Hey All,

I really like the concept of Greddy turbo being small and fast spooling. BUT it comes with a few headaches from cracking manifold to vtec dip to boost creep.

Anyone has experience doing a smaller turbo like the Gtx2867 or Gtx2871? The new gtx2976r is slightly bigger than these guys.

Will the turbo spool as early or close to the small greddy turbo?

Will it handle the full 9k rpm of the s2k?

Planning on doing a turbo kit with 1 of these trusted turbo guys. Instead of the famous gt3076r gt3076r, I want to out the gtx2976r

Thanks for all the input!

 

why not a t3 gtx3071r?

 

One of the turbo kit manufacturers told me the spooling characteristics of both 3076 and 3071 are pretty much the same. No noticeable changes.

 

Autox'd a car a few years back that had a GT28 and made 344whp on E85. It was pretty much insta spool.

 

The GTX2976R is a horrible mismatch of compressor to turbine. The 3076 is bad too. You're better off either doing 3071 or 3576. The 3576 spools pretty much the same as the 3076 but makes 50whp more. The 3071 will spool much faster than the 2976 and probably make within 25whp.

 

When you say mis-matched, what exactly does this do to the driving experience versus a matched compressor to turbine?
Or is this just online chinese whispers?

 

Mis-match is a more simple way to say a wheel combination that results in a really poor blade speed ratio on the turbine side. Poor blade speed ratio results in poor turbine efficiency. This results in slower spool-up/transient response/higher backpressure.

Have a read:
Turbo Tech: Compressor and Turbine Map Details

 

For a given respective compressor: A smaller turbine wheel (usually) results in a lower boost threshold because the smaller turbine is more efficient at the lower gas-flow rates (at lower RPMs), and has a smaller moment of inertia; At higher gas-flow rates (at higher RPMs) this results in more turbo-lag - A really rubbery feeling on/off throttle response.

If you primarily want good boost at lower RPMs and simply want to maintain it while on high throttle openings (drag racing), then it could be a fair compromise.