Two turbo families suitable for VR4s

[djb160]

Okay, so with the exception of particular people (Valmes) it seems there's only two common candidates for replacement turbos that people consider. TD04s and GT25s.

Please correct me if I'm wrong or misinformed here.

e.g.1. TD04H 13T ; I get that the '04' part is the turbine description and 'H' describes the shape of the wheel. The '13' describes the compressor wheel size and 'T' the compressor wheel shape. Is it true that basically the larger the letters the more aggressive they are? If so how much more so with each increment?

e.g.2. GT2560R - 9 ; The 'R' means it's a ball bearing model correct? What do the '25', '60' and '9' mean? I'm guessing that the '60' has to do with the compressor housing and that you have to look at the specific inducer/exducer sizes to tell what is happening? for example the GT2560 - 4&9, the 9 has a slightly smaller C-wheel but a slightly larger T-wheel, so this would make it more responsive and .......?????

I've seen a couple of references to GT2530's, what has been matched with what for this setup?

With the examples of the GT25s from garrett http://www.turbobygarrett.com/turbobygarrett/products/turbochargers.html

How come the maps are SO different just because of slight changes in wheels and what would this mean in terms of application.

[bradc]

The Garrett name scheme is complicated, a GT2530R is a 3rd party hybrid huge turbo that is half GT30R.

The real Garrett names are GT2554R - GT2560R, then GT2854R - GT2860R - GT2871R.

The second part of the number 54,60,71 is the compressor wheel size, the first part of the number is the size of the turbine (but not in mm)

All GT25xxR have a 53mm turbine, GT28xxR have 53.8mm It is all explained on Garrett's site in their FAQ's

As for TD04's, basically the larger the number 9, 13, 15 the larger the turbo. Check out Jeff Lucius's stealth316 website for more TD04 details

[djb160]

So is a 60 trim as per their site a bit too big for our engines coz they seem quite reasonable given the charts, then again I might be reading them wrong.

[bradc]

depends on how much lag and top end power you want.

[Goku]

So what would be the best TD04 for the 6A13 then, relative to power and lag.

The best medium ground I guess

[bradc]

a 13 or a 15, capable of about 450-500hp

[djb160]

Okay now are the compressor housing largely different within 04 or 05 wheels? What about the housings for 13 and 15 as these would be the largest of the two housings yes? Where is the overlap between the different compressor/turbine wheel/housings and the next sizes up (bollocks eg) say a 13T produces a similar flow the same as 15 given a matching scaled turbine?

[bradc]

td05's are a bigger family than td04's, all td05's are bigger than td04's

[djb160]

but what about the compressor side of things? Is a TD04 15X flow the same as a TD05 15X except for the turbine responding differently of course?

[bradc]

I'm not sure on that one!

[Turbo_Steve]

I'm not 100% certain, but I think you'll find the compressors are still different. Annoyingly, their peak flow rate is likely to be the same, but the charecteristics definitely change between ranges: Induction and exduction pipework is larger on the TD05 for a start. Very VERY similar, though.

[djb160]

Okay then is the compressor housing the same size for say a TD04 13G and a 13T?