Garrett Medium Frame Gtx Turbos

[scotty nm35]

My gut feeking is that Garrett have a bit too much compressor capacity in a "GTX3076R" and their partial fix is to use a GT35 turbine with the "76X" wheel to get GT3582R type performance .

Time will tell if the GTX3071R becomes the replacement for the GT3076R 56T .

Its more than a gut feeling, that is why the newer gtx3576 was released, I don't think the results from the gtx3076 were at all good and Garrett cant afford to release any more poorly performing turbos . I cant seem to find any decent graphs for the GTX3576 though. In theory it should get close to 400kw on e85 right?

I feel I have maxed the gtx3071 compressor, not sure if I want to go bigger yet or not. I was hoping to fine tune it up to 350kw but squeezing that last bit will be hard as i'm changing back to the .82 housing soon.

[afb312]

Have a look on http://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=TP&Product_Code=GRT-TBO-185&Category_Code= for a compressor map of the GTX3576r.

Or were you looking for a dyno plot? (which I do not have)

[R31Nismoid]

Its more than a gut feeling, that is why the newer gtx3576 was released, I don't think the results from the gtx3076 were at all good and Garrett cant afford to release any more poorly performing turbos . I cant seem to find any decent graphs for the GTX3576 though. In theory it should get close to 400kw on e85 right?

I feel I have maxed the gtx3071 compressor, not sure if I want to go bigger yet or not. I was hoping to fine tune it up to 350kw but squeezing that last bit will be hard as i'm changing back to the .82 housing soon.

A GTX3576 should easily hit 400rwkw on E85 you'd think? Given a run of the mill GT3076 on E85 will do 330rwkw or there abouts on it.

You'd need to be running some decent boost of course.

[wolverine]

I think the GTX 76mm compressor will run out of puff before 400rwkw given that the GTX 71mm seems to be all over at 330ish (DD dyno + E85).

[The Mafia]

Why would the GTX3076 be a bad option then? I'd love an easy 360-370rwkw on E85. Maybe even get a little crazier and put a 0.63 rear housing on and see how it goes.

350rwkw with the launching ability to out pace a cruise missile over the quarter mile?

[zebra]

^^ 360 can be done with a regular gt3076 with the .82 on a 25...providing the head is prepped

.63 rear will never do that

[The Mafia]

I made a bit over 320rwkw on a 0.63 rear on a RB25 completely stock. 22psi. About 750nm of torque. Water meth though.

I know the exhaust manifold pressures will be high, but I think the lower temps of the E85 should counteract this a little bit. Or I could be wrong.

I reckon I could have got close to 350rwkw with E85 on that setup.

[discopotato03]

Another gut feeling is that with the larger 1.06 AR Garrett GT30 turbine housing you could get a bit more squirt out of a GT3076R or GTX3076R . As has been said before other compressor upgraded GT3076R style turbos have used the larger T04S compressor housing and they would not do this without good reason .

Don't forget that these 0.70 AR comp housings were standard fare on turbos using the old 409535-1 (60-1) compressor wheels and they are ~ 76mm OD . Same deal with the er 7/14 bladed versions of the "GT3076R" turbos .

I think it depends on what you're trying to do , if its just maxing the turbo then the largest available housings are probably the best way to achieve that .

Most people have issues with turbo lag doing that and with good reason , out of most of you I think Mr Mafia is one of the few who quotes torque figures and torque is god as far as I'm concerned . I think he's right saying that E85 is a good way to decrease combustion temps and therefore EGTs and this would count for something when using not the hugest turbine housings .

It would be interesting to try a GTX3076R with a larger compressor housing in 0.63 and 0.82 sized Garrett GT30 turbine housings . If money was no object a decent exhaust manifold flanged to take the Evo 10 style Garrett 0.94 AR twin scroll twin integral wastegate GT30 turbine housing would be very interesting particularly burning E85 .

Mafia your R33 must have been a bit of a missile with the 0.63 and WMI combination , feel sorry for its rear tyres .

Sadly Garrett never made a T3 flanged 0.73 AR GT30 turbine housing , HKS did make that size but in T2/25 flange and no integral wastegate . People who used ext gate GT3037s liked 0.73 turbine housings and on SR20s the 52 comp trim ones were torque mountains - for an SR20 anyway .

Cheers A .

[STATUS]

Most people have issues with turbo lag doing that and with good reason , out of most of you I think Mr Mafia is one of the few who quotes torque figures and torque is god as far as I'm concerned .

tractive effort not torque.

[zebra]

Disco - why the affinity with internal gate turbos?

If a custom manifold is needed why not go external/twin external gate and reap the benefits

[The Mafia]

I had a not bad experience with my old setup.

RB25\30

Ported exhaust Ports

Ported exhaust manifold

GT3076 56trim, 0.6 Surge slotted Cover, 0.82 Int gate rear housing

256in/ex poncams

No water meth

Vipec

Vipec Boost control kit

Ignore the drop off at the end - The dyno straps were a little loose on the last 2 runs and the drop in load caused the boost to drop off a little meaning the torque follows suit too. Most runs it stayed flat all the way to the limiter.

Edited April 19, 2012 by The Mafia

[black bnr32]

a gtx35 result on a turbo bmw from the usa:

http://forums.bimmerforums.com/forum/showthread.php?t=1823611

[Lithium]

Most people have issues with turbo lag doing that and with good reason , out of most of you I think Mr Mafia is one of the few who quotes torque figures and torque is god as far as I'm concerned .

Plenty of us refer to power at particular points in the rpm range, which is probably more definitive than the tractive effort readings the dyno puts on a "torque" curve as you can't really compare those numbers between dynos or necessarily even the same dyno with different cars.

I think he's right saying that E85 is a good way to decrease combustion temps and therefore EGTs and this would count for something when using not the hugest turbine housings .

Absolutely he is - I take quite different considerations when matching a turbo for something running pump gas vs E85 etc, I picked a .82a/r hotside for my car partly because I was going to be using stock manifolds and pump gas on a motor with cast pistons etc. E85 is amazing stuff, I wish we had it at the pump here.

It would be interesting to try a GTX3076R with a larger compressor housing in 0.63 and 0.82 sized Garrett GT30 turbine housings

As I've mentioned before, ForcedPerformance imho have done a better job with the GT30 and GT35 "improvements" than Garrett - and they use a modified .70a/r T04S cover for their GT30 varients, there have been some very impressive results for their GT3076R-HTA running .82a/r hotside. If money was no object, I'd try one of their GT3073R-HTA turbos out on an RB25 - could be interesting.

[discopotato03]

Quote

Disco - why the affinity with internal gate turbos?

If a custom manifold is needed why not go external/twin external gate and reap the benefits

Because not everyone wants the trouble and expense of external wastegate/s . The only reason I suggested a one off manifold is because nothing short of an Evo 10 manifold fits the only Garrett twin scroll twin integral gate GT30 BB turbine housing made . If they did one in twin entry T3 flange it would be even easier , how many of you could resist a twin scroll twin IW turbine housing that fitted your std exhaust manifold ? More torque and better turbine response than your getting now with single scroll housings and how cheap and easy compared to two external gates and the extra plumbing they need .

On a trailer sailer it doesn't matter but on the street it does .

Tractive effort is that which is needed to harness high torque , the best you're gonna get there is AWD in anything street driven . A wise person once said to me that AWD was the best answer to turbo torque on the dirt and thats why all the decent rally rockets went to AWD . Not the go for all out tubbed drag cars but thats so far away from anything with number plates anyway .

I reckon without front wheel drive on the track a GTR would just be a larger Sierra .

In the locomotive world they measure tractive effort in thousands of pounds - in the US anyway . The other way is to look at a percentage of the beasts gross mass in its draw bar pulling capacity . So say 30% of a 132 tonne unit = lots .

Recent tests our mob did with AC traction units showed the horse derated itself from 4400 to 2750 Hp just to hold its feet . What this shows is the difference between power/torque and tractive effort , how you go about getting your power to the ground is a different issue .

A .

[zebra]

Ahg yeah I see your point re internal/external

That video lith posted up mentioned twin entry t3 for the gtx28s but not if they were internal gate or external

[AngryRB]

Its more than a gut feeling, that is why the newer gtx3576 was released, I don't think the results from the gtx3076 were at all good and Garrett cant afford to release any more poorly performing turbos . I cant seem to find any decent graphs for the GTX3576 though. In theory it should get close to 400kw on e85 right?

I feel I have maxed the gtx3071 compressor, not sure if I want to go bigger yet or not. I was hoping to fine tune it up to 350kw but squeezing that last bit will be hard as i'm changing back to the .82 housing soon.

Where is the evidence to prove a GTX3076 is a "poorly performing turbo" ?

Is there any strong evidence here or just guess work, if it has performed poorly is it because of the turbo or someones lack lustre setup? according to the flow maps it is just as good or even better than a GT3076. And for upto 350Kw surely it is a Very Good performing turbo.

[zebra]

the compressor side isnt the issue, I'm sure the compressor wheel is great like most garrett GT turbos

the turbine side is not so great

so combine a not so great hot side with a really good comp side...and they don't perform like they should

[AngryRB]

hmm, well my car is untuned and unfinished but i have the gtx3076 0.82, external gate , cams etc , should i be sourcing the normal compressor wheel and put it on so i have more of a compressor match to the turbine side? cause id like the best result possible with response.

or should i just see what happens with it?

Edited April 21, 2012 by SliverS2

[scotty nm35]

I have tried quite a few combinations of turbo out so far and what I have found is if you restrict the turbine the top end will be limited. According to the compressor map the GTX3076 should flow like a GT35 so why doesn't it? The rear is simply too small.

With the GTX3071 the extra compressor flow was compensated by upping the cropped turbine wheel to a full GT30 60mm version. It seems to have made it behave like the GT3076 but with better response. If this new GTX3576 can do the same, flow like a GT35 but with better response, it may be the turbo of choice for those chasing 350-400kw+.

[scotty nm35]

hmm, well my car is untuned and unfinished but i have the gtx3076 0.82, external gate , cams etc , should i be sourcing the normal compressor wheel and put it on so i have more of a compressor match to the turbine side? cause id like the best result possible with response.

or should i just see what happens with it?

Thats not to say your GTX3076 is crap, it just doesn't live up to its hype. These turbos were supposed to be on another level which the 71 seems to be but the 76 was just restricted a little too much. At the end of the day it will make good power but not what the compressor is capable of making. Go for it, tune the sucker, you wont be disappointed.