Is there a fix for understeer in A6 2.7T
09-02-2002, 09:39 AM
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Is there a fix for understeer in A6 2.7T
Have tried to analyze the results of simples mods to a 2000 2.7T A6 w/ standard suspension. 17" light OZ superleggerra wheels and Plus one tires did not make much of a difference in high speed (>70 mph) handling. Removing 392 servotronic module gave more feel at low speeds, but steering remains isolated and overboosted at high speeds.
Best mod so far is the 18 mm sports susp rear antisway bar. Decreases steady state understeer, making for more neutral turning.
Still disconcerting is the throttle on understeer, like a FWD car, only w/o torque steer, I suppose due to front heavy weight distribution and the front/rear torque split settings. The front end feels like it floats and moves to the side. There is drop throttle oversteer, which I like.
Would like to be able to have some throttle on oversteer, like RWD cars. Has anyone been able to set up their car to do this (or at least to decrease the understeer)? Will be experimenting w/ e.g., left foot braking combined w/ throttle application to induce oversteer when I get a chance in safe surroundings.
Best mod so far is the 18 mm sports susp rear antisway bar. Decreases steady state understeer, making for more neutral turning.
Still disconcerting is the throttle on understeer, like a FWD car, only w/o torque steer, I suppose due to front heavy weight distribution and the front/rear torque split settings. The front end feels like it floats and moves to the side. There is drop throttle oversteer, which I like.
Would like to be able to have some throttle on oversteer, like RWD cars. Has anyone been able to set up their car to do this (or at least to decrease the understeer)? Will be experimenting w/ e.g., left foot braking combined w/ throttle application to induce oversteer when I get a chance in safe surroundings.
09-02-2002, 09:47 AM
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I think you understand the problem perfectly
And I don't think there is a solution. The only thing I can even think of us putting wider tires on the front than back to try to soak up some of that excess front torque instead of sliding out.
But it would look stupid and probably wouldn't work anyway.
But it would look stupid and probably wouldn't work anyway.
09-02-2002, 10:11 AM
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The drive-by-wire system will not let you "left-foot brake" and apply power above a
certain rpm...can't remember off-hand what that is. I've had friends at track events "warming up" their brakes by applying brake-pressure while keeping a constant speed...only to have the car's power "cut-off". Came "back" as soon as they released the brake.
HTH
HTH
09-02-2002, 10:15 AM
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Always wondered about left foot braking
Was going to try it next time out, just see what happens. Maybe we cant get the full benefit but maybe we save a tick or two by being on the gas a hair quicker with the Tip. Who knows
09-02-2002, 11:00 AM
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Are you sure? I did a lot of heel - toe work in my S4
and never had a problem.
For those that haven't done it, that is where you keep your heel on the gas and pivot your toe over to the brake to apply just enough pressure to distribute weight to the front tires. It is especially hard in the S4 because of the petal set up.
Once you have it down, it is unreal what you can do.
For those that haven't done it, that is where you keep your heel on the gas and pivot your toe over to the brake to apply just enough pressure to distribute weight to the front tires. It is especially hard in the S4 because of the petal set up.
Once you have it down, it is unreal what you can do.
09-02-2002, 11:09 AM
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Holding the car with "left-foot braking" while getting the rpms up for a decent
launch and "left-foot braking" while keeping the rpms up for boost while braking on the track are very different. The DBW will not let you do #2 (ummm...I can't believe I just wrote THAT!)...anyway, I think you know what I really mean.
An instructor for the Bridgestone Winter school (she has a DBW A4 1.8TAvant) complained about not being able to left-foot brake her car on the track...our resident turbo experts explained about the DBW system and that is one of the limitations.
As I said, you can do it for starts, but I forget what the maximum rpms you can hold with the brake "on" is.
Cheers,
An instructor for the Bridgestone Winter school (she has a DBW A4 1.8TAvant) complained about not being able to left-foot brake her car on the track...our resident turbo experts explained about the DBW system and that is one of the limitations.
As I said, you can do it for starts, but I forget what the maximum rpms you can hold with the brake "on" is.
Cheers,
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09-02-2002, 11:09 AM
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Sport Springs, Shocks, sway bar + 10psi more in rear tires
I can get some throttle on oversteer by inflating my rear tires to about 45 PSI with the fronts at 35. The S03's have a max pressure of 51 PSI, I beleive...
09-02-2002, 11:14 AM
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Along with the sway bar be sure to use poly bushings as well
I already had the 18mm bar, but it was still pushing pretty bad. I added the poly bushings (which fit in the stock brackets perfectly)and now as long as I throw it into the corner a little bit, I can induce oversteer throughout the corner. However, on the R compound tires I reverse DLow's tire pressures, Higher in front.
09-02-2002, 11:16 AM
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Are you "double-clutching" and still on the brake while "blipping" the throttle? I
can do that with my car, although you are right...the pedals are not placed/set up properly for this. I have my right foot on the brake, clutch "in" and swing my heel over to bring the rpms "up" for the next (lower) gear...all while shifting. I can "match" the needed rpms that way and engage the clutch while still braking. I think the clutch being "in" is why I don't experience the DBW system "de-faulting" to the brakes and not giving more "revs".
HTH
HTH
