E36 Roll Center Correction Experience(s)

[aeronaut]

Good point, I would have figured that out pretty quick. lol. I guess I can lower the adjustment collars until all preload is gone, then easily drop the spring low enough to compress the damper a good bit.

[ScotcH]

Good point, I would have figured that out pretty quick. lol. I guess I can lower the adjustment collars until all preload is gone, then easily drop the spring low enough to compress the damper a good bit.

yeah, most coilovers pretty easy to remove the spring. You should not very little preload .... but we use helpers, so can just compress by hand

[aeronaut]

helper springs, CHEATER!!!

The way I've been doing things lately, I would have done this the hard way, then about halfway through....oh...I could have just loosened the spring. lol.

[aeronaut]

MRT update.
Checked all nuts for torque. All good.
2 events (4 days) later. Near last session, steering started pulling noticeably to left.
Checking suspension, 3 nuts loose on the MRT setup. One, saved by the cotter pin.

I'm done with these.
Ordering SLR's, unless someone says the new TMS are the way to go.

[ScotcH]

Yikes.

[aeronaut]

Vid of the worst one. From 80Nm tight to several turns loose in 4 days. This was not after initial install, but after a few prior tq checks.

https://www.amazon.com/clouddrive/sh...s*=0&mgh=1

[aeronaut]

Ordered an SLRspeed BMW mini kit today. Considered the new Turner kit, but I couldn't find any specs.
Trying to save $200 cost me $550. Not unusual in this hobby.

[aeronaut]

After a 2 day event, one side of the MRT kit was loose again. Probably 1/4-1/2 turn to get to TQ spec.
Patiently waiting for the SLR kit to come in, they are waiting for a part to send out a bunch on order.

[Def]

You should toss some nordlock washers on them to see if it'll keep the fasteners tight.

[aeronaut]

That's a good idea.
Or tack TIG them.

[Def]

Welding plated nuts/fasteners is a total PITA. You have to remove all the zinc, then hope you get a good strong tack.

I would want secondary retention of all those fasteners since they're subjected to external rotation due to suspension member deflection and steering.

[aeronaut]

Yea, I was just kidding.
I would also consider safety wire...but the nuts are smallish (13mm IIRC) 12-pt nuts with an 80lb-ft torque spec. I'm concerned drilling a safety wire hole would weaken the nut quite a bit.
For now, I'll just check them after each event, and wait for the SLR kit to arrive.

[ScotcH]

ON the GC kit, they are castle nuts and cotter pin ... and much bigger than 13mm.

[aeronaut]

It's a flange nut, so the the small socket size is a little misleading. I should measure the bolt size.
The SLR kit has a huge nut at that attachment point. Once I get the SLR kit in, I'll make some measurement comparisons.
A castle nut / cotter pin is a good solution, or safety wiring. Now that I'm paranoid, I'll probably drill and safety wire a few of these nuts on the SLR kit.

[ScotcH]

It's a flange nut, so the the small socket size is a little misleading. I should measure the bolt size.
The SLR kit has a huge nut at that attachment point. Once I get the SLR kit in, I'll make some measurement comparisons.
A castle nut / cotter pin is a good solution, or safety wiring. Now that I'm paranoid, I'll probably drill and safety wire a few of these nuts on the SLR kit.

Yeah, I don't see why that's not standard on a race part! Definitely a good easy solution to prevent wheel falloff, lol.

[aeronaut]

Just noodling about all this.
Looking at the GC kit, it looks like a nice solution. Different approach than SLR, TMS, MRT. But it doesn't change the steering ratio.
And, now that I've got a dozen weekends with a quick steering ratio, I couldn't live without it. Now, when the car steps out, it's a casual correction rather than a "can I keep up without flailing" steering event.
The ideal solution may be a kingpin with the steering attach point cut/moved/welded, and the GC RC/bump kit. If it were the off season, I'd probably go that route.

[ScotcH]

Just noodling about all this.
Looking at the GC kit, it looks like a nice solution. Different approach than SLR, TMS, MRT. But it doesn't change the steering ratio.
And, now that I've got a dozen weekends with a quick steering ratio, I couldn't live without it. Now, when the car steps out, it's a casual correction rather than a "can I keep up without flailing" steering event.
The ideal solution may be a kingpin with the steering attach point cut/moved/welded, and the GC RC/bump kit. If it were the off season, I'd probably go that route.

I think it would be very difficult to cut/reweld the attachment point. That is a cast part, and I had some work done on ours to reinforce it ... the welder said he would not trust a fix like that. The SLR solution is probably fine for what we do ... so many other things to address first The next (large) step would be a new machined kingpin ($$$$ yo).

[aeronaut]

I think it would be very difficult to cut/reweld the attachment point. That is a cast part, and I had some work done on ours to reinforce it ... the welder said he would not trust a fix like that. The SLR solution is probably fine for what we do ... so many other things to address first The next (large) step would be a new machined kingpin ($$$$ yo).

Interesting, and good intel. The drift guys cut/weld these things all day long.
Oh to have a CNC machine and suspension design knowledge.

[jakermac]

The next (large) step would be a new machined kingpin ($$$$ yo).

I would kill for something like this. CAD designed, CNC'd Aluminum spindle with a bolt on hub/bearing assy from an E90 with a raised mounting point (about 1.5 to 2" would do), relocated (for faster steering) and bumpsteer corrected tie rod attachment, roll center correction (maybe a modular setup to allow adjustment) and some sort of modular setup for brake caliper attachment for a variety of brake configurations. Oh, and they come in at about 1.5-2lbs lighter than OEM!

And on the SLR setup. I have not tracked the car, but I have autocrossed heavily and daily driven for 20-30k miles and I've never had anything loosen off. And some of my daily driving has been "spirited". And I understand the stresses of track driving. I've done a bunch of lapping in the past, including some slick shod cars (not just Nittos, Toyos, Hoosiers, but actual GoodYear R240 and R080 slicks).

[aeronaut]

Another weekend, and.....nuts loosened again, ~1/8th turn (which is probably 40-60 Nm rather than 80Nm spec)?
Basically, check every day, re-torque after ever weekend.
Ordering some nordlock type washers.

Hoping the SLRspeed kit ships soon.

[jdehaan]

My SLR kit nuts have loosened on me a couple times, so I paint marked them so I can quickly check on them but I think it's just the way it is with these designs.

[ScotcH]

That is some serious bullshit. I would be drilling the bolt and using a castle nut with cotter pin, or a safety wire nut. Loose nuts on a race car, especially suspension is bad news! Race cars are massive vibration buckets with solid joits and stuff ... this stuff maybe wasn't engineered beyond the street crowd??

[BlackHawkRacing]

That is some serious bullshit. I would be drilling the bolt and using a castle nut with cotter pin, or a safety wire nut. Loose nuts on a race car, especially suspension is bad news! Race cars are massive vibration buckets with solid joits and stuff ... this stuff maybe wasn't engineered beyond the street crowd??

Second the sentiment.

[aeronaut]

All agreed, but this particular application (MRT kit) doesn't allow for an easy solution.
Safety wire not possible (12 point high torque nut, no space for hole without compromising strength).
The 'bolt' already has a hole for a cotter pin, and is used. But it's not a castle nut. And I have not found an 11mm castle nut of the correct height to cover the hole.
I can put a washer between the top of the nut and the cotter pin to reduce travel of the nut if it comes completely loose (which it did, once).
I don't care for loctite, but might use some red in this case.

Nordlock washers ordered. (Also, SLR solution ordered....like 3 weeks ago.)

[aeronaut]

And, purely random.....received tracking number from SLR!