I just picked up an 01 S4 the other day, the previous owner told me he thought the turbos were blown due to a dramatic loss in power. I did a boost leak test and found no leaks although the oil in the pan was bubbling alot (leaking through the oil return). I hooked up a boost guage and took it for a drive and got 0psi all the way up to 5k. There was no rattleing noise or smoke, only a very slight whine at higher rpms, nothing that sounded too horrible. I do know of theproblems these car have with eating turbos and even gota pair of used oem units when I bought the car butthe lack of smoke and noisehas me doubting that the turboshave failed. Any advice or suggestions would be appreciated, I may check shaft play if I get a chance today. Thanks

 

sounds like they are not connected or deliberately disconnected for the sale?

 

Take it back to the dealer and tell them they sold you a broken car [:@]

 

I purchased it from a private seller so no dealer.

Well theres no boost leaks and I'm not sure the prev. owner had the technical know how to rig it to run at 0 boost. He said he let a friend take it for a drive and a when he got it back there wasa completeloss of power. I've never heard of a turbo failing so un-dramatically, especially at 59k miles.

 

The cost to upgrade to k04s is way more than I wanted to spend on a car I plan on daily driving.I dont mind installing thestockers I have , I just didnt want to change them if I dont need to. At this point I just want to diagnose the problem. Thanks

 

in order to run 0psi of boost the wastegates on both turbos would need to be opened, not sure how you prop both wastegates open. when you did your test are you sure you were on a line that was indeed boost and vacuume?

 

0 psi @ 5000rpm's the turbo's are working, just not a lot. If the turbo's were totally not working at all, it would 20-25 ichm (vacuum)

I would vag the car for stored codes. It might be a N75 valve, leaking wastegate lines, or bad actuators.


If you are going to drop the engine to replace the turbo's, you are really better off spending the extra $1000 on K04's! More power, & more realiblity.

 

I teed off of the FPR boost reference line, so that should have been a good reading.

It comes out of vacuum toatm. pressure quickly once Im on the throttle, which would be expected even if the turbos werent spinning.

Ill search, but whats an N75 valve? It feels like the wastegates are just staying open at all times.

I thought to get a set of k04s on the car it would run 2000+ with the IC pipes and intakes?

Thanks for the help.

 

Ok, so the N75 valve controls both wastegates. If the valve fails, wires come disconnected, etc, do the wastegates stay open or closed? I would think open for safety. Where exactly is it located and how do I check it for proper operation.

 

Whats a good place to pick up K04s for a good price?