discopotato03

Hi all , I've been reading about Garrett GT30 turbine based turbos and Mr Buschurs testing shows that the FP3076HTA is pretty impressive particularly with the boost wound up . He did mention that he disliked the std Garrett GT3076R and I'm curious to know what it did or did not do .
There is also another compressor alternative using FPs 73HTA on the GT30R cartridge but its not one you hear much about . I'm not sure if these use the T04E or T04S compressor housing and I'd like to see any test results if they are available .
No one I know was ever happy with Garretts old GT3071R and I was wondering if the 73HTA compressor was a better alternative with a slightly lower boost threshold than a 3076HTA .

Thanks in advance cheers Adrian .

03whitegsr

iTrader: (8)

I would expect very similar results between the GTX3071R and the HTA3073R. I think either is probably the best GT30 based option, but I sent a PM describing why.

94AWDcoupe

iTrader: (125)

the gt30 is a small diameter fussy turbine wheel. it really wakes up with the lighter hta wheels attatched to it.

hydra

I ended up having FP make me an HTA73 in a T04S housing. I don't know why the gt3071 gets such a bad rep on here, the nissan sr and rb25 peeps seem to love them. As for GTX vs HTA, everything I have seen so far seems to indicate that the latter comes out on top, especially where spool is concerned...

JohnBradley

iTrader: (30)

3071 chokes out too fast on most of our setups. To put it in perspective we have done the following-

These cars used S2 equiv or larger

std 3076 on 10:1 2.0L / E85 pulled WG line, 34psi max - 562
HTA3076 in DSM housing on 9:1 2.0L / E85 29psi out of fuel - 557
std 3076 on a 9:1 2.4L / E85 29psi falling to 22 - 572

This car used S1s

HTA 3076 on stock Evo 2.0L / 92 octane / 26psi - 453 road race tune

Having recently done some GTX3076 stuff on larger motors it seems that it can make good power per psi. Unfortunately it was on a 2.2L SR20 which I dont really have a good feel for comparing to an equivalent 4G63. It did make 463whp@20psi with a ported head and the BC272 (12.55mm lift) on MS109 so it was starting to look cool. It had a Tial housing on it, I believe the 0.63 or 0.64, not 100% sure.

I would like to see the car with a twin scroll HTA3076 for eventual usage but even a HTA3076 dropped into that housing would tell me alot. Based on our testing with the GTX42 vs the HTA42 the GTX stuff doesnt even begin to match the HTA until high pressure ratios (4:1) and then dives off significantly again.

Aaron

03whitegsr

iTrader: (8)

Anybody measure the HTA73 compressor wheel?

The GTX71 is an extended tip wheel that measures roughly 73mm on the exducer tips; it is hard to get an exact measurement on 11 blades. The largest diameter of the hub area is 71mm though making it a "71mm wheel." I think the HTA wheels are also extended tip so I'm curious if the 73mm is the hub diameter or the exducer tip diameter.

I would expect the GTX3071R to make similar or better power numbers as the standard GT3076R as it has more compressor flow capacity. The spool has been reported to be within 100 RPM on the GTX3071R compared to the GT3071R by the MS3 guys (another group that likes the GT3071R).

Like mentioned, the GT30 stuff all needs lots of boost to do anything impressive though.

94AWDcoupe

iTrader: (125)

hta73 has same inducer as gtx3071. right at 53mm. hta has 14 blades vs 11 blades for gtx. they likely perform nearly identical. slight win for shift recovery for gtx, slight spool advantage for hta.

discopotato03

Yes its interesting that many people think that GT30 turbines are not the most responsive things down low but work well at high boost pressures . As I've said in the past I think the trim size (84) is big on GT30 and GT35 turbines and its a shame Garrett never did them in a smaller trim like they do with the ball bearing GT37 and GT40 turbines which are 78 trim . I think the BB GT30 and 35 turbines are actually called UHP series meaning ultra high pressure ratio .
I've wondered at times if its possible to fit a GT30 turbine in a tool and cutter grinder and reduce the trim for test purposes . Not something I can do .

That aside the feeling here in Oz was that the trim size of the 30 turbine prevented it driving the 71mm GT compressor fast enough early enough to make boost much sooner than a GT3076R . People here tried them with 0.63 and 0.82 Garrett GT30 turbine housings and they wanted to surge on the smaller and felt laggy on the larger housing . Maybe an in between size would have helped .

I think some of the agro is caused by (sometimes) lack of suitable turbine housings with ARs and mounting flange size . Unfortunately Garrett didn't make GT28 turbine housings in T3 flange and slightly larger AR ones should have stretched that 76T GT28 turbine a bit further .
HKS did a few 0.73 AR GT30 turbine housings but they were in T2 flange which limits their usefullness .
Also its a pity that the twin scroll turbine housings Garrett did for the 4B11T were not also done for 4G63Ts .

Lastly to compressor housings , AFAIK the GT3071R/76R all have T04E housings and I think the GTX versions have a new version of the port shrouded E housing . FP likes to use T04S housings I think on HTA73/76 but not sure on HTA71s .

Always with turbochargers the turbine and housing are the most difficult to get right , these are something Garrett hasn't done anything with for many years and really needs to IMO . Offering GT30 and 35 turbines in 78T would be easy for them and possibly a 0.73 turbine housing in T3 flange as well .
Nowdays its easy to dial in compressor wheels since they are carved from billets and making a few to play with is not the casting deal it used to be .

Also Hydra , what results did you get with your GT3073HTA ?

Cheers A .

03whitegsr

iTrader: (8)

I think the GT wheels were specifically designed to use a high trim in an effort to reduce inertia. Take a given minor diameter (roughly proportional to flow capacity) and cut down the major diameter to reduce inertia. Design the blades to work with it and you end up with good efficiency, low inertia, and lots of flow.

Again though, there are lots of communities that like the GT3071R and report it to drive a lot better then the dyno says it will in comparision to the GT3076R. The communities that like to judge a turbo by twisting the boost knob to 11 are typically the ones that don't like the GT3071R simply because on a dyno chart, the GT3076R just kills it on power.

94AWDcoupe, thanks for the inducer sizes. Any chance you have exducer tip and hub diameters for the HTA73? I feel the saem though, it would probably be hard to tell them apart on a dyno.

High_PSI

iTrader: (50)

I don't see a point of a 30r now with bb reds and blacks. The power of a black is superior and the red makes as much power with way faster spool. Outdated for the Evo IMHO

94AWDcoupe

iTrader: (125)

the hta73 has a 76mm exducer. larger diameter gets air moving quicker for given shaft speed. has no effect on max flow. inducer diameter and hub size pretty much determine flow.

03whitegsr

iTrader: (8)

Scott at FP would disagree with you there. There is a post or two here where he goes into the exducer being the limiting factor. Mostly based on airflow speed at the tip being in the 1.2+ MACH range.

discopotato03

One thing I notice in US boards is the practise of calling compressors by inducer diameter where most turbocharger manufacturers classify a wheel by its exducer or major diameter . The way I see it you can have a range of wheels within a family that have the same major diameter and trim sizes alter the inducer diameter - and usually exducer tip height .

With Garretts turbos/turbines its interesting that their competition versions or TR30R series are very different wheel wise on both sides . The crucial detail I reckon is in those TR30 turbines - basically 60mm versions of the GT28 NS111 76 trim turbine though TR30 are usually 73 or 76 trim . These have fewer more open blades than GT30 UHP turbines and there must be something in this .
From memory there is a 76mm 56 trim compressor wheel version of the TR30R and I think they are 5/5 bladed .
I can only assume Garrett won't give us the TR30R 76T turbine because its either too expensive material wise or will not survive long term burst testing .

As I said before they did come back to 78T on BB versions of the GT37 and GT40 turbines , bush bearing diesel turbo versions are the same agricultural 84 trim size so there must be something in the BB reduced turbine trims .

A .

94AWDcoupe

iTrader: (125)

about 10 years ago turbonetics increased the exducer of their compressor wheels. they were otherwise same dimensions. no compressor cover machining. the new wheels were prefixed "super" ie 60 trim and super 60 trim. they were 5mm taller than the standard wheels.

they supplied compressor maps for both. the max flow was same. but map was taller with super wheels. they were able to run higher pressure ratios. and they were advertised as being able to spool sooner even though the wheels were taller.

maybe scott was pointing out they flow more at higher pressure ratios. which would be true.

03whitegsr

iTrader: (8)

I think the TR30 turbine wheel either has a blade profile that might either be too complicated to cast effectively or might not be strong enough in the normal inconel material. The GT28 turbine wheel has pretty similar features as the TR30, but it might be the smaller size enables the design to have enough strength to survive in inconel.

94AWDCoupe, I understood him correctly.
https://www.evolutionm.net/forums/5843171-post242.html
Not saying he is without a doubt right, but it's another perspective. I haven't done the math to really figure out how pressure feeds into it though, as the speed of sound in a gas is related to temperature and not pressure. This means compressor efficiency, inlet temperature, and boost pressure all feed into what makes the compressor outlet temperature and there by have an impact on limiting the flow.

His basic premisis though, blade tip speed is the limit and your flow will be determined by blade height and likely blade exit angle. The flow is not generally limited by inducer size. It seems like when I did a few calcs, that inlet airflow is typically in the 0.3 MACH range for many turbochargers when reaching the choke flow limit. This is well below the point where the inlet would be the limiting variable.