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Dave have a look at the diagram below, sourced from http://www.turbobygarrett.com/turbobygarre...bo_tech102.html

post-19642-1197586232_thumb.jpg

You can see that the A/R is a mathematical representation of the physical layout of the snail. It's the relationship between the size of the air passage within the volute, and how open the scroll is.

Usually unless you are comparing two housings from the same family, it's not a legitimate comparison because the A/R is a ratio only, not a measure of absolute size. The Garrett info suggests that for a compressor, A/R size does not significantly affect compressor performance, though a larger A/R housing may be specified to optimise a low boost application, while a smaller A/R may be used to optimise higher boost applications. Note that the rider is for housings from the same family.

I'll take a stab and suggest that you will see some subtle differences in characteristics between your setup and (for example) Lithium's with his 0.60 A/R. The 0.70 housing is physically larger, and I'd say will take a little more turbine effort (and time) to give you full boost. The freer flowing housing should remain efficient at the higher end of your RPM scale, and may give a few more hp (not many though) because the air isn't being forced through so tight a radius within the scroll.

So in summary, take away a couple hp + response down lower, pick up a few higher up. Not a massive difference, but back to back you'd probably pick it without resorting to dyno sheets.

My opinion only.

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Hi Cubes , I don't think you'll see a GT3076R/GT3037 with a 0.70 A/R compressor cover and its hard to imagine one needing it .

Just to keep things on track the 76.2mm GT 37 series compressors used in the above mentioned turbos have T04"E" series comp covers , the 7/14 blade T04S and GT40 compressors (ie GT3582R) use T04"S" series comp covers .

There is such a thing as a 0.70 A/R T04E comp cover but its an ugly thing with the same sized inlet/outlet as a 0.70 A/R T04S comp cover . If you dig through T04E compressor wheel specs there are 76/76.2 and 82mm OD versions and I think the 82mm ones used the larger 0.70 A/R covers at times .

Cheers A

Hi guys

on the compressor a/r, can the housing be too small? I have a 3076 (5012) fitted with machined out std r33 housing .5 ish i pressume, and had a machined out .6 std exhaust housing, which i have since change to a avo .73, which did fix the compressor surge issue but hasn't given up much more top end.

Does feel like it has more torque, with 500 rpm more lag, have been told should see 270 rwkw but only gets 240 might get 250 with a push. Anyway the hot pipe gets bloody hot could this be related to big wheel little housing?

Adrian

Hi Cubes , I don't think you'll see a GT3076R/GT3037 with a 0.70 A/R compressor cover and its hard to imagine one needing it .

GCG/XTR sell "GT3076Rs" with a .70a/r compressor cover and ATPTurbo sell a GT3076R-WG (actually, do they still sell these? I can't be bothered checking) runs a T25 rear end with trimmed GT30 wheel and a .70a/r comp cover. Both I believe are TO4S...

  • 11 months later...

oh emm gee bump old thread much :down:

Im after defintive CHRA and turbine housing part #s for a:

GT3076 internal gate with a .82 60mm turbine wheel

ive just been looking through the GCG and garrett websites,

no info on the garrett site about the I/G housings and the GCG only lists ones for a 54.xmm rear wheel (i assume its the remanufatured OP6 housings modded for the GT30 series cropped wheels.

also none of the part #s mentioned in the above posts match anything on the Garrett or GCG websites regarding CHRA numbers and turbine housing numbers.

Cheers

Andrew

http://www.turbobygarrett.com/turbobygarre...R_700382_12.htm

And most if not all the numbers for the real 3076 talked about in the thread are still there.

Just drag out the numbers you want and build the turbo your after. Simple really...................lol

From what I was told the Garrett IW T3 flanged GT30 turbine housings were developed here in Aus and I'm not so sure there is any complete GT30xxR unit sold through Garrett with one .

You can option them provided your turbo supplier has them .

If you read the Garrett blurb page on GT3076R's it tells you that the cartridge and compressor housing is sold as is and you option turbine housings for them - well someone in the supply chain does anyway .

Find a turbo supplier than can get the GT3076R turbo pn 700382-12 and tell them you'll only accept the genuine Garrett T3 flanged GT30 integral wastegate turbine housing in 0.82 A/R ratio .

Others here have done it through mobs like (I think) Slide or GCG .

If you don't trust your own judgement post the ID Tag no's on anything that looks interesting and I'm sure someone here will tell you if it's what your asking for or not .

If anyone has pics of the above mentioned turbo post away , actually I'm reasonably sure that combination is what Cubes is using .

Cheers A .

Disco..

Mine was imported from the US. Box was sealed from Slide. Took quite a while to get over here.

Bill at Adelaide Turbo Services has sourced me a .82 IW housing relatively quickly (a few weeks) for Lithium. Just the housing I remember was up around 800ish from memory. Lithium may remember as I shoved the receipt in the box.

I've got a few pics of mine in the My Garage under Modifications.

Have some new pics of the larger actuator that is near impossible to lift off its seat. :P No more boost drop. :D

They can be had its just a matter of having to wait to get it. :S

I just ordered myself a GT3076R EW and I have the following supporting mods already installed on my RB25DET:

3" Full exhaust

FMIC

PFC

Sard 550cc injectors

Sard FPR

Bosche 023 fuel pump

Turbosmart boost controller

Turbosmart Plumb back bov

Cometic 1.3mm by 87mm head gasket

Splitfires

Will I need cams or anything else to support 280rwkw or more?

Also, I will be looking into get custom dump and intake piping, i already got the top mount manifold, where is a good place to get this done? and what sort of cost am i looking at with the custom piping?

Cheers.

Fair enough Cubes , I imagine that would have been the cheapest way to get them at the time .

8 hunnet for a turbine housing , that's getting painful .

I've got too many other things going on at the moment to worry about turbos for myself - Skyline anyway .

I will be keeping an eye on the twin scroll twin integral gate Evo 10 variant of the GT3076R , I doubt its model specific footprint could be easily adapted to a twin outlet T3 manifold but you never know . A TS 0.94 A/R housing would be creamy on a well set up RB25DET .

A .

nah mate, I made 314rwkw on 18psi, with standard cams.

I wouldn't waste your money on them unless you are aiming to make over 350rwkw with a GT35r.

With water/meth injection.

Its simply not possible on regular PULP.

Apologies for slightly OT - Ignoring the initial set up costs say $1K, and the fact that you have to carry a bottle of Methanol with you on holidays, what are the down sides of having a water meth injection system?

Say for instance, if you left your car for a fortnight, would the bores rust? Leakage into the sump?

Anyone know? It seems a cheap way of getting more power without having to look for an E85 bowser in downtown Tennant Creek/Bourke etc

There was a bloke at the dyno day yesterday (boostworx dyno).

He is running a GT30 core 56.8mm turbine wheel with a .7 avo IW housing and machined rb25 comp cover.

He can probably state the specs a little better as he is on these forums but from my understanding he pretty much max'd out around 17-18psi and 244rwkw on PULP.

Dropped E85 in a street tune with a wide band and reeled off just over 300rwkw and a little over 20psi.

Damn impressive considering the small rb25 comp cover IMO. :)

As a guide the boostworx DD dyno reads on par with mainline dyno's the week or so before at another dyno day cars were running pretty much smack on the same power figures +-1-2rwkw.

E85 FTW. :)

thats good to know people are getting some good results with the 56.8mm rear wheel and the bolt on exhaust housing, means ill be able to save some cash and get the bolt on jobbie, only chasing around 270-280rwkw on pulp at around 18-20psi, and if i doesnt quite deliver ill just play with cams till i get what i want.

thanks for the info guys :)

Andrew

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