I'm currently building an engine to replace my stock internal twin turbo. This engine is to be used in a single seater off road race car. The racing style is very much based on stabbing the throttle and short, point to point, squirts. As such broad spread of torque and quick throttle response are essential. The GT2560r's I currently have are an incredible turbo, meet my every need on the stock internal engine. However with the new engine I'm attempting push the boundaries a little. With a lower cr, stronger rods and pistons I'm hoping to run around the 700hp mark. Using the squirrel performance site the GT2871r 48 trim looks to be close on perfect. However it'll mean changing my compressor housing plumbing to suit. I wondered if anyone had experience with any of the GT2871r's and where in the RPM range they made power. Or even if someone else had good experiences with another turbo that they think would be suitable.

 

edited:

I thought you were talking about the GT2860r's. sorry

 

Garrett rate them at 330 per turbo. Thats max flow potential. I think I'd be lucky to pull 620 flywheel hp with them (I'm probably 40hp shy of that now). They also drop off dramatically at the upper RPM end of the boost map, limiting my max rpm range.
I'm actually thinking of biting the bullet and going the GT2871R - 472560 - 15. Which will force me to use more RPM. With the Cosworth heads and high duration zk2 cams it should work... theoretically.
Then there is also the HKS GTRS...

 

Getting 700whp out of the GT2560's would be greatly pushing them. The GT2871R's .63 a/r are a much better bet and lag increase would be little. GT2871R's can be pushed to about 750whp so you'll still be pushing them but at least they would spool quick.

BTW- maybe this will help make it bolt on: http://www.atpturbo.com/mm5/merchant...egory_Code=GRT

 

i wanna see a dyno of a VQ making 700+ on a pair of 2871s.