J Chen

70 to 80 % at most & don't forget rev
limit at 6800 rpm.

Edman951

mrfixit951,
I have a 84trim wheel in a .63A/R turbine.
Whitch is about the same as a #8 kkk turbine except that the housing is bigger.

I don't think i would go smaller.
It spools up good and it drives nice on the street.
I get 15psi by 3500 rpm and 18psi at 3800rpm.
And i'm runing 10.5:1 during the boost buld up.
I am trying to lean out the fuel curve from 2500rpm to 3500rpm.
This way it will spool even fast.

I actually lean it out a bit last night and the car just spun the tires like crazy. Since i lean it out i did not check the boost vs rpm. But sure feel much better.

It's like Dark Lightning,
I actually made a few extra hp with the GT30R at the same psi but with a worst A/F ratio.

The GT30R (GT3037) i got seem perfectlly sutted for a 951.
I'm sure the GT3071R would be even better at lower rpm.

J Chen

Oooh Edman,
I've not even finished tuning my GT25R
& you're already tempting me. Let's
see what my results would be like.

Edman951

OPPS,
We both need to finish tuning our cars and get some dyno #'s.

Andrew Wojteczko

Edman951, the GT3071R is not listed in the Garrett catalogue, is that still a full Garrett? Order from any Garrett dealer?, do you have the map for the 3037 as well, and is it a full Garrett?

Thanks,

Andrew Wojteczko

Corleone

3037 is a HKS/Garret and listed in their catalouge.
Here is the HKS list

J Chen

I don't think they are the same Corleone.
The 3037S comes with a TO4S housing
like mine. Even if the wheel trims are the
same, the use of different turbine &
compressor housing will have a different
flow characteristics. ATP says it spool
sooner by 1000 rpm. Edman is making
15 psi at 3500 rpm. So does that mean
that this turbo will do 15psi at 2500rpm ?
I really doubt so. Maybe 3000-3300 is
acceptable. The problem we all are
facing is that we don't get the actual
maps of the turbos that the vendors
mixes & match. So, the safe bet is
to get a turbo which is a standard
issue. Than at least the map will be
quite accurate.

hally

Sounds like Tim at SFR has performed a quantum leap in bolt on performance for the 951. Great work Tim! Hopefully u sell enough to bring production costs down in the future.

mrfixit951

Edman,

The GT32 and GT3071 both have 71mm Comp wheels with a 0.5A/R housing and very close trims: GT32 is 52 and the GT3071 is 56 trim. It is interesting what a shrouded compressor inlet does to the flow map. It moves the surge line to the left, which clears up the point where I was poking out.

It is interesting to note that the spool up curve you just reported fits to the right of the surge line on a GT32. But with tuning, it will fall back to the left hand side again.

I will look into the your T3 housing with 0.63 A/R and 84 trim. A smaller compressor should let me open up the exhaust side slightly.

I sure would like to see the dyno plots of your torque curve. I am after a nice wide flat curve, like the Vitesse's setups, not the K27/6 type curves.

Ben

J Chen

mrfixit,
You've got to compare apples with apples.
The major might be the same size, what
about the minor, blade design, height of
the compressor wheel, contour of the
blades etc. All these will affect the
performance of the turbo. Look at
Edmans turbo, if you check the specs
from ATP's site, it's the same wheel trim
as the 3071 but the diameter is 6mm larger.
why ? Are they using the same compressor
wheel or is it from another series ?
BTW, what kind of hp are you looking for ?

Dark Lightning

Note that compressor trim numbers are measures of proportions and can only be compared to other trims of the same model line.

T3 50 trim vs T3 60 trim, 60 is larger.

GT30 56-1 trim vs GT30 60-1 trim, 60-1 is larger.

But can't compare T4 52 trim vs T3 60 trim directly since the T3 60 trim isn't necessarily a larger turbo. However, a look at the respective compressor maps will tell the tale.

J Chen

That's what I've been saying all along.
People are always confused by AR &
Trim figures.

J Chen

Hey Corleone,
Heres the spec of my GT25TO4S.

Compressor 48 trim, major 3.00 inch minor 2.09 inch
Turbine 76 trim, major 2.12 inch minor 1.85 inch

mrfixit951

J chen,

I am in the process of looking into the exact issues you listed and several more. Both 71mm wheels are in the Garrett's GT series, so I feel I am comparing apples and apples. After talking with a turbo supplier about the GT3071, I found out that I was wrong the GT3071 and GT2871 do not use ported shroud compressor housings. Maybe the GTXX71 wheel and housing can be bolted to a non ball bearing center section?

I am curious to see your dyno plots of your torque curve with the small GT turbine housing. 325-350 ft-lbs up to 6500 RPM will keep me happy for a long time.

J Chen

If that's the case why not just go for
a K27/6 or 8. It's a drop in without
any hassle. Get a Guru chipset &
upgrade the injectors & you're done.
I'll post my chart when I'm done with
tuning. Believe when I say this. It's alot
of work to adapt the GT turbo to our cars
If you can't diy the work yourself, the cost
of labor & parts will end up much more than
the cost of the turbo.