Originally Posted by shiv@vishnu

Hi guys-- Here's my take on the ATP 3071, fwiw. It does indeed spool up just like the 3037 (also .63)/custom tubular manifold set up I had on our One Lap car. However, it does this with a *stock cat* and not the test pipe that I run. All things equal, I suspect it to have 700-8000rpm spool up advantage to the GT3037 which is really quite good. Also, on our dyno, boost lag tends to be exaggerated due to the way the engine loads up. Well, not really exaggerated... but it comes close to representing the boost lag you feel on the street when you load it up in 3rd gear. If tested with a much slower ramp-up rate (simulating the first 5 or so seconds of a Dynojet pull where the big rollers are slowly getting up to speed), boost response with drop by another 400-600rpm which is where I suspect ATP is getting their sloop up claims. As such, their claim is perfectly valid and the difference in spool up that we are seeing is based mostly on differences in testing methods. Nothing to create a controversy about, IMHO To give you an idea of how different loads and different gears can effect spool up, look at this: In 4th gear, lugging from a low RPM, the big GT35 on my car can reach 20psi by 4500rpm. In 3rd, it takes until just under 5000rpm. In 2nd, it takes until past 5500rpm. So spool up numbers, by themselves, don't explain the whole picture-- especially when dealing with bigger turbos.

And as others pointed out, we'd really love to get a car with cams, gears, test-pipe (or at least a high flow cat), full race gas to test this kit on. But so far, with this car, the results are quite good. We have established that putting a bigger turbo on an EVO without upgrading cams leaves a lot on the table as exhibited by the power roll-off above 6000rpm. Still, the car made plenty of power given the few mods

my 2c,
Shiv

Originally Posted by Az3ar

en1ma19 thanks man. however. I dont know if it will fit the helix exhaust??? since its huge. Helix has one with out engine check light so I think i will get one from them except if yours fits my exhaust and check engine does not come on. i will post dyno tomorrow as I dont have scanner at home. I just relized that I made about 390 whp on dynojet with 97 gas that means I gained about 390-238=152 whp