I have a 2000 A4 1.8t with a GIAC 1 bar chip. I've been noticing that I've been getting very poor gas mileage in town, no matter how mildly I try and drive. (usually around 16 mpg) It always felt like the turbo was kicking in too much no matter how lightly I would press the accelerator.

This weekend I installed a VDO boost gauge so I could get a good look at what the turbo was doing. Figured it was a worthwhile modification to make, and extra gauges are always good. :) Indeed, even the slightest acceleration pushes the needle up over 0 into boost territory. Try as I might, it's very hard to keep things down in the vacuum range while doing any sort of acceleration. (unless I accelerate like a grandma, which tends to pack up cars behind me waiting for me to get up to speed.) :)

Perhaps this is all normal for the GIAC chip. Since I didn't have the car very long before I chipped it, I'm not sure what the mileage was doing pre-chip.

So, here are my questions:

1) for those of you with chipped ECUs and boost gauges, what sort of readings to do you get during regular acceleration around town and while cruising out on the highway at around 80mph?

2) for anyone with the 1.8t engine, what sort of gas mileage do you get in town and on the highway? I'm personally getting nowhere near the 22/28 that was listed on the sticker. (I expected some mileage drop with the chipped ECU, of course, but not as drastic as I'm seeing.)

Thanks for the info!
-joe

I just installed a guage and have a GIAC 1.0 bar chip. Haven't noticed any change in mileage and I am driving more aggressively (meaning there is probably an increase in mpg) Boost goes from -20 to 13-14 only under extreme acceleration. It immediately dropps back down to vacuum state with the slightest fluctuation in throttle. Probably in vacuum state 80% of the time.

I get around 24 in town and 28 on the hwy.

My car averages 10 in hg vacuum while cruising along the hwy. When I accelerate, I get around 5 psi of boost. When I go all out, I spike up around 16-17 psi, then evens out around 15 psi up to 5k or so, then a steady decline to 5 psi at redline.

APR chip.

It sounds like your ECU is confused about throttle position and needs to relearn.

Try unplugging the ECU, plug it back in. Put your key in the ignition, turn it to the "on" position, don't start the car. Wait 3 minutes. Start the car. (Some say to wait another 3 minutes after you start the car but I have found that's not necessary) That should do it. If you have VAG software you can do the whole thing in about 30 seconds.

Good luck!

I recently purchased the VAG-COM software which is currently in beta so not all the features are there yet, including adaptation. I have been told that the newest version includes the adaptation functions and is almost available. Given this, it sounds like I need to try the ECU unplugging you mentioned to get the re-adaptation to happen.

Thanks for the info. Hopefully that'll help!
-joe

You can e-mail me by following the registry link below - you'll see my address there.

One thing to remember, you will get into boost pretty quickly when accelerating, even if it's a modest amount of boost.

Yes, the new release of the VAG-COM software will let you reset the ECU quickly. Just access block 060 and away you go. If you have the VAG-COM software, the Bentley AS/S4 manual is a must.

I need my office space or I'm going to burn the building down!!!!

With an APR 1.0 in a 2001 and under "normal" driving - city streets, some commuting up to 60mph in traffic - the car is in vacuum mode 99% of the time. I jumps into greater than 0 pressure situations only when I goose it.