Quote:
Originally Posted by fred_boosted
I never did a turbo build on a non turbo car.
People telling me if I want to do that I have to make it less than 10:1...
Which means I have to do an engine build, and this is the only one thing I don't want to...
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Not necessarily...
Example: the new 5.0 coyote mustang motor has 11.0:1 compression... not exactly what you want for boosting an engine but C'est la vie... there are plenty of boosted coyote motors running around at 6-7psi on 91 octane up to 8 psi on 93, and if you want to run ethanol (like I would do) I believe they are getting up to 10psi. thats on a stock engine.
One of the limitations is the fuel and the density of the air charge. Ethanol is EXTREMELY knock resistant as most people on here know. You also run it alot richer than 91 or 93 (about 15-20% richer generally). Another limiting factor is the lower end... I'm thinking they are going to go forged internals... it just makes sense if they want the motor to spin up to 7500 or 8000rpm... this is good news for boosting the motor. If the compression ratio is over 11.0:1 it would almost be not worth it to boost the motor, to get real power it would need a rebuild and lower compression.
In my car (Cobalt SS with the LNF) the engine is built from the factory to take murderous amounts of boosted power. stock boost is 15+/- psi. I am running 24/25psi on my ethanol tune... that said the compression ratio is like 9.2:1. There are plenty of guys getting almost 500whp on a daily driver Cobalt SS (turbo swaps). But this is just an example of a more ideal motor for boost.