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http://www.turbo-kits.com

quote me $1429 + postage for a GTX3071R with a 0.78A/R split pulse turbine housing. Send them an email to get a quote.

this is the one to watch.... IMHO the only turbo for an unopened RB25 that might be as good as (or possibly better) than the HKS 2835

Okay... Now I'm confused... Got me a r34 gtt and don't really want to forge my engine so I want a 280-300kw 'safe tune', doesn't sound safe but surprisingly it does well amongst most... and obviously 350kw for the odd car which I cannot rape. Now would the gtx3076 be the go for that? A 3582 would give me a safe tune on 300 or less however I'd assume much more lag... but future aspirations of good old fashion power rape... Or do I go for a 3071 but what optimistic power figure would I get on a rb25? Only thing pushing me away is the less lag of the 3071 but the 3076 will have more power which my engine may die from and the 3582 can run safely with much lag and possible engine detonation when we get trigger happy on our little boost controllers :-(

Lots Of Love,

Purple skyline with a ridiculous white front-mount.

Isn't the GT3082 basically a GT35?

If so then how does the GTX3076 come on later and make ever so slightly less power? Just doesn't make sense.

or is it the transient response which the dyno does not show where it has the improvement over it?

Okay... Now I'm confused... Got me a r34 gtt and don't really want to forge my engine so I want a 280-300kw 'safe tune', doesn't sound safe but surprisingly it does well amongst most... and obviously 350kw for the odd car which I cannot rape. Now would the gtx3076 be the go for that? A 3582 would give me a safe tune on 300 or less however I'd assume much more lag... but future aspirations of good old fashion power rape... Or do I go for a 3071 but what optimistic power figure would I get on a rb25? Only thing pushing me away is the less lag of the 3071 but the 3076 will have more power which my engine may die from and the 3582 can run safely with much lag and possible engine detonation when we get trigger happy on our little boost controllers :-(

Lots Of Love,

Purple skyline with a ridiculous white front-mount.

A 3582 will not necessarily give you a 'safer' 300rwkw than a smaller and capable turbo would. Both a 3071 and a 3076 are capable of 280-300rwkw given the rest of the setup.

Power is power, theres a certain level of power any given motor can produce before it starts to pull itself appart. Above the 280 mark is going to start impacting the longetivity of the RB25 as mentioned.

Simply look at what turbo is capable of what power level in the RB25 dyno thread and decide from there. The garretts are known to make the numbers without too much stress on the motor (charge temps etc). High flows are still under scrutiny in this respect. An easy and good feeling 280rwkw is generally acheived from a 3076R .82IW.

Its simple.

If you can afford the rebuild, chase over 280rwkw.

If you can't, then don't.

The man speaks the truth!

Isn't the GT3082 basically a GT35?

If so then how does the GTX3076 come on later and make ever so slightly less power? Just doesn't make sense.

or is it the transient response which the dyno does not show where it has the improvement over it?

Nah, still a gt30 turbine. You would assume transient response would be better with the smaller wheel but it should be reflected to a degree in the dyno as it should spin up faster initially and the effect compounds.

The theme i am seeing here is that the gtx wheel has a comp map that is comparable to the next size up gt wheel, the gtx turbos response is comparable to a turbo with the next size up gt comp wheel and same turbine.

Have garrett wasted a heap of development money making a small wheel that ultimately performs the same as an old gt wheel or are we just not seeing the right results?

From left field and a theory about this result, a gt3082 is too much compressor for a gt30 turbine, you'd probably see a better result for both response and power from a gt3582. Does this then carry through that ideally the gtx76mm compressor should be matched with a gt35 turbine and in that scenario we'd see better results?

Okay... Now I'm confused... Got me a r34 gtt and don't really want to forge my engine so I want a 280-300kw 'safe tune', doesn't sound safe but surprisingly it does well amongst most... and obviously 350kw for the odd car which I cannot rape. Now would the gtx3076 be the go for that? A 3582 would give me a safe tune on 300 or less however I'd assume much more lag... but future aspirations of good old fashion power rape... Or do I go for a 3071 but what optimistic power figure would I get on a rb25? Only thing pushing me away is the less lag of the 3071 but the 3076 will have more power which my engine may die from and the 3582 can run safely with much lag and possible engine detonation when we get trigger happy on our little boost controllers :-(

you aren't going to chase 350rwkw+ until you have spent another 5k so i would say go for a GTX3071 .78 IW as it will be the most lag free and fun way to get to ~280rwkw and then IF you decide to rebuild, sell the turbo then and by a 35XX

A 3582 will not necessarily give you a 'safer' 300rwkw than a smaller and capable turbo would.

+1 i think he is going off the whole less psi is good train of thought...

remember psi = pounds per square inch so that for example, 15 psi from a 35XX will actually be cramming around the same amount of air into the motor as say 19 from a 30XX

Without driving the car it is hard to judge the transient response of the GTX turbo. The GTX3071 is still the one I want to see more results on a RB25.

i would say go for a GTX3071 .78 IW

Slight correction there is a 0.63, 0.82 and 1.06 IW (in the Garret range) the 0.78 is a ext twin scroll housing.

Nah, still a gt30 turbine. You would assume transient response would be better with the smaller wheel but it should be reflected to a degree in the dyno as it should spin up faster initially and the effect compounds.

The theme i am seeing here is that the gtx wheel has a comp map that is comparable to the next size up gt wheel, the gtx turbos response is comparable to a turbo with the next size up gt comp wheel and same turbine.

Have garrett wasted a heap of development money making a small wheel that ultimately performs the same as an old gt wheel or are we just not seeing the right results?

From left field and a theory about this result, a gt3082 is too much compressor for a gt30 turbine, you'd probably see a better result for both response and power from a gt3582. Does this then carry through that ideally the gtx76mm compressor should be matched with a gt35 turbine and in that scenario we'd see better results?

I believe yes. I'd like to see a GTX3576R

OK I am even more disappointed with the GTX3076R than I thought I would be. I had said before anyone tried results than I suspected it was going to be more or less like an expensive GT3082R, but it actually looks laggier than I expected it would be.

To be honest I am starting to doubt that the GTX3071R will be as awesome as I thought it would be. Now it looks like its probably going to end up with (baring in mind there is pretty much no noticeable spool difference between a GT3071R and a GT3076R) a GT3076R which makes slightly more power with slightly more lag. Hardly worth it.

My prediction - when more Borg Warner EFR results come in, the GTX turbos are going to be made to look stupid.

I believe yes. I'd like to see a GTX3576R

Not convinced here. The GTX 76mm compressor appears laggier than the GT 82mm compressor, which has imho a better overall pumping efficiency. Its basically got nothing on it, going from results I've seen so far. The GTX 76mm so far seems like an expensive waste of space to me.

Why bother with a GTX3576R when there is a perfectly capable GT3582R which appears like it'll have no more lag, at least worth mentioning?

My prediction - when more Borg Warner EFR results come in, the GTX turbos are going to be made to look stupid.

Agreed. The one independent result that's out there already looks promising.

  • Like 1

Agreed. The one independent result that's out there already looks promising.

Yeah. Garrett GTX looks like it does next to nothing over the old turbo. Borg W EFR seems to be offering better spool. Still waiting to see more results but that lighter turbine wheel seems to be good.

Results:

SR20DET fitted with a GTX3076 .82 tuned with BP98 Fuel - 408hp @ 1.5bar

Well the GTX3076r looks to be identical to the GT3082r ! (both turbos were using the same rear housing)

Below is the Power and torque readings @ 1.5bar

The boost actually starts off at 1.4bar and creeps to 1.5bar toward redline

Thick line is Hi boost setting, Thin line Lo boost setting

nYPDkl.jpg

Interesting..

A comparison for you:

GTX (above) VS GT 3076 52 trim twin scroll .78 (below) on SR20 on same dyno at around same boost.

4000rpm 100hp (GTX) vs 240hp twin scroll GT

6350rpm 390hp (GTX) vs 388hp twin scroll GT

Peak 408hp (GTX) vs 388 hp twin scroll GT

Twin scroll...virtually more torque everywhere and hgher peak

3076Dyno.jpg

Edited by juggernaut1

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