Fine Tuning: Suspension / Handling / Steering

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sd-mk2
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Fine Tuning: Suspension / Handling / Steering

Post by sd-mk2 »

Hi guys,

After owning my e12 for several years I finally went through a resto of the exterior and interior. Now, I want to start getting into fine tuning some of the mechanical and functional components. Please be patient, I'm not mechanically inclined and will do my best to do as much on my own but for the most part I have a mechanic and a very knowledgeable shop do most of the heavy lifting.

I have questions about Engine / Drivetrain / Suspension, in this post I'll ask my questions regarding Suspension.

In advance; thank you for all your help and advice.

Current Suspension Setup:
- Bilstien Sport Shocks
- B&G lowering Springs
- Alpina 16x7,16x8
- Bridgestone Potenza RE 760 205/55/16, 225/50/16
- ST Sway Bar Kit (not installed)

Recent Work:
- 2x Drive Axel
- Drag link
- 2x Inner Tie Rod
- 2x Outer Tie Rod
- Wheel Alignment

Vehicle Use:
Regular street driving, spirited street driving, spirited canyon driving, potential long road trip


So after doing some work and adding new parts the car handles pretty well. When I first got the car it felt sloppy and didn’t feel stable. Kinda shakey when breaking. Now its stabilized quite a bit. The new tie rods really helped add some stability, specially when hard braking when going fast. The wheels and tires also made a huge difference with handling and overall ride comfort. The Sport springs are a little on the stiff side for a daily driver but its ok.

What I’m looking for is your expertise and experience with tuning this car in areas that I might not know, because to be honest I just purchased the suspension upgrades that I thought would improve the car. I know it tends to roll quite a bit but thats as far as go with common knowledge of handling issues.

I want a car that handles super tight on canyon roads and not be too harsh for regular street driving. I realize there will need to be compromise which is totally fine. I guess I'm looking for a sporty steerable car as most my driving is sporty driving.

Are there any small upgrades or parts I should look into replacing that I might not of thought of? The guy who did my alignment said the rear was out of spec but both sides read the same… so that means its ok???:?
Are there any bushings I should consider replacing? I saw an upgrade for a rear trailing arm bushing set.


Steering:

This is a big one for me, the one thing I have always hated about this car is the steering. It straight up just feels unsafe. Theres play all over the steering wheel. I’ve been told its the type of steering box it is, I’ve been told the steering pump on these cars make the steering super sensitive and should look into a Bavaria steering pump. I’ve read upgrading to a urethane coupler will help…
Any light on this subject would be greatly appreciated.

I realize my post is a little vague, but like I said I’m pretty green in the mechanic department. I love driving my car and Im just looking to make it the most enjoyable experience as possible. I’m hoping I can get a little clarity from talking to you guys.

Thanks so much!

A pic, because everyone loves pics:
Image
1980 BMW 528i, 1987 VW GTI, 1987 VW Golf GL, 1974 Alfa Romeo GTV 2000
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RonDwyer
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Post by RonDwyer »

Years back I had a 66 2000CS and a 67. The 67 was set up for full autocrossing with ridiculous sway bars and tight shocks. It was not a comfortable ride. Eventually one could get beyond the point of an enjoyable car to drive and end up with squeaky bushings, and wondering if the seats could be improved to make the ride smoother. Plus the tightness transmits more shock throughout the chassis. Cracking the body attachments like my 74 CS experienced.
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Lock
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Post by Lock »

I really hate play in steering too, and when I got mine it had a lot. I jacked up the car, shook all of the steering components and found the problem (the drag link to steering arm), replaced that, then spent an afternoon adjusting the steering box.
My car is oem and the suspension is tired but the steering is now sharp, no play at all. Gives me a lot more confidence when driving it especially in the rain.
Moral of the story; even though mine just gets standard parts, steering is just as sharp as my new cars. Assuming your steering box isn't so worn there's no adjustment left and everything that moves doesn't have play, your steering can be made to feel precise like a new car too. I'm guessing there's still worn joints somewhere.
I don't know about suspension mine is terrible. I was just going to get stock replacements for pretty much everything.
Also, that shade of red looks just as great in the daytime as it does in the night pictures.
1979 528i - M30B34 with 9.5:1 B35 pistons, 5-speed conversion G260/6, e28 rear subframe, e34 LSD 3.9:1, glass sunroof, e30 elec speedo, cruise control
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RandyM
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Post by RandyM »

based in my minuscule knowledge of suspension, do you have urethane bushings at the sway bar end links? (Turner Motorsport) Also check the state of your sway bar bracket bushings(Avail. from dealer), as well all the rubber bits in the suspension. Might help a bit with steering tightening up too, just guessing.
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sd-mk2
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Post by sd-mk2 »

Well I definitely don't want an overly tight / ridged track car. I've had cars that were too aggressive with the suspension and it was very uncomfortable.

It's definitely not a track car. I need comfortable sport driving on curvy roads.

As for the steering, sounds good I'll have the mechanic do a thorough inspection of all steering components.

As for the sway bars, I just purchased the ST set, it's sitting in my living room now ready for install. Do these sets usually come with the parts you're referring to? Or is that a separate purchase?

Thanks guys! Gonna have some of this done during the week
1980 BMW 528i, 1987 VW GTI, 1987 VW Golf GL, 1974 Alfa Romeo GTV 2000
GripGreg
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Post by GripGreg »

Without saying it what Ron means is that if you have polyurethane bushings
they will squeak more often than not!
Plus they create a more firm ride than comfortable rubber bushings.
That's a polite way to say a harder/uglier ride. I recommend rubber replacements
for a nice feel. :)
Good luck,,,,Greg

Ps: Before you play with the steering box you MUST mark where it is before
you start adjusting! It's critical.
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sd-mk2
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Post by sd-mk2 »

ah ok. gotcha, I'll stay away from that then. Noise is actually a bit of an issue on the car. I need to get some dynamat laid down for sure.

Truth is the first couple cars I messed around with I would go pretty aggressive on suspension. didn't care about noise or comfort.

Now, I care. Don't get me wrong, I want a super fun driving car... but i also need to be able to take a lady-friend out on a drive with it. my goal is finding that sweet spot of comfort and performance.

Im gonna have the sway bar kit installed and have the steering looked at... that should make some significant changes. I'll feel it out and report back after a couple of drives...

unless theres something else I should look into while we're down there?
1980 BMW 528i, 1987 VW GTI, 1987 VW Golf GL, 1974 Alfa Romeo GTV 2000
GripGreg
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Post by GripGreg »

Your five series to me, is the correct car to give you good handling and is
comfortable enough to roll with a lady!
My Rosallina has stock springs with Bilstein HD's all around.
I'm very happy with the feel and I'm an old skool slalom dude! 8)
The newer cars just don't give me enough feedback to know where I am
in the turn! :roll:
Just my opinion,,,,Greg

Ps: Yes, while you're down there take a look at the rubber with a flashlight!
Rosallina/'80 528i
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RonDwyer
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Post by RonDwyer »

I was out on a date once and drove Mount Hamilton Road out of San Jose to the central valley. It didn't go well...
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Post by GripGreg »

Ron,,don't leave us hangin'! What happened on that date,,,,,no head?? :?
Rosallina/'80 528i
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Hit the apex in Long Beach
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sd-mk2
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Post by sd-mk2 »

hahahaha well, with all the bouncing happening she didn't have to do much work. ZING! 8)
1980 BMW 528i, 1987 VW GTI, 1987 VW Golf GL, 1974 Alfa Romeo GTV 2000
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sd-mk2
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Post by sd-mk2 »

The guy at the BMW shop does a ton of E9 Coupes, so he's got the suspension set up pretty dialed in. He told me I might like HDs better than my Sports, as they can be kinda stiff. Thats what he uses on all his builds.

I used to daily drive my e12 with the current set up and I really didn't notice the stiffness of the shocks until I went with the 16in wheels.

Now I drive around I feel it here and there. Not a big deal at all.
1980 BMW 528i, 1987 VW GTI, 1987 VW Golf GL, 1974 Alfa Romeo GTV 2000
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Post by sd-mk2 »

Quick update: got the car back with new sway-bars installed. boy does this car feel great now.

like I mentioned before, I've spent a lot of time replacing all the old rubber and steering components. So the car was feeling really good before the sway bars were installed, but now its really feeling great!!!!

Although, I must say the steering play is still bothering me.

We've replaced all of the steering components, outside of the steering box itself... we did not adjust the steering though. My mechanic said in his experience tightening it only helps for a little while and then it gets loose again. Leading to eventually wearing out the box.

He said it was my call. I told him to hold off until I drove it around with the sway bars. now that i have, I'm still not happy with the steering feel.

What do you guys think? I've done everything but tighten the steering, should I give it a go?
1980 BMW 528i, 1987 VW GTI, 1987 VW Golf GL, 1974 Alfa Romeo GTV 2000
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CabbageFumes
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Post by CabbageFumes »

Im not sure, but It sounds like you want this to respond like a GTI or something. These boxes are soft by design. If you want the responsiveness that it sounds like, source a close ratio(rebuilt) box from an e9 CSL. That will do what you want it to do, but the last one we found cost 1500 Euros. I guess it depends on how badly you want an e12 to do what you want it do do. You can try an 1/8 turn at the box, which might help a little, but at the expense of the longevity of your box. Of course, you could just have a heavily worn box (insert tasteless joke). You can always look for a low mileage box and swap it out to see if it helps.
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sd-mk2
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Post by sd-mk2 »

I think it's a combination of both, this one might be worn and I do have 3 other cars with nice steering to compare it too.

Although I will say this, no way I'm being unreasonable. There's something up with that steering. I've driven more shitty old cars in my life time to know this steering is not what it should be.

It feels like my dads old work van from when I was 14 years old lol
Ok, maybe that's a little exaggeration.

Is rebuilding or getting a newer steering box a complete ordeal?
1980 BMW 528i, 1987 VW GTI, 1987 VW Golf GL, 1974 Alfa Romeo GTV 2000
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