Whats the difference between RS6-K04's and RS4-K04's???

**1 point 8 tee** · 10-09-2008 01:40 PM

im about to go stage 3 relatively soon and was looking at my available options and saw some sets of RS6-K04's and RS4-K04's...I was wondering if anyone knows the exact difference between these turbos. and opnions on if the performance difference is worth the extra $$$....i was also looking into the different softwares available....i was thinking of either ASP or VAST also input on that would be very helpful

**pit viper** · 10-09-2008 01:44 PM

The RS4 is a direct bolt-on, no modifications needed.
The RS6 has a different CHRA, with a bigger compressor wheel, and has a larger turbine housing that requires you to weld a new flange onto your downpipes.

I've only seen 1 set of dyno's from straight RS6's, but the spool up looks to be quite a bit slower.

**1 point 8 tee** · 10-09-2008 01:47 PM

do you have any input about my question on the software subject....I am mostly considering ASP or VAST..

**pit viper** · 10-09-2008 01:51 PM

Originally Posted by 1 point 8 tee

do you have any input about my question on the software subject....I am mostly considering ASP or VAST..

Nope. I'm in the same boat myself, picked up a bone-stock 2.7 A6, been doing a ton of research on turbos, tuning, etc...

**2ndEngineS4** · 10-09-2008 02:09 PM

Some info I found:
"
Specs:
As follows in comparison to a regular RS4 K04.
Compressor wheel OEM RS4: 40mm inducer, 51mm exducer
Compressor wheel JHM RS6: 42mm inducer, 56mm exducer. The turbine housing a/r is also much larger. There will be a lot of gains on the hotside due to its larger size. Works with K04 inlet pipes and stock exhaust manifolds, coolant and oil lines
"

Tuning: I would personally choose Vast, but Jason can certainly give you more details.

http://www.jhmotorsports.com/shop/ca...products_id=18