Suspension Overhaul

C

ChillZ4

Member
Over the next few weeks I intend on changing various parts of the suspension on my 06 si 3.0. First off this week I will order the eibach pro kit and the powerflex bushes. Does anyone have any experience with this combination or would you just changed the bushes for now. I just find the suspension a bit wallowy when driven hard.

Thanks
 
Get Koni shocks and Rogue Engineering RSM's. If you find the suspensions "wallowy" right now and it bothers you, you're not gonna like those Eibach springs on stock dampers. You'll feel like a living bobble-head doll.
 
GP20 said:
Get Koni shocks and Rogue Engineering RSM's. If you find the suspensions "wallowy" right now and it bothers you, you're not gonna like those Eibach springs on stock dampers. You'll feel like a living bobble-head doll.
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Thanks to GP20's trial and error, that's the set up I have.
 
GP20 said:
Get Koni shocks and Rogue Engineering RSM's. If you find the suspensions "wallowy" right now and it bothers you, you're not gonna like those Eibach springs on stock dampers. You'll feel like a living bobble-head doll.
Click to expand...

Can I ask what the result of this change is? Smoother ride or more track focused?
 
I dont understand the issue with the eibachs, I have only ever heard good things. I am surprised that no one on here has changed to powerflex bushes!
 
ChillZ4 said:
I dont understand the issue with the eibachs, I have only ever heard good things. I am surprised that no one on here has changed to powerflex bushes!
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I didn't say there's any issue with the Eibachs. They're decent springs. It's the stock dampers that are the culprit.

Plenty of people have done powerflex bushings with good experiences. You should do a research.
 
Would you say it would be good to just fit the powerflex bushes to the standard setup instead of the eibachs?

Thanks
 
Topshelf said:
GP20 said:
Get Koni shocks and Rogue Engineering RSM's. If you find the suspensions "wallowy" right now and it bothers you, you're not gonna like those Eibach springs on stock dampers. You'll feel like a living bobble-head doll.
Click to expand...

Can I ask what the result of this change is? Smoother ride or more track focused?
Click to expand...

It can be both. The Koni dampers are rebound-adjustable. They can ride really soft or really stiff depending on the settings. They can also ride more comfortable than stock while handle better than stock at the same time due to better valvings.
 
ChillZ4 said:
Would you say it would be good to just fit the powerflex bushes to the standard setup instead of the eibachs?

Thanks
Click to expand...

Yes you'll see some improvements from upgrading just the bushings only. But if budget allows, you might as well do Eibachs/Koni's at the same time so you won't have to pay for another install and wheel alignment.
 
GP20 said:
.....They can also ride more comfortable than stock while handle better than stock at the same time due to better valvings.
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Now this is something I'd be very interested in. It's just the rebound that's adjustable, so is there a known setting that achieves this prior to installing them? Looks like Koni Sport Shocks would run around $650, plus those springs, RSM's and an alignment. Guessing this is about a $1,000 investment? Not too bad if it can actually settle the car down a bit.
 
In all honestly I don't find the ride with just the Eibach springs overly bouncy - it's absolutely fine IMO. I know GP20 is very much against this, but I've been running with std dampers and Eibach springs for about 6 weeks now and the ride is absolutely fine. I would however, like the option of firming up the damping for some possible trackwork so will be considering Koni's at some point in future...

And I've got Powerflex bushes sitting ready to fit - just haven't got the tools to do it myself or the £££/time to get them fitted by a garage!
 
Yeah I'm against it - for a reason. I put the Eibachs with stock dampers on my '04 3.0i and the ride was bouncy. I hated it and swapped them out for the Koni's. I installed the Eibachs on another friend's Z4 3.0i and he wanted to be cheap and keep the stock dampers even after my insistence that he should do it right the 1st time. And guess what - he found the ride bouncy and ended up getting a set of Koni's.

Some people are incapable of discerning the differences. If you find the stock dampers fine, keep them. Don't get the Koni's, 'cos they'll be a waste of money for you.
 
Yep, if money is tight don't buy or do cheap mods.

If the bushes are all you can get, get them.

Personally I think unless you need/want to lower the car, even lowering springs are usually not going to make much difference. Dampers are where you can really tune/change the handling and grip performance to your driving style, while retaining the good OEM overall stiffness balance.

I'd buy the best dampers you can afford first, even on stock bushings. They will see the biggest all-round improvement potential on road or track performance driving from the off.

Dave
 
All I'm doing is giving a different view of Eibachs! I'd guess for 75% or Z4 owners they'll struggle to see a difference.

My reasons for fitting Eibach springs were NOT performance-related (well, sort of...): Eibach springs are a cheaper and IMO better/safer solution if you need to replace 2 x snapped rear springs, outside of warranty, like I did. Certainly better performance than snapped springs, and IMO not massively noticeably different to stock springs. Replacing snapped BMW with more snap-prone BMW springs wasn't something I would ever do on a Z4.

ChillZ4 - just bear in mind that the fitting costs for bushes could be almost as much as the bushes themselves! I doubt my bushes will be getting ftted until I decide on buying Koni's...

Ally
 
I rekon you could get someone to make some Z4 spec springs up, that are not prone to snap.

My worry with all aftermarket springs is, you just have NO idea what you are getting. Stiffer? How much? Lower? How much? Progressive rate? How much?

Then all the questions about how they are optimised with the rest of the OEM setup.

That is why I've never bothered on any car bar fitting same model uprated (ie, I'd fit Alpina kit to my car)

Not sure on the BMW M stuff, some funny setups for the 4 seaters with highly progressive rears (still road/loading biased), not sure if this is the case on the Z4 M's...

Dave
 
Mr Whippy said:
My worry with all aftermarket springs is, you just have NO idea what you are getting. Stiffer? How much? Lower? How much? Progressive rate? How much?
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Hence why I chose Eibach-branded springs - they're original equipment in many cars (not BMW) and have the best reputation for aftermarket springs. So I knew what I was getting. At least the likes of Eibach actually tailor the springs to the actual model of car, i.e. spring rates, height, etc. unlike cheaper springs brands.
 
I've got to agree with Ally, I've just completed a 1100 mile trip over the weekend with Eibach springs on sports suspension and did not experience any undue bouncing, if anything I found the oposite, not that car was bouncy in the first place but every time you hit an inperfection in the road, that was transmitted through car and resulted in your body being thrown out of the seats and then acting as the shock absorbers, I found that the ride had improved with the initial thud over anything bigger than 1mm imperfection in the road removed, I did not fit the springs for any performance improvement but to get away from the snap happy BMW springs.
 
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