When we first got the GTX2867 on there it felt quite lethargic especially compared to the K03 when it came to spool. 20psi was reached around 3400 RPM on a catted downpipe and 3" exhaust with just an air filter and FMIC on the intake side.
This is not a bad spool at all for the GTX2867 but after working with VVT, managed to bring spool down around 400 RPM so now we get 20psi at around 3000 RPM in 4th without changing any hardware. And yes we are pretty much out of fuel throughout the power band. Timing is conservative and with higher octane we can see gains through timing but fuel is right on the edge with the stock system.
Here are two 4th gear pulls with the VVT changes
And here's the spool difference but this time on 3rd gear pulls. You can definitely feel the difference in response and it feels like a bigger motor spooling the turbo and you can see the torque gain down low as well.
Pssh, I did this black magic and spooled my stock turbo at 1000RPM. Get with the times. Beat that :wink:
Joking aside, do you have a probe to know how hot EGT was getting? I'm assuming you bumped overlap a bit to get the extra EGT, but how much EGT do we need for 400RPM sooner?
I know we all hate the headifold, but considering it's designed for the turbo on the car, it's actually superior in performance and cost for the stock setup than a separate manifold. Spool is dramatically improved, and the cooling significantly helps longevity.
I'll take one headifold design for the GTX2867 please
