RPM limit of a stock 99 head?
#1
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RPM limit of a stock 99 head?
So it looks like I toasted my head maybe a crack in the combustion chamber as well as blowing a hole in a piston during my on track catastrophe a few weeks ago. As rebuilt bottom end I believe started pressurizing the coolant system with combustion gas. Don't think its going through the head gasket.
Going to put basically a stock head on for a while on my built 2.0L and wondering how much I need to lower the rev limit if at all. I was running up to 8600 rpm I might move the stiff valve springs over and not worry about it. I also have a set of OEM sodium filled GTR exhaust valves I'm considering using but Id have to re-shim it.
Anybody have any hard evidence where the stock springs start to not work?
Going to put basically a stock head on for a while on my built 2.0L and wondering how much I need to lower the rev limit if at all. I was running up to 8600 rpm I might move the stiff valve springs over and not worry about it. I also have a set of OEM sodium filled GTR exhaust valves I'm considering using but Id have to re-shim it.
Anybody have any hard evidence where the stock springs start to not work?
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Now for those of us with no handy dandy springs to move over, what is the answer? So far I have maintained the stock redline in my MS3, but I know that after I get the forced induction installed over the next couple days the temptation to go to higher revs will be singing it's siren song in the back of my head... so how far is too far on stock head and block?
Keith
Keith
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Now for those of us with no handy dandy springs to move over, what is the answer? So far I have maintained the stock redline in my MS3, but I know that after I get the forced induction installed over the next couple days the temptation to go to higher revs will be singing it's siren song in the back of my head... so how far is too far on stock head and block?
Keith
Keith
old thread
There was something more recent, but this, I think, answers your question.
#10
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The rev limit question from me has more to do with a 6 speed in a car with the stock 4.3 ring and pinion... I currently drive it as a 3 speed using 2, 4, and 6 for normal daily driving. A bit more RPM would make it more livable until I can source a 3.636.
Keith
Keith
#16
I'm also pretty sure that if it's capable of 25 psi it's already there. Your logic says the head doesn't matter, I'll just run 100 psi. You can't cram more air into chambers and runners that won't take more air. It isn't psi, it's volume.
#18
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OK, so it might not help in the daily driving, but at the drag strip toping out 5th gear will get me to 105 mph, revving it out to 7500 would get me to 113 mph. At my race weight 250 whp should have me trapping around 108...
Later,
Keith
#19
I would love to see dyno results with a stock head that continues to climb past 7k. Everything I've seen starts to drop around 6800.
I'm also pretty sure that if it's capable of 25 psi it's already there. Your logic says the head doesn't matter, I'll just run 100 psi. You can't cram more air into chambers and runners that won't take more air. It isn't psi, it's volume.
I'm also pretty sure that if it's capable of 25 psi it's already there. Your logic says the head doesn't matter, I'll just run 100 psi. You can't cram more air into chambers and runners that won't take more air. It isn't psi, it's volume.