What's the highest compression u can rum on pump gas N/A. I know people run 11.1 but can u run like 13.1 and have 2 different tunes?
N/A highest compression on pump gas
- Thread starter 99vertcobra
- Start date
There would only be one tune for that type of compression, race gas or E 85 only. Max comp on pump gas i've seen was just just over 12.1 and running very strong for 93oct, but i can't say what car make or I'll get flamed lol. On our cars i would expect no more 11.3-5 comp on 93 pump.
So I can run 12.1 on 93. Id really like to do that.
well you could run it and make up for it in timing. Remeber your motor is a combination factor of timing advance, octane and compression, they work in sync of each other
Are you sure that 12.1 runs around with pure 93 and not with a splash of torco? I'd be afraid of getting bad gas when trying to push things.
my goal here is to make as much power as i can N/A but still be able to drive my car on the street without spending an arm and a leg on fuel you know what i mean? i dont mind buying race fuel when i go to the track but if i have to run race fuel all the time the car becomes a trailer queen quickly and i dont own a trailer. lol thats why i was asking if you can run 12.1 or 13.1 compression and just pull timing on a street tune to be able to run 93 octane and then have a tune for race fuel. i wanna run 10.50's with a big bore 5.0 heads cam ported intake and 11.1 compression is that possible or am i dreaming
it really depended on the head/piston design, my 2005 600rr had 12:1 and it ran on 87. my 00 civic si had 10.4:1 and I had to run at least 91. My 2007 600rr Had a 12.2:1 and I had to run 93
can you keep in touch with me on how it turns out? who is tuning your car? are you having head work done as well and are you running an aggressive cam or going conservative?
I plan on getting it tuned with Performance Dyno out of Concord, NH. I'm having the heads ported and milled in order to achieve that compression and running comp stage 2 cams part #106400.
ok yea im gonna have a custom cam ground and im using pistons with valve reliefs cause i plan on have a pretty aggressive cam
I can't see running over 11:1 on pump gas, talk about sending your engine to the school of hard knocks. But that's just my opinion.
thats why im asking lol cause i wanna graduate from the school of hard knocks and never go back lol
Great point! The compression is the constant in the equation and the fuel mixture, octane, and timing, among other things are the variables in the equation with the goal of getting as close to the limit of detonation as possible.
I believe that you can go really far with compression with an na engine, even farther than 12:1. Once you reach the limits of what pump gas can offer, you can use meth injection to keep detonation at bay. It works just as good on high compression na cars as it does on forced induction cars.
I'd like to see what the highest na compression someone on this board has with a na motor.
As long as the timing isnt too aggressive there shouldnt be any problems
My 5.4 car is running 11:1 with no issues.
Operative word is "over". I agree 11 is ok but not 12 and other such madness on pump. Choosing static CR also depends on use, street occasional track you can go higher, OT use, it's better to be a little lower for safety margin.
Look at the new 5.0 Mustangs. They are running 11:1 on 91 Octane.
:shrug:
check my post above...
The new 5.0 is very different than our motors so cr discussion would be separate for the two designs.
check my post above...
The new 5.0 is very different than our motors so cr discussion would be separate for the two designs.
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I use the cobra on occasional use. And the new mustangs can do that because of the variable valve timing I believe
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