It seems that many b5 s4 guys judge turbos based off which tuner is marketing the turbo, the dyno sheet, and ¼ mile times. Here is a turbo review more from a driver’s point of view.
I have actually driven/ logged/ tuned k03, k04, FT, 605, 770, gt25, rs6’s, and pte 6265 on a b5 s4. Not sure if this will give me any “street cred” but here is my review. I’m not selling anything, just stating from a driver’s perspective how these turbos “feel” to drive.
Much of this has been said before, just not all in one place. Let’s have an intelligent discussion, no that turbo sucks, or this tuner sucks.
k03- Stock turbo which may or may not last on any tuned file. Great tq down low and will put a smile on your face if you mash on it in 6th gear on the highway. A strong stage 2+ setup should run about 12.8 @110. I had a buddy go 12.38 @ 114 on 93+meth. Of course, the JHM 12.28 run on race gas is the record holder.
(pretty sure about the trap) I believe high 11’s to 12 flat is possible on race gas or e85. of course these won’t last long on a file that runs low 12’s @22-23 psi. My buddy Dave’s lasted 6k miles with 135k miles total.
k04- perfect street turbo for DD. early tq onset and decent top end makes me happy every time I drive one. Proven time and time again, good for high 11’s to low 12’s. We all know JHM went 11.1 on these with race gas… something no one can seem to replicate. We’ve seen them dyno 360whp+ on ots tunes to over 450whp on e85 and race tunes.
Ft- Again another good DD turbo with early TQ onset. Capable of holding more boost out to redline and good transient response. With the reliability questions out there I have seen some die out of the box and get replaced with no issues, and some have been installed for 10k to 25k miles with no issues. The shaft on these turbos is not as robust as I would like but they seem to work just fine. NOT AN Rs6 or 605 CONTENDER, they simply don’t flow enough. Nice top end, just not in that leauge.
Rs6- Oem turbo with some housing modifications works great on the 2.7t. The Tq onset hits a little later than k04’s but when it hits it’s much harder. I’ve seen these dyno from 450whp on 93 to 550whp+ on e85. The best thing about this turbo setup is the big fat powerband. I consider this a good DD turbo setup. This is also a very potent ¼ mile turbo setup. Good for high 10’s on race gas or e85. I have seen an 11.4@133 run on e85.
HYBRID RS6’s- I’m looking forward to seeing some more info out on these new billet hybrid Rs6’s with bigger wheels and monster top end. We’ve seen the JHM 10.8 run on these recently; managing that time with a throttle body issue is impressive. I have no experience with them yet.
605- The 605 and rs6 drive very similarly. 605’s can hold more boost up top and like a higher Pressure ratio, as has been brought up before by many others. I have seen one 605 turbo blow and get rebuilt 2 times on the same car never having seen over 30 psi. I have seen several sets running flawlessly for many miles. The power band is very similar to the rs6’s but the top end is a little better.
GT2560- This is a laggy setup compared to the rs6 and 605… TQ onset hits around 4k rpms, several hundred rpms later than rs6 or 605. Ball bearing Turbo reliability and top end comparable to 605’s = win in my book. The new gtx models look very promising as well. If you like your insta-spool this is not your turbo unless you have it “billetized,” and even then I’m not sure this setup would be for everyone.
770- I really like this turbo, but it’s not for everyone. Tq onset is a little later than rs6’s but not so bad like a BAT 1.8t. There is still a Big power band even if only reving out to 7500 rpms. This Turbo is a top end monster on the 2.7t. Ball bearing reliability, check. Power does not fall off up top, check. Drives more like a big turbo setup, because it is, duh. This season we should get some good ¼ mile data since we have several of these setups running around now. Not my choice for a DD turbo if you like your insta-spool.
Pte 6265- All I can say is Wow. If you are going to go the single turbo route and you want big top end, here you go. The turbo is laggy on the 2.7t, Tq onset starts around 4k rpms. Once you are in boost you will not want to leave it. Even at 25 psi the turbo just performs. At higher boost expect good things to happen. I plan on playing with this setup some more in the future.
