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Garrett Medium Frame Gtx Turbos


SimonR32

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If I was eyeing off a GT3076 before I would be looking at the GTX3071 now.

I would be crossing my fingers that lag is identical to the old GT3071 but will flow like a GT3076.

I would also be crossing my fingers that the throttle response is kickarse with the lower mass compressor wheel.

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If I was eyeing off a GT3076 before I would be looking at the GTX3071 now.

I would be crossing my fingers that lag is identical to the old GT3071 but will flow like a GT3076.

I would also be crossing my fingers that the throttle response is kickarse with the lower mass compressor wheel.

My thought on GTX3071 outcome is like this:

Response somewhere between old 3071 and old 3076

Peak power similar to old 3076

Actual RIP like an amplified 2835

= monster.

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Hopefully the response of a GTX3071 is closer to the old 3071 than the old 3076 otherwise its just an old 3076 lol

There was only a handful of people around that ever went with the GT3071, and no real evidence of ANY response superiority over the GT3076 despite its inability to flow as much air as big brother.

I see it as a hard one to call whether there's going to be this great real-world improvement or not - but at least it gives the punter more options to trial. Look at the flow comparisons between GTX3071 and GT3076 - compressor can do much the same thing but higher speeds required for the 71. Both would in honesty require the 0.82 turbine housing, so hot side flow capacity/efficiency is identical.

Sure is going to be interesting to see a few fitted up and running to see what eventuates.

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There was only a handful of people around that ever went with the GT3071, and no real evidence of ANY response superiority over the GT3076 despite its inability to flow as much air as big brother.

I see it as a hard one to call whether there's going to be this great real-world improvement or not - but at least it gives the punter more options to trial. Look at the flow comparisons between GTX3071 and GT3076 - compressor can do much the same thing but higher speeds required for the 71. Both would in honesty require the 0.82 turbine housing, so hot side flow capacity/efficiency is identical.

Sure is going to be interesting to see a few fitted up and running to see what eventuates.

I cant comment on the response difference but I know at least 1 3071 that made a nice 290rwkw. I think a lot of the poor 3071 results you see are the ones with the cropped exhaust housings to bolt up to standard dump pipe.

Has anyone had a back to back comparison of the response difference between a 3071 and a 3076?

I know the HKS GT2835 Pro S has more response and it has a 3071 wheel but it is running a 0.68 rear.

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I cant comment on the response difference but I know at least 1 3071 that made a nice 290rwkw. I think a lot of the poor 3071 results you see are the ones with the cropped exhaust housings to bolt up to standard dump pipe.

Has anyone had a back to back comparison of the response difference between a 3071 and a 3076?

I know the HKS GT2835 Pro S has more response and it has a 3071 wheel but it is running a 0.68 rear.

Not a direct back to back but i went from 3071 to 3076 52 trim on my SR with larger dump/exhaust and made identical peak (~ 290rwkw) but the 3076 52 trim actually had reasonably more mid range than the 3071 - possibly due in part to the larger dump.

HOWEVER, shortly after the new setup was installed I noticed that my Hypertune intake had a crack in it (for the 2nd time). It is possible the car was tuned with the crack when the 3076 went on as there were no tell tail signs anything was up as the crack was underneath so was not obvious and did not have a high idle speed. I only found out one day when I happend to put my hand underneath the intake and my fingers were being sucked onto the intake at idle. Funnily enough it would still fry the tyres in 1 and 2nd from around 3500rpm even with the crack and leaking boost.

In finalising I want to say Peter at Hypertune has come to the party and is supplying me with a brand new plenum to refit at no cost.

Edited by juggernaut1
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Not the 1st time I have heard of their plenums cracking/splitting they are very thin.

Have garrett done anything with the turbine wheels? I know the housings are the same...but Im not convinced that the 3076 turbine will flow enough to make the most of the new comp wheel?

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Hopefully the response of a GTX3071 is closer to the old 3071 than the old 3076 otherwise its just an old 3076 lol

Lag or response. I was choosing my words very carefully.

I swapped out a GT-RS from the Stagea to a HKS2835ProS.

The response of the GT-RS was superior. The 2835ProS clearly makes more power throughout the full range and is ahead of the GT-RS from quite early on. I am hoping with some more attention to the fuel/ign maps on the ramp to boost we can close the gap a little. The low mass and small diameter of the GT-RS turbine was lightening fast to react to on/off throttle situations.

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What exhaust housing and dump pipe combo would be best for a responsive RB25 setup? I'd prefer something that bolts onto factory front pipe if possible, but not required :/

Huh? Not quite sure what your asking here. Garrett turbos can be supplied with a kit that includes a dump pipe that will bolt onto the standard front pipe. Although you really should change the front pipe to a 3" to match, which will also fit.

The 0.82 is the best overall exhaust housing to choose from the Garrett range as has been previously said.

Although you said responsive, the 2871R (HKS GTRS equivalent) would be the best turbo for response on an RB25.

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Lag or response. I was choosing my words very carefully.

I swapped out a GT-RS from the Stagea to a HKS2835ProS.

The response of the GT-RS was superior. The 2835ProS clearly makes more power throughout the full range and is ahead of the GT-RS from quite early on. I am hoping with some more attention to the fuel/ign maps on the ramp to boost we can close the gap a little. The low mass and small diameter of the GT-RS turbine was lightening fast to react to on/off throttle situations.

Interesting point yeah thats something that I have only just got into my head.

So yeah is the response of the 3071 much different to the 3076? It is a smaller wheel isnt it?

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I recall HKS released a document that showed 2835 response to be on par with that of the GTRS, after all they both share a 71mm compressor.

I have honestly always suspected the 71mm compressor to yield a more desirable result for the 2.5L motor. The reason for this is flow characteristic, its small enough to ramp fast and large enough to flow a decent number.

I am confident I am going to end up deciding on a GTX3071, I just need to get my JZ in the 33 already.

I think the key to these turbos is exhaust housing, when I do mine I am going to pay the extra for the HKS 3037 rear housing. I carry no flame for any of the garrett housings, there are too many dubious results to warrant risking the outcome/longetivity of my build due to a poorly designed housing. While most of the .82 garretts seem fine, the design is too different from the HKS item for me to think is good.

If anyone gets one of these turbos I seriously recommend buying the HKS housing to suit from GCG or elsewhere.

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It is hard to pick between the gtx3071 and gtx3076 at this stage as we dont have any results to see the difference in response between them. I know if the response difference was minimal as it is with the gt3071 and gt3076 then Id be picking the gtx3076 to have some extra head room if wanting more power later on.

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I find it funny how everyone is debating 3071 vs 3076 when it is quite obvious the 3076 will make more power with minimal lag difference..

I think the main thing to be concerned with here is how much can the stock motor handle..

It seems to me that the gt3071 was the turbo of choice if you wanted the motor to hold up, 3076 if you weren't to concerned with longetivity, as it would make more power but engine could only take so much of it..

Now with these new profiles its a whole different ball game...I mean 300kw plus for a gtx3071, how long is a stock engine going to handle that for, my guess is not very long..Dependant on usage of course..

both of the new profiles are going to make more Hp..but you have to consider what your motor will handle...I dont think stock engine is going to handle either for long if driven hard which opens the Q...what end result do you want?

Cause i reckon once you get up around or over that 300kw milestone...driveline becomes the issue..not much point having the power if you cant get it to the ground right??

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I wonder why Garrett persist with both the 3071 and 3076 if there is not much difference in response?? Why not ditch the 3071

I reckon 3071 would have to be better with sudden change..IE.. twisty roads etc on off throttles.

Whereas 3076 more for the floor it and go crowd..

If that makes any sense..

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