Pump gas compression?
Pump gas compression?
Posting Legend
Joined: Sep 2001
Posts: 30,255
Likes: 37
There is no answer to that question. Look up DYNAMIC COMPRESSION RATIO at piston manufacturers sites or on the web. Even then combustion chamber shape, coatings, materials, surface finish, swirl. and squish/quench all make a difference.
Posting Guru
Joined: Sep 2005
Posts: 2,238
Likes: 0
From: Kiefer, Northeastern Okla
Red69, I would be interested to know how you are able to run 87? octane with almost 11:1, as I'm sure others would be also. I've run 11:1 with aluminum heads, a pretty radical cam, and careful tuning, but it required 97 octane to keep it out of detonation.
Let's say very interested.
Pete
Let's say very interested.
Pete
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Tuned
Joined: Dec 2004
Posts: 340
Likes: 8
From: Rock Hill, SC
I have a 1970 302 block. Centrifical advance Mallory Unilite at 6 dergrees BTC. Flat top .040 cast piston, 58cc heads millied .010 w/1.94/1.50 valves and port job. Cam is a .525/290 hydraulic. F4b Edlebrock intake with Holley 750 vacuum secondaries. I put a #55 power valve and #31 squirt nozzle in it. Headers with 2-1/4 exhaust and corvair turbo mufflers. T-10 4-speed and 4.10 posi.
The only time it ever pings is if you lug in 4th at 20 miles an hour or so. I have used octane boosters and different brands of premium fuel and can tell no difference.
The only time it ever pings is if you lug in 4th at 20 miles an hour or so. I have used octane boosters and different brands of premium fuel and can tell no difference.
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Posting Legend
Joined: Sep 2001
Posts: 30,255
Likes: 37
If you de-tune an engine by backing off on the timing and playing with the mixture as well as running real easy to turn gears you can run almost any compression. Of course mileage, power, and efficiency will suffer horribly.
Postmaster
Joined: Dec 2004
Posts: 2,941
Likes: 30
From: Maple Valley, WA
Originally Posted by Red69
I have a 1970 302 block. Centrifical advance Mallory Unilite at 6 dergrees BTC. Flat top .040 cast piston, 58cc heads millied .010 w/1.94/1.50 valves and port job. Cam is a .525/290 hydraulic. F4b Edlebrock intake with Holley 750 vacuum secondaries. I put a #55 power valve and #31 squirt nozzle in it. Headers with 2-1/4 exhaust and corvair turbo mufflers. T-10 4-speed and 4.10 posi.
The only time it ever pings is if you lug in 4th at 20 miles an hour or so. I have used octane boosters and different brands of premium fuel and can tell no difference.
The only time it ever pings is if you lug in 4th at 20 miles an hour or so. I have used octane boosters and different brands of premium fuel and can tell no difference.
Posting Guru
Joined: Oct 2003
Posts: 1,955
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From: Quesnel, BC, Canada
Cylinder Head Volume (cc) 58cc
Piston Head Volume (cc) 0cc
Gasket Thickness (in.) 0.040"
Gasket Bore (in.) 4.06"
Cylinder Bore Diameter (in.) 4"
Deck Clearance (in.) 0.00"
Stroke (in.) 3.00"
STATIC COMPRESSION RATIO 10.295
I plugged those numbers in the KB-silvolite.com calculators and came up with that 10.3:1 ratio. Thats a zero decked block, that and the head gasket thickness made the most difference.
There are also claims about these "Singh" grooves that allow you to run high compression on 87 octane without a radical tune. Cruise through this thread if youre intruiged and follow the links https://www.ford-trucks.com/forums/2...ormance-3.html
Piston Head Volume (cc) 0cc
Gasket Thickness (in.) 0.040"
Gasket Bore (in.) 4.06"
Cylinder Bore Diameter (in.) 4"
Deck Clearance (in.) 0.00"
Stroke (in.) 3.00"
STATIC COMPRESSION RATIO 10.295
I plugged those numbers in the KB-silvolite.com calculators and came up with that 10.3:1 ratio. Thats a zero decked block, that and the head gasket thickness made the most difference.
There are also claims about these "Singh" grooves that allow you to run high compression on 87 octane without a radical tune. Cruise through this thread if youre intruiged and follow the links https://www.ford-trucks.com/forums/2...ormance-3.html
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