[lolachampcar] Performance Upgrade Efforts

[zwede]

The idea is that propulsion decreases the toe-in as bushings deflect. So static 0.3 dgr toe-in turns into close to zero as the car is in motion.

Front wheels do the opposite as there is no propulsion on them so you can safely set a tad static toe-out.

I'm no suspension engineer so I could be wrong, but that's my understanding for the Tesla spec being what it is.

 

[lolachampcar]

I guess it is a matter of degrees (pun intended ). Race cars have solid a-arm bearings so toe movement is more of an issue on full throttle acceleration exiting a corner. Road cars have softer bushings but I would still think straight line constant speed forces would be but a small percentage of those encountered while accelerating hard (which is the case most suspension settings target). 250 KW/Hr exiting a corner should be a lot more loading than 30 KW/Hr in a straight line.

The above said, if you see higher consumption with near zero toe then obviously you do not want to run near zero toe. Its the old Swedish saying "If the map and the terrain do not agree, believe the terrain."

 

[lolachampcar]

I just got some very nice looking full on production arms (longer to fix negative camber issue in the rear of MS) from Chris as a thank you for the stuff I sent him. These are beautiful and would seem to be perfect for the task at hand.

Nice work!!!

 

[SeminoleFSU]

Hey lola,
I've never been big on making changes to cars (other than stereos) so I'm trying to follow everything I read over the past 20-ish pages. I'm curious about the changes you noticed to the front suspension (think it was the A-arms or something) where at some point Tesla started using the same upgraded parts that originally were part of the P+ package on all cars...

For those of us with coils, does that still apply? If so, when do you think the change was introduced? I'm trying to figure out if my car has the old or new new parts on it based on the VIN... P11,5xx...

If it wouldn't have gotten the new parts off the line, do we know if this is something that Telsa would swap out as a TSB? The reason I ask is, I remember them swapping out something related to the suspension as part of a TSB or good faith, etc... but I don't remember what it was. I'll have to go back and look through the repair/service log sheets they give you as a hard copy the 3-4x I've been in for service.

Sorry if this question can be answered by re-reading... It gets confusing deep in the middle of the thread when this topic comes up, and is difficult to ascertain whether this upgraded/new part was for air suspensions only, or coils too... and when the part started getting introduced.

I'm asking all of this because it seems like those parts may have added some additional performance or safety benefits- and if it is something I could ask for them to swap the next time my car is in the shop, I'll definitely give it a try and see what they'll say...

Thanks for sharing all your findings and documenting it along the way. It sure seems like you did a LOT of work trying and testing different configurations, and for that we all learned a lot and can benefit if we want to follow in your footsteps, so thank you!

 

[lolachampcar]

It has been a while so what little I knew of the change over from old to new rear lower a-arm bushings has been shifted out

I remember that I had pre-ordered them from the service center for my wife's car (ViN 30xxxish) and found that her car was delivered with the uprated bushings already in place. I kinda knew something was up as her car felt really good in the back (no snide comments guys). I thought it was just the coils but it turned out to be coils and lower a-arms.

The service center should know when the cross over was. I would say ride height and lower a-arm bushings are the two biggest factors in the feel of the car and thus well worth pursuing. Obviously Tesla felt the stiffer bushings were a good idea as that is all they use these days.

Your 11xxxish ViN is well past the soft rear sub-frame bushings. Those gave a really vague feel to the rear of the car and word has it those cars had a hard time holding alignment (thrust angle).

 

[SeminoleFSU]

It has been a while so what little I knew of the change over from old to new rear lower a-arm bushings has been shifted out

I remember that I had pre-ordered them from the service center for my wife's car (ViN 30xxxish) and found that her car was delivered with the uprated bushings already in place. I kinda knew something was up as her car felt really good in the back (no snide comments guys). I thought it was just the coils but it turned out to be coils and lower a-arms.

The service center should know when the cross over was. I would say ride height and lower a-arm bushings are the two biggest factors in the feel of the car and thus well worth pursuing. Obviously Tesla felt the stiffer bushings were a good idea as that is all they use these days.

Your 11xxxish ViN is well past the soft rear sub-frame bushings. Those gave a really vague feel to the rear of the car and word has it those cars had a hard time holding alignment (thrust angle).

Oh I see so we're talking rear lower a-arm bushings... for some reason I was thinking front. It was a while back that I read through this thread in one sitting (wow) so some of the details have escaped me too.

So if I wanted to go to my service center and ask them if I have the new(er) equipment, I need to ask if I have the "rear lower a-arm bushings" that were introduced as P+ upgrades, but later became standard equipment for everyone. Would that be specific enough for them to know what I'm referring to?

Glad to hear I'm well past the old sub-frame, now it's just a question of the a-arm bushings. I think I'm going to keep ride height where it is, because I don't want to run into any dragging/scraping if I have a full car. Most of my friends are my size (6'2" 275lbs-ish) and 4 of us really add a lot of weight to the car

 

[linkster]

the soft rear sub-frame bushings. Those gave a really vague feel to the rear of the car and word has it those cars had a hard time holding alignment (thrust angle).

Could the process of changing the soft rear sub-frame bushings to the higher durometer ones be performed in one's own garage?

 

[dennis]

Could the process of changing the soft rear sub-frame bushings to the higher durometer ones be performed in one's own garage?

It could, but unfortunately you can't buy the new bushings from Tesla. In fact Tesla doesn't supply the bushings, they buy completed sub frames from an outsourced supplier. So you have to purchase A new subframe with the upgraded bushings.

- - - Updated - - -

So if I wanted to go to my service center and ask them if I have the new(er) equipment, I need to ask if I have the "rear lower a-arm bushings" that were introduced as P+ upgrades, but later became standard equipment for everyone. Would that be specific enough for them to know what I'm referring to?

IIRC @lola discovered that the part number for the lower a arms for his wife's S 85 was the same part number as the P plus a arms. If that is the case then all you need to know is that part number in order to have the service center check which version is on your car.

 

[lolachampcar]

dennis,
IIRC, the Tesla part number for the rear lower a-arm did not change. Tesla simply made a specification change and let production eat the old ones to phase in ones with the stiffer bushings. It was when I checked the part number cast in the bushing rubber that I knew something was up. The newer bushings are a slightly larger OD.

All of this is going back a ways so I suggest checking with the Service Center and asking them. I'm not sure they will know, but it has been too long for me to be sure.

 

[HyperMiler]

Near zero toe-in makes perfect sense as negative camber produces significant toe-in equivalent due to the conical shape of the tire at its interaction with the road surface (think of your rear wheels as conical coffee cups with the smaller end to the inside of the car: both want to roll towards the middle)


Interaction with Camber


When a wheel is set up to have some camber angle, the interaction between the tire and road surface causes the wheel to tend to want to roll in a curve, as if it were part of a conical surface (camber thrust). This tendency to turn increases the rolling resistance as well as increasing tire wear. A small degree of toe (toe-out for negative camber, toe-in for positive camber) will cancel this turning tendency, reducing wear and rolling resistance. On some competition vehicles such as go-karts, especially where power is extremely limited and is highly regulated by the rules of the sport, these effects can become very significant in terms of competitiveness and performance.

Toe (automotive) - Wikipedia, the free encyclopedia

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.

They look beautiful to me. My camber numbers are less, but my 4 "toes" are nearly identical to yours and I am on track to achieve 40K (currently at 32K) from my original 21 Conti's.

I am unsure why zwede wants you to scrub your rear tires though, his recommendation just makes my particular S less efficient. But then again, I have never been a factory spec guy in the past as I used to carry 2 "bottles" in the trunk in case another "street thug" got the jump on me and one wasn't enough. :biggrin:

 

[linkster]

Hyper

Thanks for posting this very important explanation along with a basic, simple (so that even I can understand it) analogy. This now makes perfect sense to me especially since I have been doubled over with laughter every time i read something like camber is not a wear angle....blah, blah..... by a serial poster whom I disagree with 80% of his/her umpteenth thousand posts. I am currently at 35K miles on my original 21 Conti's with 2.5 (the 1/2 represents a rear only "flip") tire rotations. You have added so much clarity for me. Thanks again!

 

[Cosmacelf]

Lola, sounds like you find the new coil suspension works well? As in well enough to not need the air assuming you aren't made of money?

 

[lolachampcar]

I cheated.
I wanted the P+ package but also wanted coils so I replaced my existing air springs with coils using all Tesla parts. I am happy

I've written this elsewhere, but I feel the best value today is P with coils lowered to somewhere near air standard ride heights. I find that the larger sway bars actually detract from the car's overall feel. The last thing I might do is to replace the front dampers with P+ units. The reason I say might is the modest increase in damping of the P+ over standard P air dampers may not be worth the $5K in effort to do the swap (damper assemblies are sold complete springs with dampers and thus are expensive).

 

[HyperMiler]

As lolachampcar (he's my favorite TMC hero!!!) pointed out, it seems as if in order to maintain negative camber at all ride hights, the route Tesla chose was trying to offset some of the significant camber impact by a moderate toe-out. With the upside that the car likes to enter into turns more, but with the downside of it going less straight at times. Which might explain why under heavy acceleration (the wheels running forward in relation to the car) with softer bushings the rear end feels a bit wobbly: the wheel with less traction might be in a more toe out configuration than the other side.

Btw, at a 2,5 degree negative camber, the inside of a 285 mm wide tire is compressed by 12.44 mm compared to the outside. Which explains why with 8 mm of usable rubber, you are looking at inside canvas before noticing much wear on the outside.

Hyper

Thanks for posting this very important explanation along with a basic, simple (so that even I can understand it) analogy. This now makes perfect sense to me especially since I have been doubled over with laughter every time i read something like camber is not a wear angle....blah, blah..... by a serial poster whom I disagree with 80% of his/her umpteenth thousand posts. I am currently at 35K miles on my original 21 Conti's with 2.5 (the 1/2 represents a rear only "flip") tire rotations. You have added so much clarity for me. Thanks again!

 

[lolachampcar]

HeHeHe
He said compressed by 12.44 mm (1/2").
Canvas before outside wear.
I love this way of describing it.

 

[offset]

I just placed an order for the Lolachamp rear upper suspension links. I get my car late this month, I'm going to slap them on and get an alignment right when I get it. I like the 21" wheels much better than the 19's, if this is what it takes to get more miles out of my car then that's what I have to do.

I'll keep a log, I'm going to be doing about 160 miles a day so it may be a fun test, if it hasn't been done already.

Now if I can only find a good alignment shop in LA that has done a Tesla alignment...

 

[lolachampcar]

offset,
I'm running about 0.1 degree per side or a total of 0.2 degrees of toe in on the rear of the car. The links took me to right about 1.4 degrees of negative camber and I am running slightly lower than air low. I'm over 16K miles on the original Pilots and will likely get another 1K before running out of tread (but no cord).

 

[FlasherZ]

Here's an update on my tire wear situation.

If you recall, when we last left this intrepid adventurer, we had the Tesla "sloppy bolts" installed to reduce my camber, and I asked the service center to perform the alignment to take out as much camber and toe as they could, within the specs.

This March, I took off my 19" wheels and put my 21" wheels back on, with new Conti's. I have since put 12,000 miles on the car, and while there is some rear shoulder wear, it's not down to the cords and the tires can easily be rotated to the front, presumably for another 12,000 miles or so.

I'm much, much happier - to go from scrubbing a new set of rear tires in 4,000 miles to getting a projected 18-24k out of them is much, much better.

 

[3mp_kwh]

The service center should know when the cross over was. I would say ride height and lower a-arm bushings are the two biggest factors in the feel of the car and thus well worth pursuing. Obviously Tesla felt the stiffer bushings were a good idea as that is all they use these days.

Your 11xxxish ViN is well past the soft rear sub-frame bushings. Those gave a really vague feel to the rear of the car and word has it those cars had a hard time holding alignment (thrust angle).

I've operated a Tesla search under the assumption that it was about 6000-8000 VIN, when the sub-frame swaps happened, without understanding that the lower a-arms were a big deal. It sounds like Lolachampcar, you are putting more weight on deflection issues stemming from the lower arms, then? I'd try to do both, but wonder how close to "there" just the lower arms would get someone? The end of Q1 2013 was about the sub-frame changeover. Arms have to be easier to swap. At one point, I think a quote on sub-frame was ~$2,000.

As it is, if I go 2012, the 21's come off for 19's and cheaper, maybe Ventus, tires. While I've had LCA issues with a track car before, most of THIS stuff on a Model S would come down to tire life. If I had more chances to "track out" in my commute, I wouldn't be looking at Teslas .

 

[lolachampcar]

If you are thinking just LCAs, it was my understanding from the Service Center that you would need the current sub-frame then do the current LCAs.