truffle shuffle under hard braking

[Sebringjetta]

ok so here is something new to me and i will apologize in advance for my description of what it feels like...i always hate trying to describe car issues...always feel like that non car guy that comes into the dealer trying to explain a funny noise that only happens in certain conditions...

so entering corners under a high rate of speed i have noticed the car doing what i call a truffle shuffle... the car will do a quick wiggle to the left and right.... im not new to the track and this happens when braking in a straight line... the car as pfc-08 pads, endless fluid, on oem edc w/ a kw coilover kit...tires nto1...the only thing im guessing is the aggressive pads and r-comps are too much for the susp....an ideas fellas

[Billj747]

Don't think nt01s and 08s are too much for your suspension. Does the tail wag side to side under braking (where if it gets worse you'll spin out)?

What rear pads?

[Sebringjetta]

Originally Posted by Billj747

Don't think nt01s and 08s are too much for your suspension. Does the tail wag side to side under braking (where if it gets worse you'll spin out)?

What rear pads?

its not at the point of spinning unless i go too deep and begin to turn in....rear pads are 08 as well....i came from a full track e46 and this is only my 4th time on the track with the e92

[e92ben]

Back in the day my 335i developed something very similar to what your describing under very heavy braking. From the front end. Couldn't find the cause of it until I got an alignment at a dealership and they said my thrust arms were ready to be replaced. Once I did that the truffle shuffle went away for me lol

[dnvrdrvr]

Not sure if it's the same thing I dealt with when I was tracking my E90, but I ended up softening the rear tires by 1 pound and the rear end settled nicely under hard braking after that. I was also using EDC with the Ground Control conversion kit (Eibach springs), with a square set of Continental tear-offs.

[Sebringjetta]

Originally Posted by e92ben

Back in the day my 335i developed something very similar to what your describing under very heavy braking. From the front end. Couldn't find the cause of it until I got an alignment at a dealership and they said my thrust arms were ready to be replaced. Once I did that the truffle shuffle went away for me lol

ya 1st thing i did was get the alignment checked out....it was perfect....

[Sebringjetta]

Originally Posted by dnvrdrvr

Not sure if it's the same thing I dealt with when I was tracking my E90, but I ended up softening the rear tires by 1 pound and the rear end settled nicely under hard braking after that. I was also using EDC with the Ground Control conversion kit (Eibach springs), with a square set of Continental tear-offs.

ya im running 275 square....i will try dropping the tires next week 1lbs and see what happens..thank you



i have to be honest the worse it ever happened was entering the cork screw...almost shot me into the wall on the left....that puckered the corn hole pretty good that time...arty0030 :

[Billj747]

Maybe try a 97 rear pad instead?

[Sebringjetta]

Originally Posted by Billj747

Maybe try a 97 rear pad instead?

well my bbk goes on next week...and im going to try out their race pad and see what happens:

[jphughan]

It could be the diff. I don't know how many miles you have and how much of that has been track time, but over on the 997 GT3 forums, the truffle shuffle under straight-line braking is a common symptom of a diff requiring a rebuild; apparently GT3 diffs don't last long at all on the track (kind of surprising/disappointing IMHO) and are frequently rebuilt with Guard internals. Turner Motorsport has a diff rebuild service for our cars if it comes down to that, and you can either rebuild it to stock specs or get a different kind of diff in exchange for cash plus your core.

But I agree with others that there are other possible causes that should definitely be inspected/tested first.

[s85e90]

sounds like front end bushings somewhere to me. Def not seem diff related, check easy stuff first.


Jack car up and check the front wheels; this feeling is also exagerated as your running a big ass tire on front

[yandy]

I've felt this a couple of times, and after bringing down air pressure 1-2psi, it's always gone away. Felt it this weekend with the NT-01 275 all around, first couple of sessions, trying to get the pressure right. At one point, hot was 42psi, then 39, then finally hit 38 and it went away.

Though now I hear 35-36 is even better, but just something to consider .

[Billj747]

Originally Posted by Sebringjetta

well my bbk goes on next week...and im going to try out their race pad and see what happens:

Which bbk? F&R? The 08 and 97 are race pads

[Sebringjetta]

Originally Posted by jphughan

It could be the diff. I don't know how many miles you have and how much of that has been track time, but over on the 997 GT3 forums, the truffle shuffle under straight-line braking is a common symptom of a diff requiring a rebuild; apparently GT3 diffs don't last long at all on the track (kind of surprising/disappointing IMHO) and are frequently rebuilt with Guard internals. Turner Motorsport has a diff rebuild service for our cars if it comes down to that, and you can either rebuild it to stock specs or get a different kind of diff in exchange for cash plus your core.

But I agree with others that there are other possible causes that should definitely be inspected/tested first.

never thought of that...car has 50k miles...bought it from the orig owner that as never even been to the track to spectate a professional race... its been to the track 4 times....but maybe it is something to look at..thank you

[Sebringjetta]

Originally Posted by s85e90

sounds like front end bushings somewhere to me. Def not seem diff related, check easy stuff first.


Jack car up and check the front wheels; this feeling is also exagerated as your running a big ass tire on front

going to check out the bushings this week...thank you

[Sebringjetta]

Originally Posted by yandy

I've felt this a couple of times, and after bringing down air pressure 1-2psi, it's always gone away. Felt it this weekend with the NT-01 275 all around, first couple of sessions, trying to get the pressure right. At one point, hot was 42psi, then 39, then finally hit 38 and it went away.

Though now I hear 35-36 is even better, but just something to consider .

so 35-36 hot...w/ no cool down lap?

[Sebringjetta]

Originally Posted by Billj747

Which bbk? F&R? The 08 and 97 are race pads

380 front st60 355 rear st40

[yandy]

Originally Posted by Sebringjetta

so 35-36 hot...w/ no cool down lap?

coming off a hot lap into the hot pits and measuring, I'd go for 36-37, but more towards 36, will be testing that soon. I was running 37-38 most of the day without issues. that wiggle thing only happened when above 38

[Sebringjetta]

Originally Posted by yandy

coming off a hot lap into the hot pits and measuring, I'd go for 36-37, but more towards 36, will be testing that soon. I was running 37-38 most of the day without issues. that wiggle thing only happened when above 38

this might be m issue then!!!! im comming way too hot

[PrimeBMW]

What you are describing sounds similar to what people experienced years ago when the first round of folks took their car to the track the E9* M3. Maybe some more will speak up. If memory serves me right it happened more often with lowering springs or even the first Dinan set ups. But with that said it is something that happens with the stock suspension when run with stickier tires and/or aggressive pad compounds. Sure you can drive around it, lower pressures, change pad compounds, etc... But I think it may be happening because the springs are a little soft and the nose is diving, thus there is less weight on the rear tires. Then the tail wags a little. Get some real coilovers with stiffer springs and it will most likely go away.........you know you want them anyway!

[Sebringjetta]

Originally Posted by PrimeBMW

What you are describing sounds similar to what people experienced years ago when the first round of folks took their car to the track the E9* M3. Maybe some more will speak up. If memory serves me right it happened more often with lowering springs or even the first Dinan set ups. But with that said it is something that happens with the stock suspension when run with stickier tires and/or aggressive pad compounds. Sure you can drive around it, lower pressures, change pad compounds, etc... But I think it may be happening because the springs are a little soft and the nose is diving, thus there is less weight on the rear tires. Then the tail wags a little. Get some real coilovers with stiffer springs and it will most likely go away.........you know you want them anyway!

ohh i do want and need them...the bbk, te37, and cage work i paid for this week says different....im going to pick up some GC in may..

[RickyBobby]

Are those NT01's new?
Sounds like tread squirm. It goes away after two days of use.