Turbo Question - Gt2560

[aaronjod]

Hey Guys,

Got a question about a set of Turbos i bought. I was under the impression these are similar to -7's and good for 300kw.

The serial is 446179-29. Upon googling, comes up as a GT2560.

Stamped on the inside of the exhaust housing is .48 and on the outside of the compressor is .42. I figured this was the A/R.

Now if its what i think, they're stock sizes for for stock GTR Turbos, not similar to -7's or R34 N1's. More like R34 standard turbos ?

I realise they're ball bearing and steel wheel, so they're still an upgrade, but am i going to stuggle to get 300kw ?

Is there something i'm missing? Do they have different sized wheels inside that will allow for 300kw ?

[Booki]

Only Turbo on garretts site for GT2560 are these

https://www.turbobyg...oductCd=GT2560R

Turbine housing (PN 466541-4 only) is cast from high-nickle "Ni-Resist" material Turbine wheel (PN 466541-4 only) is cast from "Inconel" material for extreme applications OEM turbocharger on Nissan SR20DET engine Upgrade for GT2554R (471171-3), outline interchangeable except compressor inlet.

Serial is different to what you posted though.

Edited October 7, 2012 by Booki

[R31Nismoid]

Ignore Garrett's website in some respects, they changed the ID/Part numbers a while back so if they are a old set it's misleading. They were 2560s initially so some have old tags, some have new - depends on the age.

Rear should be .64 for -7

Turbo ID: 707160-7

CHRA: 446179-54

Turbine: 53.90mm 62trim 0.64 A/R

R34 standard turbos are not steel wheel.

[aaronjod]

http://www.turbomaster.info/eng/applications/ball_bearings_chraGT.php

Was where i got the details from.

All it has written on the plate of the turbo is BI 0144J then underneath 446179-29.

But like i said .42 and .48.

So these turbos are not similar to -7 or N1's and i would struggle to get 300kw?

[R31Nismoid]

Well it's not the same as a -7, put it that way. The problem with that TM site, is they are listing all the old part numbers for products not on market anymore.

The comp wheel for that CHRA has a higher trim than a -7 on the comp wheel, but a lower trim on the turbine. So front "should" flow more, but the rear won't.

Will be 300rwkw-ish you'd think as the comp wheel is basically the next size up from a -7 (but not as much as a -9, almost a half step).

It'll all come down to that rear housing, I'd be guessing it's not a .48 anymore and it's been hi-flowed to fit the CHRA...

[GTScotT]

OP crack the housings off and take proper measurements, you can then work out what youve got from there.

They dont sound like a good 300kw application to me. Being a GTR you really want to do it once and do it right. You would hate to need to do the job of installing them twice let alone the cost of a wasted tune if they arent as great as you hope.

[aaronjod]

When you say to fit the CHRA, what exactly do you mean? Like it was originally a thrust type turbo with the ball bearings fitted instead? I will pull the housings off tomorrow and measure. These turbos were supposed to be of a 8k old r33 N1 crate motor. I realise r33 n1 turbos are thrust type bu wast assured these were ball bearing, and according to the serial they are.

[discopotato03]

Yep 446179-xxxx are bal bearing cartridges .

Something is a bit screwy about the lists I've looked at because they show units with 53.8 /53.9mm turbines as being GT28 turbine based units .

They show the turbine as being 62 trim and if its od is 53.8/.9mm then that wound indicate the smaller trim version of the NS111 turbine .

The compressor details are 60mm 60 trim .

Also BTW the specs I've seen for the BB GT2556"CR" which is for Nissan are turbo number 702987-3 using cartridge no 446179-42 , I assume these are the OE R34 GTR turbos .

One more to check , cheers A .

[R31Nismoid]

When you say to fit the CHRA, what exactly do you mean? Like it was originally a thrust type turbo with the ball bearings fitted instead? I will pull the housings off tomorrow and measure. These turbos were supposed to be of a 8k old r33 N1 crate motor. I realise r33 n1 turbos are thrust type bu wast assured these were ball bearing, and according to the serial they are.

I mean - the rear housings have been "hi-flowed" to take the larger CHRA (ie, larger turbine wheel).

I can also tell you they are not R33 N1 turbos as the R33 N1 had larger rear housings as the turbos were laggy junk.

In summary - Go and get a photos of the exhaust housings and post them up.

[aaronjod]

Okay, pulled the exhaust housings off and here are the pics. Let me know if i need to measure and where..

[Moodles2]

I may be completely wrong, I'm looking at the exhaust wheel and it's triangle nut which makes it seem as they are actually stock ceramic turbos.

Looking at: http://homepage.ntlworld.com/tbroom/Turbos.htm

There's only one turbo that has 0.42 compressor A/R and 0.48 turbine A/R which makes it seem like these turbos started out their life as 270 degree journal bearing ceramic turbos from either a R32 or R33 GTR. If they are high-flows then it's probably been converted to 360 degree journal bearing at least.

[aaronjod]

http://www.skylinesaustralia.com/forums/topic/276643-how-to-tell-the-difference-between-a-ceramic-and-steel-wheel-turbo/

According to that they're steel wheel...

[aaronjod]

Okay, so I think I've figured most of it out, but still have a question or two.

Stock GTR turbo specs:

Compressor wheel: 42.5-60mm

50 trim

O.42 A/R

Turbine Wheel: 41.5-50.5

62 trim

0.48 A/R

Turbos I have:

Compressor wheel: 46.5-60mm

60 trim

0.42

Turbine wheel: 42-53.8mm

60 trim

0.42

So these have slightly bigger compressor wheels and slightly bigger exhaust wheels, but the exhaust trim is smaller?

They are definitely steel wheel/ball bearing so this will be an upgrade too. With these specs, dropped onto a stock rb26 with injectors/cam gears/stock manifolds ported out/ aftermarket dumps/ fuel pump/power fc running high boost (20 psi? Should be ok because steel wheeled?) I was hoping for the 300kw? Are these capable?

What effect would the smaller trim and similar to stock a/r have compared to say 34 N1/-7s? Will I see better response with less top end?

[R31Nismoid]

The exhaust wheel is larger, whilst the trim is smaller - trim being such a small difference while the wheel is larger - should flow more, but it's hard to say.

They should be very responsive in a .48 housing but will most certainly fall over given -9s fall over by 7500rpm with their housing/turbine/compressor combination.

At a stab maybe all over by 6500, 7000 at a stretch.

Given the rear housing is smaller & larger comp wheel, it'll be interesting to see if there might even be issues with surge as positive pressure is attained in higher gears/low RPM. Similar to what a Garrett -10 but earlier given the size differences and would probably go away a lot easier.

Honestly I wouldn't waste time, it's all quite a bit of guess work and if it doesn't work - what do you do then? Spend more labour to get them out and swap?

Probably why they were for sale in the first place.