Quote:
Originally Posted by derass
Why do you say this? If it were the 7163 with the mixed flow turbine I'd agree.
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The turbine wheel on the GTX and GT series is a 20+ year old design. The redesigned (read: billet for the GTX) compressor wheel is the only update. However, a turbo's power capability is depicted by the turbine wheel. So in essence, same boost onset, transient response, etc, but with improved compressor efficiency. So what that equates to is, the GTX wheels produce more power than the comparable GT at the same boost. However, due to the archaic turbine wheel design, the true issue has not been addressed. As the saying goes, you can put lipstick on a pig, but it's still a pig..............
The 7163, 6758 and 6258 share the same turbine wheel design and back housing size and mounting plate (the name escapes me) dimensions. The only difference is the mixed flow wheel has extended tips o the 7163, so the inertia and spool between all three is very similar. In addition, the Gamma-Ti alloy wheel is LIGHT years better than the Garrett in terms of weight and efficiency. Yes, it's a little more brittle in theory, but all current Indy Cars are powered by EFR turbos, and I am sure they go through much greater shock loadings and heat cycle (not only in magnitude, but occurrence) than anything we could image on Zilvia (and all during a proper qualifying session, not even considering the race).
I have also ran 2 step launch control on mine and have destroyed 3 cats and the turbine wheel is still holding up.
The Garrett is just simply OLD technology, all said and done.