O.K. this is my first Audi and my first experience dealing with a turbo.
2001 A4 quattro 1.8T, I purchased this car as a project car, was told it needed a engine swap or rebuild, turns out the oil pick-up was plugged which I believe also toasted the turbo, anyway I have cleaned the screen, installed a new oil pump, replaced maf sensor, replaced dv valve with 710N (thanks to looking thru these forums) And I put on a new aftermarket turbo (BIG MISTAKE!) lasted less than 500 miles and then was told it needed to be re-balanced before installation. I have now installed a used correct application audi turbo and things seemed fine the first couple weeks but now I seem to have very little boost and the turbo is louder than when first installed, doesn't sound bad just sounds as though it is not developing any pressure so it is just reving way up.

I have done the recomended leak test and found none, replaced vacuum lines although I found none that were cracked, the only thing I can think to do now is the n75 valve but I can't find anything that tells how to test it. Because of all the initial problems the car had I cleared all codes and right now there is nothing indicating a problem other than lack of performance still drives nice, idles nice, and gets up to speed, just no pep.

Any ideas would be appreciated, I will be getting a boost gauge soon I hope but am hoping somebody has an idea what I'm up against.

thanks, Kevin

 

maybe the wastegate its messed up. the louder turbo noise could be caused by a messed up wg, this also would explain the boost coming on slower. the car still would idle and drive nice just be lacking power.

 

I will check that out tomorrow and post what I find, thanks.

 

thats just a guess. you are taking all the right steps to find out

 

You did check for an exhaust leak right? The turbo to manifold is a well know gasket blow out location and will kill performance and change the sound some, a ton if really big. I run no gasket in there and works perfect for me. I would check there to start.

 

Any NEW turbo should be balenced when you recieve it. Either it wasnt new or it was rebuilt and not done well. And what turbo was the by chance?

 

This is the aftermarket turbo I purchased thru ebay,http://cgi.ebay.com/ebaymotors/ws/eB...m=120126606185 I thought the same as you are saying, being new it should be ready to install, nothing on the ad said anything about re-balancing, it was when I inquired about warranty that I was asked if I had rebalanced, if not the warranty would be void.

 

that's not an aftermarket turbo, that's a K03. the K03 comes standard on all audi 1.8T engines, although your 2001 may have originally been equipped with a K03s, which is a "sport" turbo.

 

No thats a Chinese/Korean ko3 KNOCK OFF turbo. Im shocked it lasted 500miles. A real used stock turbo can be had i the classifieds for $100-200 and most last well over 100k miles.

 

how would you check for a blown gasket in that location and how would you check to see is you exhaust manifold is cracked or leaking?