Suspension choice..AT LAST !!!

[nick///M3]

Well after a long time since i asked around for what suspension i should buy
for the M3 it seems that i finally made my choice.

After the 'thread" on here about suspensions i finally got a KW V III for the M3...

not long after i moved on and changed the front springs, raised the car to the same height as the csl and tried to like my set up...

I searched around in Greece and found a technician that does suspensions for over 30 years for road and race cars..

After a visit in his shop he explained to me that in the M3 he does not change suspension with any aftermarket unless the car is seeing 90%
track time and 10% road, maybe less..
He takes off the OEM suspension and he re-valves the shocks giving
them more rebound and a good amount of bump and he re-uses the stock springs cause the roads here are terrible and the key to make the
car work is the suspension travel...

At first i didn't want to believe it..
i said "what the f@ck is he saying???"
I asked if he can do something to the KW and the answer was no.
He told me to raise the car and change the springs front and rear
to stiffer ones to help the shock maintain some suspension travel..

Well i did that and the improvement was huge !!!
But still not what i was looking for...

Went back with the shocks in my hand and we put them on his dyno
The numbers were not quite as good as what he recommends for the car
And the big problem was the height of the shocks..
From the stock ones the KW's was about 50mm shorter both front and rear..
This means that no matter what i did the problem of bottoming out
in our roads would never go away.

So i started talking to some companies that a lot of you are using their
suspensions and managed to get some data for their shocks.

From the power point the shocks were pretty darn good
But i never found out what was the height of their shocks

So i found a csl suspension in the Ebay and bought it

Went to the tech once again and asked him to build them
so that i can give them a try

So the next day he called me and said the following
" well i have done about 10-12 M3's and this is the 1st time
that i saw this. The forces on the front ones are EXACTLY the same as
i build the normal ones. And the rears have no difference in bump
and rebound from the standard M3. And the shocks are about 1 cm shorter.
The other thing is the springs..
The front one though it seems like the standard M3's spring is a
bit shorter BUT the principal of making it is totally different !!!
It's like a torsion rod and it works both vertically as much as horizontally..
As for the rear its just phenomenal. It's height is 20cm and i put it on the
scale, compress it 10cm and the coils seem like they can go another 5-6cm MORE !!! Just amazing...
Are you completely stupid for ever wanting these off your car???
Come tomorrow and pick them up"

Frankly i was shocked and i was thinking to my self this guy is
building wrc cars, Group B cars , F40's,
btcc cars ( yes there are quite a few of them here..)and other things
and he is so amazed with the oem csl suspension...
is it really that good??

Next day i pick them up, put them on the car ( they are wayyyy lighter
than the KW ) and went for a small drive.
The car seats about 5mm lower from the csl and that must be from the weight difference.
As for the car in the 30 minutes i was in it i am really really amazed from its "behavior".
Although there is some bouncing cause of our roads
it bounce way different, very smooth and "forgiving"..
and the rest of it is just simply marvelous...
It even accelerate and brake better !!!!
I just can't believe it...
In the next days i am going to get some more time behind
the wheel and conclude my testing..

Now for some numbers

The tech builds the normal ones like this :
Front
88mm/sec : rebound 1226N - bump 441N
176mm/sec : rebound 2207N - bump 736N

Rear
88mm/sec :rebound 1177N - bump 441N
176mm/sec :rebound 1570N - bump 736N

The csl ones are :
Front
88mm/sec : rebound 1294N - bump 579N
176mm/sec : rebound 2491N - bump 726N
Rear :
88mm/sec : rebound 814N - bump 431N
176mm/sec : rebound 1344N - bump 785N

Mine were build with a bit more power
cause of the weight difference.

Front
88mm/sec : rebound 1402N - bump 559N
176mm/sec : rebound 2648N - bump 726N
Rear :
88mm/sec : rebound 912N - bump 539N
176mm/sec : rebound 1402N - bump 824N

Shocks height
Front : 60cm
Rear : 68cm

Springs Height
Front : 23cm
Rear : 20cm

As for the spring forces there are kind of progressive so
the measurement is not right...

I know this REALLY big to read, but i thought i ought to
explain what happen...

well all comments welcome...( i am going to hear " i told you so" !!)

All the best

[shane@mbtech]

Im confused

Do you now have standard M3, standard CSL, or KW V3 on your car?

For a road car the CSL stuff is unbeatable IMO, but it lacks adjustability for really fast track driving.

Spec your car to suit your use.

[The Gorilla]

Hi,

Quote-

''Im confused

Do you now have standard M3, standard CSL, or KW V3 on your car?


From what he posted he is running re-vamped
CSL front and rear.

The rates quoted do not make much sense in
that he posted that he wanted more travel
due to the conditions of his roads.

To go progressive stiffer spring rates and then just
valve for bump and rebound at the rise and
fall of the dampers will make for a siffer set up,
which is not what you want.

Car should sit on the springs and the dampers do
the work, and the fine tuning is with the ARB's etc.

Would be much better set up for the bad road conditions
if the dampers were valved to be at say 100%
valving at 75% travel which would work well
with correct progressive spring Rates.

The car needs to ''rise and fall'' not crash and bang
on the bump stops.

Its been said many times before there is no really good
half way house on suspension.

Your either good for the road or good for the Track.

Regards,

The Gorilla.

[nick///M3]

Originally Posted by The Gorilla

Hi,

Quote-

''Im confused

Do you now have standard M3, standard CSL, or KW V3 on your car?


From what he posted he is running re-vamped
CSL front and rear.

The rates quoted do not make much sense in
that he posted that he wanted more travel
due to the conditions of his roads.

To go progressive stiffer spring rates and then just
valve for bump and rebound at the rise and
fall of the dampers will make for a siffer set up,
which is not what you want.

Car should sit on the springs and the dampers do
the work, and the fine tuning is with the ARB's etc.

Would be much better set up for the bad road conditions
if the dampers were valved to be at say 100%
valving at 75% travel which would work well
with correct progressive spring Rates.

The car needs to ''rise and fall'' not crash and bang
on the bump stops.

Its been said many times before there is no really good
half way house on suspension.

Your either good for the road or good for the Track.

Regards,

The Gorilla.

Mr Gorilla is right the car is on csl re valved suspension

and since the car seats lower i believe that there is a good combination of
shocks and springs..
don't forget i have almost everything now for the next step...if i decide someday...

And it just pass another big test
My wife on the way to the doctor to see the incoming baby
she actually made a comment for the car
She said that it felt tight but not make her get off her seat when bumps showed up on the road...now that is a BIG win for the suspension
Also felt really stable and neutral in the highway with a modest speed of 130-140 km/h...

All good so far.

[alexk]

Good that you found a good solution.