Garrett GTX3076R BB Turbo?

[911TT33]

Originally Posted by TurboKraft

41mm exhaust port I.D. = 1.61" I.D.
Add tubing wall thickness, ex: 16ga to get O.D. = 2x 0.065" + 1.61" = 1.75" O.D.
So to port match to your heads and not add a flow restriction you would ideally use 1.75" primary headers.

Will 1-5/8" headers work? Yes...

Thanks, Chris!

The next question is, who makes/sells off the shelf 1 5/8" 930 headers with heat? I recall at one stage B&B use to sell them

So, if one were inclined to just use 1 1/2" 930 headers on a Carrera motor, what would be the issues there? Poor exhaust flow into the primaries? Exhaust leakage?

Wouldn't the slightly smaller primaries increase exhaust gas velocity and improve spool?

Keeping in mind, this setup is for a pure street car, not track car.

[EBELLO RACING]

Originally Posted by 911TT33

Hi guys,

Anyone here tried one of the new generation GTX3076R ball bearing turbo's?

I'm told they flow as much power as a GT35R (~625HP) but the spool characteristics are similar to a GT30R.

Should make a very nice daily street turbo with great top end power too

Thinking of taking this path with a 3.4L 8.0:1 upgrade on my EFI'd setup.

Anyone?

I tune a bMW M3 with two GTX30 .63 it dyno 1140hp 1030tq at 36psi but i perfer GT30 HTA .82 from FORCED PERFORMANCE

[911TT33]

Originally Posted by EBELLO RACING

I tune a bMW M3 with two GTX30 .63 it dyno 1140hp 1030tq at 36psi but i perfer GT30 HTA .82 from FORCED PERFORMANCE

INSANE power!

[quattrorunner]

Originally Posted by EBELLO RACING

I tune a bMW M3 with two GTX30 .63 it dyno 1140hp 1030tq at 36psi but i perfer GT30 HTA .82 from FORCED PERFORMANCE

Happy Eddie is back!!

[EBELLO RACING]

Originally Posted by quattrorunner

Happy Eddie is back!!

i just been very busy, test new heads. getting ready for the track.

[911TT33]

Anyone tried twin GT2871R turbo's with 0.63A/R turbines?

They flow ~400HP each! Wonder how they would perform on an EFI'd, EVO CAM'd 3.4L @ 8.0 - 8.5:1 C/R

Wonder if they'd be a "lag monster" with those 71mm compressors?

[herman maire]

So, just to confirm, a GT3076R is not a good turbo for a 3.3 930 engine with the usual mods. BB headers, intercooler ect...

My buddy is offering it to me for $400. Thoughts?

[quattrorunner]

I'd listen to Chris but $400? I'd gamble with that and see?

[TurboKraft]

Originally Posted by 911TT33

Anyone tried twin GT2871R turbo's with 0.63A/R turbines?
They flow ~400HP each! Wonder how they would perform on an EFI'd, EVO CAM'd 3.4L @ 8.0 - 8.5:1 C/R
Wonder if they'd be a "lag monster" with those 71mm compressors?

Is 800rwhp enough for you?
But for all-around power driven on the street, there are better choices.

[herman maire]

Thanks,

I see you have the .82 turbine housing . Are you happy with it on your 3.0L ? did you go Vband?

The turbo that is available has the .63 turbine housing I have not been studying turbos as much as I should but .63 seems too small ....

[TurboKraft]

For $400 it's hard to go wrong -- provided you are doing all the labor and count that as "free."
In our experience, they come on quickly and sizzle out in the midrange, restricted by the small exhaust side.

[herman maire]

Thanks for the info.

It sounds like its putting money in towards the wrong piece of kit..... I currently have a old style ( non ball bearing ) GARRETT T4 60-1. Maybe ill just stick with that for now . My car is not even running yet ....

[quattrorunner]

Originally Posted by herman maire

Thanks,

I see you have the .82 turbine housing . Are you happy with it on your 3.0L ? did you go Vband?

The turbo that is available has the .63 turbine housing I have not been studying turbos as much as I should but .63 seems too small ....

I have headers now. A change from my first post. I get full boost (.8bar) by just over 3k. I wan't thrilled with that at first, but my threshold is about 1800rpm and this turbo really is wicked! Thrust never stops for my 3.0 till forever. I never go over 6500rpm and the turbo never stops for my application.
I don't have true vband, mine is a bolt on vband to make it easier to change mufflers etc.
And my compression is stock 6.5/1 and I know thats where some of my lag is from as well.
I'm used to the response now and love it. I use a weak 915 transmission and if I had boost sooner it would make that issue worse. I feel my car is perfect in regards to power with my current setup. I can't use more power with this narrowbody. First gear is not used more than half throttle and second gear is predictably a tail wagger on boost every time. More boost would be silly till I can afford a g50 or 930 box.
I love the GT3076r on the 3.0t

[charge]

Originally Posted by 911TT33

Anyone tried twin GT2871R turbo's with 0.63A/R turbines?

They flow ~400HP each! Wonder how they would perform on an EFI'd, EVO CAM'd 3.4L @ 8.0 - 8.5:1 C/R

Wonder if they'd be a "lag monster" with those 71mm compressors?

This is the sort of Question I could do with answering!!

I have a 3.4 Evo cam'd H/C engine on throttle body's and Motec.
This had an open chequebook build, with Titanium everything, carbon plenums, and cylinder liners that screwed into CNC huge valve heads to prevent leakage at high boost.
It was built with a pair of KKK 27's and on having some map work done recently (to actually make it drivable), it showed they were not even coming on song till 5,000 rpm, but cracking on with 1.4 bar round and well past 8,000 with no sign of slowing, with the engine still willing to pull to 9,000.
Great for the 800bhp on pump gas, but not really suitable for how I want to use/ drive the car.
The mapper, suggested a pair of smaller garrets, but this is a minefield for one like me.
I like the top end power, but would be happy if they were at their max around 7500 if I could pull some decent power in lower down.
Advice or recommends would be much appreciated.

[RarlyL8]

Turbo sizing is just one parameter of the build. Soooo many things affect lag and boost power curve. Cams set the stage on where the meat of the power curve will be. Boost level and required output narrow the turbo choices, engine management and exhaust system design stretch the power band and improve driveability.
A K27-7200 stuck on an otherwise stock engine reaches full boost at ~3400rpm and has a power band to ~5300rpm.
Now add SC cams, performance muffler and RL8 or like tuned headers and the same turbo now reaches full boost at ~2700rpm and has a power band to ~5700rpm. Driveability is same as a stock Carrera.

[Tippy]

Quote de 911TT33

Anyone tried twin GT2871R turbo's with 0.63A/R turbines?



They flow ~400HP each! Wonder how they would perform on an EFI'd, EVO CAM'd 3.4L @ 8.0 - 8.5:1 C/R



Wonder if they'd be a "lag monster" with those 71mm compressors?

This is the sort of Question I could do with answering!!



I have a 3.4 Evo cam'd H/C engine on throttle body's and Motec.

This had an open chequebook build, with Titanium everything, carbon plenums, and cylinder liners that screwed into CNC huge valve heads to prevent leakage at high boost.

It was built with a pair of KKK 27's and on having some map work done recently (to actually make it drivable), it showed they were not even coming on song till 5,000 rpm, but cracking on with 1.4 bar round and well past 8,000 with no sign of slowing, with the engine still willing to pull to 9,000.

Great for the 800bhp on pump gas, but not really suitable for how I want to use/ drive the car.

The mapper, suggested a pair of smaller garrets, but this is a minefield for one like me.

I like the top end power, but would be happy if they were at their max around 7500 if I could pull some decent power in lower down.

Advice or recommends would be much appreciated.

If I had an open checkbook, I would have used Garrett ball bearing turbos or Borg Warner EFR series turbos. K27's are very dated, old tech turbo's. I am not knocking them as they are said to be bulletproof but when money is no object, I'd be looking for turbos that spool very early plus do not fizzle out on top end on your build.

I wonder if you did if you'd pick up another 50-200hp?

[Raceboy]

We just finished tuning an M5 E34 with 3,6liter motor, CP pistons, Pauter rods etc. Turbo is Holset HX50 with 17 cm2 turbine. Made 622rwhp @ just 0.95 bar boost and full boost is already available @ 3300 rpm.
Today was a One Mile Challenge event (standing mile), result was 303 km/h. Next step is to up the boost to 1.4-1.5 bars and traget is at least 900 hp.

This is just for reference, turbo cost €200 from the local truck scrapyard but to be fair, the truck had low mileage before it crashed lol

[Tippy]

I should have went HX50 myself looking back. I'll get a 6-blade HX40 wheel in the future and ditch the 8. That'll be the ticket!

[charge]

Originally Posted by Tippy

If I had an open checkbook, I would have used Garrett ball bearing turbos or Borg Warner EFR series turbos. K27's are very dated, old tech turbo's. I am not knocking them as they are said to be bulletproof but when money is no object, I'd be looking for turbos that spool very early plus do not fizzle out on top end on your build.

I wonder if you did if you'd pick up another 50-200hp?

My checkbook struggles to see light of day! The open one was the previous owner, who was guided by the builder who runs a 935 in Britcar, and had a pair of these on the shelf. He said to me himself that apart from a remap ( which I have had done) the turbos would help wih midrange, but the car was only built for top end, and he obviously knew the 27's had the top end capacity.
My priorities are different, hence my request for guidance.

[Spenny_b]

Originally Posted by charge

My checkbook struggles to see light of day! The open one was the previous owner, who was guided by the builder who runs a 935 in Britcar, and had a pair of these on the shelf. He said to me himself that apart from a remap ( which I have had done) the turbos would help wih midrange, but the car was only built for top end, and he obviously knew the 27's had the top end capacity.
My priorities are different, hence my request for guidance.

Brian makes a good point Charge about the cam choice - the eventual turbo choice may well also come with a cam change recommendation....I remember the previous owner, as you say, going for all out power and was trying to twist my arm into also going for GT2 cams on my build - as it happens a very lightly used pair came up via a pal locally straight out of a 964 Carrera which (from what I understand) is about one notch below the GT2's but hotter than the often used SC's.....other than that, I know Chris @ TurboKraft (and others) have their own recipe grinds they use, that may be better dialled-in for your (bonkers!) spec.

Cheers
S