Garrett Gt3071r Discussion & Results

[turbomad]

What size housing have you got on your 3071?

[BHDave]

.63

["EN4CER"]

Any luck sorting out the boost issues?

[BHDave]

i still have a creep issue, but it is more in line with what i'd call traditional creep. Boost is now stable up to about 4k and then it starts to rise. I have some time on a dyno booked next saturday for an initial play, and if we can get it to hold 16-17psi (which is the boost i run for track days) then we go for broke and stretch it's legs.

[Dale FZ1]

This wastegate upgrade should put the venting capacity somewhere near the HKS Pro S performance level; maybe with a higher level of discharge turbulence due to the casting design. But it will be very interesting to look at your graph with a boost overlay against torque.

I'm running a turbotech with 1 bar actuator on the 3037, max boost bumped to 17.5psi with street legal sound levels. The boost curve does not have a sharp knee, in spite of the turbotech. It just climbs and hits near its peak, with a 0.5psi rise/fall between 4-6500rpm. Hopefully this is the sort of creep you're experiencing?

Bring on the results of the tuning

[BHDave]

replace .5psi with .5 bar and you'd be closer to the mark..... 99% certain it is now tune related, 1% still worried about the gate flap shrouding the outlet in the split dump (which is a very easy test anyway, just wire it open and go for a drive).

[zebra]

What sort of Split Dump are you using?

Is the join back into the main system smooth?

Id possibly try a new dump pipe, maybe a bell mouth style one (which should give more area for the wastegate gasses to escape into) If you havent allready.

Andrew

[Roy]

Well this should give an indicator of what a 3037 can do with reasonably good tuning on an internally stock engine and running a free flowing (reasonably noisy) exhaust. That is ~ 290kW for the mathematically challenged, with boost peaking @ 18.6psi and tapering to 18.0psi using a Turbotech adjuster. AFR is held steady @ 11.95-12.1, and max reported knock was 16.

Slightly shaky looking graph at the top end indicates it wants more ignition, but that results in higher knock figures. I have a solution to that issue.

Running with an extra baffle, power drops 24hp to ~ 270kW, and the increased backpressure holds boost back to 17.3psi.

There are no complaints about either delivery or quantity of power.

Are you positive the rpm scaling on your graph is correct?

[robots]

So to sum it up ? What kind of gt3071 exhaust housing should one get for rb25 ? .63? Or .82?

Also, what is the Garrett part number for the IW exhaust housing ? They don't specify it on the webiste ? Or is it non-existent ?

Last one, if running a external wastegate with the real gt3071. Which wastegate size is to go ? will a mere 38mm do a job ? around 14-16psi boost ?

Thanks!

[BHDave]

If i were to do it all again, i'd probably go an ex gate .63 with a 44mm tial on a 6boost manifold

Mine is on the dyno on Saturday so i will have a better answer for you then.

[robots]

Pls don't forget to do so

Thanks!

[-33-]

If i were to do it all again, i'd probably go an ex gate .63 with a 44mm tial on a 6boost manifold

Exactly my thoughts. Didn't want to go external gate to keep it a bit more undercover but given the extra cost... should have just plumbed an ext wastegate back.

So yes. In retrospect 0.63 all the way, couldn't be happier with the size. But put it this way

Externally gated housing - save around $250

External gate - spend $400

6boost - spend $900

NOT wasting time and effort grinding out bullshit internal gate - ??? (fill this one in for me Dave)

All up looking at a bit less than $1000 for much better flow and less headf**s, and probably a better overall result. Live and learn. Turbo is still an animal though

[BHDave]

NOT wasting time and effort grinding out bullshit internal gate - ??? (fill this one in for me Dave)

It was a solid day of my time by the time i removed it, removed lines, packed it up and took it to gcg, picked it up mod bracket to suit new actuator, realign housings, reinstall lines reinstall turbo. Probably add half a day in redoing some burned lines, heat wrapping and generally repairing stuff that got melted that i hadn't expected to melt....

then another $550 for new heavier actuator, replace gaskets and enlarged gate.

A 6boost manifold is more than $900 isn't it?

[-33-]

It was a solid day of my time by the time i removed it, removed lines, packed it up and took it to gcg, picked it up mod bracket to suit new actuator, realign housings, reinstall lines reinstall turbo. Probably add half a day in redoing some burned lines, heat wrapping and generally repairing stuff that got melted that i hadn't expected to melt....

then another $550 for new heavier actuator, replace gaskets and enlarged gate.

A 6boost manifold is more than $900 isn't it?

Yeah you're right, round the $1300 mark for an RB25 one... i was probably thinking about the 4 cylinder ones. Still worth it i reckon.

I really cant be bothered doing much about mine at the moment. In the two months i've had it boost has crept to a max ~21psi. I may just leave it for a while... when I get bored i'll order in the ext. housing, get a 6boost, ext gate, cams and gears and be done with it.

Anyway, good luck with it, let us know how it goes Dave

[BHDave]

Well i still have boost control issues.

And once again the dyno and the road boost responses are different enough to make it hard.

In a nut shell, the midrange creep is still there on the dyno. It'll come up to about .9bar on the actuator only (with some more preload wound in), then slowly creep up to about 1.3bar by 4500 and then roll off to 1bar and go dead flat to redline. Switch on the boost controller and it'll go to 1.1 bar, creep up to about 1.4 bar and again rolls off to 1bar. Enlarged wastegate flap was being blown open by back pressure. We could hold it shut and make more boost.

On the road (3rd gear runs as there is no way i'm going to try and watch the boost gauge at over 200km/h) the boost curve, for lack of a better term, was similar but it was about 1000rpm delayed. The peak of 1.4 bar hit about 1000rpm later and it still dropped off but it didn't get below 1.3 bar by the time i hit the limiter.

dyno sheet to follow later on.

[BHDave]

The run that starts at 16psi is on the actuator with ebc running. Can't remember which setting it was on as i'm pretty much over it for the moment

The one that starts at 20psi is ebc off with the tuner holding the gate closed and at about 4500 back pressure increased and blew it open anyway

At the moment the tune is a bit of an abomination. as it is so touchy with egt's and boost climbing i don't have the option of removing a lot of timing as temps increase so it's got a bit of extra fuel in the bottom 5 rows of the map.

Once i get over the utter disappointment of this nugget turbo and suppress the urge to sell it i'll have a think about what i'm going to do.

[dangerman4]

he fellas

looking at the dyno graph with the ebc on it looks very similar to a issue i had wen i first installed my gt3582-iw .82

but that was resolved by changing tuner, to one that had a better handle on the do's and dont's of the pfc ebc.

now i have no issues at all and im still running the standard gate port size.

im also running a lot higher boost 24psi, and keeping it within 1 psi from full boost to the 7.5k limiter.

so maybe spend a bit more time working on the ebc setup.

off topic

the other day going up a large hill i was able to keep the car in overdrive at 2500 rpm and i found it was making 5 psi.

i was fairly impressed by this seeing as its a 700hp turbo on a rb25

[BHDave]

That was actually one of the possible ways to mask the issue we thought about. I have an old blitz dsbc so set gain, set duty and that's it. I am considering a swap to one that is more intelligent (such as the pfc boost control kit).

It doesn't resolve the wastegate being blown open issue though (which i could possibly live with in all honesty as it seems to be less obvious on the street)

Edited May 18, 2008 by BHDave

[dangerman4]

how was the tuner holding the gate shut and what was he wanting to achieve?

what's the psi of your actuator? 17psi?

i run the 17 psi with the pfc ebc at 52% to sit nicely on 1.8 bar.

so im guessing if your ebc isn't handling the fine line between gate open and shut very well.

if you back some timing out of it and then aim for 20psi to try and find a happy spot with the gate half open, maybe that would work.

[BHDave]

how was the tuner holding the gate shut and what was he wanting to achieve?

crowbar We ran a few different settings on the ebc and it would drop back to 15psi within 100rpm consistently. We added some more pre load on the actuator (it's a 16psi one) and it held for an extra couple of hundred rpm before dropping off. We were just confirming whether the compressor was out of flow or whether there was another issue. 99% certain the issue is the back pressure in the .63 housing holding the gate open when it should be closing.

Where do you get your actuators from DM? I'm considering a 20 odd psi one as the 16psi one held all of 12psi with the big gate. Also thinking about a big diaphram model as they have a stiffer spring for a given pressure from what i've been told which may help with the boost drop off at the top end.

So with the pfc ebc, does it have a target boost so it's constantly adjusting the duty to achieve that boost, or is it a straight duty thing? It has both in the setup screen on the hand set. I don't want to spend the money only to find it's a dumb controller with a worse solenoid than my current one.

Everything with this turbo is a f**king balancing act.....