Originally Posted by XethW
I'm probably displaying a lot of ignorance here, but wouldn't a 5-7psi boost be enough to get our cars around the magical 300hp mark, without stressing our engines? I don't see any reason why we couldn't run a supercharger with 6psi pushing an extra 80-100hp, which would bring us somewhere between 298 and 318hp (assuming the car is still stock - my hp figures are a rough estimate of 15hp per 1PSI, with a little bit of play on either side).
I'm also curious if adding a blower would effect those of you who have aftermarket chips in your car?
Thanks for doing all this research for us - You got a fan club watching to see how it turns out!
--X
Nah, you're not displaying ignorance at all. Taking into account the parasitic loss of a supercharger, 7psi would probably net you somewhere around 80hp above stock (maybe a little less, but for the sake of this post, 80 is good enough). That puts the car at around 295bhp. I'm being a bit optimistic with this next number, but if you factor in 15% power loss through the drivetrain (on a manual gearbox, at least) you'll arrive at right around 250rwhp. That would make for a very quick Crossfire.
I'd be a bit leery of going much higher than this, though. Being that no one has converted a NA Crossfire to FI before, there isn't any background information on how much boost the stock engine can handle. You've also got the rest of the drive train to worry about. Everything from the gearbox back seems pretty sloppy, so I don't know how well it would hold up to the added power.
Of course, you've also got to worry about fuel delivery and tuning. Being able to bolt on boost isn't any good if you can't supply the fuel to accomodate it. Odds are, however, that the stock fuel pump and injectors are sufficient for low boost and AMG parts can be swapped in should you need more. I just don't know how well the ECU will adapt. You might be able to get by with a S-AFC or similar tuning device, but again, I just don't know.
Then there's the exhaust. The stock manifolds might flow well enough for low boost, but might prove to be restrictive north of 8psi. Again, AMG manifolds can probably be swapped in here.
I've been reading the Mercedes forums a bit, but that hasn't proven to be too helpful. The friend of a friend I mentioned in a previous post actually worked on the Crossfire before its release. I guess he would know as much as anyone about the inner workings of the system and should prove to be a very useful source of information in my little project.