Custom Garrett Turbo's ?

[Ziller]

Hi Guy's, around a couple of year's ago I purchased a pair of Garrett 350hp 2860 turbos for the R, punching out an 11.8 on a near stock engine at Calder made my night, with my tune shop no longer trading and having been bitten by the bug I had a new engine built, with only a few thousand km on the turbos and an engine being built, the new workshop suggested I have the turbos checked out, he asked me if they were dash 5 or 10s this was all new to me at the time.

Having the turbos returned to me fully rebuilt (not even a phone call) he told me they were custom dash 8s (not listed) and that the 10s rated at 400hp would have given me around 40kw more with a full dyno tune.

Skip ahead, dash 10s fitted WTF! only 5kw extra, headed to Bayswater for the answer, dash 10s are really GT2871-10, big bastards! rated at 460hp the dash 8s turned out to be GT2871-3, with a Ind 49.2mm and 71.0 Exd on the compressor, almost the same frigging Turbos!

What I find odd is the 2871-3 are listed with a different compressor housing the tube type like on the RS' model, my one's bolt straight on like the dash 10s so maybe they are a custom or special order turbo, can anyone shead any light on this. Thanks

[some_cs_student]

Would that be this one?

http://www.turbobygarrett.com/turbobygarre...1R_743347_3.htm

Linked from here http://www.turbobygarrett.com/turbobygarre...bochargers.html ?

[Ziller]

Would that be this one?

http://www.turbobygarrett.com/turbobygarre...1R_743347_3.htm

Linked from here http://www.turbobygarrett.com/turbobygarre...bochargers.html ?

That's the one, if you compare the housings (click for flange dimensions) you will see they are not the same yet my dash 3s are bolt on's.

[discopotato03]

I don't have time to chase this now but later on .

Basically I think Garrett do two different families of compressor housing for RB26 specific GT28 based turbos .

From memory the smaller ones are based on the old T3 foot print sized backplate and the larger ones the T04 sized plate .

The design of these housings extenally looks nothing like a generic T3 housing or a T04 truck housing , its the backplate diameter and internal passage that tells the story .

Now to a degree the slightly smaller sized compressors live in T3 sized housings where the larger trim 60mm wheels and 71.1mm wheels tend to get the T4 sized housing .

Later , cheers A .

[discopotato03]

Ok to Garrett GT2871R series turbochargers . I have to assume that by -3 and -10 you mean the 48 and 52 compressor trim versions of that series turbo .

I still have to look in turbobygarrett's site but I gather that there are several versions with RB26 specific turbine and compressor housings .

The fact that (I think) HKS markets an RB26 version of the Garrett GTRS (GT2871R 52T or 446179-67 CHRA) means there must be housings to suit an RB26 and highly likely the compressor one is a Garrett part .

As for non catalog spec GT28xxR turbos , yep that's possible . I had GCG built me a GT2554R turbo not too long back with the better NS111 turbine and S15 turbine housing on it . I call it GT2854RS for the same reasons Garrett would it they produced units like this . The S on the end means altered specification - same deal as for example a GT2860RS .

Depending on what you started out with and what components the builder/supplier can get a few things are possible with GT28 based GT BB turbos . Its always best to get a std spec turbo if available but if you're sure you have a more suitable spec for the application bitzers can be made .

Now if going larger in compressor wheel or its trim size its an easy enough job to machine (re profile) the compressor housing to suit . Going smaller generally means buying a housing to suit the wheels smaller inducer size and blade profile .

A .

[Ziller]

Hi Discopotato and thanks, my understanding is the GT2871-10s are the same turbos as a HKS GTR-S with the only difference being the 71.2mm major Dia opposed to a 71.0 major on the Garrett, and a 0.64 A/R with the option of a 0.86 A/R, I'm no expert with turbos so I don't understand what the compressor trim 48 to 52 is, the Dia on the compressor housing is 52mm which reducers down to accommodate the 49.2mm inducer on the compressor wheel, could it be reasonable to assume that my dash 3s are just the same as the dash-10s with a smaller inducer with a housing to suit the dash 3 compressor wheel, supplied by Garrett at the workshops request? I rang Sydney were I'm sure they came from and the guy wasn't sure what I was talking about, I do remember the guy who supplied them saying that Garrett hate's these types of orders, and also the word custom being used, I just don't want to make a Goose of myself if I move them on down the track.

[discopotato03]

Well I don't recall HKS specifing a special cartridge (center section and wheels) for GTRS turbos . If anyone with a GTR specific GTRS turbo can post their cartridge numbers or a pic of the turbos ID tag that'd tell the story .

I'm also not aware of any GT28 based low mount bolt on RB26 turbo having a 0.86 A/R turbine housing . All the 0.86's I've seen are not the compact type , rather the normal SR20 style turbine housing .

Just to make it obvious Garrett and HKS have compact GT28 housings AFAIK in 0.64 A/R only .

Garrett and HKS make SR style housings in 0.64 A/R .

Garrett only make 0.86 SR style housings .

HKS make 0.64 A/R housings to suit RB20/25's with a "T3" inlet flange and RB20/25 dump flange .

HKS only make a port shrouded compressor housing for RB20/25 .

Confusion always with these turbos because they can be SR style or RB26 style , actually HKS even do an RB20/25 version of the GT2871R 52T/GTRS and these housings are different again .

I shouldn't keep saying GCG but they seem to be the most interested when it comes to non std or custom GT BB turbos . The "mother" mob only seem interested in selling or possibly repairing std units .

Hope this helps , cheers A .

[Ziller]

Thanks Discopotato, yer its a bit confusing, I should be picking up the dash 10s next week from the workshop to compare, when he measured the compressor wheel he just said it measures up as a 2871-3 but it wasn't till I got home that I checked the garrett web site and found that although he was correct, the housings were different, Ill take the dash 3s to the workshop next week so we can both have a good look at them and maybe solve what has been a two and a half year mystery for me

When I get to the bottom of this Ill post a thread for those who remember, Thanks Guys!

[discopotato03]

Hi Ziller , if you can post some pics that would be handy .

There is a bit of variation in what many consider is the norm with these GT28BB based cartridges and compressors .

HKS used to have a slightly odd one they called GT2535 and later on a compressor variation in their spec RB26 specific GTSS .

I don't think its too often that people get brave enough to physically change out compressor wheels themselves , mostly (but not always) thet change cartridges and if nesessary remachine their existing housing/s to suit .

Generally the numbers on the cartridges ID tag tell the story , look for something like 446179-50xx or -xx .

They don't always have it , sometimes its a turbo pt no or even a model no ie 2871R 52T .

Cheers A .

[Ziller]

Looked every were for the camera cable, yes have pics and will try to post today, the car is at Nizpro under going a long list of changers and its a long hike from were I live so I'm eager to compare the two turbos, Simon can then have a good look and hopefully identify them if I can't solve it before hand, after all that I'm going back to what I thought I may have had in the first place, 2860-5s