Leszek

A lot of people complain about a small hesitation that the 1.8T has between 2000 and 3000 RPM. I’m certainly one of those people. The hesitation exists regardless of the chip in the car. From personal experience in my car: stock chip has it. Wett 0.8 and 1.0 bar have it. Garrett stage 1 and stage 2 used to have it. The more power the chip has, the more apparent the hesitation is. Garrett stage 2 therefore had the biggest hesitation. It was also the “roughest” chip of the bunch.

I’ve send e-mail to Garrett a couple of weeks ago pointing him to the A4.Org discussion on the hesitation topic. He wrote back that he had an idea and started working on a possible solution. A week ago I received the new software. I’m now starting the second week. To say that I’m impressed would be an understatement. The new chip is the best chip I have ever driven period. It wins my top awards in two important categories:
- It is the smoothest chip I have driven. It’s even smoother than the stock chip!!! I have driven stock, Wett 0.8 bar, Wett 1.0 bar chips in my car and APR 1.0 bar chip in my friends car.
- Subjectively of course, it feels that it has the best seat of the pants experience. Published torque numbers (270ft-lbs) might have something to do with it.
To anyone with a Garrett chip – get the new software. It is well worth it!

On a different note, APR made a post a while back that they are also working on the hesitation fix. Hopefully soon my friend will be able to get the new APR software so that we can have a comparison. <ul><li><a href="http://www.giacusa.com/welcome.html">Garrett Integrated Automotive Corp.</a></li></ul>

Francis Y.

when i called APR, i was told that is was actually just a restrictive exhaust problem. i'm not sure that is true, but i have found a workaround for the hesitation, at least in my A4: if you progressively increase the pressure on the gas, more so at 2200-3200 rpm then elsewhere, the car doesn't have much pause in that range. if you just use a linear pressure on the gas, it happens.

Francis
'98.5 Cactus Green 1.8TQTipSX/APR

BDW

with my stock or Wett 1.0 bar chip. The only hesitation my car has ever shown is at low RPM with the AC going hard, hesitation, more like a little "stumbling," between first and second gear shift with stock chip. Only with AC running. Wett chip has helped smooth that out considerably.

Now during "enthusiastic" driving with the Wett chip I do notice a bit of turbo lag which I never did stock, but I'll gladly suffer that with a smile in return for the kick in the pants!

BDW

Hugh

The hesitation at 3000 is very noticeable. I know that this is also the rpm range in which the boost really kicks on, however the hesitation can be noticed by starting at 3000 as well as lower. In other words I can notice the big post chip push at 3000rpm or 3400rpm depending upon where I start. At this rpm range the engine has to increase 3-5 hundred rpm for full boost to come on line. At higher rpm it is about half that.

The hesitation is much less at 4000rpm. Because of this I am skeptical that the problem is one of back pressure. Backpressure is caused by the natural restriction of the exhaust system. The higher the flow of gas the greater the pressure differential or back pressure on the engine. If the hesitation were caused solely by backpressure you would think it would be greatest when the engine is flowing the most gases. This would be at high RPM. Practically speaking this is not the case. With my APR chip there is very little hesitation at 4000 and a lot at 3200.

Spool up time is important. At higher RPM the turbo will build speed faster due to the greater force exerted on it from increased gas flow. I don't think a chip could change this unless it adjusted the wastegate to be kept partially closed all of the time to keep the turbo spinning. (I'm over my head here)

I would be very interested in a solution and I have been planning to pay close attention to the lag at around 3000 after I install my APR exhaust. Frankly I am more interested in that than in hp gains(at least right now). If I notice anything interesting I will post it.

Hugh

99.5 1.8Tqms Avant APR'd