just did a compression test
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do you know why you lower compression for a turbo? its all about peak cylinder pressure and the energy in the spent gasses of combustion.
in other words high compression has little to do with turboing a car.
in other words high compression has little to do with turboing a car.
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From: New England
Originally Posted by spectacle,May 4 2009, 12:53 PM
There you go.
Do it! explain the ideal compression when installing a forced induction system.
I don't know....explain it to me.
I will apologize if I'm wrong. I'm not ashame to apologize.
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if you reread my post on what i was gonna do you would see where i said 3mm hglike 3 times lol. my options are low comp pistons or new rings and a 3mm hg.
topend cleaner is basicly seafoam if you know what that is. cleans out carbon buildup around the valves and such. and its crazy cheap lol.
plenty of ppl on here had done pretty well turboing a stock engine.
a health stock egine should take 9-10 psi no problem on pump gas.
my high boost tune will be on meth inj.
from what i know(could be wrong who knows) ideal cr for boost is dependent on what psi you will be running.
a stock s2000 with a greddy kit at 10 psi will be much faster then a s2000 with 9-10:1 cr with a greddy kit on 10 psi.
realalisticly what non turbo engine is ideal for boost? na engines are designed to be na from the factory. same goes for turbo engines. they are tuned for boost from the factory.
in reality isnt that what most of us are here doing?? taking a car and retuning it to be better then or couldnt from the factory????
well i i will be redoing the compression test and a lead down to pin point where i need to work on. if it is the vavles i will be port n polish the head and do a 3mm hg. if it is the rings i might just get some cp low comp pstons. from what i read cp pistons work with out fiber cylinder walls. ether way after i fix the problem until its turbo i will have the slowest s2000around lol.
topend cleaner is basicly seafoam if you know what that is. cleans out carbon buildup around the valves and such. and its crazy cheap lol.
plenty of ppl on here had done pretty well turboing a stock engine.
a health stock egine should take 9-10 psi no problem on pump gas.
my high boost tune will be on meth inj.
from what i know(could be wrong who knows) ideal cr for boost is dependent on what psi you will be running.
a stock s2000 with a greddy kit at 10 psi will be much faster then a s2000 with 9-10:1 cr with a greddy kit on 10 psi.
realalisticly what non turbo engine is ideal for boost? na engines are designed to be na from the factory. same goes for turbo engines. they are tuned for boost from the factory.
in reality isnt that what most of us are here doing?? taking a car and retuning it to be better then or couldnt from the factory????
well i i will be redoing the compression test and a lead down to pin point where i need to work on. if it is the vavles i will be port n polish the head and do a 3mm hg. if it is the rings i might just get some cp low comp pstons. from what i read cp pistons work with out fiber cylinder walls. ether way after i fix the problem until its turbo i will have the slowest s2000around lol.
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This is on the wrong forum.
We have a very high compression motor. I have seen superchargers put out 6-7 lbs boost without headwork. That is about where I feel comfortable with crappy oxygenated gas and 115 summer temps. With good gas, a custom intercooler, methanol injection, my thoughts would be different.
Doubling the horsepower is a major job and cannot be accomplished without lowering the compression.
We have a very high compression motor. I have seen superchargers put out 6-7 lbs boost without headwork. That is about where I feel comfortable with crappy oxygenated gas and 115 summer temps. With good gas, a custom intercooler, methanol injection, my thoughts would be different.
Doubling the horsepower is a major job and cannot be accomplished without lowering the compression.
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From: South Florida
Originally Posted by INTJ,May 4 2009, 05:39 PM
This is on the wrong forum.
We have a very high compression motor. I have seen superchargers put out 6-7 lbs boost without headwork. That is about where I feel comfortable with crappy oxygenated gas and 115 summer temps. With good gas, a custom intercooler, methanol injection, my thoughts would be different.
Doubling the horsepower is a major job and cannot be accomplished without lowering the compression.
We have a very high compression motor. I have seen superchargers put out 6-7 lbs boost without headwork. That is about where I feel comfortable with crappy oxygenated gas and 115 summer temps. With good gas, a custom intercooler, methanol injection, my thoughts would be different.
Doubling the horsepower is a major job and cannot be accomplished without lowering the compression.
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From: New England
I dealt with turbo through out my life...this is the only job & business I know.
I can go on and on and tell you thousand of stories how people blew their turbo & engine. I guess some people knows better.
I been helped here many times and very grateful. In return, just trying to help a little.
I only have one advice, visit my graveyard.
http://www.mjmturbos.com/Graveyards.htm
I can go on and on and tell you thousand of stories how people blew their turbo & engine. I guess some people knows better.
I been helped here many times and very grateful. In return, just trying to help a little.
I only have one advice, visit my graveyard.
http://www.mjmturbos.com/Graveyards.htm
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From: Jacksonville, FL
Definitely this thread is headed in the wrong direction for this forum. If folks have questions about what is possible with a stock F20/F22 being boosted, do some research in the FI forum. Note that with the right tuner (and that's a big caveat) there are examples of boosted s2ks putting down between 600-700whp...with completely stock internals and head gasket.
To the OP's question, personally I would recommend starting with a good engine before boosting. Lotus7racer's suggestion of retesting with a cap full of oil in the cyl is an old trick that certainly will give you a clue as to the reason why the compression is lower. Get a leak down test done to confirm if it is rings or valves causing your compression loss.
If you rebuild and want to lower compression, it is probably better to use pistons rather than the hg. Many have suffered hg failure with the thicker gasket. Pistons would be safer.
To the OP's question, personally I would recommend starting with a good engine before boosting. Lotus7racer's suggestion of retesting with a cap full of oil in the cyl is an old trick that certainly will give you a clue as to the reason why the compression is lower. Get a leak down test done to confirm if it is rings or valves causing your compression loss.
If you rebuild and want to lower compression, it is probably better to use pistons rather than the hg. Many have suffered hg failure with the thicker gasket. Pistons would be safer.
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check all your retainers... i cracked all my intake ones... bad bad bad... thats where my loss of compression went... valve was partially open well sorta... hard to explain... upgrade valve train before u turbo it!!!!! i just rebuilt my head... ran me about 1100 full tit everything.. spoon headgasket... now im running 247 compression... and building a turbo kit
