RB30DET turbo choices

[Jaws]

.82 is too small small for a VL, yet for a 260z!

last 2 VLs i have put GT35/40s on with .82, ended up changing to a 1.06 with 1 month of road driving.

.82 are fun, but boost comes on too hard to quick. (again this comes down to the application of the car, .82 would be good for circuit work.)

I'm going with a gt3040 on the rb30det

The car weighs 1200kgs and I am unsure if I should go 1.06 or .82?

The engine wont be reving past 7000rpm and aiming for 500hp at the fly.

Using a turbo that generates extra power past 7000rpm for this motor would be useless.

[GTR-Ben]

So what exactly is my turbo??

AR .70 Intake

AR .82 Exhaust

The center core has Japan Allied Signal. 700177-17 CK0103J

[Steve]

sounds gt30 ish.

[Sydneykid]

if boost response is a priority use a GT30R with the larger 1.06 exhaust housing and a large external gate.

Hi DP33, it's great to have a turbo educated person on the forum, please hang around, lots. Can you please explain the above? I would have thought a .82 would have been more responsive. I have found engines with "excessively" large wastegates to be very poor controllers of boost ie; lots of fluctuations. Whereas engines with "correctly" sized wastegates have good boost control. My experience has been that "correctly" sized is a bit smaller than is usually recommended.

If I can ask one more question, what are your thoughts on the Turbonetics T66 compressor as far as "up to date technology" goes?

[GTR-Ben]

sounds gt30 ish.

Is there any way I can find out?

It being bolted to the RB30DET.. so I don't want it to be useless..

[RS500]

So what exactly is my turbo??

AR .70 Intake

AR .82 Exhaust

The center core has Japan Allied Signal. 700177-17 CK0103J

GTR-Ben,

this core number is not listed as a standard Garrett core.

It must a variant from HKS.

does the plate say anything else on it apart from the CHRA Part No.?

[GTR-Ben]

Nope thats it.

Doughboy has given me some info on the turbo. Should do what I want for now with my engine. Thanks for your help guys.

[drunkenmaster]

Revive the dead thread

I was pretty much sold on the idea of the gt3040 but the seller of the internally gated gt3540 has come back to me and now I am tempted again.

Is it really too big?

What would be the effect?

Bear in mind that it will be cheaper than the GT3040 which seems to be mid to high $2000's plus supplying your own rb25det exhaust housing?

[Guest INASNT]

3540 internally gated, u will never be able to control boost with a internal gate on that turbo.

[drunkenmaster]

3540 internally gated, u will never be able to control boost with a internal gate on that turbo.

Why is that?

at around 15psi I thought it still may be up to the task?

Maybe you think that this power level will only keep me happy for a short time before i get silly with the boost? I am sure this will not happen due to a few thoughts of mine:

My 3L engine is not built with stronger internals, don't want to break anything.

I never plan to run 20psi+ for power runs etc, numbers are not my interest.

i have fully seam welded the car, but short of a full cage, the paper thin chassis will have trouble with too much torque across it.

250 at the rears will be plenty.

To testify to the power delivery I want, i almost bought a VH45 before this motor was built.

Anyways, I appreciate the input and if you can clarify to me why you think this it would be great

Thanks

[Guest INASNT]

the internal gate is so small it cant bybass enough exhaust gas to control boost properly and creates 2 much back pressure in the exhaust system. Internal gated turbo are good for little T28's.

[drunkenmaster]

the internal gate is so small it cant bybass enough exhaust gas to control boost properly and creates 2 much back pressure in the exhaust system. Internal gated turbo are good for little T28's.

It doesnt look THAT small :aroused:

[Steve]

You answer your own question.

"250 at the rears will be plenty' at this sort of power a GT30 will be fine - a gt35 will be a bit of overkill, unecessary lag. The bigger the compressor, the later you should be making boost or else you will get surge.

If you want to go a GT35 internal gate, make sure you run a decent AR ratio on the turbine, otherwise the internal gate will have to do too much work. If you can imagine that wastegates are like taps - the more flow you need the bigger the tap should be (garden tap v's fire hydrant). If the turbine AR is too small, it will not be able to pass enough gas to hold lower boost pressures, resulting in boost spikes. Also, the larger the AR, the greater the lag - its always a compromise somewhere.

[drunkenmaster]

Thanks,

I understand, I guess I am just looking to take advantage of a bargain.

the big online suppliers all do an internal gated GT30 or GT3040, I think on an exchange basis with the stock turbo to use the exhaust housing. These are over $2k plus the exchange turbo which I dont have, but they seem like the way to go for this application.

[Guest INASNT]

It doesnt look THAT small  :aroused:

The wastegate is just the little flap on the right, so yes it is small

[Bl4cK32]

If u had the choice, (to anyone out there), Out of a GT35/40R (Part number 714568-0001) and the HKS 3037s (both with 0.8 housings) which would u choose?

Money is no problem, and all support sysytems are taken care of. I have the choice of both of these, but dont know which to choose....I am leaning towards the HKS 3037s though.

Going on an RB31DET (same as Joel's:))

[drunkenmaster]

The wastegate is just the little flap on the right, so yes it is small

I understand what it is, but i was referring to its size respective to the CD on the left. Considering popular external gates start at around 38mm, it doesnt look that far off.

[Skyrine-Dave]

If u had the choice, (to anyone out there), Out of a GT35/40R (Part number 714568-0001) and the HKS 3037s (both with 0.8 housings) which would u choose?

Money is no problem, and all support sysytems are taken care of. I have the choice of both of these, but dont know which to choose....I am leaning towards the HKS 3037s though.

Going on an RB31DET (same as Joel's:))

Garrett GT35R

but i am biased

[Guest INASNT]

I understand what it is, but i was referring to its size respective to the CD on the left. Considering popular external gates start at around 38mm, it doesnt look that far off.

Any performance shop u talk to will always tell u to go external gate with such a big turbo. Coz in the long run u r better off

[RS500]

to all,

fwiw, the BA XR6 turbo doesn't have any problems producing 250+ rwkw with an internally gated Garrett GT35.

if it's lower boost you're looking at running, i think it should do fine.

Bl4ck32,

what's your power target? this should help u make your decision.

the HKS 30307S (A/R .87) will help you make up to 330-340rwkw on anywhere up to 25psi, but the Garrett GT35R will allow u to make closer to 380rwkw with the same boost, although bare in mind, the garrett GT35R has larger wheels so the response would be worse when compared to the HKS GT3037S.

but then again, it all depends on how much power u want, and how u want it.