to protect eng not to make power

[@goldsgarage8236]

Thanks Larry. AG

[@roym.9875]

Right. The Engine Masters crew did a bunch of dyno runs on different octane fuels and couldn't measure the hp difference

[@Airman..]

Octane is to push up the timing curve, timing is what makes power

[@Aladinscave]

Octane does make power it makes it possible to make adjustments and that results in more power just doesn’t make power on its own

[@MVPisME383]

Octane allows more compression which will make more power, an engine likes a certain amount of timing which can be determined by combustion chamber design, piston size/shape ect... some LS engine like 29degrees and you can crank them up to 34-36 and not make more power

[@kiesha104]

With 11k viewers, I'd say your doing something right..lol I feel bad for the ones who haven't found you yet, but they will find their way, sir... Cheers from SC

[@goldsgarage8236]

Very nice compliment from SC. Motivates me to keep digging. Thanks. AG

[@billlittle4285]

It's good to see North Carolina,...,an expert is some one who is 500 miles away, us Canadian's are a pretty smart bunch, but we have learned from the best in the USA!

[@user-bc9sz1dj1g]

Hey AG, Tim here, again, i apologize for arguing via ur chanel with a certain individual, since i respect you/ur chanel, i will refrain from attacks......its difficult sometimes, cuz of my passion, and reading a persons comment that bashes YOU, when they are VASTLY wrong, grates on me......but maybe i shud make my statement, and leave it alone.....we cant fix the uninformed, and YES, i dont know everything either, but i DO have yrs of toil with engines, and seen ALOT, i will, from now on, make my statement, and then leave it be, i had no intention of disrespecting you.......GREAT vid this morn......i hope we move fwd, and we can enjoy your vids w/o any attacks......TY for ur time!!...PEACE to you sir....

[@goldsgarage8236]

Thanks Tim. all good!. AG

[@daledavies2334]

AG, being a long time mechanic, I call them infernal combustion engines. Essentially they are all similar in operation.

[@goldsgarage8236]

Thanks Dale, funny but true. AG

[@alleyoop1234]

I have TWO very low mileage rebuilt SBC 400's. One is a large front serial pad '78 that I pulled out of a motorhome, the other a short pad that a friend stopped by on his way to the scrapyard. .BOTH have detonated pistons(one has TRW forged) with blown out ring lands ! BTW, to me getting old is forgetting half of what I learned decades ago !!😉

[@goldsgarage8236]

Good point alleyoop. The problem is we don't know what we have forgotten. That is why we have to keep learning. AG

[@johngoddard6644]

Thank you another great episode!!

[@goldsgarage8236]

Thanks John. I responded to your email today. AG

[@toddbrown2236]

Another great video, Allan. Thanks for the good technical discussion. I'm learning something new each time I watch one of your videos. Keep them coming.

[@goldsgarage8236]

Thanks for watching and commenting Todd. AG

[@stevesadusky8634]

As always, another great video 👍👍👍

[@goldsgarage8236]

Thanks Steve. AG

[@brianrose2487]

Another great video! Thank you

[@goldsgarage8236]

Thanks Brian. AG

[@carllattimore8227]

Definitely adding your videos! learned a lot in 21 minutes!

[@goldsgarage8236]

Great to hear! AG

[@ITSNOTMEITISYOU]

Never quit learning and listening! Another great video Allen. Your ever down around San Antonio I’d love to buy you lunch!

[@goldsgarage8236]

Thanks INMIY, for sure, i would enjoy that. Thanks for the invite. AG

[@JoshF89]

Thanks for your tips. Great video!

[@goldsgarage8236]

Thanks for watching and commenting Josh. Lot's more to come. AG

[@mattbaker6818]

Great information!

[@goldsgarage8236]

Thanks for the comment Matt. AG

[@Smurf_Choker]

Love watching and learning from your videos. I'm building my first engine and these videos help a lot!

[@goldsgarage8236]

Thanks for the comment. More to come. AG

[@davidwoods8982]

I enjoyed your video. Your accuracy and humility make for a wonderful video to help us understand what it takes to truly build an engine.

[@goldsgarage8236]

Very nice compliment David. Thanks for watching my channel and commenting. AG

[@johncalhoun8011]

Mr Gold! You are knowledgeable. You are Teaching me things that never even heard of. Thanks a lot.

[@goldsgarage8236]

Very nice, thanks John.AG

[@billhendon1017]

Thanks for the info!

[@goldsgarage8236]

Thanks for watching and commenting Bill. AG

[@mattvogel6565]

Excellent explanation a lot of useful information in here that more people should know

[@goldsgarage8236]

Thanks Matt. Nice compliment, more to come. AG

[@autonomous_collective]

“Disagreement is the pursuit of truth when all are participating in good faith.” This is why I block trolls who bear no understanding of themselves. It is a waste of time to engage with them.

[@goldsgarage8236]

well said, thanks for the comment. AG

[@robertgeary7520]

Your right on point great video 👍

[@goldsgarage8236]

Nice comment, thanks Robert. AG

[@larryburns4605]

Good video AG thank you .

[@goldsgarage8236]

Thanks for watching and commenting Larry. AG

[@1996slamster]

Another great video!

[@goldsgarage8236]

Nice compliment Slamster. Thanks you. AG

[@harrywright2233]

Enjoying the videos mate, got a 307 in my 84 S10 so following your videos on that, from 🇬🇧

[@goldsgarage8236]

Sounds like Australia? Thanks for the comment. AG

[@waynetessier481]

Very nice I like to see the Brits playing with S-10's, don't hear much on 307 but it's definitely a better choice than a 305. I run a 94 Sonoma in Olean NY. until I retire next year and move it back to my hometown Windsor Ont.

[@harrywright2233]

@@waynetessier481 sweet man love the sonomas, i actually bought the truck under the impression it was a 350 however later discovered it was a 307! but i still enjoy it and look forward to seeing what numbers i can get out of it

[@GMengineguy]

Good stuff! I'm glad to hear you credit DV! You and Uncle Tony are the only ones I've heard mention him! Thanks

[@kevinclemence4661]

It seems DV gets his share of abuse in some of the forums. For me personally, I have all his books!

[@mkimble21]

David Vizard has made positive comments on this channel.

[@steveb7310]

You certainly gave me a lot to think about and try on my Oldsmobile. I’m running a carburetor so that can change my mixture anytime and I’ll have no idea. I will try those ignition changes to hopefully get rid of the detonation problem.

[@goldsgarage8236]

Good luck with that Steve. AG

[@allhailinternalcombustion]

Excellent video, well planned and executed. I used to have a high compression engine, and I know about the diminishing return. I diminished my bank account having to buy starters over and over, then finally a Tilton Superstarter.

[@goldsgarage8236]

Thanks for watching and commenting Allhail. AG

[@rayowens4355]

Good info sir! I would like to add, good quench and swirl will help alot. Also i have been seeing good info on water and water/methanol injection. David Vizard has a good video on these.

[@goldsgarage8236]

Thanks Ray. I had quench on the list but i just missed it in the presentation. I plan to cover it in a follow up. AG

[@billlittle4285]

Volumetric efficiency also sdds to cylinder pressure at high rpm, can add 8 to 12 percent off total cylinder volume, it happens at higher rpm and you may not hear it especially with open headers or loud exhaust, good video Alan.....you never stop thinking!!

[@goldsgarage8236]

Good point, thanks Bill. That is a little scary for sure. AG.

[@heathvice8365]

Very Informative

[@goldsgarage8236]

Thanks for watching and commenting Heath. AG

[@wtf0101]

Great info, Thank you sir👍

[@goldsgarage8236]

You are welcome and thank you for watching and commenting. More to come on this subject. AG

[@d2dap636]

I'd love to hear you and @cattledoggarage chop it up in a conversation! I enjoy listening to you both break it all down 👍

[@goldsgarage8236]

Thanks D2. That would be interesting for sure, I have seen his videos and i am a subscriber. AG

[@hotrodrich7444]

Great list , and well presented. Only thing I would add is outside air temperature. Hot dry desert air here in Arizona with very little moisture to cool the intake charge can cause it to detonate. Also, loading the engine with A/C in that 110 * heat . I had a new Bronco in '87 that had that death rattle no matter what I did with fuel. It made it to 85,000 miles, and the pistons were toast. No doubt emission controls had it running lean. On a cool rainy day, it was happy. We run 91 oct. Chevron here in our hot rods.

[@goldsgarage8236]

Thanks for your comment Hotrod. You are correct, the ambient conditions are also a factor. AG

[@tomstrum6259]

Big Thx for taking Time putting up one of the best Organized, Intelligent & Helpful '60's --'70's oriented "Muscle Car" era High Perf engine channels !! .....Detonation engine Protection while running on the Octane/CR edge is real Challenge with so Many variables & build Mistakes sometimes difficult to correct for customer & some Oem brands worst than others....Late '50's & all '60's Pontiac Oems seem Prone to Pre-Ignt & Detonation more than other GM's....Definitely engine builders taking Chances with Over 180 Psi crank numbers.....Can Detonation happen in the Top Rpm range where it's Harder to Hear ??

[@goldsgarage8236]

Thanks for your comments as always Tom. High RPM detonation is a concern for sure. I am making a follow up video on this subject. AG

[@darrelkinney9856]

Cool video like the info.

[@goldsgarage8236]

Thanks for watching and commenting Darrel. AG

[@johncalhoun8011]

Thanks for your Videos Sir Gold.😊

[@goldsgarage8236]

Thanks you John. AG

[@johncalhoun8011]

Mr Allan! I need some direction in having a Street 350 Engine built. For weekend driving and an occasional Chirping of the tires. Maybe a Power Shot of Nitrous. Just in case. How would you go about it? Maybe 4-450 Horses with A.C.

[@goldsgarage8236]

Thanks John, last fall I made a series of videos about Will Casey's 350 Corvette engine. We made over 400HP. You might find them helpful. AG

[@johncalhoun8011]

@@goldsgarage8236 Good morning Sir Allan! Did you get my email about the Engine Builder?

[@GrandPitoVic]

Great info sir!!!

[@goldsgarage8236]

Thanks for the comment Grampito. AG

[@GrandPitoVic]

Yes sir!!!!

[@JW-hm6ou]

Thank you for a good video. I was looking at how much compression should you run in a prochrched street/strip engine.

[@goldsgarage8236]

Thanks JW. Sorry, I don't have any experience with Prochargers. AG

[@zoomzoom3909]

I agree with everything you said good advice

[@goldsgarage8236]

Very nice affirmation, thanks Zoom. AG

[@andymaynard6474]

Enjoyed the video very much and I also enjoyed the video you did on "quench." I would like your opinion on how much you think the correct or incorrect quench affects detonation. Im looking forward to the next video. Thanks Allan

[@goldsgarage8236]

Thanks Andy, if you notice on the screen shot i included quench in the video but then i missed it in the presentation. Yes it is important. Try to get it as close as you can. AG

[@nonamegarage6721]

Thanks for the information on CR. I have a special interest in these Pontiac rebuilds. As I have a 49,xxx original mile '67 GTO. Also Thanks for the detonation information. I didn't know that the engine was more prone to detonating at a lower RPM. Looking forward to seeing the rest of the videos on the Pontiac engines. The Butler one piece Viton rear main seal is awesome....ask me how I know.

[@goldsgarage8236]

Ok, how do you know? AG

[@nonamegarage6721]

@@goldsgarage8236 the two piece seal didn't work for me...I had it replaced with the one piece. No leaking. Thanks

[@marsv7777]

Great video to explain some of the mystery lol, In Australia we can readily get 98 pump fuel. so we can run higher CR, I typically go for 200PSI, eg my 406SBC has 12:1 CR, 8.8DC, gives me 200psi. made 642HP 547ftlbs. run zero deck, 0.38 quench. 24 deg initial; 33 Total timing. Engine temp normally around 170 deg. I have seen 220psi run no problem on a windsor 347 also. Again Great video. Cheers from Australia

[@goldsgarage8236]

Hello Australia, my #3 country next to Canada and USA. Thanks for the info. That is a nice combo and you are fortunate to be able to run those numbers on pump gas. good work. AG

[@waynetessier481]

Really liked your comment, I have a 1st gen. 10.7 to 1 399ci. stroker that makes 641@6400 and 560ft lbs.@5700 on 91 pump with Brodix C-Series 18* cut to 17* heads.

[@marsv7777]

@@waynetessier481 Great combo, heads make a big difference. Nice power and ftlbs.

[@elainestamper3873]

Good information! Didn’t know anything about the heat range with spark plugs. I’ve messed with cars and engines my whole life never heard of a Ct400 , no clue what that is. Must not be a USA engine. Thanks for the information! Good video!

[@goldsgarage8236]

Thanks for the comment Elaine. A CT400 stands for circle track 400 which is the standard GM crate engine for all Pro Late Model circle track race cars in NA. The nominal HP is 400 although they dyno a little more than that. They are essentially a ZZ6 crate engine with a different oil pan and valve covers. AG

[@ericuncapher9922]

Looking forward to new videos!!!

[@goldsgarage8236]

More on the way, Thanks Eric. AG

[@markbogle8062]

Thank you for the infor

[@goldsgarage8236]

Thanks for watching and commenting Mark. AG

[@BP-fx3qc]

Good stuff

[@goldsgarage8236]

Thanks BP, more to come. AG

[@3Repete]

Well said. I have been a proponent of all the concepts you touched on. I am definitely still learning too. I have a Chevy small block with an unknown cam, bore, everything. It's a rebuilt 350 from Summit. But since I also have the OE block I'll eventually build it for the car. I think I'm going to check the block and if it passes muster I'd like to design it either as OE stock, or with a 3.75" stroke and aluminum heads so I can run above 10:1 to make good power. I may also see if it would function with the OE heads on that cam and stroke. That way it could go back to something resembling stock by reinstalling the factory top end. I realize that's over designing, But it's hot rodding right? With me, you are preaching to the choir, but I'll follow to see what I may have missed or not considered. Or just to see the details of your builds. Please touch on piston ring materials, block hone values and their meanings, and bearing materials. I think a guy like you could clarify using roller cams in flat tappet engines too.

[@goldsgarage8236]

Thanks for the comments and suggestions. We will get to all that eventually. AG

[@1958johndeere620]

There are many right answers. There is more than 1 right way to do things. As far as carbon I remember my auto tech teacher who was from Holland show us how to get rid of it. He always had a coffee cup in his hand, always. One day he was showing us under the hood of a car. It was running, he took off the air cleaner, revved up the engine and poured a drink in the carb. We laughed, it was un expected. He steamed cleaned the cylinders with coffee.

[@alleyoop1234]

I worked in a carb shop back in the 80's, I did that often, but with water not coffee ;)

[@goldsgarage8236]

Thanks John, that all new to me. Thanks for sharing. AG

[@briannietsch1859]

I want the motor in the back looks awesome

[@goldsgarage8236]

Thanks for the comment Brian, Pontiac's are a pretty piece for sure. AG

[@donaldspeck9212]

Want to Thank you for your videos , They are awesome. I'm in the process of learning all I can about my 09 5.4 3v mod motor that's in my f150. I want to build a upgraded replacement motor just bit more hp above stock. Factory says 310hp at the crank I would like to get to 375 at the crankshaft. This truck will continue to be my daily driver. Was hoping that raising my compression from 9.8 to 10.5 would help

[@goldsgarage8236]

Thanks for the comment Donald, we will continue to provide information that will be helpful for you. AG

[@brandonpriest3604]

The real deal channel....

[@goldsgarage8236]

Nice compliment Brandon, thanks. AG

[@nerradnosnhoj5122]

Thank you for the video 91 -92 octane in this area , we say 91 is common in this area you lucky with higher octane in your area , varying numbers ooctane #s is an issue for sure

[@goldsgarage8236]

Thanks Nerrad. Octane is an issue and I doubt it will get better. AG

[@musclebone7875]

My 496 big block is around 8.8:1 to 9.1 compression ratio. It works great in my 4,200+ pound '68 impala

[@mickangio16]

What is your cranking pressure?

[@musclebone7875]

@@mickangio16 around 150 psi

[@Dboyquicks10]

I've been considering pulling the 350 out of my s10 to freshen it up. Wanting to go with flat top pistons I should be fine. Nv3500 transmission and 3.73 gears.

[@goldsgarage8236]

Thanks for the comment. If you have dished pistons now, flat tops will improve your CR and quench. AG

[@martinbeckmann9376]

Thank God for KZbin, not just for engines ……

[@goldsgarage8236]

Thanks for the comment Martin. AG

[@Scottpeatross]

Good discussion. At what point does backing off the timing to stop detonation become a poor alternative? Say a SBC needs to be backed off to 26-28 degrees to avoid detonation, is that ok? Or time to explore a cam change or some other alternative.?

[@goldsgarage8236]

Thanks Scott. That is a great point and maybe material for a follow up video video. You add compression to make power, then reduce timing to compensate for the compression and take the power back out. If you are down to 26 degrees I think you are giving up significant power. Maybe on a future dyno we will experiment with 26 degrees and see how much it is. Retarding the cam or using a cam with a later IVCP will help cranking pressure but you still may have too much dynamic pressure. Bill Little made a good point on another comment, if you have good volumetric efficiency high speed detonation that is hard to detect may still occur. AG

[@michaelmorgan2977]

what about different combustion chambers open an closed and medium likeon big block chev

[@chrisreynolds6520]

I have had good results at around 9:1 dynamic compression with iron heads and 9.5:1 with aluminum. The 10.25:1 static, 9:1 dynamic 350 with iron Vortec I am running performs great on 87 octane. The 11:1 383 with aluminum heads is at 9.5:1 dynamic and performs best on 91+ although it will run all day long on 87 with the timing at 30* total at WOT.

[@goldsgarage8236]

Thanks for sharing your knowledge and experience Chris. AG

[@daledavies2334]

Stoichiometric on pure gasoline is 14.7:1. When you have ethanol as most gasoline now has, the ethanol stoichiometric ratio is "richer". This means E10 which is common now requires more like 14.0 to 14.3:1.

[@goldsgarage8236]

Thanks for the info Dale. You spelled it right. AG

[@basedsigma5634]

High compression needs an appropriate bleed off of cylinder pressure by correct cam choice, so it does not ping at low rpm. Its that simple.

[@goldsgarage8236]

Thanks for your comment Based. AG

[@nagyandras8857]

I'm not even building a v8 , or v6 or i6. I em building an inline 4. Even so , its not even a petrol engine. Its a turbo diesel. Not even direct injection . Its indirect. As those what I can find for cheap , and they rev up quite high for a diesel. About 5k or so rpm. Still i enjoy your videos . The basic principles apply . Both are piston engines. Keep up the good work.

[@goldsgarage8236]

Thanks Nagy, good point, the laws of physics are universal. AG

[@GTStuning-]

Also don't forget about intake air temperature. The hotter your engine's incoming air is, the greater the potential for detonation.

[@goldsgarage8236]

Very good point GT. Yes, I should have mentioned that, I will try to fit it in to a future video comment. AG

[@mrmo9125]

11.5 or so w good aluminum heads, proper quench

[@goldsgarage8236]

Sounds right. AG

[@jonesbretth]

I'm curious about the Texaco items on the walls. Where you employed by them? My father worked for them from 1969 until retirement in the mid 90's. Most of his time was in the Seattle plant, then he finished his career in Houston.

[@goldsgarage8236]

Thanks you for the question Brett. i started working at a Texaco service station at the age of 15. i worked there all through high school and college. I loved working on cars from a very young age so it was my dream job and a game changer for me. The Texaco star will always have special meaning for me. AG

[@evcass69]

I still wonder if I'd get better acceleration with less compression and more advance. I've read that the better the head, the less advance needed? My 418 ls3 scr is 11.9, dcr 8.8, quench .041, compression test dry results 205-220psi but with carbon build-up on pistons. An unmodified version of my oem heads generally likes 22-24° advance. Mine are milled for compression, the least advance which gives the best acceleration is ~19°. Curb weight w/o occupants 3360, 1st gear 2.66, final drive 3.73, TR6 plugs, 180 tstat. I use the best 9x fuel wherever I need to fill up, I don't use >E10. My best accel times are at .83-.89 lambda depending on rpm range. I had to relocate the oem ls1 knock sensors compatible with my ecm from the valley cover to side of block, which means the knock detection isn't as good, so I error on slightly less advance because I'm not confident in the knock detection.

[@goldsgarage8236]

Thanks for the input ev. That is a good point and i wish i would have mentioned it. I will try to cover it in a future video. AG

[@magnusdanielsson2749]

I guess things change also in relation to how good your carb/intake works or if using electronic engine management.

[@goldsgarage8236]

Thanks Magnus. Yes, these are all variable factors. AG

[@tools6106]

As a big block ford guy, I’ve driven old dirty big ci engines, in big heavy convertibles. Detonating has been an issue, I look forward to building my scj to clean big power. Your video is concise and easy to follow. Thank you!

[@goldsgarage8236]

Thanks for the comment Tools. AG

[@user-bc9sz1dj1g]

Oh, btw, i know Ben Almeda vids well, i have followed for some time now... smart fellow

[@goldsgarage8236]

I agree. AG

[@dannymusgrave4516]

Thanks for the information I have a 65 tempest with a 400 GTO engine and sniper EFI stock bore and small cam runs great giting ready for a rebuild what do you suggest on pistons and bore trying to get it one 10 s

[@goldsgarage8236]

I don't have enough information to calculate that, but you can use the Summit calculator with the info that you have. AG

[@kenwatts5410]

Guys and Al, go to the GT 350 Garage, he explains todays fuels and how to tune for High Compression, very informative, I personally build all my motors 11.0 to 11.5 to 1, I have 1 heavy car and 1 light car, no issues

[@goldsgarage8236]

Thanks Ken, I have watched that video and it is very informative. I recommend it also. AG

[@craigewing3054]

Curious about twin-plug heads as seen on Porsches, Mercedes-Benz and Harley’s some say it enables higher compression?

[@goldsgarage8236]

I don't have personal experience with this but it makes sense. Efficient combustion and fast burn rates are the reason for quench and 2 spark plugs should also help. AG

[@turbo32coupe]

I run an aluminum headed, aluminum blocked FE ford at 10.8:1 compression. Cam is 248/254 at 0.05 on a 110 LCA. Quench head with 0.03 clearance at TDC. On 93 octane there is no detonation. The dynamic compression ratio should not exceed 9.0:1, but 8.5:1 is definitely safe. Static compression ration isn't really important. Modern heart shaped or figure 8 heads have a lot of quench and are more resistant to detonation. 4 valve heads are also resistant to detonation because the spark plug is centered in the chamber; e.g.,, 2JZ or Ford cobra and coyote heads.

[@goldsgarage8236]

All good points Turbo, thanks for sharing your knowledge and experience. AG

[@doughelmle6575]

Hey allan, could you elaborate on the connection of the intake valve closing event with compression .I believe this would show up in the static compression ratio and the cranking compression PSI. I"m asking because I need to select a cam for my stroker 360 mopar [408 cid]. I have trick flow 190 heads ,harland sharp 1.6 rockers.A scat rotating assy with 20 cc dished icon pistons giving a compression ratio of 10.4 [.39 thou head gasket] 60 cc chambers. The cam will be a hydraulic roller for 90% street driving #3500 pound CUDA, 2800 stall converter and 4.30 gear.

[@goldsgarage8236]

Thanks for the question Doug. If you apply the formula, you will see that the IVCP only effects dynamic compression and cranking pressure. If the IVCP is 70 degrees ABDC, then nothing is being compressed until it does close. For a 4" stroke, this may be 1" from BDC. Therefore, your dynamic CR will be less than your static CR. AG

[@coryholbrook4643]

IS the Wallace calculator accurate? Because I have a high compression gen2 LT1 going together that the smallish camshaft had me somewhat concerned about. When I went to to do DC calculators I was getting around a 1 point spread from 9:1 to 10:1 and Wallace was one of the lower ones at 9.17:1. I’m ok with that number since the LT1 has many cooling system changes from the factory that push the ability higher than an old carbureted SBC with no knock control. Even specified a 185psi cranking compression which is just 1psi more than a factory stock LT1. So if you’re really vouching for the Wallace calculator I’m hoping when I do a cranking comp reading that it’s close tonWallace’s calculation

[@goldsgarage8236]

Thanks for the question Cory. I have had good results using the Wallace calculator. Remember to use the advertised duration numbers, not the at .050" numbers, for your IVC which is very important. AG

[@mikequesenberry7976]

We got a 13 to 1 360 dodge runs mid ten with 87 but we use water methonol injection and hasnt blown up been together for years

[@goldsgarage8236]

Thanks Mike, I will have to learn more about water injection, it seems to be very popular. AG

[@aaronnoyb]

In regards to avoid idle conditions, do you have advice on what cruise RPM to aim for, for a majority street vehicle?? Is 2050RPM too low for a 4200lbs vehicle?? I'm redoing my driveline and contemplating a different differential ratio. 2050RPM is my current top gear(4L80E), torque converter locked up RPM, at my normal highway speed.

[@goldsgarage8236]

Thanks Aaron. It does seem to be low. One of the factors is the stroke of your engine because it determines piston speed. A 383 with a 3.75" stroke at 2784 RPM has the same piston speed as a 350 with a 3.48" stroke at 3000RPM. A 427 has the same 3.75" stroke. I don't know what engine you have, but you have a fairly heavy vehicle. Subjectively, I think that 2500RPM minimum would be better. AG

[@rockybruce3750]

am I understanding this correctly? with static compression results I can get a good idea of what my compression ratio is and if so is there a chart or some documentation that can be used as a guide?

[@goldsgarage8236]

Sure, thanks for the question. First Summit has an online compression calculator. It is easy to use. Then Wallace has an on line dynamic compression calculator. You apply the results from the Summit calculator to the Wallace algorithm and you can calculate your static CR, Dynamic CR and cranking pressure. Hope this helps. AG

[@nwrob1]

Great stuff. Does cylinder volume affect the likelyhood of detonation all else being equal? I'm building a 2 liter L6, with a modest 166psi dynamic cranking pressure, and a low volume to pressure ratio of 44. I'm having trouble finding info on how to use that figure.

[@goldsgarage8236]

Good question Nwrob. Larger volumes are more efficient because the ratio of area (for heat transfer) to volume improves. I think you are safe at 166PSI. i am curious, what are the metrics of your calculated volume to pressure ratio? AG

[@nwrob1]

​@@goldsgarage8236 Thanks for the reply. I used Wallace Racing's calculator. Here are the metrics: 2 liter 6 cylinder 2.9" bore 3" stroke 5.7" rod length Intake closes 68 ABDC Static compression ratio of 10.5:1. Effective stroke is 2.24 inches. Dynamic compression ratio is 8.09:1 . Your dynamic cranking pressure is 165.96 PSI. V/P (Volume to Pressure Index) is 44

[@nwrob1]

@goldsgarage8236 "Larger volumes are more efficient because of the ratio of area to volume improves". I don't think that is correct. If you do the math, larger cylinders have lower area/volume ratios than smaller ones. For a 3" piston with a 3" stroke, the area to volume ratio is 2. A 4" piston with a 3" stroke is 1.66. Edit: larger pistons have better volume/pressure ratios, though.

[@dorianleclair7390]

Yes higher the octane less chance for knock or pre ingnition. Especially in higher compression engines.

[@goldsgarage8236]

For sure, thanks for watching and commenting Dorian. AG

[@nsmturbo5902]

Just bought a Blower Shop 192 supercharger for a 355 SBC. Its not a race car just a fun street cruiser. The engine has 9.5:1 CR with basically a stock cast bottom end, however I did open up the ring gab a little. Ide like to stay with 91 octane fuel. My question is, what do you consider max safe boost pressure and max safe ignition timing? Im also considering water/methanol injection just for added peace of mind. I know there's way too many variables to accurately answer my questions, but can you give me a rough ballpark answer to boost psi and timing? Thanks!

[@goldsgarage8236]

Thanks for the question Nsm. I'm sorry i just don't have enough experience with boost to give you a good answer. I don't want to guess, it's too important. Bill Little, are you watching? can you help us out with this question? AG

[@davidreed6070]

I have a question for you. I am experiencing an engine that it seems the cam chain is 1 tooth slow. It runs hot, the header tube are 600 degrees at an idle, it has a terminator x so it's not the tune. What would you check without taking it apart?

[@goldsgarage8236]

Good question David. You could put a degree wheel on it and degree the cam. If the IVC (Intake Valve Centerline) is on spec you are good to go or it will tell you how much you are off. A little tricky if it is in the car. Hope this helps. AG

[@richardharris492]

The spark plug is the ONLY WITNESS to combustion. They never lie.

[@goldsgarage8236]

Good point Richard, thanks for contributing.AG

[@robertwood3970]

If you use water injection you can pretty much run as much compression as you would want.

[@1996slamster]

Unfortunately water injection is just band aid. It's keeping the engine alive, but killing a huge amount of power in doing so.

[@robertwood3970]

@@1996slamster Well, I can see you have never used it. If setup properly you could run 87 octane fuel. Engine would make more power than with race fuel.

[@1996slamster]

Well that’s a super cool secret you got going on there. Don’t let anyone know otherwise every racer out there in the world will be dropping their race fuel and start running on water. Pro-Stockers won’t know what hit e’m.

[@robertwood3970]

@@1996slamster Well, you can be condescending if you want but how do you think the Germans ran their planes in WWII with crap synthetic fuel that had a 93 octane rating? They ran 50# of boost on their engines. Yeah, that’s right they ran water injection.

[@1996slamster]

You’re correct, the Germans did run water injection on the planes. It helped with varying altitudes. You know, dense air at sea level and the opposite as you increase altitude? Also the fuel technology just wasn’t what it was back in the 40’s. But if you really feel water injection is the shite, I would suggest going to a race event and walk around the pits counting up all the water injection units you find on the various race cars.

[@kenw1049]

Lots of good information in this video. But one factor I was hoping you'd cover is "quench". Does quench allow a person to run more compression? How much more? What's the minimum safe quench and what's the max quench distance before it's a non factor?

[@bobbyoshomebuilt2544]

I built a 408 SB mopar stroker, Closed chamber aluminum heads, flat top pistons with zero deck height and .038 head gaskets. It cranks 217 psi. It has a very strong ignition and perfectly tuned carburetor's. I had trouble on 93 pump gas with cast iron manifolds. I built good port matched headers and now have no detonation on 93 pump gas. I'm pushing the limit for sure. Another potential risk is piston to head contact. None as of now, but if the pistons or bore ware, and piston rock increases enough, contact! And of course I'm always Leary of getting lower octane fuel out of the 93 pump. I have had that problem a few times, not cool. I would not recommend doing what I did unless you are capable and prepared to accept and repair the potential issues that could arise. It's my "opinion" that proper quench allows much psi more cranking cylinder pressure than non quench. I'd never build another non quench engine. Even if lower compression, it also seems to cold start easier with the quench.

[@kenw1049]

Thanks for sharing your experience with your sbm. I would have never thought that headers vs cast manifolds wound affect detonation. I too am a Mopar guy and I'm planning a build for a 340 to replace the tired 318 that's in my 74 Charger.

[@goldsgarage8236]

Thanks Ken. i had a bullet about quench in the screen shot but i missed it in the presentation and didn't notice until it was too late. I will cover this off in a follow up future video. Cylinder head design and piston design are factors to provide a good quench area. The conventional thinking is that .040"-.045" quench height is ideal. i think the issue is the less the better as long as the piston doesn't hit the head. Ben Almeda Racing has a good video on this subject so you might check it out. AG

[@bobbyoshomebuilt2544]

Yes I was pleasantly surprised after adding headers. I thought I'd be buying race gas for any spirited driving. I'm thinking the headers must scavenge the cylinders better. My headers are port matched perfectly to the heads and exit straight in line with the ports up and out the fender wells. Good luck with your build. @@kenw1049

[@95Sn95]

When I was in tech school in 92 the school was like 80+ miles from anywhere and a guy had a beautiful driver 69 mach 1 that apparently had been babyied and had been carboned up really bad, well he brought it to the school to have it worked on well he gave it a hot supper all 80 miles from Bangor to the school and few days later after it was brought into the shop it started rattling and banging bad it sounded terrible in top end the teacher started to panick asking did someone drop a bolt down the carb!? He was upset, everyone was like no one barely touched it, well the teacher got thinking and figured it was carbon breaking loose so he rolled the dice and set the rpms up off idle maybe 1500rpm and started misting water down the carb with spray bottle it was running bit rough and actually started to sound worse clack bang bang for a bit but then it started blasting black water out the tailpipe and after a bit the noise started to fade until it was completely gone and it ran fine but he was lucky because the way it sounded it could have cracked the head or a piston and or bent a valve, the safer thing would have been pull the heads and clean it all but his gamble worked. With that much carbon it must have spark knocked under load bad and been down on power big time. Who could have a 69 mach 1 and drive it like a grandma, Also I had an 80+ year old woman ask me to pull her old 60s fast ack mustang with a lumpy idle n loud exhaust out of storage building n up a hill she said I'm not good at driving a manual... I said no problem but how in world do you have a car like this? She said her husband had died and she wouldn't sell it and she would bring it home park it for summer in driveway n take it back to storage in the fall, what a cool car I wanted to say could I please drive it to your house but didn't quite dare to. I also thought hey you need some free work around the house and a new friend? Not really lol

[@goldsgarage8236]

Thanks for sharing your experiences Budget. AG

[@turbo32coupe]

Great story. Old carburetors were notorious for running rich at idle. They didn't atomize well, especially Holley's. When the manufactures went to port injection all the fuel distribution problems disappeared. Also there was no wall wetting. When we tore down late 80's and early 90's 5.0 Fords, the was no cylinder wear. We just broke the glaze and put them back together with new rings.

[@bernielehman8288]

Positive Crankcase Ventilation difference of PCV valves. I don't want the blowby going back into the intake ?

[@goldsgarage8236]

Good observation Bernie, Race cars don't have PCV valves, but i don't think a little blow by will hurt anything. AG

[@mike4fo]

Where I live I have plenty of E85

[@goldsgarage8236]

Thanks Mike, you are fortunate, that is an alternative for sure. AG

[@troymyers5144]

Pulled a LQ9 had 200 compression factory at 2000ft elevation .

[@goldsgarage8236]

Thanks for the info, that's a lot. AG

[@JudgeMeNotLeMans]

Water/meth injection for a higher compression on pump gas? I’d be interested in hearing your opinions and advice on my project I’ve been working on and slowly piecing together. Planning for this to be a drag bracket racer that looks stock… 68 LeMans original engine is a 350. Building a 455 +.030 flat top stock crank and rods for now (stroker down the line) stock dual plane 4bbl intake and 800 cfm Q-jet. Found a set of #16 heads the seller claimed were of Royal Bobcat fame. The numbers work out to 12.5:1 CR. David Vizard’s 128 rule calculates a 105 LSA and probably gonna be tough to find that unless it’s custom so 106-108 maybe? With stock rods being the limiting factor for higher rpm I should keep RPM below 6000 so peak HP around 5500 I think would be safe so what do you think a good duration would be for 1500-5500 rpm range would be? Any and all advice is welcome! Thanks, Ken.

[@goldsgarage8236]

Thanks for the question Judge. For street use about 230 degrees at .050" +/-, but with 12.5 compression and if you are racing it with high numerical gear ratio you could go higher. AG

[@v1-vr-rotatev2-vy_vx31]

See old school engine builds at 15to1 compression, on pump gas with distributor total advance at just 22° to compensate for the pump gas octane deficiency... That is 1,000 horsepower

[@goldsgarage8236]

1,000 is a lot more than I need. Thanks for the suggestion. AG

[@mac6746]

My Hellcat heats up to 222F before the thermostat opens up then it rums at 200F all day. I took it to the dealer they said it was normal. What do you think?

[@goldsgarage8236]

Thanks Mac. I would not worry about it. The boiling point of water at 15PSI (above atmosphere) is 250 degrees. Your cooling system pressure is probably higher than that. As long as your coolant remains liquid (and not steam) you are ok. AG

[@SomebodyNobodyAnybody]

How do u get the gold colored exhaust runners and keep the head castings the grey color

[@goldsgarage8236]

Good question Somebody. Th exhaust heat just changes the paint color naturally. AG

[@mac6746]

Does rpm effect compression ratio? As rpm increases cylinders become more full especially with a high performance na cam.

[@goldsgarage8236]

Good question Mac. I addressed this point in a follow up video to this one. Static compression does not change, but volumetric efficiency (cylinder filling) improves at higher RPM as the inlet fuel/air mixture gains velocity and inertia. AG.

[@loafbred]

Probably a non-issue for most people who use an aftermarket intake manifold, but EGR (exhaust gas recirculation) reduces combustion temperature, for the purpose of reducing nitrogen oxide emission. It also reduces power and efficiency, so we used to disconnect it. Often times disconnecting it would immediately result in detonation, all else being equal. If you intended to run without EGR, you needed to richen fuel mixture.

[@goldsgarage8236]

Thanks for the info Loaf. I am sure some of those watching can relate to this. AG

[@davidphillips3953]

Better than adding excess fuel to cool it a recurved distributor to retard timing a few degrees at part throttle would improve efficiency.

[@loafbred]

I guess every engine was different, but if efficiency was important, you might give up a little power.@@davidphillips3953

[@jarmominkkinen9409]

Grate Video Runn back in The day.Corvette 356cui and Dellorto 48mm carbs.Real Street car.Brodix 11x Heads roller cam 0630 lift.1600kg car Th400 Aut. No no transbrake .60 foor 1 62 weely.10.76 210 kmt. Runn thes taime 1992.Still have The car Build Twin Turbo 1995 Carborator.The Engine Ghos tou lean broke 2 piston runn Anyway 9.90 223 kmt 402m..*1995) Tou day I have Efi VEMS .Hope come Out 2024.Have even Camaro 68 Efi Big staff and Procharger F2.Only 12 psi in Boost 1100hp.25.4 Chassi. Have noth drive thes Camaro thats bad Mayby 2024 it come Out..Love cars 62 gears old still plaing with cars! Have grate day..Jarmo Spell like hell sorry four that.Dou The best I can..

[@goldsgarage8236]

Hey Jarmo. Lots of good stuff here, thanks for sharing your knowledge and experience. AG

[@cam3002]

Comment on octane, there are two different standards used throughout the world and the US uses a blend of both. RON (Research Octane Number), think this is the most commonly used and is typically reported as a higher number. MON (Motor Octane Number) that is typically reported at a lower number. And the US, Canada, and Mexico uses (R+M)/2. So a European 100 octane could translate to a US 93 or something close to that.

[@goldsgarage8236]

Thanks for the info on Octane Cam. AG

[@Addmaster1]

The compression is just limited by the knock of the petrol right? If I use a alcohol water injection with a 120 octan, I could without any problem go to 16-17:1 compression right? If of course the same power output as with the original fuel is the goal, as a kind of ecotuning. But if theoretically the same HP is achieved, the stress from compression does not matter since its way less, one tenth of that of the combustion, right?

[@goldsgarage8236]

You are correct Add. Measured static compression is just an indicator of the health of the engine. MEP, Mean Effective Pressure is what makes power, and sometimes what does the damage. AG

[@Addmaster1]

@@goldsgarage8236 thanks for reassuring mate

[@frankglasgow]

Will static compression go down at high altitude, like 6000 ft? Vs sea level altitude for the same engine.

[@goldsgarage8236]

Good question Frank. Yes it will. The atmospheric pressure at sea level is 14.7PSI. i used an on line calculator and based on my calculation, the atmospheric pressure at 6000ft is 11.78PSI. Theoretically, if you have 10:1 CR at sea level you will have 147psi cranking pressure. If you have 10:1 CR at 6000ft you will have 118PSI cranking pressure. Results may vary because there is a dynamic effect cranking an engine and using a compression gauge. Hope this helps. AG

[@elainestamper3873]

Always used factory spec plugs

[@goldsgarage8236]

Nothing wrong with that. AG