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Spool/power Of Gt3040

vaccine

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vaccine Apprentice

vaccine

Posted
Posted

i am about to put on a gt3040 on my 3lt. has the 4" inlet .7AR cover, and 1.06 rear v-band.

running a 38mm turbosmart gate and avc-r. It is going on a subaru outback H6 flat-six motor. the motor is currently stock running 10.7:1 compression, so i am going to have to run low boost till the motor is re-built with low-comp pistons. Then it will get 2 bar of boost. i imagine that full spool would be around the mid/ high 2's, 3000rpm at the latest.

was wondering what sort of power is made around the 11-14psi mark???

you guys seem to run these turbo's more than the subbie boyz.

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R31Nismoid Grand Master

R31Nismoid

Posted
Posted

On a 2.5ltr RB25, a 1.06 rear housing wont be making 14psi (or 1bar) till 4200-4500rpm or there abouts

So now 3ltr, i think it'll be a hard ask to have it @ 14psi by mid-high 2000rpm with a 1.06.... totally depends on the head/flow and so on in many respects.

I have no idea about a subie 3ltr & head trickery so its hard to say, someone else might have a better idea.

The Dan Grand Master

The Dan

Posted
Posted
1.06 rear housing on a gt3040 is going to be one laggy turbo even on a 3ltr. If you still have the option get a different turbo with a smaller housing.

I wouldn't downsize the housing without upsizing the turbo.

If you want to make 300awkw then you will do it with a GT3082 with a 1.06 rear. If you down size to the 0.82 it makes it harder without ballistic head work. So upsizing the turbo to the GT3582R with a 0.82 is a better option.

With minimal head work, your 3L scooby doo would see 1 bar at around 3500-3800rpm with the 1.06 rear, 3000-3300 with a 0.82, 3200-3600 with a 35R / 0.82 rear but you'll make more power at less boost than the 0.82 on the 30R.

Those engines are not overly efficient so you need to make best use of aftermarket head options. Start with cams, but if your budget allows, get the head porting and larger valves done too as it will knock you under the 3k mark with a 0.82 rear on a 30R if that's what you really want.

vaccine Apprentice

vaccine

Posted
  • Author
Posted (edited)
1.06 rear housing on a gt3040 is going to be one laggy turbo even on a 3ltr. If you still have the option get a different turbo with a smaller housing.

really??? what do you define a laggy??

anyone else tried or have?

as friend had a twisted gt35R on a subiie 2.5 motor. 0.82 rear and 4" .7 front.

made 280 @ 20psi, full boost @ 4000rpm.

now i have a smaller exhaust wheel, but larger housing.

cant imagine it too be laggy. perrin did a gt35R on same motor.

made 438whp on yank 4x4 dyno running 16psi.

they then fitted a gt4088 and it made 24psi by little after 4000rpm and 600whp @ 6000rpm.

i already have the gt3040 sitting on the shelf at home. + at this stage i think i will need the larger 1.06 as the heat and back-pressure might be a little too much for the stock 10.7 compression motor. so the differences between the gt35R and the gt3040/1.06. the gt35R is more efficient and not so miss-matched? so will make more down low for less?

Edited by vaccine
The Dan Grand Master

The Dan

Posted
Posted
really??? what do you define a laggy??

anyone else tried or have?

as friend had a twisted gt35R on a subiie 2.5 motor. 0.82 rear and 4" .7 front.

made 280 @ 20psi, full boost @ 4000rpm.

now i have a smaller exhaust wheel, but larger housing.

cant imagine it too be laggy. perrin did a gt35R on same motor.

made 438whp on yank 4x4 dyno running 16psi.

they then fitted a gt4088 and it made 24psi by little after 4000rpm and 600whp @ 6000rpm.

i already have the gt3040 sitting on the shelf at home. + at this stage i think i will need the larger 1.06 as the heat and back-pressure might be a little too much for the stock 10.7 compression motor. so the differences between the gt35R and the gt3040/1.06. the gt35R is more efficient and not so miss-matched? so will make more down low for less?

I can't imagine too many people here would be talking from experience considering it's a Skyline forum.

But anyone who reads 1.06 automatically reads laggy. It's not that large a number really. 2.0 L engine go for the 0.6x, 2.5L engine go for the 0.8x, 3.0L engine go for the 1.0x

Rotary = start at 1.0x and work your way up from there :/

An effective power band is the biggest factor to consider. Don't pick a 1000hp turbo if you want boost before 4krpm. It just doesn't happen on anything less than a 6 or 7L engine. IMO a 1.06 A/R turbo would be absolutely perfect for your 3L engine but you won't see a bar of boost until 3800 or maybe even as late as 4k. But he will have an effective power band as any small capacity engine that wants to make power, needs to make it higher in the rev range.

SLAPS Rising Star

SLAPS

Posted
Posted (edited)

The GT3040 1.06 feels much like the GT35r .82.

IMO GT35r .82 is a much better option for the RB30.

Now the HKS3037S is now available from garrett (GT3076r .6 port shroud comp cover) the list goes....

GT3076r .82 (pump fuel tops out around 320rwkw with cams, E85 tops out around 350-360rwkw with stock cams/manifold)

GT35r .82 (with suitable cams and exh. manifold tops out around 380-390rwkw on pump fuel, E85 who knows)

Drop the GT3040 from the line up. It was only a viable option when the good GT3076 wasn't available.

I wouldn't bother with any smaller than the GT3076r .82 on the RB30 they have next to zero lag and respond unbelievably in first and second gear. Feels much like a factory turbo'd car but with a hell of a lot more grunt.

Edited by TheRogue
R31Nismoid Grand Master

R31Nismoid

Posted
Posted
I wouldn't downsize the housing without upsizing the turbo.

If you want to make 300awkw then you will do it with a GT3082 with a 1.06 rear. If you down size to the 0.82 it makes it harder without ballistic head work. So upsizing the turbo to the GT3582R with a 0.82 is a better option.

Maybe the subie head is super nasty but i mad 270rwkw 17psi on a GT3040 (600hp variant) with a .82

Considering the head was stock... the subie head would wanna be nasty piece of work otherwise 300rwkw really isnt out of the ball park for the larger of the GT30XX.

I cant say i could agree if its the 600hp

The 500hp variant i would agree with you though - would most certainly struggle to reach it as it'll be buzzing its heart out on the comp side.

Depends what model he has really (500,550,600) :/

as friend had a twisted gt35R on a subiie 2.5 motor. 0.82 rear and 4" .7 front.

made 280 @ 20psi, full boost @ 4000rpm.

20psi and only 280rwkw from a GT35? Something doesnt sound right as they will make upwards of 350rwkw on 20-24psi on a RB26/25's They are a 700hp turbo afterall.

Being every motor is different etc the 2.5ltr may have inherrant issues where the RB head might be pretty reasonable?

vaccine Apprentice

vaccine

Posted
  • Author
Posted

whats the difference with going from from a gt30R to 35r to 40R. are we talking roughly 4-500rpm in spool. bill @ ATS in adelaide was telling me today there is about 2-300rpm difference between housings, 0.82ar and 1.06ar. the 30R exhaust wheel i have is obviously going to be the restictor, but my guess would be spool should be almost the same if not alittle sooner than the 35R.

Rezlo Community Regular

Rezlo

Posted
Posted

Ive just put a 3040 .63 onto a S2 quattro that origionaly had a 3076r .63... Car spools up 250rpm faster than it did with the 3076 (which died due to twit not using air filter and ingesting a small rock) once up in the rev range the 3040 also feels a little more responcive.

For the 3L i would say the 1.06 was a good idea, In the little 2.2L I5 im getting 28psi by 4200rpm and with antilag its amazing!

discopotato03 Grand Master

discopotato03

Posted
Posted

Always with Subaru there are a couple of issues that become the great eveners .

Firstly they use split aluminium cases so will not really be on the same page as an RB anything block .

Secondly , lots of Subie cases don't have closed decks so super powering an engine that is firstly cast in aluminium and also limited upper cylinder support can be iffy .

Then theres those sometimes adequate aluminium split cased gearboxs , they do you twice , and the all paw traction to think about . Usually Zoob use clutches designed to slip rather than overload their AWD gearboxes , the AWD also means no front or rear only wheelspin which while not desirable can limit the torque loads thrown at the gearbox .

I don't know where you go with the trans other than possibly an auto one .

Some won't agree but I stand with the feller above on the GT3040/GT3082R being a stop gap until Garrett marketed their GT3076R/GT3037S .

With whats available ATM I reckon the GT3076R is a better thing and I'd say even it on a H6 with 5MT could easily break things .

The wait is long but I think the Evo 10 twin scroll twin integral wastegate turbine housing GT3076R would be worth it .

Lastly the impression I have of the Sube flat 6's is that they are not a real high performance 3-3.3L engine , just more capacity and torque than the 2-2.5L flat 4's .

I do realise that later Zoobs have a six spd trans but while being beefier than the five speeders are a longer still split cased ally box so not as bullet proof as some .

I'm pretty sure Tojo went away from split cased boxes (4AC/4AGE) to a center plate design (like Nissan uses) for their 3L engines like 7M and 2JZ in heavier cars .

This sounds very much like a thread at the "Au" site .

vaccine Apprentice

vaccine

Posted
  • Author
Posted

discopotato03 -> i am running full v7 sti drivetrain, so 6mt, plated 2way rear, sti shafts, 6-puk clutch, brembos and sti wheels. i have no fear of anything braking with the power that i am after. it loves being launched at 6K, and the 6mt's have no history of braking, like the 5mt's. guess we can thank porsche for their input on the design. :woot:

but we digress.

i was really just after a rough power/spool of the turbo. which i think for the time being i will be more than happy with. general concensous says it should be OK. so hopefully running the 10-11psi that i want, it will crack 200.. making my wagon more than enough drivable for the time being. just gotta find an external gate now.

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