[jgalaxy]

I went to my first track event in my 335XI. It was fun, but when pushing the car just a little, the car had a tough time through corners. Uneasy feeling of wallowing in and lumbering out. There is no doubt that most of this is attributable to the driver.

It took me a while to figure it out but the xDrive system does undesirable things to the balance of the car as the system applies/cuts power to the various wheels, pitching the car just ever so slightly out of balance.

Q. Does one drive with DTC/DSC or off (Is it really ever off)?

I have low profile staggered wheel setup on 19" rims (9" F and 10.5" R). Although it looks great, it may not be the ideal setup for the track. The car never really seems to hold the corners like the other cars on the track.

Q. Go square setup all around (8.5"), but what size? I'd love to get 17" to save on the weight and the general burn rate we spend for tires. 17" or 18"?

Thanks

[leftcoastman]

Yeah I can't say for the XI but I had a student with an STi and that thing felt weird. The center diff would bias power mid-turn and totally change the attitude of the car.

It was like DSC on steroids. I didn't like the unpredictability and the intervention. I trust my right foot, thank you very much.

That said, go with Kosei K1 17x8.5 and 255 all around. Really dials out the understeer and much cheaper than 18s. And 16.8 lbs a piece to boot! Oh and $165 a pop.

[longodj]

I've been to two HPDE weekends in my E90 335xi and will be going to two more next week. If I were you (and if you're happy with your wheel/tire combo) I would try a rear sway before switching to 17" Koseis. Don't get me wrong I love my Koseis, but the difference with the rear sway is so noticeable that you may be fine just changing that. I guess I didn't really notice a difference with the Koseis as my wheels were nonstaggered to begin with but like I said the difference with the rear sway was just huge. The only problem is labor is a bit hefty, something like 4 hours. All in all it will most likely be cheaper than a set of Koseis with tires. I can definitely tell you that with just nonstaggered wheels the xi still pushes like a royal bitch.

I drive with DSC/DTC off, I find I have more control of the car. And, now with the rear sway I feel almost as if I can throttle steer around the corners....in my xi....lol The xi also does drive differently through the corners. When I was having trouble some guys on here recommended giving the car some gas when it starts to understeer as the front will bite down and pull you through. It worked like a charm. Experiment with different throttle control before making any changes but if you're still not happy I recommend the sways as I almost think I want to go staggered now :-P.

[leftcoastman]

Yup, listen to the XI guy. I'm a RWD guy.

For the "I" guys, DO NOT do the rear sway. Without LSD, the rear sway equalled spin city and with the LSD, it just made the car waay too twitchy.

$150 bar. $500 to install. $500 to remove. I felt like an idiot.

[AWD Addict]

Rear sways were the first mod for the autox suby guys. I'd start there, and def take off DSC / DTC

[sayemthree]

I prefer a square set up and it would help your turn in and reduce some fo the understeer inherent to AWD. but get in a few more events on your stock set up first. concentrate on being VERY VERY smooth with all the controls.

In AWD the turn in is very important, smooth brake release, and be patient getting the car turned. once turned you can use the advantage of AWD and get on the throttle earlier than RWD cars.

[longodj]

Originally Posted by sayemthree

I prefer a square set up and it would help your turn in and reduce some fo the understeer inherent to AWD. but get in a few more events on your stock set up first. concentrate on being VERY VERY smooth with all the controls.

In AWD the turn in is very important, smooth brake release, and be patient getting the car turned. once turned you can use the advantage of AWD and get on the throttle earlier than RWD cars.

I agree with sayemthree. jgalaxy do you autox? autox helped me a ton in figuring out how to turn in my car.

[leftcoastman]

Originally Posted by longodj

I agree with sayemthree. jgalaxy do you autox? autox helped me a ton in figuring out how to turn in my car.

Aren't you too old to still be playing in the parking lot?

I echo sayemthree's advice about smoothness. Whenever I see someone jerking their car on the street, I know for a fact that they would get creamed on the track.

[longodj]

Originally Posted by leftcoastman

Aren't you too old to still be playing in the parking lot?

I echo sayemthree's advice about smoothness. Whenever I see someone jerking their car on the street, I know for a fact that they would get creamed on the track.

hey no way man, I will never be too old for autox. I have tons and tons of fun at HPDEs but I learn more in a 1 minute session at autox than I do in a 20 minute session at HPDE hands down.

[leftcoastman]

Originally Posted by longodj

hey no way man, I will never be too old for autox. I have tons and tons of fun at HPDEs but I learn more in a 1 minute session at autox than I do in a 20 minute session at HPDE hands down.

Ahh, different strokes...

I think autox is too rapid to learn anything. You hit a corner FOUR times a day at most and it comes so quickly that it's basically a rhythm thing to me.

On the track, you hit the corner 7-10 times per session (28-40 times a day) and you have enough time between corners to think about how you're going to manage the car this time. And when it slides, the car is going much faster but typically the slide is slower and you have more time to correct it.

Different strokes..

[Ramos]

Originally Posted by leftcoastman

Yeah I can't say for the XI but I had a student with an STi and that thing felt weird. The center diff would bias power mid-turn and totally change the attitude of the car.

It was like DSC on steroids. I didn't like the unpredictability and the intervention. I trust my right foot, thank you very much.

That said, go with Kosei K1 17x8.5 and 255 all around. Really dials out the understeer and much cheaper than 18s. And 16.8 lbs a piece to boot! Oh and $165 a pop.

I am looking at that setup for my 335i (RWD) .. what tire size though?
I've seen many different sizes: 235/45 245/40 haven't seen anyone run 255..

[jeho]

so when upgrading sways on just an "I" without LSD, upgrade BOTH FRONT AND REAR sways?

[leftcoastman]

Ramos - I run 255. On my fourth set of em.

jho86 - it's not a balance issue. An antisway bar makes the axles act more like a solid rear axle (think pickup truck) and therefore causes wheel lift. A thicker rear sway will make your inside rear tire spin like crazy, regardless of what you do to the front.

That said, if it's a boulevard queen, the swaybar makes a bit more sense. If you're never near the limit, you shouldn't have any issues and I know a lot of people like the "feeling" of a flatter car.

[Ramos]

Originally Posted by leftcoastman

Ramos - I run 255. On my fourth set of em.

.

What's your tire profile?
Are they 255/45R17 or 255/40R17 ?

[nicknaz]

no experience in an awd BMW but my last DE car was a WRX with a slightly larger rear sway bar, so I have some track experience with AWD

personally, i found that AWD compared to RWDlets you apply full throttle earlier during corner exit, and it is much easier to control yaw because you can just apply throttle to stop yaw angle from increase

i recommend you start by learning the school line really well, getting all of the rotation done during turn in, and focus on applying power earlier and earlier in the corner to maximize your AWD traction advantage.

also, i found that in some corners i had to do 'auto cross-like' things such as lifting big off the throttle/applying some braking during turn-in to get the car to achieve the rotation i wanted.

lastly, i think the power reduction thing you experienced is an unfortunate side effect of having open rear and front differentials and electronics that prevent wheelspin through braking. this might go away as you learn to manage the traction better, and drive the car within its traction limit

[leftcoastman]

Originally Posted by Ramos

What's your tire profile?
Are they 255/45R17 or 255/40R17 ?

40

[longodj]

255/45R17 will NOT fit, 255/40R17 will. I'm on 245/45R17 (cheap) and it works wonderfully.

[Ramos]

I just found this site http://www.miata.net/garage/tirecalc.html
and comparing the original sizes 225/40-18 Front and 255/35-18 rears
both to the square setup running different sizes, I found what Leftcoastman is running 255/40-17 to be the closest.. The 245/45-17 not as close

Q. How well do the Kosei rims fit these tires? Arent't the tires too wide?

[leftcoastman]

Originally Posted by Ramos

I just found this site http://www.miata.net/garage/tirecalc.html
and comparing the original sizes 225/40-18 Front and 255/35-18 rears
both to the square setup running different sizes, I found what Leftcoastman is running 255/40-17 to be the closest.. The 245/45-17 not as close

Q. How well do the Kosei rims fit these tires? Arent't the tires too wide?

255 is the largest recommended for 8.5

Some say that you get massive rollover, but I haven't found that to be the case (granted, I have camber plates). I got such perfect wear on my last set. a 9.0 or a 9.5 would be ideal but (1) Kosei doesn't make one (2) the 8.5 barely fits in the front. In fact, you get oh so slight rub during parking lot maneuvers.

My rationale was 2fold in picking the 255:

1) Same tires front and back to rotate tires to save money.
2) Same tires front and back to rotate car for fun.

Since the 255 was the largest I could stuff in front, that's what I went with. Coincidentally, with camber plates (-3 to -3.5 on track), I am absolutely perfectly neutral. Give it gas and I push, lift lightly and I oversteer. It's very sublime, this chassis.

[Ramos]

You are a wealth of info pn the subject.. Thank you

1 more things.. I will be running stock suspension, no camber
Want the square setup for the reasons you mentioned..(same size all around)
Want 17" to save money as this will be my track setup

What is the better size for me for tires? 235, 245 or 255?
What profile?
What width on the rims? Do the Kosei come in different width?

[T Bone]

Originally Posted by jgalaxy

I went to my first track event in my 335XI. It was fun, but when pushing the car just a little, the car had a tough time through corners. Uneasy feeling of wallowing in and lumbering out. There is no doubt that most of this is attributable to the driver.

It took me a while to figure it out but the xDrive system does undesirable things to the balance of the car as the system applies/cuts power to the various wheels, pitching the car just ever so slightly out of balance.

Q. Does one drive with DTC/DSC or off (Is it really ever off)?

I have low profile staggered wheel setup on 19" rims (9" F and 10.5" R). Although it looks great, it may not be the ideal setup for the track. The car never really seems to hold the corners like the other cars on the track.

Q. Go square setup all around (8.5"), but what size? I'd love to get 17" to save on the weight and the general burn rate we spend for tires. 17" or 18"?

Thanks

If this is your first track day, do not spend any money on mods..... spend money on events / hotels....you need seat time. Seat time is the best mod.



The XI will push out very hard on track out full throttle, BTW.

[leftcoastman]

Correction: "I am wealth of learning through screwing it up, lol."

I'd go 255. You will beat the crap out of the front outside shoulders, so watch it and rotate between every track day. Also, flip the tires on the rims halfway through their life. ignore the directional sign or inside/outside markings as long as you're driving in the dry.

Kosei K1 17x8.5 from tirerack at $165-170 a pop. 16.8 lbs of pure goodness.

255-40-17 in something friendly like a Falken Azenis RT-615. Squeals like a biotch at the limit so you get auditory feedback on how you're doing.

17s not only save money but I surmise give better performance. MUCH lighter than 18s and also effectively lowers your gear ratio, enabling better acceleration.

Originally Posted by Ramos

You are a wealth of info pn the subject.. Thank you

1 more things.. I will be running stock suspension, no camber
Want the square setup for the reasons you mentioned..(same size all around)
Want 17" to save money as this will be my track setup

What is the better size for me for tires? 235, 245 or 255?
What profile?
What width on the rims? Do the Kosei come in different width?