Gt3071

[sIIgtst]

hi

i need some help

does anyone know about or has a gt3071 on an rb25det

how do they perform?

max boost level

respnse (rough rpm spool rate)

will they make about 260rwkw

ive been offered one and need to know if it will

suit my needs (response and around 260-270rwkw)

any info would be great.

cheers.

[bazr33]

gt3071 I have been reading posts of the install that Nabil did on his r33

237rwkw on like 13psi

Also im pretty sure r31nismoid, had similar turbo made aroun 270rwkw on 17psi

boost start spooling at 3000 full boost at 3950 ( quote from nabil)

im looking at the same turbo, with the .82 rear housing, which i should be buying in a couple of weeks

Only other thing im looking at after turbo install will be cams. But yeah cant wait.

I have been looking at a fair few turbos, and this one seems to be the go'er, sounds like an all rounder.

[sIIgtst]

cool

what A/r exhuast housing was on the turbo

to spool at 3950

as the one im looking at has a .71 so should come on boost

abit earlier

and yes i have to agree they do look like the go'er

[sIIgtst]

Does anyone have anymore suggestions

on these turbos. specifically the .71 exhuast varient

Cheers

[bazr33]

im looking at the one with the .82 rear housing

the one that did 270rwkw was a .82 rear im pretty sure.

[sIIgtst]

does anyone know if you can get a

dump/front pipe for the gt3071 to suit

the rb25

thanks

[R31Nismoid]

My turbo was a bit bigger than a 3071

There are a few results around, have a crack @ the search button as there is some info from discopotato03 thats invaluable.

[Kaido]

This has probably been said many times, but i'll still mention it. At that power level goal, you should just go with a GCG hi flow, and save money by keeping all the stock lines and piping. Plus I believe it would easily out-spool a GT3071. I hear the spool is almost like stock.

[bazr33]

but the option you have with a gt3071 is you can get close to 300rwkw without a gcg hiflow running close to its efficiency.

Cause like most of us you'll hit 270rwkw, sit on that for a while, then you'll want to go more.

But yeah gcg hiflow would be a good option if you were only goin to get close to 270rwkw and thats it.

[Lithium]

This has probably been said many times, but i'll still mention it. At that power level goal, you should just go with a GCG hi flow, and save money by keeping all the stock lines and piping. Plus I believe it would easily out-spool a GT3071. I hear the spool is almost like stock.

Well my turbo is a GT3076R, is laggier but not a crap load laggier than stock - and a GT3071R is advertised by Garrett/ATP as spooling MUCH better than the GT3076R. I reach 8psi by 3300rpm with the GT3076R, I'd say it stands to reason than a GT3071R should be at that point by 3000rpm quite happily.

[Cubes]

but the option you have with a gt3071 is you can get close to 300rwkw without a gcg hiflow running close to its efficiency.

Cause like most of us you'll hit 270rwkw, sit on that for a while, then you'll want to go more.

But yeah gcg hiflow would be a good option if you were only goin to get close to 270rwkw and thats it.

Depending on how happy the dyno is.

Aim for 250-260rwkw so you don't dissapoint yourself.

Well my turbo is a GT3076R, is laggier but not a crap load laggier than stock - and a GT3071R is advertised by Garrett/ATP as spooling MUCH better than the GT3076R. I reach 8psi by 3300rpm with the GT3076R, I'd say it stands to reason than a GT3071R should be at that point by 3000rpm quite happily.

Lithium, when do you start seeing/feeling boost?

[Lithium]

Depending on how happy the dyno is.

Aim for 250-260rwkw so you don't dissapoint yourself.

Lithium, when do you start seeing/feeling boost?

I've not driven in the last couple of weeks (under going further mods), but I'm pretty sure positive pressure is from ~2000rpm - if it weren't for the whistley turbo passengers reckon they'd not know they in a car with a bigger turbo... you definitely feel it building boost in the 2000-3000rpm range, maybe not so much in 1st - but it goes past too quick to notice.

[discopotato03]

Hi all , this GT3071R/GT3076R question is on the minds of a lot of RB25 owners so I can pass on what I know but have not been there - yet .

I'm hearing tuners overseas say they think the GT3076R (the real one) is nothing special but much of their opinion are is going to be based around what they were trying to achieve and how they went about it . As I've said in the past I think the 52 comp trim version is probably a better turbine/compressor match but thats my gut feeling only .

In the past reports about the GT3071R were a bit mixed and I think this is because its a bit of a wild cat or hybrid and likes things around it to be just so to suit it . Probably the hardest thing to get right is the exhaust manifold and turbine housing in order to get the compressor speed range to match the power requirements in the engines speed range . The gap in Garretts GT30 turbine housing A/R's is a little wide ie 0.63 and 0.82 A/R and something like HKS's .73 would lessen the compromises of the other two .

What in my opinion people need to consider is what else they can do to to their particular combination to get positive results . As Gary (SK) has said things that let you push more ignition timing help out big time . It allows the engine to have its cylinders fired and pressurised so that it can make more torque before and after the onset of positive inlet manifold pressure . When you can do this it tends to pull down boost threshold so you get more earlier in the scheme of things .

Having said that the same old gang rate a mention , tuning/intercooling/tuning/low restriction exhaust/tuning/cams tuning/headwork/tuning/effective exhaust manifold and wastegate/tuning tuning tuning . Really everytime anything is changed that affects how an engine breaths it needs the fuelling and timing checked .

ATM I am very lucky (sometimes) to have the ear of a fellow who used to work in Garretts aftermarket section OS and hopefully he can point out to me the real world differences between the above mentioned turbos . So far I get the feeling that the GT3071R will allow the engine to pull from slightly lower revs which is logical given its slightly smaller diametre (71.1mm vs 76.2mm) compressor , and I think the fact that its compressor cover is 0.50 A/R compared to the 3076R's 0.60 A/R .

On the nitty gritty side of things the 3071R's compressor is good for in theory ~ 44lbs airflow and the 3076R 52T ~ 49-50 lbs .

The extra airflow comes at a cost and its the turbine power required to drive it . If the compressor makes life easy for the turbine the turbine creates less restriction for the engine and so it will make better part throttle squirt as well as come on stronger earlier when nailed . This is where the person making the changes has to decide what they want and live with the compromises . If I had to go out on a limb I would say that if you are not prepared to change many things go conservatine on the turbo and make sure that its compressor is a good match for its turbine . Bigish turbos on otherwise standard engines are cops because there is generally insufficient exhaust flow to drive them and even when they spool up the inlet restrictions make for high boost to get the performance . They tend to ber laggy down low , ok in the upper middle , and choked up high .

I would like to add more about the twin scroll turbine housings but I'm out of time and fingers and probably mentioned most of it previously . Again comes back to how much time/effort/money you are prepaired to spend to get a good all round result .

Cheers A .

[Lithium]

So far I get the feeling that the GT3071R will allow the engine to pull from slightly lower revs which is logical given its slightly smaller diametre (71.1mm vs 76.2mm) compressor , and I think the fact that its compressor cover is 0.50 A/R compared to the 3076R's 0.60 A/R .

Definitely agreed...

Bigish turbos on otherwise standard engines are cops because there is generally insufficient exhaust flow to drive them and even when they spool up the inlet restrictions make for high boost to get the performance . They tend to ber laggy down low , ok in the upper middle , and choked up high .

OK - just curious, have you actually ever driven a RB25DET powered Skyline with a GT3076R or a GT3071R fitted?

[Cubes]

I've not driven in the last couple of weeks (under going further mods), but I'm pretty sure positive pressure is from ~2000rpm - if it weren't for the whistley turbo passengers reckon they'd not know they in a car with a bigger turbo... you definitely feel it building boost in the 2000-3000rpm range, maybe not so much in 1st - but it goes past too quick to notice.

Thanks buddy... I really think the GT3076r is going to be exactly what I want on the 3ltr.

I'll be sure to let you all know what I think of the combination wether you want to or not. lol

[sinistaGTR]

gt3040 ftw

[Cubes]

Well see.

[Dale FZ1]

Well I'll step out on a limb and say that while the GT3071 should (with the right selection of supporting external hardware and good tuning) be able to support somewhere in the vicinity of 250-255rwkW, the boost and engine response available from certain 76mm compressor combinations should have little appreciable difference in response as Lithium has alluded to.

The 7 blade T04S style impeller has been lambasted in many threads as being old-tech, but it does offer a large amount of air-moving capacity at lower turbine speeds. With the right turbine, that means it can respond ok, even if it won't have the high speed efficiency and power capacity of the 6 blade impeller.

It would be worth researching and finding what users of that actual combination have to say. There is one SAU member who has run both 6 and 7 blade compressors that I'm aware of.

I'm not saying to go one way or the other, merely to search before deciding.

[Cubes]

Dale.

Thats pretty much power wise what I have observed.

Response and low gear spool.. You can never really tell when a car is on the dyno as the ramp rate gives even a large turbo time to spool nicely. In a low gear on the street that massive turbo hardly makes any real grunt in first gear but on the dyno its not that far off a smaller turbo that pulls well.

GT3071 - 250ish (pulp)

GT3076 - 280-310ish (on pulp)

Then GT3040 doesn't appear to have much on the GT3076 unless your running some decent fuel, assuming due to the small turbine not being able to pass the required exh. resulting in back pressure where detonation sets in due to contamination of the inlet charge. - 280-360ish. (pulp, martini and c16)

If I crack 280rwkw on the GT3076R on the rb30det with the r32's gearing (All though I've dropped to a 4.08:1 with no noticable loss of off idle torque, the larger motor is strange the way it reacts to higher gears.) and weight I think it will be a damn quick off idle/overall package that will be difficult to touch.

[Dale FZ1]

Trying to keep the original thread on-track, I'd suggest that the 3071 is more of a compromised unit in terms of balanced power:response than either the 6 or 7 bladed 76mm compressor options available when mated with the GT30 turbine. I'd suggest that it just doesn't have the pumping capacity up top to make big (>250rwkW) streetable power, and the GT30 probably flows a bit too well to get it pumping early. Progressive and driveable - yes to a point; but I think the 71mm GT35 compressor is better served with a higher speed GT28 based turbine from a street car perspective. You may lose 10kw off the peak power number but gain appreciably better response down lower. If higher power is the target I'd say the GT3076 is the most logical choice.

To Cubes: I'd think the GT3076 will do all that you want, especially with the 3 litre engine capacity. I also reckon that using that gearing will do wonders for performance within streetable speed ranges.

In many ways the relative merits and characteristics of the 6 or 7 blade 76mm compressor is something to get your head around. One will offer more low down pumping capacity (7 blade), while the other will offer more high speed capacity and efficiency (6 blade). Neither is inherently "bad" or "better", but they are different.