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I got a GT3540 with a 1.06 rear on my car, and ive got a GT3040 with .82 rear.

I was wondering if i was able to use the 1.06 rear and put it on the GT3040 ? what would this achieve compared to the .82 that came with the 3040 ?

I am looking to downgrade the power, the 3040 will go a little tooo low, probly about 280rwkw with the 1.06 this would go up to about 300ish ? or not work at all?

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I got a GT3540 with a 1.06 rear on my car, and ive got a GT3040 with .82 rear.

I was wondering if i was able to use the 1.06 rear and put it on the GT3040 ? what would this achieve compared to the .82 that came with the 3040 ?

I am looking to downgrade the power, the 3040 will go a little tooo low, probly about 280rwkw with the 1.06 this would go up to about 300ish ? or not work at all?

i reckon you will make more than 280rwkw with the GT3040. you should exceed 300rwkw with the 0.82

no, the turbine housing from the GT35 won't fit.

Edited by wolverine
Sadly no , the GT35's turbine diameter is ~ 68mm where the GT30 is around 60mm .

I always wanted to know how a GT3076R with a 1.06 AR turbine housing on an RB30 DOHC would go but I can't talk Cubes into it ...

A .

what happens if i try it? will it be very laggy and not work ?

what happens if i try it? will it be very laggy and not work ?

Basically. Their will be a gap between the turbine wheel and the exhaust housing. If would sping super slowly and with out much force if at all.

Why don't you just change to a .82a/r GT3582R housing? They are a fair bit less laggy than a 1.06 and the 1.06a/r GT30 housing on a GT3082R has about the same amount of exhaust flow as a .82a/r GT35R but you have less matched wheels. ie, you'll probably have a nicer drive on a .82a/r GT35R than a 1.06a/r GT3082R.

In the old days of T04B's, to hi-flow them, the turbines were machined back. This ranged from trimming the tips to machining the whole wheel back.

In a modern turbo, the clearance between the wheel and the housing act as a seal to help spin the turbo up early in the rev range.

I would think that the 3040 with a turbine that is that big would be a slug. but once it come onto boost, it would have awesome topend power.. I would think that it would actually make boost. but it would come on rather slow at first.. and be kinda spongy.

my 2c anyways

Maybe it's just me, but I've only ever heard of a turbine wheel being "clipped" on the top or crown i.e. the surface that faces you when you look into the turbo's pooper, not around the edges. In effect, you make the turbine wheel "shorter".

Those petrol spec GT UHP turbines (GT30 and GT35BB) have quite thin section blades particularly towards their outer extremities to help keep inertia down .

This is a lot of the reason why they are easily damaged if anything goes through them .

I don't know how you'd go trying to alter the profile of the blades , if you did it would probably have to be some kind of grinding operation and its probably more trouble than its worth .

Older T series turbines were a lot more rigid in their blades so can possibly be attacked with a tool and cutter grinder .

I always felt that you can get stuck between a rock and a hard place with those GT3040R's/GT3082R's (same thing) . They are really a GT30 hot side with an 82mm GT40 hot side and arguably the match is a bit squiff . They can be cheaper and more plentiful than either a GT3076R or a GT3582R and I could never work out why .

I do know that HKS had a Garrett make a slightly different version of the GT3040R/GT3082R , their spec had the 82mm GT40 compressor in 50 rather than 56 trim so no doubt they had issues using the larger trim compressor .

I guess all you can do with those two is to use smaller ratio turbine housings and if they surge modify the comp housings to have a ported shroud .

Another option would be to swap someone with a GT3076R that wants your larger turbo .

Cheers A .

I want to play with what i have got, and i got a 3040 and a 3540

OK sweet as, was unsure as to how much effort you wanted to put into it - as you can't mix and match the parts between the two turbos your only other option is to just use the .82a/r GT3082R for reasons others have already outlined. It won't exactly be gutless, and will make a reasonable amount of power.

For what its worth EVERYONE I know who have had GT3082R have not stayed with them for long and moved on to a GT3582R and have been happier with them, the main thing I think which leans towards a better daily drive is at least its not a 1.06a/r housing like your GT35R.

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