Lan-suspension new shock absorbers and springs front and rear

deQuincey

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deQ' now that you have had some time in the car on the new suspension what are your thoughts?

New springs and dampers take a little while to settle so have you noticed any change in ride height yet?
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hi hijacker !:-D

no worries here, it is good to share about the same issue

as to your question about my thoughts, well not too much time driving the car yet, but clearly an improvement from the previous setup and performance

mostly the front axis performance has improved a lot,

the rear one and me, we are somehow getting together, and starting knowing each other, i like it, but not settled yet

considering the small negative camber that i got in the rears, i have a pending issue that is assembling a thinner top spring support, bmw provides you with two sizes, 37mm and 28mm respectively, i used the 37mm and i now want to test the 28mm ones

stay tuned !
 

Peter Coomaraswamy

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What is the max (-) camber for the rear wheels

Re-publishing DeQ's spec sheet below, can the forum members recommend the maximum (safe) neg. camber for the rear wheels and rear toe-in? I have 16 in. Alpina (knock-off's) and I have welded on the IE camber/toe adjusters in the rear- also Bilsteins and CN springs with 3 dot perches. I have removed the rear sway bar and that has actually helped a little but I'm looking for a good cornering set up. I am not tracking this thing, just want a comfortable good handling ride and this is the last piece of the puzzle (or so I think). Again, any help would be appreciated and tire wear is not really a concern.

Thanks all!

measurements after alignment operation

results:



what do the experts think ?
 

Gazz

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Peter, why did you remove the rear bar? I have the same arrangement as you to go on my car including the IE camber / toe kits.
 

Peter Coomaraswamy

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Hi Gazz,

The team that is building the club-car racer mentioned that for track use they run without the rear sway bar, I figured that would surely give them some advantage when cornering so I tried it and it seemed to help- I may dial in some additional (-) camber and then re-attach, it's all trial and error and I would also imagine that what I prefer may not be someone else's preference but I'll throw up the results as available -

Still hoping to get some specs from the group :)
 

Gazz

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I would imagine the club racer probably has very stiff springs and shocks and this may negate the need for a rear bar.
Looking forward to your impressions. Perhaps you could qualify any feedback with what you are wanting from your car, eg, a firm riding sports stance with an abrupt response from the road, or, an easy riding GT feel which allows a little responsiveness but not at the expense of fatigue inducing harshness, etc.
 
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deQuincey

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the final setup

it has been a while since i started this thread trying to improve the ride on my coupe

the real thing is that i drive it quite hard, so after getting rid of the boaty behaviour of the front axle using the CN springs + bilsteins, the performance of the rear axle was not good enough, it tends to drift when cornering

clearly this has to be said, the original setup might not be perceived as safe, but it is indeed, hard cornering did not end in drift, so car kept the track perfectly

nonetheless we are not used to that behaviour and we prefer stiffer front axle

so CN springs and bilsteins are ok, but there is something to be done on the sway bars

it might be good to remove the rear bar, i do not know

what i know, is that keeping the 18mm rear and swaping front sway bar from stock 17mm to 25mm makes the trick

this is another car, cornering speed can be increased with not the sligthest drift neither the drift anouncing noise form the rear tyres

left + right fast cornering does not lead to instability, the car sits straight and perfect in every condition

so IMHO this is the definitive setup for the coupe
 

Bmachine

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what i know, is that keeping the 18mm rear and swaping front sway bar from stock 17mm to 25mm makes the trick

this is another car, cornering speed can be increased with not the sligthest drift neither the drift anouncing noise form the rear tyres

left + right fast cornering does not lead to instability, the car sits straight and perfect in every condition

so IMHO this is the definitive setup for the coupe

25 front, 18 rear. That makes sense .

Maybe I missed something but were you running 17 front and 18 rear before?
 
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Lotuss7

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It is all about driving style and balance preferences.

In my 2800 the front bar was 17.5mm +/- with the rear at 18mm. Original springs etc. didn't last long when I purchased the car. A Buick would have put it to shame on the backroads.

I was interested in tightening everything up, dropping the car a bit, going to a more neutral handling balance weighted to oversteer.

With the flexi body the suspension setup is compromised for optimal tweaking...too stiff a bar may not be the right answer. This is a fast cruiser, not a canyon carver.

I went with Hardy and Beck's suspension. Springs and specially valved Bilsteins. They recommened swapping the from bar out with a 23mm bar from a 530.

ALL rubber suspension bits, tie rods, etc. were replaced with genuine BMW parts.

The result is perfect for my taste. Compliant and extremely predictable. Quick and when pushed will start to drag the tail out without panic.

Lot of ways to set these cars up, Korman bars are 22mm front / 19mm rear... thinking they recognize the inherent nature of this pillar less coupe as well.
 

aearch

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i have the 19mm rear and 23 front
before hepassed boyd fechner set up mine
from the existing system cut and used 3.0 SPRINGS
rides like a cadilac and handels like a ferrari.
dropped it an inch or more
 

deQuincey

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hi stefan, is there any reference figure in your mind for this distance ?

HERE YOU ARE THE RESULTS:



ALL DIMENSIONS IN (mm)

...............................LEFT SIDE: ..............RIGHT SIDE:

GAP FRONT ...................35 ..........................35
GAP REAR .....................32 ..........................35

FLOOR FRONT ...............275 .........................280
FLOOR REAR .................300 .........................300

WHEEL CENTRE FRONT ...350 .........................352
WHEEL CENTRE REAR .....347 .........................350


hi,
@Stefan
you never posted your dimensions
possible ?
 

Bmachine

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Sorry I'm not Stefan but I do have some rough measurements...

With Hardy&Beck springs and Bilstein B6 in the rear with the 2 dot rubber spacer I have the same measurements you do in the rear. 64.5mm from floor to wheel arch.
In the front, I still have B&G springs but same Bilstein B6 and my number is 66.5mm. Which, to me, makes sense since the wheel arch comes up higher in the front than in the rear. My tire size and inflation is the same front and rear.

I question the fact that your "floor" measurement is different in the front and the rear. Is your tire size or inflation different? I would think it should technically be the same.
 
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Skiver

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Hi folks
I know this is an old thread but wanted to get help on ride height question
My rear left is sagging. The difference between in heights vs right side is approx 20-22mm depending on which measurement you use. Either way a noticeable gap.
I changed the springs to new stock ones from jaymic hoping it would solve the problem but no.
When replacing the springs I checked all the rubber and they are fine and same dimensions
When I lift via the differential, the left side certainly hangs more.
Questions I’m wondering:
- Do I have a twisted chassis?
- could I level out by adding a rubber or aluminum spacer ring to the top of the rear coil to address the gap?
Thoughts welcome!
Ivor
 

Henrik

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There is a possibility that your rear shock absorbers have different pressures. Have you replaced them recently?
 

Skiver

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Thanks Henrik - they’re not that old, around 6 years. I have the bilsteins but maybe I should swap them and see if the gap is still there. Although would the shocks influence the gap when I raise the car by the differential?
 
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