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from others expirianes, people who have the .63 ( i was reffering to the gt30/.82 on an rb25) they come on quite sharply inducing wheelspin and not making the car as friendly.

And rear housings impact the power output too dont forget.

and even bigger, 1.0x is too laggy on a 25, but my comments are related to a street car. Keep that in mind. If your racing is different of course.

yes totally understand mate, i too am going to be in the turbo choosing boat later on after i get my engine back together. the .82 rear is seeming the wise choice, i was going to go 1.06 as i was told that would be awesome but i want a broad power band not the very narrow band.

I had a gt30 on my rb25. It had the .82 rear housing. Made a best of 310rwkw on pump. Nothing below 3500rpm. Full boost at 4500rpm. Would die by 6500rpm. When it came on boost fried the tyres. I personally didnt like the characteristics of the turbo and the amount of boost needed to make that power. The smallest i would personally go is the .87 rear. I had 1.05 rear on my t88. Full boost @ 5000rpm held all the way to 8000rpm. Started making boost at 3800rpm and dip in power up top either. Didnt come on savage too.

Id say the .82 is better suited for like an rb20/ sr20/ or 280rwkw rb25.

That just my experience.

Gt3540r are making big power on 30det as said. Just gota choose the right one for your set up

yeah, i am bumping my rev limit to 8000rpm so i wouldnt want it to run out of puff by 6500!!! thats abit silly. What does the TD06-25G housing equate to that u had? that was good aye? hav eu had any experience with the TD07-25G?

my gt30 .82ex doesnt run outta puff @ 6500, it makes power all the way into the 7000rpm range with ~270rwkw and only drops off at the limiter of around 7500, and then thats where cams are probably are required for that little bit more.

I've got 200rwkw+ by 4000 and its very smooth to the 7000rpm/270rwkw mine doenst feel at all weak above 6500rpm.

Mind you its not a hell amount of boost either, it'll take a few more psi on pump yet.

just gotta get another as mine shat a bearing. Just about brand new so its a rarity

I was thinking along the lines of the GT3540R (a real one not the seven bladed TO4S piece of crap) and a REAL GT style .82AR exhaust housing . I would like to see positive pressure at a bit over 2000 and .8 to 1.0 Bar from 3000 to 6800 . So is anyone using the real one ?

Our project R33 RB25DET is running a 700hp version of the GT3040 with .70a/f and .82 rear. - Garrett version not HKS

Its on full boost by 4700rpm with standard cams at the moment. It dies a little bit up top in 1st & 2nd gear between 6500 & 7000rpm but it 3rd and 4th its opposite it pulls even harder when it hits 6000 to 7500rpm. Because its such a large turbo it takes a while to get going so in 3rd and 4th the topend is huge.

On the drag strip 1/4 a small shot of nitrous will help get it off the line.

GT3530r should be fine on a RB30DET i'd like to see how it goes. :)

:)

Jun

Bingo...why have a huge arse turbo, but no cams....?

yes, but remember, for the little bit.

In the whole cost vs result, it would be a an improvement of course. But as my budget is extremely tight i cant justify the cost of cams when the stock head for the most part is doing very well.

Cameron.. i would like to know the number also, never heard of a 700hp GT30 in 70comp/.82 rear

Cameron I looked into that one too , my Garrett contact (in US) said he would not put that on anything because of the difference in turbine vs compressor diameter ie 60mm and 82mm . In his opinion the extra work the turbine is asked to do to drive the GT40 compressor costs it turbine efficiency (slip losses at the turbine) . These are his opinions so I'm not desputing anyone elses choise . Its a shame the Garrett PDF cattledog does not show the GT3040R so we could see the turbine efficiency graph . It does show the GT35R (GT3540R) and the turbine efficiency is I think 74% which is quite high . Its a pity Garrett don't do a larger trim GT30 compressor to use with the GT35 turbine , I believe it would work like a GT28RS scaled up 50% .

Cheers A .

CHRA # 700177-14 has the usual 84 trim/60mm 30 series turbine wheel but has the 82mm, 56 trim GT40 on it - flowing ~65lbs/min. This is an off the shelf Garrett item. Can you ask your Garrett contact why he doesn't want to "put" that compressor wheel on that sized turbine, when you can buy one directly from Garrett?

Also, you can get a larger trim GT30 compressor wheel (T04S - don't be fooled by the "T04S" designation as these are the new line) than the 56trim offered on the GT30R, there is a 60 trim wheel available that flows ~60lbs/min. CHRA # 700177-13 has that combo. That is with a 76mm exducer diameter, and 59mm inducer.

Side note: there is a T04S 63 trim wheel but it has an exducer diameter of 84mm, but it flows ~70lbs/min. Rockin'!

Its been customized internaly. The computer with the digital camera pictures on it has a broken video card but i'll try and get it thursday for you.

I was told that its the new model of the garrett GT3040. You carnt tell the difference apart from the normal 600hp and the 700hp version as its internal work thats been done.

I've got one pic here:

http://www.skylinesaustralia.com/forums/at...achmentid=21556

I've tryed seaching for the part number in garrett catalogs and can't find it anywere.

;)

Jun

Was at dyson rotary today, craig built an rb25 using a gt3540, on 18psi made 480rwhp on pump. Built engine with hks cams and cam gears, plenum etc etc.

Should be out at the track once finishes off some things on it.

From what craig told me it has a .6* (*not sure either a 4 or 7 or what) rear housing.

Hey discopotato,

How does the Garrett guru align his opinions on compressor/turbine relative sizing, considering the radically differing conditions each are operating in, i.e gas velocity/density? Would the more sizeable turbine with its inherently costlier inertial energy requirements not lead to losses of its own, i.e. slip? I am also considering this turbo for my next '30DET build but am unsure what to pick between the .82/1.06 tubine housing. What does he think?

Intreresting thread.

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