How much more timing can/should you run with 9:1 compr.?
01-26-2008, 06:33 PM
#1
How much more timing can/should you run with 9:1 compr.? I started with 15, have edged up to 17 so far.
Just curious how much additional timing I should expect to be able to run with the lower compression ratio...
Turbo, rear mount, 11 psi so far.
Just curious how much additional timing I should expect to be able to run with the lower compression ratio...
Turbo, rear mount, 11 psi so far.
01-26-2008, 07:40 PM
#2
I'm no expert, and if you really want to talk to some, I would try in the tuning section on the board.
It will also depend if you are on pump gas, intercooled, meth injection, or all the other things that will help keep you away from detonation.
Guessing you are on pump gas with no meth injection and some form of intercoolers, I would say on 11#'s of boost you could go up a bit higher. If you have a good tuning tool, you should be able to see when you are approaching detonation. At that point assuming the fuel delivery is not the limiting factor, just keep creeping it up to the getting close point, and then you should see where you are timing wise.
My car has 8.8:1 CR, 15#'s of boost on 93 octane with a large FMIC and meth injection I safely got 26 degrees of timing.
It will also depend if you are on pump gas, intercooled, meth injection, or all the other things that will help keep you away from detonation.
Guessing you are on pump gas with no meth injection and some form of intercoolers, I would say on 11#'s of boost you could go up a bit higher. If you have a good tuning tool, you should be able to see when you are approaching detonation. At that point assuming the fuel delivery is not the limiting factor, just keep creeping it up to the getting close point, and then you should see where you are timing wise.
My car has 8.8:1 CR, 15#'s of boost on 93 octane with a large FMIC and meth injection I safely got 26 degrees of timing.
01-27-2008, 12:27 AM
#3
Thanks, that's good to know.
I am running pump gas, no meth, and a big intercooler. IAT so far is normally no more than a couple of degrees higher when boosting than when not boosting. (but it is winter...)
I plan to keep creeping up on the timing using my hptuners and LM1 wb combo, but was just curious what to expect, and what was reasonable.
I'll keep creeping up on the upper limit as far as how much boost I can get out of this 70 rear mount too.
I am running pump gas, no meth, and a big intercooler. IAT so far is normally no more than a couple of degrees higher when boosting than when not boosting. (but it is winter...)
I plan to keep creeping up on the timing using my hptuners and LM1 wb combo, but was just curious what to expect, and what was reasonable.
I'll keep creeping up on the upper limit as far as how much boost I can get out of this 70 rear mount too.
01-27-2008, 01:42 AM
#4
Call911 makes some good points. IMO, with an AFR around 11, 21-22 of advance should be safe for your setup with the big IC, then you can tune slowly from there - both leaner and more advance.
I like to see a final tune where you never see KR because I don't like seeing a single solid ping in the motor.
You're definitely doing it the right way - crepping up as you learn and check data.
What pump gas is available to you?
Jim
I like to see a final tune where you never see KR because I don't like seeing a single solid ping in the motor.
You're definitely doing it the right way - crepping up as you learn and check data.
What pump gas is available to you?
Jim
01-27-2008, 10:45 AM
#5
That's good to know. I started very conservatively after blowing a used swap engine (v6->v8) that I turbo'd 6 months after the swap. It gave up on the first wot application.... That was a couple of years ago. Took a long time to get it back on the road again.
I figured 2-3 degrees below the point where I get KR is probably the best. Similar to tuning an NA setup, making more power with even less timing than "what you can get away with".
93 octane is what most gas stations have here. A few just have 91, but most are 93.
I figured 2-3 degrees below the point where I get KR is probably the best. Similar to tuning an NA setup, making more power with even less timing than "what you can get away with".
93 octane is what most gas stations have here. A few just have 91, but most are 93.
