Has anyone put coilovers on their 6?

[Mck444]

The 6 adaptive M suspension is alright for a stock suspension, but there's a bit too much wheel gap as well as body roll. I know that the 6 platform is heavy in general and there's not much you can do to completely change that but I was wondering how much impact would coilovers make?

The stock suspension just has a bit too much body roll and the car just feels like it has too much weight to haul. I've been looking at multiple options throughout the price ranges such as the KW V1/2/Bilstein PSS10 all the way to BC BR/Bilstein B12 Pro Kit. How much would any of these coilovers improve the car's handling?

Any specific experience with any of these coilovers would be greatly appreciated. I was thinking of going with HR lowering springs to lower the car but I've heard they do make ride quality worse and damage the struts after some time. I'm leaning towards the B12 Pro Kit/KW V1/BC BR.

[socalengineer]

I'll let another forum member chime in on his 640i that has the KW coilover setup. I personally have ridden in his car and I'm not sure if the combination of 21" wheels/lower KW is what caused it but it's too bumpy for me. It could be that the rebound/compression are not dialed in 100% as there are so many settings and not very easy to get to the adjusting points. He went back and fourth to the installer and had it adjusted twice but they only can allow so many adjustments before charging more. The handling is definitely improved as well as body roll and steering response.

The B12 pro kit is a monotube shock which is the same as the stock shock. Monotube provides better ride quality, so if you are fine with a fixed ride height I would recommend that.

AFAIK Billstein PSS10 is not an option for 650i/640i. Only for M6. I would definitely go that route if you could. IIRC Billstein is the manufacturer of our OEM shocks.

One other thing to note is that the stock suspension is setup for OEM RFT. So when you switch suspensions most likely the new aftermarket suspensions are going to be much better with a non-RFT tire (not to mention all the other benefits of non-RFT).

[Mck444]

Originally Posted by socalengineer

I'll let another forum member chime in on his 640i that has the KW coilover setup. I personally have ridden in his car and I'm not sure if the combination of 21" wheels/lower KW is what caused it but it's too bumpy for me. It could be that the rebound/compression are not dialed in 100% as there are so many settings and not very easy to get to the adjusting points. He went back and fourth to the installer and had it adjusted twice but they only can allow so many adjustments before charging more. The handling is definitely improved as well as body roll and steering response.

The B12 pro kit is a monotube shock which is the same as the stock shock. Monotube provides better ride quality, so if you are fine with a fixed ride height I would recommend that.

AFAIK Billstein PSS10 is not an option for 650i/640i. Only for M6. I would definitely go that route if you could. IIRC Billstein is the manufacturer of our OEM shocks.

One other thing to note is that the stock suspension is setup for OEM RFT. So when you switch suspensions most likely the new aftermarket suspensions are going to be much better with a non-RFT tire (not to mention all the other benefits of non-RFT).

KW is probably out of the picture as it would be too stiff. I'd look for the Bilstein suspension as they're generally a little cushier than the KWs. I saw on ECS Tuning that they offer the PSS10 for the 650i, but I'm not sure whether that's 100% accurate. Even now with 20' wheels w/ low profile summer tires there's some noise and you can feel some of the rougher bumps. I just wanted to know if the other people have had some experience with coil overs, but most people don't put them on these heavy cars. At this point, instead of spending a couple thousand on suspension, I might just switch to a newer F80 M3/4 in the future.

[elvisisdog]

Reviving an old thread. One of my rear springs just snapped, about 10k miles after the other side. My 640D F06 is at 120K miles so the shocks are also in the territory of getting tired so I'm looking at coilovers to change out the struts and springs in one hit. Financially it makes sense even if I don't really want to be spending big on a 10 year old car.

My thoughts are BC Racing which seem to get decent reviews at an economic cost. I don't have EDC (still frustrated by this omission) so looking for better handling, but likely to pair this up with uprated anti roll bars to really make it feel like an upgrade.

Questions for people on coilovers, what spring rates have you gone with? I'm trying to work out what I need and seen people have spring rates of 10/6 front to rear (feels a little extreme in difference).

If anyone has the weight distribution front to back that would be really helpful in making my calculations a little more accurate.

Cheers
Neil

[elvisisdog]

[edited] I've just tried to calculate my spring rate based on formulas in High Performance Academy youtube videos (seemed the a straight forward approach to a calculation - not endorsed).

I get a spring rate of 10/12 front to back. I've seen BC racing coilovers mostly come standard for the F06 with a spring rate of 12/4.5 which gives me the impression that my calcs are some way out.. I just contacted BC racing and they've tuned the spring rates for the car, they're likely to know a lot more than me armed with a tape measure and some wonky calcs in a spreasheet.

Anyone got any experience of them?