High compression on pump gas tricks???
#2961010
09/04/21 05:41 PM
09/04/21 05:41 PM
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Joined: Jan 2005
Posts: 12,478 Kalispell Mt.
HotRodDave
OP
I Live Here
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OP
I Live Here
Joined: Jan 2005
Posts: 12,478
Kalispell Mt.
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What are everyone's tricks for safely running the highest compression possible on pump gas? Also what is the most compression you have seen run safely on pump gas?
I will share a few tricks that work for me
Coolest intake air possible Keep as much heat as possible out of engine compartment, wrap headers, minimize restriction of air flow out of the engine compartment from the radiator Keep fuel as cool as possible, heat wrap lines near exhaust, keep lines as far as possible from exhaust, phenolic carb or phenolic carb spacer Very tight quench Aluminum heads when possible Sharp angle on intake valve to help break up fuel droplets Fully radius and polish exhaust valve head to keep it from getting hotter than nessacary and keep it from heating the air in the chamber Don't be afraid of ethanol fuel Coolest plug that don't foul out Very careful control of timing, tight distributor bushing, carefully curved distributor Late intake valve timing or at least not too early Coolest engine temp that is reasonable, usually 180* on the street for me Slightly loose converter EFI with return line Smooth out or round off any sharp edges in the combustion chamber Find injectors with as many spray holes as possible for the given flow rate needed Plastic intake manifold if I can find one for the application to keep the air cool (no 6.1 or eddy intake for my hemi) On the new hemi 6.4 I run the piston squirters and stick a bunch of computer heat sinks on the oil pan and filter to keep that oil cooler to keep the chamber cooler
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: High compression on pump gas tricks???
[Re: Dragula]
#2961025
09/04/21 07:13 PM
09/04/21 07:13 PM
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Joined: Mar 2011
Posts: 3,171 Michigan
A727Tflite
master
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master
Joined: Mar 2011
Posts: 3,171
Michigan
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What are you guys seeing for exhaust manifold/header temps at idle ?
Intake manifold temps after a short drive, at idle?
Water temp at the inlet and outlet of the rad after driving a bit.
Last edited by Transman; 09/04/21 07:13 PM.
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Re: High compression on pump gas tricks???
[Re: hemienvy]
#2961197
09/05/21 11:09 AM
09/05/21 11:09 AM
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Joined: Jan 2021
Posts: 1,128 rust belt
Moparite
super stock
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super stock
Joined: Jan 2021
Posts: 1,128
rust belt
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Instead of cooling the fuel, keep it warm so it evaporates better/easier. Warm and under pressure. That's a good way to kill performance. Invent a time machine and go back to the days where you could get leaded Sunoco 260! They still make it minus the lead. What you need is either higher octane or Tetraethyl lead or both. Lead was a major ingredient to stop pre ignition(not to mention it's lubricating properties) but is no longer in automotive gas. It IS still in aviation fuel (Avgas). Any aviation fuel has higher octane than what you find at your local gas station. Back in the day a local Sunoco station had race fuel available right next to the standard gas pumps. Don't think you will fine one like that today.
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Re: High compression on pump gas tricks???
[Re: HotRodDave]
#2961236
09/05/21 01:17 PM
09/05/21 01:17 PM
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Joined: Mar 2010
Posts: 1,066 Atlanta, GA
mgoblue9798
super stock
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super stock
Joined: Mar 2010
Posts: 1,066
Atlanta, GA
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Sodium filled exhaust valves allow for more compression on the same octane.
Another trick for non computer controlled ignition engines - an MSD adjustable ignition knob to retard timing if needed get out of detonation on long grades or pulling heavy loads.
Good free flowing exhaust including headers to keep temps down.
Block heat crossover in the intake to keep temps down.
Last edited by mgoblue9798; 09/05/21 01:20 PM.
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Re: High compression on pump gas tricks???
[Re: HotRodDave]
#2962110
09/08/21 10:09 AM
09/08/21 10:09 AM
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Joined: May 2008
Posts: 5,399 Aurora, Colorado
451Mopar
master
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master
Joined: May 2008
Posts: 5,399
Aurora, Colorado
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pretty much the same, tight quench, cool air & fuel. close to my 400/500" stroker at 12.4:1 compression. If I had the $$$, ceramic coated piston tops, chambers, valves, and valve seats that conduct heat well like copper beryllium valve seats. maybe the dura-bond killer B PM valve seats for a gen III hemi? I would not want to machine beryllium without special PPE https://www.dura-bondbearing.com/products/powder-metal-valve-seats/
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Re: High compression on pump gas tricks???
[Re: 451Mopar]
#2962169
09/08/21 01:24 PM
09/08/21 01:24 PM
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Joined: Jan 2005
Posts: 12,478 Kalispell Mt.
HotRodDave
OP
I Live Here
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OP
I Live Here
Joined: Jan 2005
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Kalispell Mt.
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I had ceramic long tube headers on my 99 dakota R/T with around 12 to 1 iron head 410CID and those headers you could still hold your fingers on for a couple seconds immediately after getting back from running hard down the highway even before shutting off the engine, most headers I have seen will melt your skin instantly on contact after somethign like that. Under hood temps were much lower than most other header equipped cars. Something else I did on that one was I ran an airgap style intake but it would not have much access to cool air to flow under it so I removed all the webbing I could from the huge AC/Alternator bracket and ran a big mechanical fan (I normally run electric fans) to keep a steady stream of air flowing through there. I even glued a phenolic resin type plate to the bottom of the intake to keep the hot cam oil from heating the intake.
Other things I have thought about as far as ways to keep the air cool is to use plastic ducting instead of metal (Aluminum dryer ducting), you could strip all the paint off a metal air cleaner and ceramic coat that, obviously make sure you suck air from in front of the radiator not behind it.
Sometimes lots of little things add up to make a pretty significant difference.
I always wonder why nobody makes phenolic resin intake manifold gaskets for old motors, it would be a nice way to help keep heat out of the intake manifold when plastic intakes are not available.
Has anyone come up with a good way to run reverse cooling on a mopar engine yet?
I am gonna see if my local machine shop can put copper beryllium exhaust seats in an iron magnum head I am getting ready to put in my next MPG project... I had not thought about doing that.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: High compression on pump gas tricks???
[Re: HotRodDave]
#2962195
09/08/21 02:32 PM
09/08/21 02:32 PM
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Joined: Jan 2004
Posts: 8,637 fredericksburg,va
cudaman1969
master
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master
Joined: Jan 2004
Posts: 8,637
fredericksburg,va
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I had ceramic long tube headers on my 99 dakota R/T with around 12 to 1 iron head 410CID and those headers you could still hold your fingers on for a couple seconds immediately after getting back from running hard down the highway even before shutting off the engine, most headers I have seen will melt your skin instantly on contact after somethign like that. Under hood temps were much lower than most other header equipped cars. Something else I did on that one was I ran an airgap style intake but it would not have much access to cool air to flow under it so I removed all the webbing I could from the huge AC/Alternator bracket and ran a big mechanical fan (I normally run electric fans) to keep a steady stream of air flowing through there. I even glued a phenolic resin type plate to the bottom of the intake to keep the hot cam oil from heating the intake.
Other things I have thought about as far as ways to keep the air cool is to use plastic ducting instead of metal (Aluminum dryer ducting), you could strip all the paint off a metal air cleaner and ceramic coat that, obviously make sure you suck air from in front of the radiator not behind it.
Sometimes lots of little things add up to make a pretty significant difference.
I always wonder why nobody makes phenolic resin intake manifold gaskets for old motors, it would be a nice way to help keep heat out of the intake manifold when plastic intakes are not available.
Has anyone come up with a good way to run reverse cooling on a mopar engine yet?
I am gonna see if my local machine shop can put copper beryllium exhaust seats in an iron magnum head I am getting ready to put in my next MPG project... I had not thought about doing that. On the intake gaskets, why not use mutiply, 1/8 to 3/16” thick? My 1” and 2” multipy carb spacers work well
Last edited by cudaman1969; 09/08/21 02:32 PM.
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Re: High compression on pump gas tricks???
[Re: cudaman1969]
#2962377
09/09/21 06:03 AM
09/09/21 06:03 AM
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Joined: Apr 2006
Posts: 4,220 West Plains, MO
DrCharles
master
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master
Joined: Apr 2006
Posts: 4,220
West Plains, MO
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What about sealed (to the carb/air cleaner) vs. non-sealed hood scoop ? I have a six-pak scoop on my Dart's glass hood (single 4-barrel on Edelbrock RPM manifold with 1/2" nitrous plate and 1/2" phenolic spacer). Air cleaner is 14" open. I think that the scoop opening is admitting more cool air to the engine compartment, but not as cool at the air cleaner as a sealed scoop would. On the other hand, if air is getting "behind" the radiator via the scoop, it could be impeding the flow through the grille. Seems like a trade-off between intake temp, coolant temp and engine compartment temp. My brain hurts
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Re: High compression on pump gas tricks???
[Re: DrCharles]
#2962472
09/09/21 12:55 PM
09/09/21 12:55 PM
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Joined: Sep 2003
Posts: 20,235 north of coder
moparx
"Butt Crack Bob"
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"Butt Crack Bob"
Joined: Sep 2003
Posts: 20,235
north of coder
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has anyone used a sealed air cleaner that picked up air from the cowl openings below the windshield ? if so, could you tie into that area behind the hood hinges on a 69 B-body ? what size air cleaner would work good for this ? 14x3 perhaps ?
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Re: High compression on pump gas tricks???
[Re: HotRodDave]
#2962534
09/09/21 03:58 PM
09/09/21 03:58 PM
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Joined: Oct 2007
Posts: 4,219 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,219
New York
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W/r/t "put copper beryllium exhaust seats"
Be in Kabul when this is done, safer.
Boffin Emeritus
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Re: High compression on pump gas tricks???
[Re: HotRodDave]
#2962899
09/11/21 10:54 AM
09/11/21 10:54 AM
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Joined: Jan 2003
Posts: 24,562 Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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What are everyone's tricks for safely running the highest compression possible on pump gas? Also what is the most compression you have seen run safely on pump gas?
I will share a few tricks that work for me
Coolest intake air possible Keep as much heat as possible out of engine compartment, wrap headers, minimize restriction of air flow out of the engine compartment from the radiator Keep fuel as cool as possible, heat wrap lines near exhaust, keep lines as far as possible from exhaust, phenolic carb or phenolic carb spacer Very tight quench Aluminum heads when possible Sharp angle on intake valve to help break up fuel droplets Fully radius and polish exhaust valve head to keep it from getting hotter than nessacary and keep it from heating the air in the chamber Don't be afraid of ethanol fuel Coolest plug that don't foul out Very careful control of timing, tight distributor bushing, carefully curved distributor Late intake valve timing or at least not too early Coolest engine temp that is reasonable, usually 180* on the street for me Slightly loose converter EFI with return line Smooth out or round off any sharp edges in the combustion chamber Find injectors with as many spray holes as possible for the given flow rate needed Plastic intake manifold if I can find one for the application to keep the air cool (no 6.1 or eddy intake for my hemi) On the new hemi 6.4 I run the piston squirters and stick a bunch of computer heat sinks on the oil pan and filter to keep that oil cooler to keep the chamber cooler
I ran a snow performance meth/H2O injection kit on my old 70 Charger. Worked very well. (11.5:1 440-6)
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Re: High compression on pump gas tricks???
[Re: Mr.Yuck]
#2962996
09/11/21 02:27 PM
09/11/21 02:27 PM
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Joined: Nov 2003
Posts: 1,385 Out of the State of Confusion
blue_stocker
pro stock
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pro stock
Joined: Nov 2003
Posts: 1,385
Out of the State of Confusion
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Isn't there something about changing LSA/ICL on the camshaft timing events? Where's Mr Porter? I'm sure he can shed a tidbit or two on camshaft events...
I predict future happiness for Americans if they can prevent the government from wasting the labors of the people under the pretense of taking care of them. Thomas Jefferson
Freedom must be repurchased by every new generation General Daniel Jones, WW2 Tuskegee Airmen
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Re: High compression on pump gas tricks???
[Re: tubtar]
#2963020
09/11/21 04:20 PM
09/11/21 04:20 PM
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Joined: Jan 2005
Posts: 12,478 Kalispell Mt.
HotRodDave
OP
I Live Here
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OP
I Live Here
Joined: Jan 2005
Posts: 12,478
Kalispell Mt.
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No love for thermal barrier coatings ? With high compression and low octane , combustion chamber heat can be reduced by coating the piston and chamber. I have read some interesting results from this. I am still undecided about coatings, here is why. We know running aluminum heads can allow you around another full point of compression vs an otherwise identical iron head, the reason is it conducts the heat away from any hot spot faster so the hottest point in the chamber is no longer as hot and no longer as likely to pre-ignite the fuel. Same with the piston, the heat can spread out faster from any given point. Now we would add a ceramic coating that does the exact opposite...? It is possible I am missing something, maybe just keeping the heat from being absorbed in the first place outweighs it but my though is that it would just have a hot spot with the piston behind it still trying to transfer heat evenly through out but the surface could more easily develop a hot spot, sort of an in between of the properties of aluminum and iron... One other thing I like to do that seems to work really well for me is running as flat a piston as possible, for example a 318 with stock flat top pistons, no valve reliefs set with a real tight quench and magnum heads let me get away with very high compression, lowest surface area possible for a piston to keep it from absorbing heat... it may be worthwhile to run a head with a bigger chamber so you can run less or no dish in the piston. I always prefer a perfectly flat piston if possible.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: High compression on pump gas tricks???
[Re: HotRodDave]
#2963063
09/11/21 06:43 PM
09/11/21 06:43 PM
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Joined: Apr 2008
Posts: 117 Aus
hysteric
member
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member
Joined: Apr 2008
Posts: 117
Aus
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No love for thermal barrier coatings ? With high compression and low octane , combustion chamber heat can be reduced by coating the piston and chamber. I have read some interesting results from this. I am still undecided about coatings, here is why. We know running aluminum heads can allow you around another full point of compression vs an otherwise identical iron head, the reason is it conducts the heat away from any hot spot faster so the hottest point in the chamber is no longer as hot and no longer as likely to pre-ignite the fuel. Same with the piston, the heat can spread out faster from any given point. Now we would add a ceramic coating that does the exact opposite...? It is possible I am missing something, maybe just keeping the heat from being absorbed in the first place outweighs it but my though is that it would just have a hot spot with the piston behind it still trying to transfer heat evenly through out but the surface could more easily develop a hot spot, sort of an in between of the properties of aluminum and iron... One other thing I like to do that seems to work really well for me is running as flat a piston as possible, for example a 318 with stock flat top pistons, no valve reliefs set with a real tight quench and magnum heads let me get away with very high compression, lowest surface area possible for a piston to keep it from absorbing heat... it may be worthwhile to run a head with a bigger chamber so you can run less or no dish in the piston. I always prefer a perfectly flat piston if possible. From what I understand after reading and talking to people who are doing it is the quality of the mixture delivered becomes critical especially when your making 2 HP per cube on pump gas. Another part of the picture is exhaust and how much of the previous charge is left in the chamber that will affect next combustion event. Good quench and a free flowing exhaust (good scavenging) would be the starting point and from there you can play with fuel delivery.
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Re: High compression on pump gas tricks???
[Re: HotRodDave]
#2963418
09/12/21 09:19 PM
09/12/21 09:19 PM
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Joined: Sep 2014
Posts: 4,457 Washington
madscientist
master
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master
Joined: Sep 2014
Posts: 4,457
Washington
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No love for thermal barrier coatings ? With high compression and low octane , combustion chamber heat can be reduced by coating the piston and chamber. I have read some interesting results from this. I am still undecided about coatings, here is why. We know running aluminum heads can allow you around another full point of compression vs an otherwise identical iron head, the reason is it conducts the heat away from any hot spot faster so the hottest point in the chamber is no longer as hot and no longer as likely to pre-ignite the fuel. Same with the piston, the heat can spread out faster from any given point. Now we would add a ceramic coating that does the exact opposite...? It is possible I am missing something, maybe just keeping the heat from being absorbed in the first place outweighs it but my though is that it would just have a hot spot with the piston behind it still trying to transfer heat evenly through out but the surface could more easily develop a hot spot, sort of an in between of the properties of aluminum and iron... One other thing I like to do that seems to work really well for me is running as flat a piston as possible, for example a 318 with stock flat top pistons, no valve reliefs set with a real tight quench and magnum heads let me get away with very high compression, lowest surface area possible for a piston to keep it from absorbing heat... it may be worthwhile to run a head with a bigger chamber so you can run less or no dish in the piston. I always prefer a perfectly flat piston if possible. There is ZERO truth to the oft repeated nonsense that aluminum heads can use a point more compression than iron. None. Guys running iron heads can run the same compression as guys running aluminum heads. It’s ridiculous to keep saying that falsehood. There is no possible way in hell that running along at a cruise and running into tip in rattle will stop if you switch to aluminum. Common sense says the increase in heat load happens so fast it wouldn’t matter if the heads were made of unobtainimum it wouldn’t matter. There are no “tricks” to running more compression than the “orthodox” standards we have been lead to believe. Common sense engine building, cam selection and chassis isnt trickeration. It’s common sense.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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