"lower" in this case is going to be a couple hundred rpms at most... not night and day, but probably detectable... the big thing about any of these setups on a street car is, a little lag actually helps you because of traction... if the boost comes in instantly and you go from 200hp to 800hp you have no chance of hooking up street tires... if you get the boost to fade in a bit more, like you will with a bigger turbo, then you'll have a better chance of not shocking the tires to death...

bottom line on all of this is, if you build the whole car right, the difference between twins and single is going to be a non-issue in the end... even my "lowly" supercharged Z spins ET Drags to 80mph on the street and runs mid 9s... the power potential of a turbo(s) is almost unlimited... just don't spend so much on the turbo(s) that you can't afford the best parts when it comes to EFI, fuel, tranny, rear end, suspension, etc.

 

I am pretty much set with everything else
except getting the engine finished up

 

Jeff I agree, however if you want to run some comparisons, use some of the publicly available ones, www.turbocalculator.com has quite a few maps on there, and that is what I used for comparison. They have quite a few Garrett turbo's and Turbonetics has theirs on their webpage. I can only use what is provided, and on a comparison base, it looked like an easy choice

Bill

 

You can always oversize the exhaust housings if low rpm spool is an issue. I bought mine with .68 A/R, and if I don't like it I can buy either .85 or .96 for a little over $150 each. Precision didn't recommend the latter two for a street car.

 

Like I said I am kind of illiterate when it comes to this but using DFI and a dyno cant I set up my own maps for street and at the track or is it good to have a base line to start with?