TheSkinFox

I also know that each of the GT turbos have about a dozen different configurations each, but i'll take whatever you guys got.

Here is my question. Can anyone provide a concise explanation of the differences in power (peak, power band, spool up, etc)?

Even better can any of the tuners provide a dyno overlay of them?

RS6 turbos seem to be pretty hot for ease of installation, the power, and and decent spool up.

RS6 turbos though use journal bearings? So one would think that the ball bearing GTR turbos would be able to spin up quicker while providing similar power? Or am i totally off base?

B5QShip

In general you're gonna get more lag with a larger mass to spool, but its also very dependent on the housing, comp/turbine wheel combo, and options.

As far as compatibility/ease of implementation go, Autospeed's GT kits require the most hardware. There are now 2 new bolt-in GT options available, but I'm not going to release details until the designer does so publically himself. RS6s require some adapters, but I believe are mostly plug and play. K04s obviously bolt right in with RS4 inlets.

in terms of power, if you're talking about what's been shown on a Mustang dyno (whp on 93 octane):

Stock S4: 200
Custom Tooned Stage 3 S4: 400
Custom tuned K04/RS6 hybrid: 450
Full RS6 setup: ~500+
GT28R: 550+?

GT25s are not worth the trouble imo.

Z-Tuned (Alex)

No offense, but if you think RS6>GT25, I can't take your "opinion" seriously. GT2560R's on pump gas will not only make as much power as what an RS6 makes on race gas, but spool difference is a matter of a few hundred RPM. GT2554's on pump make full boost pretty much the same as RS6's and still make about the same, if not more power than RS6's on race gas.

Have you even considered the fact that for an RS6 to make as much power as a GT25, you need to run close to 2 bar? That is far beyond the efficiency for that turbo.

GT25's will outflow RS6 turbos in lbs/min, make more power at less boost, and spool time is identical on 2554...2560 a few hundred RPM. Add the fact that you're getting a ball-bearing CHRA and running lower boost...how on earth can you say RS6>GT25?

ZKNY

Can anyone provide a concise explanation of the differences in power (peak, power band, spool up, etc)?

you need to do a lil HW. all the info is out there. go to garret's site and read all the turbo-tech 101, 102, 103. call ASP, EPL, VAST, Etc.

without getting too concise about anything... the ko4's are the smallest (housings, compressor wheels, turbines, etc). therefore, they spool the quickest; however, due to their size they run out of steam upstairs.

on the other hand, the GT28's are the largest of the turbos mentioned. however, also due to the large nature of the turbo, there is much more lag, but also there is much more flow til the redline and beyond.

if you are tryin to choose, it all depends upon what you want. do you want a peppy light-to-light turbo that will also be good for roadcourse tracking? or would you rather have a highway setup that will be way laggier?

food for thought, even though the pj KO4's arent gettin much love these days, there is much evidence to pursuing this turbo. if running w a refined tune, the KO4 can be pretty scary.

also, even w the upside power of a GT, they still havent put down great times at the track. in fact ko4's have em beat in most cases.

ZKNY

2nd. the GT2560 is rated for 660-800ish hp. the RS6 will NEVER put that amt of HP down.

TheSkinFox

I'm trying to decide between an rs6 setup and a GT setup. I just threw the K04 in there for a baseline.

I got a long block that I am going to be building up once i make my final decisions.

I've been for a ride in DAP's RS6 turbo S4, which might I add is insane.

I want power and quick spool up. Which is why i was secretly wondering how the GT25R's compare to the RS6's. How they compare in power and lag.

I've seen GT28R dyno's and the power band seems to be pretty narrow.

Dr. Jekyll

Gt2560 > RS6. As far as the 2554 vs. the RS6... I think they are about equal, more so if you are talking a hybrid RS6. Although there is hardly enough data to say one way or another yet.

Dr. Jekyll

I'd say go with a hybrid RS6 turbo (like DAPs) or a gt2554. Between the two, the RS6 is probably a bit cheaper since the only GT kit (released at this moment) that uses the 2554 is the VAG kit and that's around 10g's.

radron26

3rd, GT28 is the greatest turbo of them all!!!!

B5QShip

There's plenty left to explore with this platform, but I'm quoting numbers from dyno runs made by tuned S4s, not theoretical numbers that a turbo supposedly can support. I'm not saying it isn't possible, I'm just saying what's been done.

Me saying RS6>GT25 was not intended to claim that RS6s can make more power. The oversimplifications I made in the subject line are in reference to all of the criteria that he listed, ease of implementation included. ASP put together a GT25 kit with less than impressive numbers. It seems they have scrapped this for GT28Rs for a good reason. Until there is a bolt-on GT kit (which there now is), I'll take hybrid RS6s any day over any other option. And fwiw, only Gt turbos ending in 'R' are ball bearing.

I don't claim to be an expert on any of this, all I'm trying to do is give info based on dynos I've seen.