[lolachampcar] Performance Upgrade Efforts

[lolachampcar]

I started a thread over on TM regarding the lack of a model year concept with MS, the constantly evolving product and the need to document what we know of the changes and when they happened before this knowledge is lost. Early sub-frames and lower control arm updates would be just one of the many entries in that list.

I'll try to get something put together this weekend then put it out for edit/correction.

 

[tezco]

I got rid of the squishies! The parts that were installed - sub-frame, LCA, and upper links - are all common between P and P+ models as well. The price of the change was ~$5k including parts/labor.

This sounds like the ticket!

 

[rainman50]

Absolutely FANTASTIC news. I've been speculating out loud for some time now that a vast majority of the improvement in feel could be had with the proper sub-frame and latest lower control arms (LCAs - same as used on the P+). Passing on the thicker P+ sway bars keeps the car comfortable to drive. I think you just proved the theory!!! Glad to hear it worked out for you.

What exactly does your comment on thicker P+ sway bars have on the comfortable drive mean. Which way uncomfortable, ride \drive feel? Did you take your P+ sway bars off when you did you mods?

 

[lolachampcar]

I did not feel that MS had a roll issue thus larger bars seemed unnecessary. The larger front bar did improve turn in feel just a little bit but at the expense of head snatch when you hit a pot hole with one front wheel or go over a sleeping policeman at an angle. I personally do not like that by product of stiff bars thus tend to avoid them if possible. However, I do not dislike it enough to buy P bars and change them out on my car. Doing the rear bar is a pain in the but.

 

[rainman50]

I did not feel that MS had a roll issue thus larger bars seemed unnecessary. The larger front bar did improve turn in feel just a little bit but at the expense of head snatch when you hit a pot hole with one front wheel or go over a sleeping policeman at an angle. I personally do not like that by product of stiff bars thus tend to avoid them if possible. However, I do not dislike it enough to buy P bars and change them out on my car. Doing the rear bar is a pain in the but.

Thanks for the clarification.

 

[Laurent]

Passing on the thicker P+ sway bars keeps the car comfortable to drive.

I had the rear P+ sway bar installed on my car and I have yet to experience the “head snatch” you mentioned in an earlier post. Maybe because I’m not driving as aggressively as you are.

I saw little difference on the shock dyno between the P and P+ rear dampers so simply swapping out the front damper units would give you the most bang for the buck

My service advisor mentioned that when they install P+ shocks, they have to program the car to “recognize” them. I’m not sure what would happen if you had an outside shop install new shocks.

 

[Dave EV]

I had the rear P+ sway bar installed on my car and I have yet to experience the “head snatch” you mentioned in an earlier post. Maybe because I’m not driving as aggressively as you are.

Head snatch occurs when you hit a bump or dip with one side of the car and not the other, it does not take aggressive driving for it to occur. Many people may simply not notice the difference.

 

[lolachampcar]

And it is that monster front bar that causes the problem.

 

[dsm363]

And it is that monster front bar that causes the problem.

Could you start a new thread with your recommendations for early VIN P cars that don't want the entire P85+ package? I think that would be helpful and the ~$5k price is much more reasonable. Thanks.

 

[FlasherZ]

I can post what I did, the part #'s and what was replaced a bit later this evening. Dinner calls first.

 

[dsm363]

I can post what I did, the part #'s and what was replaced a bit later this evening. Dinner calls first.

Thanks. Think that would help.

 

[lolachampcar]

The approach that will work with the Service center is-
I would like the sub-frame and lower control arms from the current production P85. They will determine the correct part numbers. Flasher can speak to the value of the change.

Based on my first P85 (Feb 13 delivery), I believe there is significant merit to changing out just the LCAs if you already have the current production sub-frame. These are inexpensive parts and provide a significant reduction in rear squishiness (a highly technical term). My wife's Sept 13 delivery S85 had these LCAs and it made a significant difference. I was told these LCAs (actually, just updated bushings in the exact same aluminum casting) were first employed in the initial P+ production then migrated to all production MS.

and I'll revisit a more controversial position.....
I believe a very good feeling car can be generated from a coil spring current production P85 ordered with 19s. Lower the car, correct the high rear negative camber and put your choice of staggered rims/tires and you will have a stellar performer at a fraction of the cost of a P+. If you really miss the more aggressive front damping (there is little difference in the rear dampers) you can always buy the front P+ dampers and have them installed using your existing coils. Anyone interested in seeing what this feels like is welcome to drive mine.

 

[qwk]

Based on my first P85 (Feb 13 delivery), I believe there is significant merit to changing out just the LCAs if you already have the current production sub-frame. These are inexpensive parts and provide a significant reduction in rear squishiness (a highly technical term). My wife's Sept 13 delivery S85 had these LCAs and it made a significant difference. I was told these LCAs (actually, just updated bushings in the exact same aluminum casting) were first employed in the initial P+ production then migrated to all production MS.

Do you have any idea how long after the P85+ was available that this change was implemented to all cars?

 

[lolachampcar]

No, I am afraid I only became aware of the change to all production when I tried to buy P+ LCAs for my wife's car. I was told my the SC that my wife's car already had P+ LCAs on her car and that all production has been moved to the stiffer bushing LCAs that were originally developed for the P+.

Reading between the lines, I would say engineering erred on the side of noise isolation to the detriment of rear feel. They backed off that position and now there are no complaints about vague rear response under hard acceleration. Again, this is just a guess on my part.

 

[FlasherZ]

there are no complaints about vague rear response under hard acceleration.

I like to describe it as "the car hangs onto its own [butt] now".

 

[tezco]

I like to describe it as "the car hangs onto its own [butt] now".

Yes, mine is still doing a dance back there, all by itself. Thanks for the repost with all the details.

 

[einTier]

No, I am afraid I only became aware of the change to all production when I tried to buy P+ LCAs for my wife's car. I was told my the SC that my wife's car already had P+ LCAs on her car and that all production has been moved to the stiffer bushing LCAs that were originally developed for the P+.

Reading between the lines, I would say engineering erred on the side of noise isolation to the detriment of rear feel. They backed off that position and now there are no complaints about vague rear response under hard acceleration. Again, this is just a guess on my part.

Do all P+ cars have these updated arms?

Kind of curious as my P85+ seems a little squirrelly under hard acceleration.

 

[lolachampcar]

It is my understanding that the stiffer LCA bushings were first shipped in the P+ package then applied production wide when the arms to do so were available. So, yes, all P+ have the stiffer lower control arm bushings.

FWIW, my P+ feels significantly more stable on coil springs then it did on air springs.

 

[Zextraterrestrial]

Yes, mine is still doing a dance back there, all by itself. Thanks for the repost with all the details.

I'm learning better drift control...:tongue:
especially during passing maneuvers when the ass end just waggles around like a happy dog (could be the negative toe some)

 

[tezco]

I'm learning better drift control...:tongue: especially during passing maneuvers when the ass end just waggles around like a happy dog (could be the negative toe some)

I just had my alignment adjusted. If things still seem a little off I'll going ahead with the Flasher mods.