Shainiac

iTrader: (7)

I have a Garrett GT4088R with a 0.95 A/R housing. It's a bit laggy for my taste and I have the option to buy a 0.85 A/R exhaust housing for relatively cheap. I'm not looking to make huge power and the .85 GT40R housing already flows more than the 1.05 GT35R housing.
The only thing preventing me from doing this is if I am required to fab a new downpipe, not worth the hastle.

Does the A/R of the housing effect the centerline of the turbine relative to the manifold flange? What about the distance from the CHRA to the v-band?
Garretts drawing HERE only shows one dimension and no mention of a specific A/R.

Thanks

arghx

iTrader: (3)

Before you go down the road of smaller A/R, did you read this thread? https://www.rx7club.com/single-turbo...2-hpc-1087999/

There's a discussion about changing A/E and how it affects spool. Basically, if you want the engine to spool better between gear changes at high rpm, only making the A/R change may not be the route you want to go.

Shainiac

iTrader: (7)

I'm fairly satisfied with the transient response of the turbo after the RPMs are above the boost threshold. I am trying to lower the threshold to something more streetable.
This turbo makes 11psi by 3500 in 5th, 4000 in 4th, 4400 in 3rd,~5000 in 2nd, and 6000 in 1st.
I'm trying to lower that threshold.
What I'd like to know is if changing the housing will require modification to the downpipe.

IRPerformance

iTrader: (41)

There should be enough adjustment in the exhaust to compensate.