2860 Q?

[_Ryan_]

hey all,

I know that the 2860rs is the disco potato, and that the 2860-5 is the 2530 equivalent, but you can get them both in the same specs on paper... and a mate is selling his 2860rs.

So, is there any difference between the 2860-5 http://www.turbobygarrett.com/turbobygarre...0R_707160_5.htm

and the 2860rs http://www.turbobygarrett.com/turbobygarre...RS_739548_1.htm

Will be going on an rb25, aiming for 200awkw, and want good midrange: 2.5k rpm ->5.5k rpm.

Thanks for any help,

-Ryan

[heller44]

look at how the -5 and the rs bolt to the pipework. the -5 is made to connect to the rb26 original flanges.

[_Ryan_]

25 for me, and this RS is t3

[_Ryan_]

GT28RS with 0.70A/R T3 rear housing from AVO

Does anyone know how well this would be matched to an RB25? i have searched.

Merry Christmas all,

Ryan

[discopotato03]

Short version .

There are three very similar spec Garrett "GT2860R" turbos , cartridges actually and its mainly the compressor and housing specs that differ .

The one everyone knows is the HKS spec Garrett "GT2530" . These can have turbine housings to be bolt ons for RB26 / CA18-SR20 / RB20-25 . The compressor is 60.1mm 63 trim with 47.7mm inducer . The compressor wheel is believed to be a modified T3 and given the era they were developed it that may well be the case .

Another little gem is the GT2860RS AKA GT28RS or the Disco Potato Turbo . Cartridge wise same as above except its compressor is a 60.1mm 62T wheel and looks to be along more modern lines than the 63T one mentioned above .

The -5 mentioned before is very similar to the GT2860RS , same 60.1mm compressor OD trim and ~ same inducer size . The difference is the exducers tip height which is not as high as the GT2860RS' compressor wheel .

I've only ever seen the -5 version with RB26 specific housings and with the slightly less tip height I think this would better suit the more compact RB26 style compressor housings .

People seem to want to argue the toss but the GT2860RS was designed to be responsive for a GT28BB turbo used on an 1800-2000 cc four in club spec motor sport . This is why it has large housings for a GT28BB ie 0.86 A/R GT28 turbine housing and the T04B 0.60 A/R compressor housing . Its compressor has a reasonably large trim size and its high tip height blades means the collector in its housing has to be wider too . So small frame turbo with best GT28 turbine and high pumping capacity compressor - in largish A/R housings . The SR20 people often claim they are laggy for a GT2860 turbo and fit the smaller 0.64 A/R turbine housing to pull up lower end torque . Some of you may think this sounds harsh but I think they need to alter their thinking of how to get an engine to breathe and spin and make torque without small turbine housings .

Anyhow so you can ID them on sight .

GT2530 CHRA no 446172-5021 .

GT2860RS CHRA no 446179-5066 .

2860-5 CHRA no 446179-5056 .

There has only ever been one version of any of these that bolts onto an RB20/25 and thats the HKS RB specific GT2530 . The others have GT28 (T28) flanged turbine housings and no one would use the compact RB26 style GT28 housing on anything but a GTR TT engine .

Aftermarket and bored out std Rb20/25 turbine housings are a grey area because they arguably have not been developed in this form with the resources Garrett has available have had they decided to make a T3 flanged GT28 turbine housing . Thats not to say they won't work just maybe not as well as they possibly could . I do know of some respected engineers at Garrett America who could have cheerfully strangled HKS for not offering that T3 flanged 0.64 GT turbine housing in 0.86 A/R as well .

Silly really because a bit more power could have been screwed out of 2530's on RB25's without choking them up in the upper mid range .

One of the fellas here made a Hi Flow out of a GT2871R 48 trim and RB25 housings , he sounded pretty chuffed with the results . You should talk to him as its always better to follow someone elses example when the results are good . There is always risks involved with one off turbos - if it doesn't work no one else wants it and you've done your dough .

I keep a VG30DET BB turbo here because one day I may just need its larger A/R OP6 turbine housing , I sort of hate the idea of having it altered because they're now harder to find . If it was bored out to suit anything it would be that high performance GT28 NS111 turbine because going any bigger roots the housings nozzle . I'd sacrifice an Rb25 housing first and only go larger if it really needed it .

Talk to Dale about the 2871/RB Hi Flow , cheers A .

PS think smart and don't bend self and or car in the festive season .