hello everyone my question is how much compression can safely be ran on a aluminum headed stroker before the amount of compression starts to narrow the tuning window , meaning timing & boost - detonation those sort of things . Is the higher amounts of compression worth the trade off for the power gain compared to the narrower tuning window??? Thanks in advance guys for all your helpful insight and knowledge.
How Much Compression???
- Thread starter 007gn
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I wouldn't worry about a smaller tuning window as all of that is controlled by the type of fuel being used and having a cushion in the tune.having good fuel is important to controll detonation and i have found that compression is a bid deal and helps a lot.your not going to run a lot of timing on an alum headed stroker anyway.airflow and rpm will be the things to focus on and compression really helps.
That's like asking what the winning lottery ticket numbers are going to be ... with the information you've given us .. nobody can answer that question
you can run 9:1 and run into issues and you can run 11:0 and not see issues
need to know a lot more about the combo you are going to run
My car weighs 3585 with me in it . The car has 323 gears 275 60 15 . I'm doin a on center TA stroker with race ported GN1s 6870 turbo . I have a good built 200r4 . I want this car to run 9.50s off the foot brake on 93 n alky at over 140mph .
That's pretty much faster than anyone has been in TAI. You will need compression. You will need the tune to be right. You will also need a good boost controller and a lot of practice
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If you're going to push your build, you're going to have a narrow tuning window anyway.
Personalty I like compression. More compression (within reason) give more 'pop' pushing down on the piston, and at the same time more pop driving the turbo. The exhaust not sounds better too, if you like that sort of thing.
Your question is a little overly-simplistic too. Static compression really isn't an indicator of something real. Dynamic compression is the more important number. When the piston starts the compression stroke, you can't make any cylinder pressure until the intake valve closes.
If you but a huge ass monster truck rump rump cam in an engine you HAVE to increase the compression just to keep from having a soggy dog of an engine. A smaller stockish cam that has very little overlap and closes the intake earlier won't require as much static to get the needed cylinder pressure.
Personalty I like compression. More compression (within reason) give more 'pop' pushing down on the piston, and at the same time more pop driving the turbo. The exhaust not sounds better too, if you like that sort of thing.
Your question is a little overly-simplistic too. Static compression really isn't an indicator of something real. Dynamic compression is the more important number. When the piston starts the compression stroke, you can't make any cylinder pressure until the intake valve closes.
If you but a huge ass monster truck rump rump cam in an engine you HAVE to increase the compression just to keep from having a soggy dog of an engine. A smaller stockish cam that has very little overlap and closes the intake earlier won't require as much static to get the needed cylinder pressure.
Fwiw I dont increase the CR in any turbo engines to increase off idle torque or try and get more pop out of the power stroke. I do to it increase the engines ability to fill the cylinder. Particularly effective on the exhaust stroke if overlap is minimized. If you are monitoring exhaust pressure you can come to some conclusions about what to do with CR. In addition to increasing the CR the valves need to open and close at the right time. Often going backwards in overlap to get the valve timing right. If you're not looking to run numbers you can probably look somewhere else for power.
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SS/GN
Well-Known Member
- Joined
- Jun 30, 2005
You need a Russ Merritt, the guy can tune a wheelbarrow!
Last edited:
- Joined
- May 26, 2001
Russ is a smart guy and a fast learner, and he has an excellent mentor, a "Grumpy" old fart with LOTS of tuning knowledge, plus good "input" from Bison as well, that combination is among the best
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