Suspension guidance

C

Charlesf

Member
 Alma, Michigan
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We acquired our 2007 3.0 si last June, with 76,000 miles. It is a manual car and came with service records up to 2023. The clutch was replaced and flywheel resurfaced at 60,000 miles. Otherwise just routine maintenance. I have replaced the serpentine belt and the evap vacuum pump and added a Blue Bus Bluetooth interface. Other than changing the oil, we’ve simply driven it, and it’s great.

The brakes show plenty of wear left and the tires are recent. I wonder about the suspension. There are no untoward noises, but should I be considering changing shocks, struts, ball joints, bushings? As an old fart I am not looking for vastly improved cornering limits at the expense of a decent ride. I am very much in the grand (old) touring mode.

Chuck
 
If it is on the original shocks at 76k then pretty certain they'll be shot. you may not see any sign of oil leaks or 'misting' but the gas that pressurises the oil to prevent air bubbles forming is likely to have snuck away by now.
Springs should be ok, but check them to be sure not massively corroded or the ends snapped off.

I would recommend new shocks, bump stops and top mounts front and rear.
Check out all the bushes etc while that's being done.
 
Hi there,
I would get it up on a ramp and check all of the bushings and see what needs to be replaced. A garage can do this pretty quickly.

If the shocks look original or are leaking / worn I would replace too.

Welcome!
 
Thanks so much. I’m thinking Bilstein B4 shocks and struts, or should I go with oem type Sachs?
 
Charlesf said:
Thanks so much. I’m thinking Bilstein B4 shocks and struts, or should I go with oem type Sachs?
Click to expand...
Sachs were OEM. B4 are basically a direct replacement.
Never had an issue with either type tbh. I use Sachs where I can.
I have heard a couple of comments regarding corrosion on the Bilstein, but not something I have personally encountered.

For top mounts I would suggest Lemforder, Sachs or Bilstein, in that order.
Bump stops come in two sizes depending if you have standard or Sports suspension. Sports ones being a bit shorter.
For the front end I would clean and re-use the original rubber dust covers, as replacements seem to be mostly plastic and on occasion can rattle.
For the rear you can buy the bump stops with the dust covers as a complete kit. These are plastic from new anyway.
I tend to use Febi Bilstein for those.
Bearing in mind I am UK-based so availability may be different for you.
 
enuff_zed said:
Sachs were OEM. B4 are basically a direct replacement.
Never had an issue with either type tbh. I use Sachs where I can.
I have heard a couple of comments regarding corrosion on the Bilstein, but not something I have personally encountered.

For top mounts I would suggest Lemforder, Sachs or Bilstein, in that order.
Bump stops come in two sizes depending if you have standard or Sports suspension. Sports ones being a bit shorter.
For the front end I would clean and re-use the original rubber dust covers, as replacements seem to be mostly plastic and on occasion can rattle.
For the rear you can buy the bump stops with the dust covers as a complete kit. These are plastic from new anyway.
I tend to use Febi Bilstein for those.
Bearing in mind I am UK-based so availability may be different for you.
Click to expand...
Curious about gt style suspension too. Done some research but cant beat asking around so I thought I'd piggyback off this thread.

Would you say bilsteins b4s are better than b6s or b8s? What shocks go with the eibach progressive springs? I hear conflicting opinions regarding pairing them with b6s or b8s.

I was under the impression that sachs were generally though to be worse than bilsteins, is this not correct?

For the shock towers, Is it worth upgrading the rear mounts? I understand they can be a failure point?

Finally, is it worth refreshing the control arms, sway bar and sway bar drop links?

I've seen MEHLE HD front arms discussed as a good replacement for the front due to a more durable ball joint?
 
My research (from forum, and other places) when I was looking was that B4's were OEM+ and B6/B8 are stiffer, so the GT-esque ride isn't as good, but they'd be better in on track/smooth roads. Heard very similar when talking to someone at Birds Auto this week too, who I'd expect to know their stuff given the amount of BMWs (and modified BMWs) they've had through the place over the years.
 
From my research, B4 and B6 are meant for stock ride height, and B8 is meant for lowered springs.

B12 kit are B8 dampers and Eibach springs.

I am also looking for suspension upgrade. My car is SE model and I wanted something more aggressive but I am still not sure if B6 dampers can be paired with stock springs... Only thing I know for sure is that B4 will work.
 
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