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Compression ratio 12.5:1. Bye-bye Super charger & Turbo build?
Hey, guys.
See Here: http://www.ft86club.com/forums/showthread.php?t=2131 Now we know the Compression ratio is 12.5:1 This is a nightmare for people who want do a turbo or a super charger build. According to my knowledge, there are some ways that we could reduce the CR. I want discuss with you guys. First, get a thinner gasket. This only can reduce a little CR, for example 0.2 or 0.3. Even we drop it to 12:1 its still not good.:( Second, get after market pistons, rods. I think this is the best way to reduce CR, we may could reduce it from 12.5:1 to 11:1 or 10:1. But if we want crazy high boost... :iono: Last, engine build. A whole new block? If you got tons of $$$ then go for it. Those are just my thoughts based on my own knowledge, I didn't do a lot of search, so correct me if I'm wrong. BTW, intercooler, BOV, waste gate, piping, turbo will those destroy the balance of the car? I don't know, looking for answer. |
Also, what about freeing up horsepower in N/A form?
If an intake, and exhaust can get us 220hp i'll be happy with that, but would much prefer 250+hp with FI |
Thinner head gaskets will RAISE compression, not lower it.
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^ yeah you want a thicker gasket, but realistically it doesnt warrant a very good CR gains or losses.
On that note.. Boxer engines are a bit funky with gaskets EJ251-Ej255 gaskets are thinner than EJ257 STI headgaskets.. BUT EJ257 gaskets give a HIGHER compression ratio to the same blocks....weird right? |
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There's something else involved there because and thinner but otherwise identical gaskets will always increase compression... |
Do some research on boosted S2000's. It has been done a thousand times on totally stock engines, with 11.7:1 compression ratio. Results are impressive (420whp @ 12 psi for your typical bolt-on turbo kit using 93 octane, easily 500 with E85). A thicker headgasket is a bad band-aid, if you want to go high boost better build the engine and use lower CR pistons.
The biggest enemies on boosting this car will be: - DI head (complexity, tuning) - Space / packaging - Lead time to having a decent standalone system available |
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What about mill the block? Is this safe and not that costly? A set of after market pistion+rod. But those are just over my budget limit. I'm considering an used BMW M3 E90/92 now... which is... shame..:( |
DI doesn't have any negative effect on boosting anything... At this point the 12.5:1 compression is pretty much the worst thing they could have done. It's going to necessitate one of 2 things... Either Meth/H2O injection or Ethanol or both. But even then I'm guessing that you are only going to be able to run like 8PSI... but you will get good power.
The only good thing about that is... the engine will have a fully forged lower end... It really almost has to... 12.5:1 at 8k rpm or however fast they want to spin this thing... it has to have a forged lower end |
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STI runs forged cranks and rods factory, if anything id expect this car to have a forged crank since its expected to perform in the upper registries of the RPM range.
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Yes I'm not, just want begin to talk this topic. And listen to adivces. Why can't you just say why I'm wrong and tell us how to do thing right? |
Just a thought Fred...maybe this might not be the car for you! How about drive it first before deciding if it needs more power. My .02
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