I have an '03 A4 coupe with a 273 diff. I've had her since this February and, other than the suspension, the only mod that I've done on it was the flip-tie mod on the air box. I've only ever driven it in "normal" driving mode - not in Competitive mode or with TC / AH off. I want to give you a feel for how she handles in normal driving mode, then I'll get to the problem that I'm seeing...

I've noticed that it takes only moderate gas pedal to break the tires loose when turning 90* from a stop sign. In fact, this happens so easily that I have to really baby it when there're cops around. If I put my foot in it, I can fishtail and keep the tires spinning for a good four or five car lengths (or more) on worn pavement - you know, the kind that's been worn all smooth from years of sun and traffic. On newer / better-traction pavement it'll still fishtail and spin the tires, just not for as long. When the tires break loose and the car starts to fishtail, the AH message comes on and I can feel the AH trying to straighten the car out. It doesn't keep the tires from spinning, just keeps the car going straight. From a stop on a straightaway, the tires will break loose if I punch it hard and it gets up to speed pretty fast for having 273s.
The car also feels very light on its feet, as it where, and has plenty of get up and go / throttle response. Under my normal acceleration from a light (I usually get it up to around 3500 RPM per gear when I'm just cruising), it gets up to speed smoothly and quickly with no sense of effort. When I punch it, it comes alive (even with stock exhaust, the roar is nice) and climbs through the gears quickly and, again, with no sign of effort. There are some issues with shift points and firmness under "normal" throttle inputs, but that's not an issue when I'm gettin' after it. All-in-all, it runs like I always thought a Vette should.

So, here's the problem...

I read in the manual that Competitive Mode was supposed to turn off TC and allow for more tire spin, etc. and I thought, "Wow! More tire spin? I'm there!!!" So I went out driving the other day and turned on competitive mode before pulling away from the curb. I noticed immediately that the car didn't have the normal, easy acceleration that I'd gotten used to. My normal throttle input didn't get me up to speed at the same rate and the car felt bogged down. I thought maybe it was just in my head, so I kept on cruising through my neighborhood to get to a location that I like to use to blow the soot out.
On the way there, there's an intersection with a right-hand turn from a stop sign on pavement that's nicely worn and smooth. I ALWAYS end up spinning my tires here, even when I'm not trying. This time, not even so much as a squeek - and I wasn't slow-poking either. The car felt very sluggish and I had to give it a lot more gas than usual to get up to the speed limit (40 mph). From here, it's just a short way to the 60 mph road that I was heading for. It's another right-hand turn on smooth pavement, so it's another place where I usually spin the tires while getting up to 60. I was paying extra attention when pulling out into traffic here and made sure that I did it like I always do... NOT SO MUCH AS A CHIRP OR SLIP!!! Again, the car also felt VERY sluggish and bogged down in all the gears. It didn't even start to wake up in 2nd until almost 4K RPM. In normal mode, my car shoots up in RPM, the tires are slipping, the rear is fishtailing, I'm having to give it steering input to keep it in the lane, and I need tranqs to come down off the adrenaline rush... not this time. It feels like I'm driving one of the V6 Mustangs that I test drove before I found my baby!

So what gives? I didn't think that changing the driving mode did anything besides toggle TC and/or AH. I've driven the same circuit about 10 times now in both normal and competitive modes and there's a blatantly obvious difference in the cars performance between the two modes. I took it out just a bit ago, going from my parking spot, around the block and back in all three modes - normal, TC / AH off, competitive mode - just to quintuple check the feel of everything before posting. In both TC / AH off mode and competitive mode, the car definitely has the same level of sluggishness. It's like night and day between them and normal mode.

Have any of you ever seen / heard of anything like this before? Do any of you have any idea what could be happening? I don't think that I'm losing my mind but, if I was, would I know it? "Even I said I was crazy when I wrote this thread, but I showed me!"

There were two previous owners before I got the car. Is it possible that they had something done that could cause this? Is it possible that my BCM is going bad or malfunctioning in some way that would cause this? Also, when I did the flip-tie mod I did the airflow re-learn procedure (I believe that's what it's called). Could this have messed something up?

I'm going to be taking it to get dyno-tuned soon, so I'm hoping that this is something that my tuner will be able to address. I'm actually very curious to see what the difference on the dyno would be between the modes; it's the only way that I know of to for sure see the difference.

Anyhow guys and gals, sorry 'bout the novella and thanks in advance for any help that you can offer.

Shawn

 

There were no codes listed in the DIC at any time during or after my test drives.

 

I was doing some more thinking about this last night...

For those of you that know about tuning... If one of the previous owners sent the PCM off for a tune, and I have no idea whether or not they did, could it be possible that there's a communication problem with the BCM in any driving mode other than normal? Isn't there a separate control module for the transmission in these cars? Could there be something going on there?

I'm just trying to come up with ideas as to where to start checking, but I'm totally at a loss for a definite place. Does anyone out there have a clue as to how the issue I'm seeing could be happening or where I should start looking? Would I be better off just taking it to my tuner sooner, rather than later, to see if he can fix it with a complete tuning?

Any help at all would be appreciated.

 

Sounds to me like you need a rear end allignment ----When the toe and camber is off in the back --the tire contact patch can be only on the inner or outer edges of the tires--around a turn this would make it break traction easily as there is no weight transfer yet to plant the rear on the ground---Another tell tale sign is a "floating sensation" at speed--or a bad wander on uneven pavement--

 

Totally agree there - that's on the docket for when I get my new tires here pretty soon. I currently have GY F1s that slip like crazy - they were on it when I got the car and have gotten kinda hard and easy-to-slip. Thanks for pointing this out! It doesn't explain the power loss / performance hit when driving in anything other than "normal" mode, but it does explain why I'm slipping so much when taking off at corner intersections.

 

wow, interesting dilema you have here...

with 2.73's in my Y2K A4 coupe with TC/AH on and balding runflats i could not spin the tires hardly at all. sure, i could break them loose giving it hell around a 90 degree corner, but under normal driving conditions - no way. strange to hear that yours would spin 4-5 car lengths. very strange.

i recently had a 3.42 diff installed. now, of course, spinning the tires is easy - but i would still have to say that the TC still kicks in way before 4-5 car lengths.

have you tried a power break burnout with TC/AH on? you shouldn't be able to do one. then turn both off. now you should get a good burnout. in Comp mode (TC off/ AH on) you should also get a good burnout.

if it don't work like this it's not working correctly.

good luck!

jeff

 

The amount of tire spin (distance-wise as well as time-wise) that I get could definitely be related to the post above about alignment - along with my crappy tires and that I'm doing it on very smooth/worn road starting from a turn. On good, grippy road I only get maybe a car length or two, but that just feels like what normally happens when you gain enough speed and your tires stop spinning. On wet road, my tires will spin like crazy.

I have no idea what was done to the car before I got it, and I have no idea of its actual HP / TQ output. I don't have any reason to believe that it's anything other than stock though. I only wish that I had a stealth road-shredder here...

The part that bugs me is that it feels like I'm driving all the time in what should be competitive mode - TC-wise. But when I do put it into that mode, it feels like I've downgraded to a V6 and like my TC is fully engaged. I know that a lot of people drive in competitive mode all the time, so maybe it's not so bad. I'd like to know why it's doing what it's doing though - it should be working correctly.

I'll try to find a place to do some power braking where I won't get busted. In the area of Austin that I live in, the cops are crawling out of the woodwork so it's kinda hard to do much of anything like that.

Thanks for the suggestions!