Hi Guys,
just thought I'd update my thread.
After getting 243rwkw with this turbo, I set out to achieve a little more because there were a heap of spots that were hitting around the 11.1:1 mark. After leaning them to 11.9:1 or 12:1 I noticed quite a bit of difference. The car pulled a lot harder. I reckon I would have scavenged another 7rwkw making it 250rwkw easily.
Also, after a good inspection of the dyno graph, I can put a ruler along the power curve and see that its almost straight. Something that impresses me.
The means that even though the turbo is taking a while to spool (about 3800rpm) it seems to be pushing a lot of air into the motor at low shaft RPM and keeping volume of flow nice and high anyway. (I've managed to get it to come on a little earlier - fixed with some increases in low end timing)
I guess the power curve being nearly straight proves this?
Anyway, after a few long chats with Rob Stafford, he's explained that the turbo isn't bad at all, but only limited in power due to the smaller turbine and trim. This causes it to max out at around 260rwkw - 270rwkw at about 24psi of boost. Rob also confirmed the fact that even though this turbo takes a little longer to spool due to needing a lot of shaft torque, its made up for because the 7 blade wheel grabs and pushes a lot more air than the 6 blade.
BUT Rob also said that the .63 exhaust housing will ONLY let the engine breathe to 400hp. Meaning 298kw - take 50kw for drivetrain - meaning about 250rwkw.
So if you are after more than 250rwkw, then you NEED to go a bigger exhaust housing. (.8x)
I will admit, I jumped the gun saying that the turbo wasn't that good - but it actually is pretty good. Its doing exactly what it was setup for - 250rwkw, it pulls very hard for 3,000rpm, and the power curve is dead straight. Which is usually exactly what you want right?
I'll post the dyno graph up to show this.
Hopefully It will prove that they aren't as bad as everyone thinks. I guess its a case of been there done that right?
I've learnt a hell of a lot in the past few weeks.