Garrett Medium Frame Gtx Turbos

[JonnoHR31]

no its not 100% efficient, but it still spools quicker than having it completely open to both scrolls

[Trozzle]

DOes a twin scroll turbo work to 100% effiency if only one side of the divided housing has exhaust flow?

Doesn't sound right to me. Hey I could be wrong.

I'm honestly not sure you entirely understand how it works...

The valve only gives exhaust flow to one side until a desired manifold pressure, as set by the actuator that opens/closes the valve. Only while boost is LOW, the valve will force all exhaust down one side...then as boost rises (we'll say to 50% of "full boost") the valve opens, and allows exhaust gas to pass down BOTH sides of the twin scroll housing.

By forcing the exhaust down one side of the housing at low flow rates/boost, it's hitting the part of the turbine that will spin it up faster. That's the point of twin scroll, only this valve will force twice the flow down that one side (minus all the flow down the less "efficient" side for spool)

[GTScotT]

Quality of the thread just turned to shit..

I am sick of hearing about hill billy quick spool valves for christs sake, just leave it to the yanks already.

[Rolls]

I would rather that than a massive amount of turbulence pre turbo, and dubious longivity of the setup

Im dubious about the amount of turbulence and why it would last less than a normal setup.

Seems like a solid idea to me.

I don't see how a quick spool valve changes the A/R of the turbine housing. Its just a smaller entry into the same volume.

Do you know what A/R actually stands for?

DOes a twin scroll turbo work to 100% effiency if only one side of the divided housing has exhaust flow?

Doesn't sound right to me. Hey I could be wrong.

Not until it opens fully, but who cares we are trying to gain response with minimal top end loss.

Quality of the thread just turned to shit..

I am sick of hearing about hill billy quick spool valves for christs sake, just leave it to the yanks already.

and I am sick of shit posts, I want to hear about new tech that could result in faster spooling turbos for the same power, this sounds like something that could do exactly that.

Edited February 16, 2011 by Rolls

[Lithium]

Start a new thread for quick spool theories then, its well off the topic of this thread. When you start it show evidence of a twin scroll turbo with a twin scroll manifold being outperformed (to its potential) by a spool valve too. Every comparison I have seen involve with and without the spool valve with a single merge manifold (make ts redundant), or on a turbo pushed well short of its limit meaning that you don't see if the QSV is actually a restriction.

[ShiftyTys]

Start a new thread for quick spool theories then, its well off the topic of this thread. When you start it show evidence of a twin scroll turbo with a twin scroll manifold being outperformed (to its potential) by a spool valve too. Every comparison I have seen involve with and without the spool valve with a single merge manifold (make ts redundant), or on a turbo pushed well short of its limit meaning that you don't see if the QSV is actually a restriction.

Yes. New thread for that. Back to Gtx turbos. What are thoughts on gtx3071.73?

[R31Nismoid]

Start a new thread for quick spool theories then, its well off the topic of this thread.

+1

And infact, there already is one.

[Lithium]

Yes. New thread for that. Back to Gtx turbos. What are thoughts on gtx3071.73?

I am pretty sure I've mentioned at least once in this thread that I don't have full confidence in the GTX mid frame turbos at this stage. Initially I had doubts about the GTX3076R but thought the GTX3071R would be awesome, however seeing that the GTX's are laggier than the GT equivalents and there is bugger all different in lag between a GT3071R and a GT3076R it seems to me that a GTX3071R may have no advantage over a GT3076R but will definitely cost a heap more.

It seems a few other people agree with my doubts on this one. If I were in your position I'd sooner go the GT3076R with the same housing if thats REALLY the way you want to go. Its well proven, and is cheaper.

Where the GTX3071R should on paper come into its own is at really high boost levels, way beyond what you'll be running I expect.

[Legionnaire]

Yes. New thread for that. Back to Gtx turbos. What are thoughts on gtx3071.73?

First of all - what's ".73"? Is it a reference to HKS housing or something?

Second - thought are that we should wait for real-world results. As of now this turbo does not seem to justify the price difference between it and conventional 3071. On the other hand price difference is not that big, 1392 USD for GTX3071 + housing that you can buy everywhere vs. 1448 USD for GT3071 [data taken from ATPTurbo site].

Personally I think (at this stage I have no real world data, so I can only assume) GTX3071 is the best of all medium-frame GTX turbos currently available and is not worse than GT3076. E.g. compressor requires less revs to reach similar airflow to 76mm GT compressor , and in general seems to spend shaft power more efficiently. The biggest concern of course is that GT3076 and RB25 combo is tried and proven many times, as is GT3071, whereas GTX turbos have yet to prove themselves.

there is bugger all different in lag between a GT3071R and a GT3076R

Are you sure? I'm not questioning your experience with GT3076, but some results I've seen for 3071's so far, particularly with .63 housings, look awesome in that they have factory-like boost threshold with 1.5 or more times power and make more torque everywhere, which I think is the key to a nice and fun street setup The same definitely can not be said about GT3076.

Edited February 16, 2011 by Legionnaire

[zebra]

Imo, the .63 housing would hold back the new compressor to much, would be fine for a standardish street car. But It would be missing the full potential.

As for the above dyno, thats not much more power than what a GT-RS can give but without the GT-RS response, or its the same as what most people get with a GT2835/GT3071.

It isnt making 200rwks until 4750rpm. that might not mean much to some people but its rough guide I use to see how they would perform in the mid range.

But like I said if you dont have HKS 2835 money the GTX3071 would be a very nice option, pehaps not as good as the X series could have been but meh.

[Lithium]

Are you sure? I'm not questioning your experience with GT3076, but some results I've seen for 3071's so far, particularly with .63 housings, look awesome in that they have factory-like boost threshold with 1.5 or more times power and make more torque everywhere: http://forum.nistune...file.php?id=727, which I think is the key to a nice and fun street setup The same definitely can not be said about GT3076.

That link doesn't work so I can't comment, but you can't really compare a .63a/r GT3071R with a .82a/r GT3076R - especially in the context of a GTX3071R where the compressor will choke in the .63 housing (like the GT3076R).

I have never seen a GT3071R with a factory like boost threshold, I'd be very interested to see the dyno plot you are talking about. I can say mine is a nice and fun street setup, quite a lot of people have been in/driven it and I've never had a comment knocking it. It definitely gives something away to a stock setup at low rpm but that bit goes away so fast you hardly notice it.

I do know a GT3071R spools better than a GT3076R, if I knew someone with one its the kind of thing where it'd be interesting to put two cars side by side in 3rd gear at 3000rpm and give it the jandel and see what happens. My bet would be a trivial (like inches) until the GT3076R setup lets its throat clear. Where would that leave a GTX3071R which is a little lazier?

[Legionnaire]

Well, I'm sorry for the link above, I've just found out that after forum engine update I don't understand post edit feature for shit! Can't see simple tags, hence broken link. Corrected it now. It doesn't demonstrate boost curve, it is comparison of torque curve for factory turbo vs. 3071 that draws my attention. There is also a graph of the same setup after tomei poncam type B installation and tuning - I'm amaized at the torque increase.

I also apologize for not making it clear in the above post - I'm not trying to compare 0.82 GT3076 and 0.63 GT3071. I was just expressing a hope that with the same housing GTX3071 will be slightly more responsive than GT3076 without any power deficiency because of possibly better weight distribution and lower moment of inertia of the smaller compressor wheel. On the other hand it still has to move some 50+ lbs of air per minute, so its power requirement still has to be similar to that of the 76mm wheel and power for the compressor is still provided by the same turbine stage.

[Lithium]

Well, I'm sorry for the link above, I've just found out that after forum engine update I don't understand post edit feature for shit! Can't see simple tags, hence broken link. Corrected it now. It doesn't demonstrate boost curve, it is comparison of torque curve for factory turbo vs. 3071 that draws my attention. There is also a graph of the same setup after tomei poncam type B installation and tuning - I'm amaized at the torque increase.

I also apologize for not making it clear in the above post - I'm not trying to compare 0.82 GT3076 and 0.63 GT3071. I was just expressing a hope that with the same housing GTX3071 will be slightly more responsive than GT3076 without any power deficiency because of possibly better weight distribution and lower moment of inertia of the smaller compressor wheel. On the other hand it still has to move some 50+ lbs of air per minute, so its power requirement still has to be similar to that of the 76mm wheel and power for the compressor is still provided by the same turbine stage.

No need to apologise at all, I understand what you are saying (and its what I hoped until some disheartening results started to shot up) but I'm not sure the possilibity of better response is enough and on either sides case its just speculation until someone tries it.

FYI the GT3071R vs stock turbo comparison isn't very useful, there is something very wrong with the stock turbo dyno plot - its almost like the operator is lifting back on the throttle at a couple of points in the dyno run and feeding it back in or something.

[simpletool]

The GTX3071 might be interesting if it had a midway point A/R ratio between 0.63 and 0.82 considering we are talking about minor differences here. Or a twin-spool 0.82 T3

Also I would like to note that lag and the rev point where a turbo reaches full boost are not the same thing (although they are usually related). I consider lag as the time it takes to build boost after putting your foot down. This is really only relevant when already into the boost rev range, typically in the mid-range 4000 to 5000rpm (ie. on-off throttle, corner exit or short shift/gear change territory). I would think the GTX3071 would have an advantage here. We will only be able to tell once a few results are in. But if there is less inertia in the wheel then it should work out that way. Essentially "transient response".

Edited February 16, 2011 by simpletool

[Legionnaire]

No need to apologise at all, I understand what you are saying (and its what I hoped until some disheartening results started to shot up) but I'm not sure the possilibity of better response is enough and on either sides case its just speculation until someone tries it.

FYI the GT3071R vs stock turbo comparison isn't very useful, there is something very wrong with the stock turbo dyno plot - its almost like the operator is lifting back on the throttle at a couple of points in the dyno run and feeding it back in or something.

Yeah, that graph is unusually wavy in the spoolup and high torque zone, so it's quite possible that something went wrong. I have a theory, but that'd be completely off-topic here...

The results for med-frame GTX are currently disappointing, some of them predictably so, some are yet to be seen. Looks like so far we know that

- GTX3582 is shit, we're better off using either GT3582 or T04Z

- GTX3076 is utter shit, and TBH it was expected to be, as it conceptually recreates GT3082 which is not a particularly good turbo to begin with. IMO it should have been introduced as a GTX3276 instead - with a slightly larger, preferrably reworked 64mm turbine wheel in smallish 73 trim and some new large turbine housings...

- GTX3071 is yet to be confirmed if it's shit or good. But seeing results for the above two, expectations are rather pessimistic

The GTX3071 might be interesting if it had a midway point A/R ratio between 0.63 and 0.82 considering we are talking about minor differences here. Or a twin-spool 0.82 T3

Dunno what you mean by 'twinspool', if it's twinscroll then such housing does exist: http://www.atpturbo....tegory_Code=GTH

Edited February 17, 2011 by Legionnaire

[juggernaut1]

- GTX3582 is shit, we're better off using either GT3582 or T04Z

-

Do we know this?

[Lithium]

To be fair, someone has squeezed out around 900hp @ hubs with a GTX3582R on race gas....

[black bnr32]

^^^^

link?

[Legionnaire]

Do we know this?

As with anything new, real info is scarce. For the new GTX35, turbine is limiting it. In the same housing there is very little, if any, power gain, but cost difference is significant compared to GT35. It seems to love 1.06 A/R housing, but i think 1.06 A/R is not user friendly even for a 3 litre engine.

In smaller housings GTX35's power potential is similar to GTX30 with a one step larger A/R, e.g. 0.63 GTX35 is similar to 0.82 GTX30, but 35 spools slower. If for desired power level 1.06 is required, I'd prefer T04Z or GT37R because of its larger frame and more housing options. by the way, I'd really like GTX3582 to become GTX3782! The new 82mm compressor makes a good match for GT37 turbine imo.

That result is indeed impressive. Even more impressive is the fact that the engine has 13:1 CR and takes 30 psi of boost.

[juggernaut1]

As with anything new, real info is scarce. For the new GTX35, turbine is limiting it. In the same housing there is very little, if any, power gain, but cost difference is significant compared to GT35. It seems to love 1.06 A/R housing, but i think 1.06 A/R is not user friendly even for a 3 litre engine.

In smaller housings GTX35's power potential is similar to GTX30 with a one step larger A/R, e.g. 0.63 GTX35 is similar to 0.82 GTX30, but 35 spools slower. If for desired power level 1.06 is required, I'd prefer T04Z or GT37R because of its larger frame and more housing options. by the way, I'd really like GTX3582 to become GTX3782! The new 82mm compressor makes a good match for GT37 turbine imo.

That result is indeed impressive. Even more impressive is the fact that the engine has 13:1 CR and takes 30 psi of boost.

I agree, the GT35 turbine can seem to accept more compressor and as you say especially in the 1.06 A/R format.

Me thinks the GTX35 might work (albeit not necessarily for a stocish RB). My rationale is as follows. GCG do a TO4Z comp build onto an internally gated GT35 CHRA/turbine to bolt onto for the XR6 turbo. See here

http://www.gcg.com.a...mart&Itemid=101

On a Ford 4 litre (yes I know it has a few more cubes than an RB25, but the RB can rev a little harder too) the above GCG hybrid turns out around 379rwks (just over 500rwhp) bolted onto the stock Ford 6 log manifold with cooler, injectors, exhaust and tune - see here http://www.fordxr6tu...et/page__st__90.

Not bad for a bolt on internally gated hybridised turbo on an OEM log manifold.

The upshot of my ramble and these comparisons is that the GTX35 in the larger ex housing size could work on the right motor.

Edited February 17, 2011 by juggernaut1