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Out of pure curiosity has anyone used the smaller -7 or -9 (GT-SS) on a RB28?

If so I would love to see any dyno sheet to see how the first half of the rev range looks.

I've been through the Dyno Thread and can't recall anyone ever using that combo.

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I noticed ages ago when the Garrett mobile app WAS working as latest update f**ked up my phone.

I'd switch scenarios like different Power limits and rpm's and I noticed the - 9's were occasionally recommended to me over everything else. when I asked for about 650bhp max (from memory) at the fly with a limit of 8500rpm as it seems there's a narrow window in the 9's compressor map that allows for higher pressures in the later rpm's that fit the 2.8 nicely.

anyone else spot this out

Edited by mr skidz

Looking at Petes direct comparo. (That was with -5's)

In theory -9's would drop off around 6.5-7k and probably churn 350/360kw on e85 @25psi....

Or am I way off?

and considering people with RB28 -5 combos are shifting early anyway so in most cases not utilising the last few RPM in most road use.

now imagine a - 9 set up in the 1500 to

4000 RPMs and would look fatter than -5s

in that lower rpm range.

throttle response would be sick on E85

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