Audi_in_Van

I am in the market for a lower milage Allroad, between 4.2 and 2.7T right now... I drive a manual Porsche, and have always owned manual but as this would be used for business and others may drive it, Tip is the preferred option.

I've had a B5 S4 and I love the 2.7T, I never notice much of a lag, and not sure what's all the issues reported with 2.7 TIP? What the heck is brake/throttle lag on a Tip? and WHY is the 4.2 TIP is better? If I get a 2004/2005 Allroad 2.7, wouldn't it have an upgraded Tip? or Torque converter?

Also, I heard exhaust can help with the lag. If I get the 2.7T, I plan to chip and maybe do an exhuast (not too loud though), would that help?

Thanks

finiki

BTL is the result of the electronic nanny system. The brake light switch controls CPU programing that does not allow the throttle to be applied until the brake pedal is completely released. Imagine you are at a stoplight, in the intersection, waiting for a break, your left foot on the brake, right on the gas, a small gap develops, you quickly hit the gas while releasing the brake, the car slowwwwly moves to the left, yeoooow I am gonna die, oncoming traffic brakes, you live, go home, clean shorts.
The moral to the story...never drive the TIP allroad with two feet.
Some 4.2 owners claim the BTL is less in theirs, (some 4.2 owners think the sun rises and sets in their driveway). No one has ever demonstrated with empirical evidence it can lessened or eliminated. I learned how to drive with it, now I do not even notice it at all.

happy allroader

Another situation, you are on a interstate on ramp searching for a hole. You touch the brake to slow a bit and then hit the gas to jump into a gap in traffic. The car is slow to respond to request for power, you floor the gas, the car "wakes up" and then surges forward.

Chip will not fix it. I have both a engine and transmission chip and still have the lag. At first folks thought it was turbo lag but manual transmission cars don't have it.

Most of us blame the lawyers. Almost all cars will get a brake link in the future that will limit the engine power (Toyota added this recently with their name in the headlines) but whatever Audi did seems to have a linger effect that is not welcome. I can understand if both pedals are pressed at the same time but once the brake pedal isn't being pressed, I'd hope for 100% gas pedal normal response.

uber_ar

Search my posts under Uber_AR or RR_Allroad... look for "BTL" ( a term i coined actually). Much discussion and explanation.

Kristopher

All DBW throttles suffer from this BTL 'feature'. It's definitely in the programming and actually I'm surprised a TIP-chip doesn't address the issue.

That said, the delay shouldn't be nearly as long as it is. My gut tells me Audi, in attempts to save the transmission, coded the TCU to a longer delay to limit driveline shock. The 2.7 and 4.2 engines are very torquey, and in the case of the 2.7 having max tq at 1800rpm you can very easily put unnecessary strain on parts.

It'd have been nicer if there was a tq limit function rather than a BTL where you get zero power but it does allow the car to crawl forward somewhat first.

VAG did something similar with the TDI, even the manual version. RPM is limited to 1100 when both the brake and throttle are applied. Releasing the brake you certainly notice a long pause before power comes back up. I believe the reason it's not nearly as noticeable on the manual car is that most people assume it's the clutch operation limiting power delivery.

Audi_in_Van

Thanks guys... it makes sense now! However, I dont undertand why it could be more of an issue in 2.7 than 4.2?

Damn lawyers and stupid drivers who can't figure out the difference between gas and brake making car companies DUMB DOWN their cars for the DUMB people! To me, if you don't know which pedal is for gas vs. brake, you deserve to CRASH and burn, and should just hand over your license and take the bus!!! My buddy is disabled for life because of a senior lady who tried to park and mistook gas for brake and drover over the curb and crushed his leg! She didn't even make it to the court.. passed away before the court date!

Anyways... I think the issue is not as severe, and I'd probably won't be doing any heel-toe on the car, to apply both brake/gas.

I just found a 2005 4.2 with only 30K miles! Gonna check out what's the asking price on it. My mechanic told me 4.2 gas milage is A KILLER and much much worse than 2.7T. While reading posts here people claim it's just about the same...

I had a B5 S4 and its mileage was *OK*, but I really don't wanna have something that's much worse than that. How bad is 4.2? My driving would be 60% city, 40% Highway.

Mike B

I have a B7 S4. Unfortunately most of my driving is local and the gas mileage sucks; 14.9 mpg. But boy, when you step on the loud pedal, it feels like it's worth it

JustMtnB44

I have a 4.2 and don't really notice any BTL. In regular drive mode, the transmission can be a bit sluggish to respond at almost any speed but it is most noticeable at slow speeds. However, putting the tranny in Sport mode totally eliminates any such issues. Therefore I believe any issue to lie in the tranny programming. I don't ever use two feet so I don't see how I could be on the brakes and throttle at the same time.

As far as gas mileage, yes the 4.2 is pretty bad. The past few months I have been averaging about 14 with mostly city driving and a small amount of highway. The worst I have ever seen for a tank was 12 and the best was 20. I don't try to take it that easy, and I usually get on it at least once every other day just to hear the growl and feel the power.

Kristopher

FWIW the 2.7 is also much quicker to respond in Sport mode. I totally forgot about that.

And as well, on super short drives (>2mi) I'm averaging 15mpg. It's generally around 17 with normal city driving and has only averaged 18 with mixed city/highway.

uber_ar

The issue is programmed in the ECU that's why the tip chip doesn't effect it.

Aftermarket ECU programs only change fueling, boost etc and dont look into the safety systems.