Rb25/30 Neo Gt3076 Exhaust Housing Size?

[Adriano]

Hi, just about finished a 25/30 neo running acl forgies with 8.8:1 comp, gtr inlet cam, tomei 264 deg exhaust cam, r33 stock exhaust manifold. ONly looking for a streetable 300rwkw. Slide tells me he doesn't do internal gates for these turbos as they always have boost control issues, wheras morrie from HPIAB tells me he has never had any issues. I would love to run the .82 for the extra response, but the 1.06 will give lower backpressure, and possibly make the boost control easier, but at the expense of some response. However i may be able to run a little more ignition timing which will assist it off boost. The part number i have been quoted is 700382-12. I was under the impression there is a bigger wastegate flap option that changed the part number, but morrie tells me it only comes with the standard garrett flap? What do you guys think?

[Dale FZ1]

What rods, rod bolts, harmonic balancer are you running? How hard do you intend to rev the thing, and where is the target rpm range for best torque production?

Have you had any advice on the cam specs and what characteristics they will give the engine?

For me, all those factors will play a role in whether the 1.06 is really worth using, but I like your thoughts. Both Al and Cubes have had good results with the 0.82.

[Adriano]

Prepped dtock rods with arp bolts, stock r33 balancer with gtr oil pump. Only plan to rev it hard enough before it starts nosing over, probably about 6500

[Dale FZ1]

Neither Al nor Cubes seem to have any boost control issues.

What does Slide mean? Boost running away, or falling off as rpm rises?

The sort of bottom end power density offered by the 0.82 means you can probably afford to be quite lazy in driving the thing - torque on demand and pull higher gears easily. That may require a bit of good throttle control in slippery conditions.

By comparison the 1.06 would be a tad more progressive in delivery and maybe stretch the nose-over point closer to 7000. With the amount of torque produced by a 30DET able to be put to the ground a touch easier but require more downshifts when you want it to really jump. Depends if you see value in having it run like that or not but definitely not a bad choice.

[Gts-t]

Im doing a 26/30 with standard internals, will be limited to 7000rpm, 1 bar boost and tuned to 11.5 afr for a max of 300rwkw.

I am probably going to get a 3076R, etm or 6boost manifold 44-60mm gate BUT im seriously tossing up the idea of fitting the internal gate version in .82 mounted low if i can get good boost control and have it not taper off etc.

[TiTAN]

you shouldn't need anything as large as a 60mm gate if you are going to be running the 3076R near its limits. keeping in mind that if the waste gate is too large it makes boost control harder for the boost controller.

[Gts-t]

thanks for the tip, it will most likely be the tial 44

[R34GTFOUR]

What does Slide mean? Boost running away, or falling off as rpm rises?

i would assume he means boost creep, ie boost keeps increasing as the rpm goes up. Quite a few xr6t boys have problems with that (obviously thats the gt35r iw) but the most common fix is a bigger flapper and porting of the housing.

i would think the .82 iw would be ok, mainly because cubes is using it without any dramas. In saying that, i would make sure that the exhaust wasn't straight through 4inch pipe with no cats or mufflers, there needs to be some sort of backpressure to help boost control.

is this your 2nd neo rb30? if so, did you have a chance to cc this head to see if the neo head is definately smaller (combustion wise)

[Adriano]

No, its still the firdt neo one, putting it in th ecar tonight. I did cc the head, and it came to 59cc each, even lower than i expected

[Cubes]

.82

I wouldn't have it any other way for ~300rwkw, with the cams in zero position peak power was made at 6000rpm and dropped 9rwkw by 7000rpm. It pulls clean to 7k.

Often in second gear and third you can hit the limiter at 7.3k as it just doesn't feel like power is dropping off but only since the cams. Prior it felt like power was nosing off at 6.9k which is where I found i was shifting up at.

Myself, Al and Lithium all run the GT3076r .82 with an Internal gate. We all have no issues with boost creep.

Al runs 16psi

Lithium 17psi

Mysoelf 19psi tailing off to 17psi. (I now have a large Garrett actuator to control that gate better s no more boost drop over 5000rpm so I will tune her up on 20psi ish. See where it stops making peak power and leave it at that.

When I sourced the .82 IW for Lithium I was told there was two versions of the IW.

I forget the part number addition but one had the larger flapper installed from Garrett them selves. Which is what Lithium got.

Really.. You'll love the GT30 .82 on the RB30DET. Such a streetable motor.

The ONLY time I'd consider the 1.06 is if you were running the 82mm comp wheel on the GT30. Should be able to push up around 350rwkw but with not quite as much lag as the GT35r .82.

[Pattygtst]

i am doing mine in the next couple of weeks for my stock internal rb25

i am getting and this is all recommended by mtq and my tuner/mechanic

gt3076r IW with larger fapper 56 trim (rated at higher hp then 52) with turbine housing .82

Since internals stock i am aiming for a safe tune of 260rwkw on low boost and maybe 300 on high boost. But i think the high boost 300 will be to much of a temptation to only use on occasions.

Just need a custom dump and intake. From what i hear bellmouth is the only way to go for the dump without boost probs.

[Adriano]

Got the .82 the other day, thanks guys. Ps do all the 3076's have the surge slots?

[Spoolup]

Cubes what power is your engine making and at what boost

I built an engine for a guy a couple years ago, was running GT30 ( 0.82 housing ) with external gate and at 23psi it made 380 rwhp. Im just curious ?

.82

I wouldn't have it any other way for ~300rwkw, with the cams in zero position peak power was made at 6000rpm and dropped 9rwkw by 7000rpm. It pulls clean to 7k.

Often in second gear and third you can hit the limiter at 7.3k as it just doesn't feel like power is dropping off but only since the cams. Prior it felt like power was nosing off at 6.9k which is where I found i was shifting up at.

Myself, Al and Lithium all run the GT3076r .82 with an Internal gate. We all have no issues with boost creep.

Al runs 16psi

Lithium 17psi

Mysoelf 19psi tailing off to 17psi. (I now have a large Garrett actuator to control that gate better s no more boost drop over 5000rpm so I will tune her up on 20psi ish. See where it stops making peak power and leave it at that.

When I sourced the .82 IW for Lithium I was told there was two versions of the IW.

I forget the part number addition but one had the larger flapper installed from Garrett them selves. Which is what Lithium got.

Really.. You'll love the GT30 .82 on the RB30DET. Such a streetable motor.

The ONLY time I'd consider the 1.06 is if you were running the 82mm comp wheel on the GT30. Should be able to push up around 350rwkw but with not quite as much lag as the GT35r .82.

Edited November 21, 2008 by Spoolup

[Haines]

mine does

they sound sweet coming on boost

Im running the AVO housing from HPIAB (.73AR)

but cant comment on boost issues because i havent got mine tuned yet

[Cubes]

Spoolup,

23psi 380rwhp.. Sounds like the old shiety GT3076 which earned a bad name for the GT30's.

The old GT3076 is one of the big reasons why the GT3040 was such a big hit.

The version I have is identical in specs to the HKS3037S which is known as the -12.

I've got some pics of it in my Garage see if it looks the same as what you bolted on.

Prior to cams ~260rwkw on 15.5psi. 17psi saw bugger all more power. It wouldn't hold any more than 17psi either.

We assumed the 232 duration exhaust cam wasn't playing nice.

Dropped a set of cams in (265/263 8.9mm lift) and it went to 302rwkw on 17psi but it won't hold any more boost up top.

Compared to others on the same dyno with a GT35r .82 IW and a GT3040 .6 its making more power on less boost both with the std exhaust manifold.

From what I can tell it seems to be making good power compared to others on the same dyno with the same mods. The only real difference is mines had is a little head work, valve deshroud, port/polish, port match match etc.

The Z32 is hitting 5volts.

When it was down around 260rwkw it was 4.85volts and the GTR injectors were maxed out.

----

Adriano,

Whats the part number on the turbo's tag? Hopefully you didn't get one of the older gt3076's or 71's. :S

[R31Nismoid]

23psi with a GT30 is well into the 300rwkw marker IMO. 320-330rwkw you'd expect

With my GT30/.82 i was on 270rwkw @ 16/17psi back what, 3 years ago

[Adriano]

Interestingly Morrie form HPIAB said that the trimmed version with the bolt on exhaust housing performs exactly the same even though"it only a few mm trimmed off the exhaust wheel"(his words not mine, and said the whole cropped thing is a joke. Interesting considering he sells turbos!

[Cubes]

So you have the surge slots?

The cropped turbine will spool a tad earlier but will also place a greater demand on the wastegate.

SimonR32 had no issues with his. After cams his topped out at 295rwkw but mid range sucked so dialed in the cams picked up 20rwkw through the mid and dropped 10rwkw up top. Settled on 285rwkw.

He ran the .7 AVO turbine housing BUT it boost creeped to buggery so had to fit a bigger flapper.

Prior to the cams it was laggy after it was a complete different monster. Was quite impressive.... For an RB25.

[Spoolup]

I think alot of the variation is due to the dyno used - the one I was using was rated at being about 10-15% lower than the norm. And I know there are many out there that are making figures alot more than others - especially at dyno shoot out days.

Edited November 23, 2008 by Spoolup

[Cubes]

Not sure... The dyno I run on reads the same as mainline dynos. One of the lower reading dyno's in SA. Same dyno Whatsisname made 260-270rwkw and ran a 120mph TS.

So it was definitely the .6 surge slotted comp cover GT30 you had?