mkeeton

Hi,

Just wanted to share a small change that has made a big difference to my driving enjoyment. The stock caster settings are in the 10-11 degree range which is pretty high and gives the car great high speed stability and also accounts for why they feel somewhat reluctant to turn in. Compared to some other cars I have owned the E55 feels like it just wants to got straight and the off center effort is very high making it feel like the car doesn't like cornering.

A small change can makes a big difference in driving feel. The mounting point of the upper control arm has 3 bolts and is not adjustable. But if you leave the center bolt unchanged and add slight oval to the front and rear holes you can then rotate the mount enough to drop the caster by a few degrees. By doing this we were able to reduce the caster on my car from about 10.5 to 7.5. It makes a huge difference to the driving feel. The car turns in with much less effort. The off center effort required to hold the car in a turn is reduced and the straight line stability doesn't seem any less than before. I run close to zero toe (about 1/32 toe in) front and rear and factory camber of -1.5.

This was pretty quick and easy to do for a huge improvement in the driving feel. At the risk of inflaming many hard core fans of the E55... it now steers like a BMW!! Let me say that I have had my E55 since 2004 and love this car after having owned many M cars in the past. The motor got me hooked but I always felt the car would be better if it would just steer a bit more like a BMW. Now it is a lot better.

Cheers, Mark.

grantwoodtx

Thanks for feedback. Can you maybe take a few pictures of how you enlarged the holes?
Is this something the "crash" bolts would do too?

mkeeton

Don't know anything about the crash bolts. Will try and get some pics this weekend.

If you look over the top of the front tire you can see the upper control arm. The outside of the control arm has a plate with 3 bolts. If you leave the center bolt in place, and take the front and back bolts out, you will enlarge the holes so that the plate can rotate forward on the center bolt. So, the front and the back holes on the plate need to be enlarged on the back side so the plate can rotate forward. The enlargement of the holes should follow a slight arc as the plate isn't sliding forward and back but rotating around the center bolt. Hope that makes sense!

Cheers, Mark.

vntgspd

I'll wait until I test it myself buy I think I love you!

I'm in the process of selling my 911 and moving to an E55. I like it alot but do not like the way it turns in. I found this thread while searching for options to fit larger tires/wheels on the front in hopes of increasing front end grip. I don't expect Porsche-like handling but was hoping to liven up the E55 chassis a bit. Sounds like you are on the right track!

wpgfordguy

subscribed...

I miss my 911 terribly and know I need to take some caster out of my e63 to make it "better"

tbal

You guys want a better handling e55, ditch the air ride for coil overs. (yes it's
been done)

mkeeton

Hi David,

If you look at this pic the front of the car is on the left. There are 3 bolts. You can only see the front one and middle one. So, if you take the wheel off, you will see this upper control arm and the plate. Undo the 3 boots and the upper ball joint. The ball joint and plate will come off... you might need a ball joint separator to get it undone.

Then if you take the center hole, scribe an arc so that you enlarge the front hole toward the back of the car and the back hole the same direction. So, the front and the back holes on the plate need to be enlarged on the back side so the plate can rotate forward. The enlargement of the holes should follow a slight arc as the plate isn't sliding forward and back but rotating around the center bolt. We went as far as you could without getting out the back of the plate. Just used a drill and carefully ovalized the holes. Then when it goes back in place you can rotate the plate forward to reduce the camber.

Hope this helps. Photo is on the original thread.

Cheers, Mark.

Yacht Master

Don't you mean the front bolt hole should be ovalized "forward" and the rear should be ovalized toward the rear of the car. The goal is to move the balljoint forward like 4mm to reduce the caster, right?

vntgspd

This makes sense. The forward/backward can get confusing but I do understand that the upper ball joint needs to move toward the front of the car to reduce caster. I was originally confused about the "plate".

Now I see that I am essentially removing the ball joint and enlarging the forward and rearward holes. The control arm remains untouched.

I like this idea because it is completely reversible by replacing an inexpensive part should something not work out right.

I'll be doing this soon and will be sure to take pictures for the archives!

Thanks again.

vntgspd

Coilovers will ultimately increase handling ability but they will do little or nothing to improve steering feel. That's ultimately what I'm after.

My E55 is the family hauler and daily driver so racecar handling, ride, and response is not really what I'm after. That's what my racecar is for.

mkeeton

They both have to be ovalized in the same direction... toward the back of the car so that the plate can rotate forward. The ball joint needs to move forward as you suggested but that means both holes need to be enlarged similarly.

mkeeton

Exactly my thinking. Cheap and easy part to modify and reversable if you don't like the result. I adjusted mine by making sure both sides were symmetric and it netted a nice reduction in castor. When I went for alignment they were both spot on and didn't need any further adjusting.

GregMB

Any loss of high speed stability?

My recollection is that large amounts of caster can sometimes makes the car feel heavy at low speeds, but really helps it seem stable into the triple digit speeds.

I had a 911 like that.....really heavy steering around town, but it was terrific on high speed blasts.


-G

£ C43 £ AMG £

Sounds like a quick cheap and good solution.

I fitted k-mac bushes which rotate and moved my front wheels forward about 20mm. does that mean I increased the castor?
the handling improved but the steering is slightly heavier and more positive when turning at high speed.

chawkins2001

Off topic, are those Iforged Estorils Care to share anymore pics of the beast with those beauty's

Shadow5501

Nope, crash bolts not relevent here. They permit adjustment of the lower control arm to adjust camber. Wikipedia has decent explanations of caster and camber if you need clarification of the difference.

MB has used ~10 degrees of caster practically forever. The strong self centering of the steering it provides is the key secret sauce in the way an MB drives like it's on rails. Reducing caster will provide lower steering effort off center and less self centering - that may be good or bad, depending on what you like and how you use the car.

vntgspd

Well said!

mkeeton

No, those were HRE 19 inch 547r. I say were, as I sold them a while ago. Roads in SLC are pretty rough and it was too easy to bend rims. So, I went back to 18s. Much softer ride and bit easier to maintain. They were nice wheels!

mkeeton

No. Straight line stability is fine. I must say though I don't get much chance to run much above 85mph so not sure how things would be in the triple digit range for long distance cruising at those speeds. I have done a few short blasts to over 140mph and car felt fine. Steering effort definitely reduced and I like the way the car feels happier to turn in. Personal preference but less limo and more sports feel. If you look at something like the E39 M5 they run about 6 degrees so even with this change it is higher than the M5.

claywillard

Came across this during search for improving steering feel.
Can anyone comment?
Still satisfied with results?

Jakez

Checking out this mod now.. I was thinking the same as someone said about shaving one side of the left bolt and the other side of the right bolt in order for it to turn since it's pivoting on the center one, but the center bolt isn't exactly in the middle of the other two so you have to shave both outside holes in similar places.

I stuck a marker through the holes as I turned the plate toward the front of the car and these are the lines it left. So that is where I'm going to shave them down. Although I'm a little scared to shave the left one since the edge is so close... thoughts anyone?

vntgspd

I haven't done this yet but it looks like you are on the right track. The OP indicated that he machined the holes as close to the edge as possible without actually breaking through. I don't think it's much of an issue since the holes are "sandwiched" between the upper a-arm plates. Also, the bolt in the hole (on the right in your photo) opposite the one with the "thin edge" will act as a stop before the thin edge ever breaks out.

Bully Medic

I am going to have to attempt this when I get home. This may fix the only "issue" I have with my car.

claywillard

Take notice of the raised and machined shoulder surrounding the bolt holes. I repositioned the bolt holes just to edge of the shoulder.
The material is soft enough that you can actually lenghten the holes with a round file without removing the ball joint.
Best mod I have made so far. Car is significantly more enjoyable in the twisties.

josh8loop

Looks like it might be possible to either drill all three holes larger or use an end mill of appropriate size(almost looks like an 8-10mm fastener size) to elongate the aluminum upper ball joint mounting holes and gain slight improvement in camber. I wanted to ask the advice of the experts here and get a peer check on my thoughts. Naturally I will have to be extremely careful since elongating the holes could directly effects it's rigidity/structural integrity. My car is dead stock-new MB springs, new Bilstein HD shocks, new lower control arm, new ball joints all around, new front thrust arms, standard rim size, standard ride height. I plan on installing the lower control arm "repair bolts" as it is and that will get me closer to within spec, but I really need another half degree or so.