Herr Schröder

Alright, I have been trying to get my car setup (ping, crappy mileage, surging, etc.) for six months now and after giving up on myself and taking the car into a <new> local guru, he found the car to be overboosting to 1.5 bar! That pretty much starts to explain just about all my problems!

I went from being SO happy about finding this out to being seriously worried! I'd imagine my car has been overboosting for quite sometime.

My car had 80% leak down in two holes prior to having the head re-done (at 71K miles, 73K now), would a life of overboosting have caused shortened valve guide life? (may be a stretch???)

Can I pretty much bank on having to replace my turbo in the near future?

I read a few of Minhea's posts saying how horrible pro-longed overboost can be, and is thus why I'm asking all these questions and didn't know just how high 1.5 was in the scheme of things?

TIA all, your input is always appreciated!!!!

UrS4boy

gauge that goes to 30 psi (2.07 Bar) boost (relative not absolute, like the factory gauge) and 30 inches of mercury (Hg) vacuum can tell you lots about how things are running. Why are you waiting? Are you afraid of learning something about your car?

Oh yeah, your "problem" (if there is one) will be a function of how often you got into the boost. Good luck.

Dave F.

Herr Schröder

and the gauge is part of the car now, but unfortunately, I was told time and time again by my former mech, that I had no boost issues and it appears now that he may have led me down the path of some serious damage (yet to be 100% discovered). ALTHOUGH, you are right, and I should have done this six months ago.

Interesting....I asked my former guy in July, if we needed to just install one, and he thought it a waste....

Live and learn, I'll update once I learn more this afternoon..

Thanks Dave.

S_noob

::finds site for boost gauge and clicks "BUY"::

looking for some advice.. what is a good boost gauge that is relatively easy to install and looks nice ( i have tan interior ) also one that wont lighten my wallet too much...

thanks in advance

4Driver4

1.5 bar isn't overboosting.

Herr Schröder

I am just trying to get in a comfy place with this car. What range would be overboosting?

Thanks!!!

a4kquattro

but still is unable to accept 32 pounds of boost as normal for an rs2 turbo. THAT my friend, is overboost..

4Driver4

From Scott Mockry's site:

"Stock Boost Levels-How does the ECU control Boost?

The 1991 200TQ with 20V Turbo Engine was designed to run a maximum of 1.825 bar boost (absolute) or ~12 psi gauge pressure, as set by the Motronic Engine Control Unit (ECU).

The 1992-96 Audi S4 in overboost mode will have boost set to about 2.15 bar absolute. The actual boost produced will vary depending on engine RPM, air temperature, fuel quality, and altitude. The 20V boost control system is different than what was used on the earlier 10V Audi Turbo engines."

Herr Schröder

Aside from a forged BPV, all is as it was when it floated over on the pond.

Altitude!!! After re-reading your post that just dawned on me. I am at a little over 6K feet, and I believe pressure drops with increases in altitude (please correct me if I'm wrong), so 1.5 bar at sea level would mean quite a bit higher pressure levels when coverted to an actual pressure number than 1.5 boost pressure at 6K feet? Alright, Schroeder needs corrected boost pressure calulation 101...


I guess the reason I'm seeking (you) the experts time here, was a post Minhea had posted (see link) and it threw me off, as the car is pushing 1.5 past 4.5K.

Thanks again, and as much as it pisses me off that this thing has been such a PITA, I actually like getting to bottom of all this stuff!<ul><li><a href="https://forums.audiworld.com/s4s6/msgs/3743.phtml">https://forums.audiworld.com/s4s6/msgs/3743.phtml</a</li></ul>

4Driver4

Scott quotes absolute boost, while Mihnea is talking about boost over and above atmospheric pressure (one bar). Which are you talking about? In other words, how are you reading boost? What does the gauge say with the key on but engine not running?