both, among other things

 

<ul><li><a href="https://forums.audiworld.com/s4/msgs/2467599.phtml">https://forums.audiworld.com/s4/msgs/2467599.phtml</a</li></ul>

 

looks like a 40R

 

variable geometry turbo and big is similar size to that pic. At 55psi he's running high 11's... Damn I knew I should have bought a truck.

 

**Ding**

 

please keep in mind that turbo performance is made up of both the compressor and turbine side workin together....but just to give u an idea

turbo max lbs/min air max whp

k03 ~33lbs/min(total) ~310

k04 ~43lbs/min(total) ~410


To4e 50trim ~47lbs/min ~450

GT30r ~52lbs/min ~490

GT2552(twin) ~52lbs/min ~510

GT35R ~61 lbs/min ~570

GT2871(twin) ~74lbs/min ~700

GT4088 ~74 lbs/min ~700

GT4202 ~96 lbs/min ~900


Housings , trims, wheels all effect the output to some degree. this is just a guide based on their flow charts.

 

how about full RS6 turbos?

 

Ive looked but couldnt find any real maps for Full RS6's but judging by their dyno results full RS6's seem to be about a 24-25lbs/hr comp wheel.....so about 450rwhp (in their effieciany range).

the problem for the S4 community(if u want to call it that) is the variations that u can get with Twins vs single turbo.

Please note That i have ZERO experiance with the twin setups currently being run--but I have extensive experiance with singles......from my observations---it seems to me that the turbine side of RS6's are too big for the comp wheels they have. they seem to max their comp wheels around 450-460rwhp yet the spool is way over 4100rpm. That is way too high for that power.

For comparison a single GT30R 0.63 a/r will make ~460whp and spool fully spool at 3800rpm on an STi which is 2.5liter. I would bet that our 2.7L engines we could max out a GT30R (460whp)at 3100rpm and 20psi.

thats the great thing about singles...u can go from a 0.63 a/r turbine housing to a 1.06 a/r housing in 1 hr and gain 40whp and give up 500rpm spool.

i think a great matched single for our high flow heads and 2.7l engines is a T4 based turbo P-trim wheel with a small 0.58 a/r. I bet u could get itentical spool to a RS6 yet max out at 650rwhp.


none of this matters because this car has been around for 8 years and the combined expertise of the community had produce 3 cars with singles....2 that dont run.