Hi guys i have a Garrett GT 3540 RR running on a LQ9 engine.
What are the advantage of changing the compressor front wheel to a larger one from 61mm to 66mm for example. Are there any power increase using same boost(12psi) boost.
Or run same power but on less boost?

 

I can't answer that specific question directly, but I'd think your money might be better spend getting a larger turbo that better suited for the 6.0L displacement than the GT35. As I understand the compressor maps for that turbo, by the time you hit upper rpms, the turbo is way out of its efficiency range. I'm sure it spools up nice and has great low end torque though.

 

Front mount single?

 

yes its a front mount single

 

So to make sure we're talking apples to apples, to me, a GT 3540 would have a 61mm compressor inducer but the 40 frankly confuses me. That would be a 40mm compressor exducer by the new garrett nomenclature which just wouldn't make sense (I mean the only Garrett turbos I can find with 4x on the compressor exducer are tiny little things -- GT1241, etc. with 29mm compressor inducer diameter).

If it's really something like a GT 3582 RR, it will support up to 600 hp, but is recommended for 4.5L or below. Stepping up the compressor wheel probably will be a decent help (A step up from a 67mm wheel to a 70mm wheel is the only difference between an STS GT67 and STS GT70 and the 70 makes more power more efficiently), BUT if the turbine is small it won't help at all.

Can you list the states of the turbo? Like the compressor inducer / exducer diameters (or trim), turbine inducer /exducer (or trim) and A/R?

 

Yes your right its a Gt3582,but here in Australia they call it 3540 wich is rated at 700hp,but the spec are the same.
compresor wheel Turbine
ind-61.4mm wheel diameter-68.0
exd-82.0mm trim-84
trim-56 A/R-1.06
a/r.70

This is the info i can get i hpoe it helps.
I was thinking of going from a 61.4mm to 66mm or larger what do you think?

 

I'd like to see pictures of your vehicle if you have any. I wish we had the UTE over here.

 

I still think that's pretty small for a single (mostly because of the small turbine wheel) -- that's actually a turbo I looked at for my twin kit. You might be better off stepping up both the compressor and the turbine (and maybe changing the turbine shell as well).

If you are happy with the turbo and just want a little more power, the compressor wheel will likely get you some, but don't expect a whole lot -- most of the limitation in that turbo on a v8 is going to be the turbine, IMO.

 

I didnt necessary want to run more power,just would like to run same power wich is 500rw hp but instead of running 11.5 from 2200-4500 and then drops down to 10 psi,i would like to give it less boost for the same power.
I have dropped the original comp 10.1:1 (dished LQ4 piston,LQ9 heads)to 9.4:1 ,but dont have forged internals couldnt afford it.Am i safe on this boost and power with these internals?

 

I see. There might be an easier way though -- can you give us some info on the rest of the setup? Intercooled? Meth?