SPORT BUTTON ON A 4200

TimR

Member
Messages
2,656
The truth is that the 4200 Coupe Skyhook modes are only quite subtly different.
My car was without a rear ARB at all when i bought it. In that state, I wouldnt dare to negotiate urban streets without sport mode engaged, as it would readily bottom out the car- and given the very generous ride height, it was unexpected; so too the change once the ARBs was fitted. With uprated ARBs ( FD units) front and rear, the difference between modes became quite subtle, I even swore it had stopped working entirely...
Its clear then that there are many factors working in conjunction, and either with or against each other, to affect your ride. As you have reiterated, you ar no stranger to the geometry of suspension set-up.
All this to say you are reporting a ride characteristic we readily associate with the GS and the increased wheel rim sizing with the updated ECU algorithm. Perhaps you need a professional inspection to exclude the vagaries of internet diagnosis and anecdotal experience...? I suggest this because it would seem there is perhaps something going on, not usually associated with 4200 Skyhook
Your choices for remedy arent cheap, or necessarily straight forward. The essence of the issue is to first disconnect your suspension ECU. This is a simple thing, its in the boot on the left hand side over your CD changer.....If this shows you no dash fault illumination, you can spend on passive telescopes and set-up.
Ive seen plenty of cars being hawked for little more than £8-9K recently. This would inform most normal people's decision making..*
* There are folk amongst us, able to assist you in your man maths calculations, and guide you through the process of emptying your wallet quicker than you can feel pain- apply within !
 
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mjheathcote

Centenary Club
Messages
9,033
The suspension is a bit odd.
Even my 4200 with 18 inch wheels is firm, you feel the road, but at the same time it rolls a lot in corners when pushing it.
Comfort makes a little difference and it then tends to have a more boatey feeling, most notable on the motorway like riding between swells on the sea!
Consequently hardly ever drive in comfort.
I have a set of FD roll bars and springs I've never got around to fitting with one thing or another.
The roll bars will be first, to reduce the roll, I'm just a bit conscious that the springs will just be too firm.
Being an early 4200 I don't have the facelift/GS springs, which are a bit stiffer I think, but not sure, and the factory also changed slightly the anti roll bars diameters. The FD roll bars are much bigger in diameter than the later facelift/GS ones!
I've never driven a GS but just imagine it being rock hard along with the 19 inch fashion size rims too.
My daily M140i with passive suspension is really typically BMW rock hard and I've got used to it after over 50K miles, but my 4200 still feels firmer!
FD came out with there stiffer springs first, and roll bars second.
Can't help thinking that they might have just stuck with the roll bars if they came out first.
Their springs are nothing special, I had them tested, just a straight forward linear rated spring nothing fancy like a progressive.
All the info is spread over the forum, but I've never managed to find out what the spring ratings are for the standard 3200/AC 3200/classico 4200/and finally facelift-GS. The 2003 4200 onwards and GS list the same part number for the springs.
Would be nice to know what the spring rate is for the KW/rebranded FD passive coil overs too!
 

Carrera

Junior Member
Messages
102
There was at least one other case a few years back; he had done the KW swap on a 4200- I cant remember who it was - he claimed he'd simply unplugged the ECU with no faults recorded...
I have Ceika coilovers and an unplugged skyhook. No warning light and transformed handling.