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Would A 2860 -7 Or -9 Benefit From Ported Exhaust Housing?

ZT-R

By ZT-R,
in Engines & Forced Induction

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ZT-R Enthusiast

ZT-R

Posted
Posted

Hey guys I talked to ATP turbo and they said they will soon have the GTX2860 as a bolt in for the skyline. I am looking for 450-500whp in my S30 240z. I know that kind of power is typically the GT2860-5 which has 76 .64 a/r turbine. the -7(n1) and -9 (gtss) have 62 trim .64 a/r. Do you think by extrude honing the -7/-9 .64 a/r housing that would have any benefit to the turbo still using the smaller .62 trim wheel? or is the wheel what is keeping this turbine back in power?

Thanks.

lee

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

lol hold up - you know what it'll be. Just a milled housing to suit.

It won't be a proper Garrett one, and will likely mean rubbish performance as we've seen in the past.

Do you think by extrude honing the -7/-9 .64 a/r housing that would have any benefit to the turbo still using the smaller .62 trim wheel? or is the wheel what is keeping this turbine back in power?

The -5 turbine and the -9 turbine are the same size... They both use the 76 trim wheel.

The -7 uses the smaller trim.

All honing will do, is hurt the blistering response - which is why you make that turbo selection in the first place.

ZT-R Enthusiast

ZT-R

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On garret website turbo 2859r (707160-9) shows a 62 trim .64 a/r

the -7 ( (N1) 707160-7) 2860r shows 62 trim .64 a/r

the 2860-5 (707160-5) show a 76 trim .64 a/r

the site is sort of misleading because 2860r are listed as 2860r (1) 2860r (2) 2860r (3). the GTSS is the 2859r so there is 4. i believe the 2860 (3) is essentially a disco potato, its part number is 739548-9 so dont confuse the to -9 turbos.

ZT-R Enthusiast

ZT-R

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Hold up. Any more info on this?

From ATP email today.

"They would be just like the -7 and -10 turbos. You won't get the GTX comp housings with built in anti-surge though and so these will have the skyline style compressor housings with 2 bolt inlet and 2 bolt outlet and no way to integrate the anti-surge machining.

discopotato03 Grand Master

discopotato03

Posted
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Works like this , you have the basic T28 turbine in I think 62 trim and a few turbos got the nice GT28 NS111 turbine in 62 trim as well . It has fewer more open blades than the normal GT28 turbine and in performance apps is a good thing .

I don't have time to look ATM but off the top of my head the GT2854R/GT2859R/GT2860R (707160-7) turbos got the 62T NS111 turbine .

If you see a GT28 based turbo with a 76 trim turbine its the larger trim version of the NS111 like say HKS spec Garrett "GT2530s" get .

Many won't agree but my take on turbine and housing size choices is more about where you want the boost and torque to be than maximum power output up high - in a roadie anyway .

Also I doubt theres room on an RB26 style compressor housings to incorporate port shrouding and make it work with a GTRs inlet plumbing .

You also take the risk of going out on a limb with GTX compressors and plain comp housings .

Its one thing to increase a compressors pumping capacity and another to bank on it not surging . The only way to know is to try and its an expensive exercise if it does surge .

The factry style turbo layout on an RB26 was designed for a purpose and the tight packaging doesn't leave much room to make major alterations . IMO you need to try and get them right the first time and if it was me I'd go conservatively with something known like -9s .

A .

ZT-R Enthusiast

ZT-R

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Not the exhaust manifold porting, the turbine housing for the turbo. I really would like the -9 I think but I havent seen any rwd numbers close to the 500 mark. Thats why im wondering if you ported the housing of the -9 turbo from a .64 A/R to something like a .72 A/R or something (light extrude hone), if it would gain any up top, I know you would probably loose a touch of spool though.

discopotato03 Grand Master

discopotato03

Posted
Posted

Turbines and their housings are always a compromise , where you gain at the top you lose at the bottom . AFAIK Garrett and HKS only made RB26 specific turbine housings in 0.64 A/R and its questionable that porting them would make much difference .

I think the way to make an RB26 wider ranging without increasing its capacity is to give it some form of variable cam timing and play with fuel octane and static CRs . Ideally more cubes but thats expensive to do as well .

A .

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