[Mywifes335]

Hi Fellow 2-ers,

Lately, I've been experiencing traction loss with moderate throttle inputs, at low speeds (up to 40mph).

The car is a heavily modified M235i with Pure Stage 2 and methanol injection (414 whp on the street setting and 505whp on race gas setting). However, this has been happening at low speeds, part-throttle, and mid-range boost. The rear end just breaks loose. Granted, it has been colder here in Texas, but it's definitely above freezing.

I'm running Michelin PSS 265s in the rear and they only have about 3000 miles on them. Lots of tread left.

I just had the car inspected at a local shop when I did an oil change and they did not report any issues with the rear, but I'm wondering if they really inspected it.

Please let me know if you guys know of any rear subframe reinforcement kits for the F22 chassis. I'm not sure if this is a weak point on the F22, but with the amount of hp and torque I'm running, I'm just scared.

History: Tore the rear carrier off my Z3 2.8 in the past. It was heavily modified but probably only putting 200whp down. I was also stupid and did donuts and burnouts all the time.

[x233]

It wasn't a weak point until so much more power was added and those huge tires.
It's the bushings that can no longer handle those modifications.
One of the options that might help: http://www.superpro.com.au/find/supe...999501544/vid-

[Mywifes335]

Thanks. I was wondering, which pieces are attributing to the torque bias when throttle is applied?

[x233]

Originally Posted by Mywifes335

Thanks. I was wondering, which pieces are attributing to the torque bias when throttle is applied?

Not sure, but with your setup I guess I'd go with the whole set for the rear

[XutvJet]

MPSS tires aren't good in temps below 60. My bonesstock 6MT can light them from a low rpm roll in 2nd and sometimes even 3rd when temps dip below 60 and traction is minimal in the 40s. I'm not.hammering it hard either and the tires only have 9k miles. With my narrower 225 width Michelin Alpin PA4s, traction in immense below 50 degrees compared to the MPSS tires.

I think your car's problem is all the power and the general crappiness of MPSS tires in the cold and nothing to do with rear subframe. You're probably going to have add wider, stickier tires and accept the fact that the car will be quite traction limited in temps below.

[Anthony235]

Probably has more to do with tire temps (weather) and lack of grip with MPSS. I would lose grip with stock turbo and JB4 in 3rd no problem on MPSS.

Running 255 RE71R now. No grip issues and no longer need to have my 1st and 2nd gear boost limit set.

Are you running lots of camber in the rear? Could also contribute.

[kmli5]

http://www.bimmerworld.com/Suspensio...shing-Set.html

The standard subframe bushings on M135i/M235i are way too soft even for factory power. The bushings used is identical to a base model 1-series, not to mention they are designed for run-flats car. So with normal tyres on our baby M car will make the car feel even softer on the rear end.

[Pparana]

[QUOTE=Mywifes335;21028487]Thanks. I was wondering, which pieces are attributing to the torque bias when throttle is applied?[/QU


rear lca bushings, outer. Feels like a wheel is loose or a wobble under acceleration?

you can swap to Poly. I have replaced them with poly, other arms with adjustable arms with spherical bearings and the sub and diff mounts with poly. I replaced them 3 times with stock before I found poly ones from superpro. Stock ones lasted about 1000 track miles until I added meth, then I went through a set each day, then poly. No problems since.

You have to remove the arm to properly check the bushing, doubtful they did this unless you got a 2 plus hour labor bill.

[Viffermike]

Originally Posted by Mywifes335

Hi Fellow 2-ers,

Lately, I've been experiencing traction loss with moderate throttle inputs, at low speeds (up to 40mph).

I'm running Michelin PSS 265s in the rear and they only have about 3000 miles on them. Lots of tread left.

Knowing what I know about tires and being in the same area (dude: your car alone makes me want to organize a North Texas 2 Series GTG ... oh, BTW; welcome back!), I'm going to echo what XutvJet and Anthony235 have both said.

I'd try tires appropriate for the season first. It may be 80ish degrees today and we may have set a Christmas Day high-temp record here a few days ago, but average ambient high temps are in the 50s and 60s right now -- and those PSSs won't perform nearly as well at those temps unless you've really warmed them up.

Also consider that we dipped into the high teens about two weeks ago -- I'm not sure how PSSs react to being exposed to the sub-40 temps that summer tires lose almost all viscosity at (It's like driving on hockey pucks, man!), but if your car was parked outside, it's possible that the cold snap did some compositional damage to the PSS' rubber -- particularly if you've abused them with powerrrrrrr (and, thus, temp cycles) between now and the current 3K mark.

Just some food for thought.

[XutvJet]

Originally Posted by kmli5

http://www.bimmerworld.com/Suspensio...shing-Set.html

The standard subframe bushings on M135i/M235i are way too soft even for factory power. The bushings used is identical to a base model 1-series, not to mention they are designed for run-flats car. So with normal tyres on our baby M car will make the car feel even softer on the rear end.

Maybe so, but I don't see how this really has much to do with straight-line acceleration traction. I can see the benefit if you track the car often, but not in the situation the OP is describing.

[x233]

I wonder exactly what OP is talking about, wheels spinning or a wheel hop. It's not quite clear from the initial description of the problem.
Not having traction is one thing (get tires that are right for the weather), wheel hop is another (get stiff bushes to get it right).
But, again, with the setup of that car stiff bushes all around would be a good idea regardless of what the initial complaint was.

[XutvJet]

Originally Posted by x233

I wonder exactly what OP is talking about, wheels spinning or a wheel hop. It's not quite clear from the initial description of the problem.
Not having traction is one thing (get tires that are right for the weather), wheel hop is another (get stiff bushes to get it right).
But, again, with the setup of that car stiff bushes all around would be a good idea regardless of what the initial complaint was.

Totally agree. I would also imagine those that are destroying bushings in a track environment are also likely running non-DOT racing tires which have a ton of grip over DOT rubber thus the handling limits are significantly higher and all that extra load is transmitted elsewhere into the chassis.....which is apparently the bushings. No surprise here. Want a race car? Pay race car expenses. They break and wear things out quickly. There's good reason why the M2 and M3/M4 use stiffer, less compliant bushings.

[Mywifes335]

Originally Posted by x233

I wonder exactly what OP is talking about, wheels spinning or a wheel hop. It's not quite clear from the initial description of the problem.
Not having traction is one thing (get tires that are right for the weather), wheel hop is another (get stiff bushes to get it right).
But, again, with the setup of that car stiff bushes all around would be a good idea regardless of what the initial complaint was.

On say, a local road like Skillman, if i dip into the throttle at 35mph the rear end would literally slide out. This is in 4th (8AT).

From a standstill it just cant hit boost until the car is at 60. Otherwise, spinning tires.

Today, it was 80F in DFW. With 3 people and a trunk full of shit, the cer had no traction issues...but it felt slower too LOL.

[Mywifes335]

Originally Posted by Viffermike

Knowing what I know about tires and being in the same area (dude: your car alone makes me want to organize a North Texas 2 Series GTG ... oh, BTW; welcome back!), I'm going to echo what XutvJet and Anthony235 have both said.

I'd try tires appropriate for the season first. It may be 80ish degrees today and we may have set a Christmas Day high-temp record here a few days ago, but average ambient high temps are in the 50s and 60s right now -- and those PSSs won't perform nearly as well at those temps unless you've really warmed them up.

Also consider that we dipped into the high teens about two weeks ago -- I'm not sure how PSSs react to being exposed to the sub-40 temps that summer tires lose almost all viscosity at (It's like driving on hockey pucks, man!), but if your car was parked outside, it's possible that the cold snap did some compositional damage to the PSS' rubber -- particularly if you've abused them with powerrrrrrr (and, thus, temp cycles) between now and the current 3K mark.

Just some food for thought.

Dude organize it for 2017!

[Anthony235]

Originally Posted by Mywifes335

On say, a local road like Skillman, if i dip into the throttle at 35mph the rear end would literally slide out. This is in 4th (8AT).

From a standstill it just cant hit boost until the car is at 60. Otherwise, spinning tires.

Today, it was 80F in DFW. With 3 people and a trunk full of shit, the cer had no traction issues...but it felt slower too LOL.

None of that surprises me with your PS2 and tire setup.

[Dylan86]

Do you have an open diff?

[rwalker]

[QUOTE=Pparana;21037964]

Originally Posted by Mywifes335

Thanks. I was wondering, which pieces are attributing to the torque bias when throttle is applied?[/QU


rear lca bushings, outer. Feels like a wheel is loose or a wobble under acceleration?

you can swap to Poly. I have replaced them with poly, other arms with adjustable arms with spherical bearings and the sub and diff mounts with poly. I replaced them 3 times with stock before I found poly ones from superpro. Stock ones lasted about 1000 track miles until I added meth, then I went through a set each day, then poly. No problems since.

You have to remove the arm to properly check the bushing, doubtful they did this unless you got a 2 plus hour labor bill.

Which SuperPro part numbers would you recommend, Pparana ? I don't want to run sphericals anywhere...

http://www.superpro.com.au/find/supe.../cid-999501544

SPF3946K, SPF4314K?

[kmli5]

Originally Posted by XutvJet

Maybe so, but I don't see how this really has much to do with straight-line acceleration traction. I can see the benefit if you track the car often, but not in the situation the OP is describing.

mate because of the soft bushings, the subframe is constantly bouncing around and majorly affecting for the car's ability to put the power down. not to mention axle tramp.

[Mywifes335]

Originally Posted by Dylan86

Do you have an open diff?

Yup. Probably installing M Perf diff in the summer.

[Pparana]

[QUOTE=rwalker;21045724]

Originally Posted by Pparana

Which SuperPro part numbers would you recommend, Pparana ? I don't want to run sphericals anywhere...

http://www.superpro.com.au/find/supe.../cid-999501544

SPF3946K, SPF4314K?

Rear LCA is powerflex PFR5 414, subframe and diff are superpro. I would just get the whole kit for stock arms, and do the diff as well when your in there.

[Dylan86]

Originally Posted by Mywifes335

Yup. Probably installing M Perf diff in the summer.

I want to think that the LSD will make a great improvement with what you're experiencing. With your power levels, you are definitely getting held back with an open diff, IMO. In a straight line the LSD will keep both wheels spinning at the same speed. Right now, when you get on it, it goes, then the wheel with the least amount of grip is going to break loose like a banshee, causing the back end to wash out.

[rwalker]

Originally Posted by Pparana

Rear LCA is powerflex PFR5 414, subframe and diff are superpro. I would just get the whole kit for stock arms, and do the diff as well when your in there.

Thanks for the recommendations!

You don't have pics of your failed LCA bushings, do you? I may just do LCAs and call it a day.

Also: how's NVH with all that poly?