3071 Garrett

[stolen_s15]

This thread along with Mafia's and Lithiums have given me a great deal more knowledge on turbo choice (mind you alot of disco's essays still go over my head) so cheers guys.

I'm hoping that we can get some decent results of a real GT3071R .63 A/R on an RB25 soon, as I'm looking at this turbo as a real option for a mainly street driven, stock bottom end RB25. However if the guestimates of only 250-260 are correct I cant see the benefit of choosing this turbo over for example a GCG hiflow with either RB25 or VG30 housing. The cost would be much greater for the garrett when you sort out the lines, fittings, custom dump and intake. So my question is, if 250-260 is what this the Garrett is limited to then why bother?

Now, does anyone think that the GT3071R .6 could pull 280rwkw on pump fuel, stock manifolds, possibly cams? Or would the .8 be needed? Discuss

Finally does anyone in vic have a GT3071R equiped RB25, and feel like showing me what its like on the road? Would be much appreciated.

[Cubes]

With cams you might get pretty close.

With respect to the GCG highflow; cams + the highflow = 260rwkw.

Generally without cams they see in the 240-250rwkw range depending on dyno obviously.

[skylinecouple]

I agree Cubes but even then you have to push them. My GCG hi flow is useless at 220kws 17.5lbs boost. 6 different tuners and a couple of grand wasted, I'm over it. 3071 .82 here I come.Can somebody access ATP turbo and give me their honest opinion. There is two different .82 housings. One is the Garrett but the other is like a flat machined housing with the waste gate hole and then you buy the flapper and v-band module separately.

[Cubes]

Garrett IW FTW. Don't buy the other crappy 5bolt ford style.

The Garrett IW looks near identical to the XR6T IW design; but slightly improved.

Be sure to run with a well designed bell mouth dump as splits have a tendency to creep on the GT30 Garrett IW housings.

Better be safe than sorry.

Besides if boost levels are identical (of which they generally are not when running a split vs bell) if the split is plumbed in there's no difference in power. Have it screaming to atmo then yeah there is a slight power benefit. So back to back on the Dyno results have shown.

[skylinecouple]

Yeah, I changed from a split to a bell on my hi flow and gained two kws, woo hoo (sarcastic). Just kidding, I've always believed the bell is a far superior design. No resistance to flow. So as a final order I'm getting the 3071 IW non cropped 60mm turbine with 2.75 comp. inlet. That inlet should make plumbing easier. Now, this should make 250-270rwkw and boost earlier than the 3076, ok ? Please tell me this is right. I can't believe how big a decision this is.

[Lithium]

So as a final order I'm getting the 3071 IW non cropped 60mm turbine with 2.75 comp. inlet. That inlet should make plumbing easier. Now, this should make 250-270rwkw and boost earlier than the 3076, ok ? Please tell me this is right. I can't believe how big a decision this is.

As said / shown before - outright boost threshold the GT3071R seems to have nothing over the GT3076R. MAYBE (you'd have to go in both back to back) the GT3071R might have better part throttle behaviour, but I am serious when I say mine is really really nice to drive. You can tell its down on torque below 3000rpm but who drives hard there and expects to go fast aside from people with 5000rpm redlines?

Got a vid on youtube of a run from the drags this weekend where I managed to badly bog a launch with the .82a/r GT3076R racing a fairly mild R32 GTSt, gives a reasonable impression of how it pulls from low revs in 1st I think:

[BHDave]

From what i have seen on 2 sr's with proper 3071's, the response really isn't far off gtrs/2871 thresholds.

Same goes for the only rb25 with 2835pros i've been in. That thing was making 1 bar a little over 3 grand in 3rd. Admittedly it's the smaller turbine and arguably better hks housing, but it is a .68 as opposed to .63 garrett so there's a bit of a trade off there. It took next to no throttle input to hear the thing spinning up

It's unfortunate that dyno print outs of boost often don't match what we see on the road. And transient response is something you can really only experience by driving. I still believe the 3071 is the street turbo to have and (as i've said before) if my old t3/4 nugget ever dies horribly i will be getting one.

[skylinecouple]

OK, first thing Monday I'll be putting the order in and it should be here next day. I'll try to make a story out of it, lots of photos. I'll get all the fittings over here but the actuator from them. Though I have seen a beautiful machined actuator on another site but can't remember where, damn. They should have a flange and new bolts, studs. Can anybody think of anything else ?

[BHDave]

by flange you mean dump pipe flange? Don't know whether anyone has them locally so it's probably a smart move to get one sent over, same with gasket (id get 2 or 3 of them just incase).

[Cubes]

Will be keen to see the results..

As for measuring the turbo's response. Maybe pick an rpm; say 4000rpm as it should be well and truley making all its boost by then.

Second gear stomp on the throttle. Third gear at a private track only.

By using a video camera on the dash that also shows the boost gauge you 'should' be able to see a slight difference in response.

[Simon-S14]

MTQ and GCG sell the flanges and gaskets also.

Awesome info in this thread, has to be one of the better threads for info in this section for quite sometime!

[Lithium]

It took next to no throttle input to hear the thing spinning up

It's unfortunate that dyno print outs of boost often don't match what we see on the road. And transient response is something you can really only experience by driving. I still believe the 3071 is the street turbo to have and (as i've said before) if my old t3/4 nugget ever dies horribly i will be getting one.

Definitely agree re dyno print outs not showing the full thing, however showing my car bogging and recovering and destroying an R32 GTSt with stock turbo even by the end of first gear has to indicate somehow how quickly the thing builds? I think the GT3071R would be brilliant, and a bit better than the GT3076R for streetability. On the flipside its nice knowing I have 270rwkw and can EASILY go way past that. I think people are describing of GT3071R/GT2835s what I get with mine, ie - can hear the turbo spooling at minimum throttle in the 2000rpm range cruising around town. Throttle behaviour is very NA, etc. I'd *LOVE* to have an opportunity to drive a GT3071R and GT3076R turbo'd car back to back and see the difference actually.

If you are SURE you don't want more than 270rwkw, and can live with changing turbos if/when you change from the mindset of "My car is at the quick end of a mildly modded car" to "my car is at the slow end of a well modified car" or are pretty sure you won't change to that mindset then the GT3071R is the one

Edited November 9, 2007 by Lithium

[Cubes]

BHDAve,

the GT30 IW dump flange is identical to the XR6 dump flange. As Simon said.. MTQ. They are ~$30 from memory.

[skylinecouple]

Good enough then, I'll get flanges from there just in case. No need to worry that way. Yes, 250kws will be just fine, 270 a bonus. Getting back to my original post, I want to be able to run more timing with the cooler intake charge which I can't do with the high flow for whatever reason. Is it a dud ? who cares, it's gone. Will take a couple of weeks to get everything together as in lines and stuff but a new intake pipe, silicone connectors, clamps and a large air cleaner to help it breathe. Was always going to make a new air box anyway so may as well do it now. Bare in mind I'm a bit of a fussy old bastard so all has to be right before the final tune.

[skylinecouple]

As an aside, has some of you older posters remembered when a hi flow was just the ants pants ? Now there are so many choices, fantastic. I can still remember Martin Donnen putting a GT25 on a R33 and proudly gloating of it's 210kws.

[Simon-S14]

lol mine makes 220 rwkw with the stock turbo so times have come along way thank god for that

[discopotato03]

Hi skylinecouple , an alternative to ATP is FullRace Motorsport in the US . Its run by Geoff Raicer and he's had lots to do with the real GT3071R and GT3076R . He's put some time into RB25's and 26's though most of what they make or sell is for Evo Lancers/Subarus/Supras because they are available in LHD .

He would be able to give you a much better idea of their characteristics on an RB25 than ATP which is really just a box up and sell operation . I don't know if he offers the GT30 IW turbine housings but it would be easy to ask him via E-mail . If he's been there with a std manifold he may even be able to supply the oil and water lines .

Your call but I think he's the most unbiased person to talk to about turbo systems because he's genuinely interested from a mechanical engineering point of view . If you explain up front that single scroll is all you want and need the integral gate GT30 housing he'll tell you the pros and cons of this system and the choice of turbo .

Search FullRace Motorsport for the E-mail or if you can't find it lets know and I'll PM you later .

Cheers A .

[skylinecouple]

Thanks Disco, will do that right now. Damn it, keep thinking about the 3076. If boost comes on too early with the 3071 then it will be wheel spin city. But what if the smaller 71 comp. wheel needs to really get spinning as in lots of revs to move enough air to make the torque and power I'm after.? Shit, double shit.

[skylinecouple]

OK, email sent. Will wait for Geoff to get back to me but it looks like he only does RB26 setups.

[govich]

Very informative discussion. I wish i had time to get away from uni studies and really look into this stuff and contribute. My stock turbo has started making some 'interesting' noises.. i was leaning towards the GT-RS kit and blindly trusting HKS's engineers (probably a safe bet) but reading this makes me reconsider.

Out of interest, do you guys just estimate volumetric/mass flow rates and efficiency (etc.) for number crunching? I notice the Garrett site has some basic information (although non-SI units frustrate me, i'm tempted to 'translate' their site ).