Turbo Boost
 

I took my car to the dealer because I feel the car hasless power than before
and I do not feel the "Turbo Lag" anymore. At first, the dealer said that my
turbo had no boost and ordered a new turbo. But when I took my car back to have the
turbo installed, it was "found" that my turbo was actually OK. Here are the diag.
mesaages.
1. No trouble codes were found after scanning engine.
2. with 1551, found the boost to be within spec. - 1700 mBar
3. with VAG 1397, the boost was found to be 9LB/IN2 and within spec.

After scanning through this forum, I belive the normal boost should be about
0.8 Bar (800 mBar) or 11-12 PSI (LB/IN2). The number shown in 2.
suggests a boost of 1.7 Bar which is way too high. Or the number in 3 suggests
that the boost is too low.

What is 1551 or VAG 1397?? What number should I
believe?? If I do not feel the "Turbo Lag" at 3000RPM, what does it suggest?

I am taking my car back to the dealer in 2 weeks, what should I ask them to
do?

Thanks.

Shih-Liang Chiu

how many miles on the car?

225 or 180? Original DV? If yes, go aftermarket (Bailey or Forge). I have a friend who was ....
 

diagnosed with a bad turbo and Audi replaced it. When he still was losing power, Michael took a look at it and it turned out to be a split hose that the mechanics missed spotting.

Usually dealer will check boost only at 3200 rpm.
 

On 225 pressure is regulated to 1.8 bar but hits spikes of 2.2 bar in low gears. To get boost subtract barometric pressure (message block 113, item #4) from pressure before throttle (message block 204, item #4). On 225 wastegate begins to open at 2200 rpm. A good turbo will produce 1.8 bar at 2200 rpm, if dealer measures pressure only at 3200 rpm then a somewhat weak turbo can pass the test. If you want to know what's going on you need to get VAG-COM. Take all reading at WOT.