Post
by foggyjames » 11 Sep 2011 12:14 am
Torque is the important factor, and 250-300lbft is about your safe limit.
8v redblocks make torque quite easily, but peak power is harder to achieve. For example, wind the boost up to 12psi or so on the small turbo and you'll probably be making 230-250lbft but less than 200bhp. In other words, you're quite close to your limit, without actually making that much power. The plan for my turbo conversion is to keep the torque down to that sort of figure (maximum of 15psi of boost), but make as close to 300bhp as I can by making it breathe at higher engine speeds - primarily in terms of exhaust, cam, and turbo size. Just turning the boost up would be easier, but not good news for the drivetrain.
Of course when you actually break stuff has more to do with how you drive than how strong bits are. Try hard enough, and you'll break stuff with a standard B200E. Treat it gently, and you could probably get the stock drivetrain to hold best part of 400bhp.
Personally, I'd get it up and running as standard and see how you get on. I reckon a standard engine with 10psi or so of boost will be pretty entertaining. If you need more, I would look into more "traditional" tuning, rather than just taking the easy route and turning the boost up. I would also bear in mind that a reliable car with 200bhp (considering that it only weighs just over a ton, so that's still more or less E46 M3 fast) is much nicer to own that one with 300bhp that's continuously in pieces...unless you particularly enjoy fixing cars regularly, of course!
cheers
James