Gt3076 Query

[JonnoHR31]

I don't know what reasoning you have for that, but its not the best recommendation you've made imho - especially after having had both myself. The .82 only loses any noticeable amount of go below 3000rpm, where isn't a place RB25s are "about" anyway. Above there the .82a/r feels nicer, is nicer on the engine (Mafia needed WMI to suppress detonation, I and others have battled boost creep with .63s) and naturally is capable of more power.

I never looked back from upgrading from the .63 to the .82 - though again the OP has obviously also experienced a "real" 56T with .82a/r hotside and knows how nice a setup they are to drive.

+1, .82 minimum on the 3076, no point having a 550hp compressor and putting a 450hp max exhaust side on it

[The Mafia]

I don't agree. Setup properly on a RB25 you can use the 0.63 rear. I will admit that I was running WMI though.

This was a quick 1 hour tune at 18psi, then I put it in a dyno day.

Full boost at 3200rpm. All 18psi of it.

[Legionnaire]

Whoa, did you really run it that lean of AF meter was a bit off? I understand, meth injection and all.. but 12.3-12.5 AFR - it's a whole 0.5-1.5 point leaner than most setups I've seen.

How much boost/timing and what AFRs did you setup tolerate without WMI though?

[The Mafia]

I ran a constant 12.8:1 eventually with the WMI kit. Car laughed at it, and my fuel economy was pretty good under loads.

You don't need the extra fuel when you have WMI. The extra fuel is there to cool down the charge and supress the burn to slow things down. Why put that extra fuel in when the water and methanol is doing that job instead?

I was going to lean it to a further 13:1 eventually, but never got around to it.

[The Mafia]

oh, and B52 bombers ran a AFR of 15:1 on load with their water mix.

[JonnoHR31]

WMI changes everything as it masks the heat issues associated with a small exhaust side. yer you made it work, but its not a setup i'd ever reccomend, even with wmi

[Lithium]

Exactly, wmi has changed the game... You can't compare a setup running wmi with one running petrol for a start, and in this instance it's a bandaid. The result is a testament to wmi, not the .63

[Legionnaire]

Agreed, hence my question about boost, timing and AFR in .63 achievable without detonation.

[discopotato03]

Look , everyone has their own ideas about turbine lag and boost threshold but there are a few factors that come into play .

Firstly the compressor wheels and housings on these GT3037 family turbochargers .

There were originally three compress trim options (48T/52T/56T) and two comp housing styles . The 48T compressor trim version was discontinued and the 52 and 56T ones are still available . The one you see mostly is the 56T version which became the defacto std through Garrett . This is not to say it's necessarily the best but it is the largest compressor capacity version made with a GT37 series wheel . I think to get the best/most out of it also means using

the largest available 1.06 A/R GT30 turbine housing though no one seems to be brave enough to do that . Most have the idea that if they're going to use that 1.06 housing they want a GT3582R in it which is strange considering that 3582Rs use bored out GT30 turbine housings .

All that research I put into GT3076Rs a few years ago pointed to a 52 compressor trim version and yes mine has an 82 turbine housing on it as well but I think it would work better for me with the 63 turbine housing .

From memory HKS called the port shrouded version of the GT3037 "S" and had these comp housings available for the 52 and 56 comp trim versions . I'm just looking at my old HKS lists and it shows the std versions having 0.61/0.73/0.87 A/R turbine housings for the 48/52/56 comp trim units , in other words small/med/large housings on small/ medium/large comp trim units .

For the GT3037S versions they show 1.01 and 1.12 AR turbine housings on the 52 and 56 comp trim S versions .

Personally I think the 52T version is a better all rounder on a road car and to me what happens under 3000 revs is not insignificant . Its not so much that I'd want huge WOT pull under 3000 but I like road cars to have a bit of part throttle squirt as well as WOT stuff . I also don't like going up the rev range for no other reasaon than theres little or no boost when I'd like a bit of part throttle torque .

Again I stress in a road car because once you track them and bias performance towards track use its getting away from whats nice on public roads and particularly in built up areas . Std road cars have , generally , tallish gearing which works well with lowish boost thresholds that OE turbo systems generally have . When the boost threshold goes up significantly I find the engine struggles to make enough torque to pull the tall gearing well and it all feels wishy washy buzzing the revs in a lower gear just in case you want some easy grunt .

I'm old enough to realise that most won't get away with going too hard too often on the street so for me its pointless building high rev performance into a road car that can legally only be driven at 110 km/h max . To me some part throttle performance is essential if your going to get any shove in the back even accelerating to 80 km/h .

Any way if I were buying a GT3078R now it would be the 52T version (700382-10/cartridge 700177-6) and take you pick of the 0.82 or 0.63 A/R turbine housings . Provided it makes controllable torque and spins freely enough it should go like a cut snake . If its pulling like buggery at 170+ what use is that to you on the steet ? If it boosts and pulls from 2700 that's real usefull on the street because you spend a lot of time down in that area .

If your lucky E70 or E85 is available and would save you the trouble of water methanol injection so detonation shouldn't be a biggy .

Anyway people have to make their own call .

A .

[discopotato03]

I don't think it was so much a band aid as making a given engine pull lower down without detonating on less than high octane pump fuel . From memory Mr Mafia couldn't get 98 or the then available elswhere 100 octane Shell pump fuel so he went with the WMI to supress detonation on possibly 96 octane fuel .

A .

[Lithium]

Alot of speculating or trying to justify doesn't change reality, which is that once you have the same turbine, a similar compressor etc it's not going to be night and day. If you think a 56t gt30r is too laggy, you shouldn't be looking at gt30 based turbos on a 2.5.... There are laggier factory modern factory turbo cars. The difference below 3000rpm is far from night and day like you seem to think, its more like having an extra passenger up to 3000 that then jumps out and rewards you with lower egt, emp, and more kw potential once you hit those rpm.

Opinions aside, regardless of Mafias reasons for needing wmi ... Comparing something using it with a setup using straight pump gas is utter folly. Would love to see a.63 52t dyno plot, and even spool vid using pump gas. Until then you are just speculating.

[discopotato03]

Well Lithium the person to ask would be the one who walked the talk and how he felt his car performed based on his expectations and other cars . By the sounds of things he would have been in other cars quite possibly using these turbos with the 0.82 turbine housings and I think he even mentioned evaluating them at some stage .

When I say my GT3076R I mean the brand new one I bought a few years back thats still in its box .

I ended up buying a good second hand GTRS kit from Woolverine because my goals changed after I started owning AWD cars . It became very obvious that theres limited power you can get to the ground through two wheels and particularly when they are at the back end of a front heavy car . You have to buy something a bit better thought out than a 90s era Skyline to get 50/50 weight distribution and even then only half the weights sitting on its driving wheels .

That aside I'm sure with a reasonable intercooler and good tuning my GTS25T will spin its drivers even more so than it originally did but its part throttle performance should be a lot better than the ceramic turbo had , I hope so anyway . Now I don't have any roads I can legally do more than 80 on within 20-25 minutes of where I live and most of those don't take me anywhere I generally go . So for me I don't have the need for a 300 Kw turbo and particularly one thats a bit useless under 3000-3200 revs , and probably more so in 1st and 2nd gears . I'm not aiming very high and if I end up with 240-250 RWKW that will be plenty and still more than a grands worth of Michelin rubber can hold anyway .

I like good turbo response because its available 80% of your driving time rather than 30% but again that comes back to how and where you drive your car .

The thing I see too often Lithium is people here and elsewhere using more turbo than they should because they fell in love with a power number . They think they can have std turbo/engine performance ie no loss anywhere but extend the power range and numbers upwards . With a larger single scroll dryer thats very often not the case and while its fun booting it around it can be weak when just soft pedaling about .

I'm different and my ideas have changed over the years , I don't accept the compromises I would have 20 years ago . I'm conservative with turbochargers because at times they need to be a minimulist device rather that an unknown maximum one . My goal is a usefull torque band rather than extended rev ranges trying to reach or beat a power number .

I'll keep that GT3076R just in case the dirty 30 ever eventuates and it would probably work quite well with its 0.82 turbine housing .

Anyway this is only my opinion so take it as you will .

A .

[gk351]

Hey just a quick question.i also have a Garrett gt3037S(3076r) also with anti surge front with the id tag saying:GT3037s-56T and under that says T00382-12.and A/R.60 on front housing. Just wanted to no exactly what ive got. Is it a .82rear? And .60 front? Also would that make the 300kw mark(anything more would be a bonus) on a rb25det?(forged bottom end,ported head,custom plenum,nismo 740cc inj,head studs,38mm tial gate,hi mount manifold.etc etc..) just wanna no if that turbo is good enough for the power im looking for.... any advice would help thanx

Edited April 17, 2012 by gk351

[limpus]

With the right support mods and tuning...yes...

[JonnoHR31]

You have a 56T gt3076. The ID tag wont tell you what turbine housing you have as they come from garrett without a turbine housing, and they can swapped around anyway.

The only way to tell what AR housing you have is to read it off the housing itself.

Power will depend on the turbine housing but unless its a .63 IW or a non garrett housing it should be good for 300rwkw

[gk351]

i got it from gcg 2 years go. has A/R.60 on front housing also has garrett stamped on front rear housing and id tag...

[FordyR31]

I have just had an almost identical looking turbo fitted to my car. Same comp housing, stock 25 exhaust housing and it needed a 35mm spacer for the comp housing to clear the exhaust manifold. I am yet to have it tuned but has previously made 260rwkw on 16psi (RB25DET S2). My car isnt tuned yet so cant comment on response. I am pretty excited to get mine tuned needless to say.

[gotRICE?]

35mm????!! Jeezus are you sure? lol.

I dont think the compressor housing would fit between the shock tower with another 35mm hanging off it. Any pics?

[DVS JEZ]

I have just had an almost identical looking turbo fitted to my car. Same comp housing, stock 25 exhaust housing and it needed a 35mm spacer for the comp housing to clear the exhaust manifold. I am yet to have it tuned but has previously made 260rwkw on 16psi (RB25DET S2). My car isnt tuned yet so cant comment on response. I am pretty excited to get mine tuned needless to say.

What was ur old turbo that made 260kw? How was the response

[FordyR31]

Sorry. The GT3076 made 260 in a 33, my car is a HR31 with a S2 25 But thats the spacer it needed to clear the exhaust manifold. I have upgraded from an R34 turbo that made 207 rwkw at 10psi. I have a dyno printout for that one but the 3076 is yet to be tuned.