Suspension Overhaul
- Thread starter ChillZ4
- Start date
Ermm I don't know exactly. They are meatier and a bit more solid than the ones in the regular z4. It would also be interesting if we could fit the offset lower control arms bushes of the M on non m cars. They are the same bracket same size ( they are paired to the dimensionally same arm). These would add some extra caster up front together with some extra camber.
Well I had my powerflex bushes fitted today. Front wishbone rear bush, and rear suspension front bush.
Total hrs charged, 4.8... felt a bit long to me. Apparently the back ones took 3hrs.
Front ones have made a good difference I think. Steering wheel seems a bit out though, turned a touch to the left on a flat road.
Rear ones, well, it sounds like people releasing pool balls from the hopper and clacking and creaking lots when I turn or go over bumps... really horrible noise and a bit annoying really.
The front seems totally silent in comparison.
Do people recommend the rear bushes from Powerflex? I'll have to check with the garage to check they were greased, but upon my experience so far they seem to be a waste of money, a hassle to fit, and noisy and stupid!
We live and learn...
Anyone else found the rear ones excessively noisy?
Dave
Total hrs charged, 4.8... felt a bit long to me. Apparently the back ones took 3hrs.
Front ones have made a good difference I think. Steering wheel seems a bit out though, turned a touch to the left on a flat road.
Rear ones, well, it sounds like people releasing pool balls from the hopper and clacking and creaking lots when I turn or go over bumps... really horrible noise and a bit annoying really.
The front seems totally silent in comparison.
Do people recommend the rear bushes from Powerflex? I'll have to check with the garage to check they were greased, but upon my experience so far they seem to be a waste of money, a hassle to fit, and noisy and stupid!
We live and learn...
Anyone else found the rear ones excessively noisy?
Dave
Hey Dave,
The rears do take a while to fit as there is quite a few things to remove. That amount of labour seems about right, mind you i did them myself so it would take a while
Well mine do creak a bit and WERE properly greased. More noticeable when parking or slow manouvres. Nothing more than a quiet groany creak than anything embarrising or such. After a month now im waiting to see if it mellows.
I replaced all the bushes and front droplinks. I havent noticed a huge improvement, but on track it does seem a touch more pointy.
I fitted my M wheel straight after then a full alignment done, these two things probably made more difference to the feel of the car than the bushes.
The rears do take a while to fit as there is quite a few things to remove. That amount of labour seems about right, mind you i did them myself so it would take a while
Well mine do creak a bit and WERE properly greased. More noticeable when parking or slow manouvres. Nothing more than a quiet groany creak than anything embarrising or such. After a month now im waiting to see if it mellows.
I replaced all the bushes and front droplinks. I havent noticed a huge improvement, but on track it does seem a touch more pointy.
I fitted my M wheel straight after then a full alignment done, these two things probably made more difference to the feel of the car than the bushes.
Yeah, I'm just driving around with the radio on most times, or the roof down. I'm generally noticing it when I'm driving in a style that I can hear it.
I'm just not sure how much better they are at the back...
I'll get a proper Hunter alignment done and then see how I feel.
Does anyone know what the rear bush in question actually does? Is it track control or more camber related? Should I be looking out for better behaviour in any given discipline?
Hmmm
Fronts are worth it though. The front end just feels much more solid. A lighter sharpness to turn in, and more responsive and crisp dive under brakes. Coming to a final halt it really jerks the car stopped now, no floaty bounce back (though that could be in concert with the stiffer rear bushings too)
Dave
I'm just not sure how much better they are at the back...
I'll get a proper Hunter alignment done and then see how I feel.
Does anyone know what the rear bush in question actually does? Is it track control or more camber related? Should I be looking out for better behaviour in any given discipline?
Hmmm
Fronts are worth it though. The front end just feels much more solid. A lighter sharpness to turn in, and more responsive and crisp dive under brakes. Coming to a final halt it really jerks the car stopped now, no floaty bounce back (though that could be in concert with the stiffer rear bushings too)
Dave
Well my thoughts so far.
Back end squeaks alot on certain roads etc, but generally I can live with it. I'll try fix it.
Tracking needs fixing, but trying to ignore that for now.
But generally, the car now feels RFT 'stiff' and sharp through the steering, but without the lateral jumps. So what non-rft take away in sharp feeling responses, the poly front bushes seem to bring back. I'll assume my OEM bushes were still in ok order but there is a good chance new OEM front bushes may have improved things.
There is some more NVH but no squeaks. The extra 'noise' in the steering and front end feel is accompanied by valuable feedback too. Push on and let the forces build and there is certainly more good info coming through!
You really notice the increased rigidity in the front when stopping. The lower wishbone can't rotate much at all about the wheels rotational axis, so when you finally stop after braking it is sharp and decisive. No 'softness' to the stop at all. It also means the response on braking is much faster and more instant, no loading up of the bush at all as the wishbone dives. Again, new OEM's may have brought this trait back a bit, but no doubt the poly bush has added another level of sharpness!
100% recommend. Cheap to buy, cheap to fit, no funny noises, and only positives if you at all into having the Z4 as a driving car.
Back end side to side jiggle on rough roads has been massively reduced too. Again, maybe new OEM bushes may have impacted this somewhat, but I think the new stiffness is evident in improved wheel control. Much better for car composure. My concern that rear camber was excessive still stands, but now it's controlled better by that more rigid bush, along it seems with better toe control, the whole car feels more planted.
I'm not sure how much new OEM's maybe have helped here, so I'm less inclined to recommend these. I wish I'd upgraded fronts, then back ones later. They are cheap, but costly to fit, and noisy it seems.
A few months ago I went for a hoon with some other people and I struggled a great deal on the bumpier roads. The car was just lagging and I wasn't comfortable. On similar bumpy roads now the suspension just seems to get what it needs to do done much faster, and you get the response in the chassis and get the confidence. It feels like a negative feedback loop of lag has been removed to the point you can work with the car.
It was interesting because a fellow on the day has a 2.5i Z4 (he was in a Ferrari that day though), and he said his Z4 drives wonderfully.
I put this down to the M-sport suspension. Evo magazine mentioned similar on their long term test car. The 2.5i was a better more fluent drive, and the 3.0i was ruined with the stiffer suspension.
Well, I'd say with the newer bushings and non-RFT tyres, the 3.0i M-sport suspension *starts* to make sense. The first time in a long time I hit a bumpy corner in 3rd and floored it and went with the flow of the bumps all the way through and it felt fine. I didn't worry I didn't know what the car was going to do, despite having gone through that corner many times over the time I've owned the car and kept backed off!
You do start to wonder if BMW just got it a bit wrong.
Now I just need to get the alignment checked/adjusted (might pick some of my own settings here), and then go for a decent drive out again to see how I feel with it. Oh, and try remove that bloody squeaky crunchy sound from the new back bushes
Cheers if you read this far!
Dave
Back end squeaks alot on certain roads etc, but generally I can live with it. I'll try fix it.
Tracking needs fixing, but trying to ignore that for now.
But generally, the car now feels RFT 'stiff' and sharp through the steering, but without the lateral jumps. So what non-rft take away in sharp feeling responses, the poly front bushes seem to bring back. I'll assume my OEM bushes were still in ok order but there is a good chance new OEM front bushes may have improved things.
There is some more NVH but no squeaks. The extra 'noise' in the steering and front end feel is accompanied by valuable feedback too. Push on and let the forces build and there is certainly more good info coming through!
You really notice the increased rigidity in the front when stopping. The lower wishbone can't rotate much at all about the wheels rotational axis, so when you finally stop after braking it is sharp and decisive. No 'softness' to the stop at all. It also means the response on braking is much faster and more instant, no loading up of the bush at all as the wishbone dives. Again, new OEM's may have brought this trait back a bit, but no doubt the poly bush has added another level of sharpness!
100% recommend. Cheap to buy, cheap to fit, no funny noises, and only positives if you at all into having the Z4 as a driving car.
Back end side to side jiggle on rough roads has been massively reduced too. Again, maybe new OEM bushes may have impacted this somewhat, but I think the new stiffness is evident in improved wheel control. Much better for car composure. My concern that rear camber was excessive still stands, but now it's controlled better by that more rigid bush, along it seems with better toe control, the whole car feels more planted.
I'm not sure how much new OEM's maybe have helped here, so I'm less inclined to recommend these. I wish I'd upgraded fronts, then back ones later. They are cheap, but costly to fit, and noisy it seems.
A few months ago I went for a hoon with some other people and I struggled a great deal on the bumpier roads. The car was just lagging and I wasn't comfortable. On similar bumpy roads now the suspension just seems to get what it needs to do done much faster, and you get the response in the chassis and get the confidence. It feels like a negative feedback loop of lag has been removed to the point you can work with the car.
It was interesting because a fellow on the day has a 2.5i Z4 (he was in a Ferrari that day though), and he said his Z4 drives wonderfully.
I put this down to the M-sport suspension. Evo magazine mentioned similar on their long term test car. The 2.5i was a better more fluent drive, and the 3.0i was ruined with the stiffer suspension.
Well, I'd say with the newer bushings and non-RFT tyres, the 3.0i M-sport suspension *starts* to make sense. The first time in a long time I hit a bumpy corner in 3rd and floored it and went with the flow of the bumps all the way through and it felt fine. I didn't worry I didn't know what the car was going to do, despite having gone through that corner many times over the time I've owned the car and kept backed off!
You do start to wonder if BMW just got it a bit wrong.
Now I just need to get the alignment checked/adjusted (might pick some of my own settings here), and then go for a decent drive out again to see how I feel with it. Oh, and try remove that bloody squeaky crunchy sound from the new back bushes
Cheers if you read this far!
Dave
Just wanted to comment. I have also had Poly bushes installed on all four corners (haven't done the er sway arm bushes) and I am loving it. As others have said, it really firms up the handling. I'd also like to add, that at low speeds (speed bumps/parking lot speeds) the rears do make a lot of noise. Called back about it had it looked over and can't find a reason for it. The mechanic did say they shouldn't be making any noise, but for all of our cars to be making noise I think I'll trust in that. A few of the other petrol heads at work have told me that poly bushes will make noise no matter what you do. So /shrug
I'm generally ok with the noise on the rears, BUT, it's a compromise I'm happy to live with only because I want the car to drive more than to cosset.
I believe Powerflex should be more honest about these things when selling the bushes. They list a load of benefits, but say nothing of the cons. For that reason I'm very disappointed in their sales talk. It's simply misleading (tempted to email them)
Apparently a fix may be to rough up (scouring pad) the bush surfaces before greasing, so they hold more lubricant... I've also read PT85 spray is handy, so I'll be trying that too!
I'm not sure how these bushes would work elsewhere, but they seem to be perfect for the m-sport suspension on the 3.0i car... seems to bring it all together nicely!
PS, I recently replaced all the ARB bushes with OEM parts...
Dave
I believe Powerflex should be more honest about these things when selling the bushes. They list a load of benefits, but say nothing of the cons. For that reason I'm very disappointed in their sales talk. It's simply misleading (tempted to email them)
Apparently a fix may be to rough up (scouring pad) the bush surfaces before greasing, so they hold more lubricant... I've also read PT85 spray is handy, so I'll be trying that too!
I'm not sure how these bushes would work elsewhere, but they seem to be perfect for the m-sport suspension on the 3.0i car... seems to bring it all together nicely!
PS, I recently replaced all the ARB bushes with OEM parts...
Dave
Colin, that doesn't sound good. Hopefully the dampers will help once they are fitted.
This is the problem with tuning, there is no 'win win', it's always something better and something else gets worse, usually to a degree that out-weighs the benefits... hence why BMW spend so many miles testing things to get them as good as they can be...
I'm generally in two minds over the benefits of the bushes. Yes they are better, but considering my old ones were worn, would new OEM ones have got me 75% of the poly bush benefits for feel/sharpness, but retained decent NVH and no creaking etc, and smooth ride?
Hmmmmm...
Hehe, I've just been down some bumpier roads today and the ride is lots more in-yer-face...
Speed bumps just feel a lot harsher.
Lumpy roads are ok, ie, country lanes etc, but pothole/broken surfaces like you find in some urban areas where they spent money on big lumps of tarmac instead of making the road smooth... yuck.
Still creaking lots at the back. Gonna jack it up tomorrow and have a go at spraying this GT85/PTFE stuff in there and see what happens...
Dave
This is the problem with tuning, there is no 'win win', it's always something better and something else gets worse, usually to a degree that out-weighs the benefits... hence why BMW spend so many miles testing things to get them as good as they can be...
I'm generally in two minds over the benefits of the bushes. Yes they are better, but considering my old ones were worn, would new OEM ones have got me 75% of the poly bush benefits for feel/sharpness, but retained decent NVH and no creaking etc, and smooth ride?
Hmmmmm...
Hehe, I've just been down some bumpier roads today and the ride is lots more in-yer-face...
Speed bumps just feel a lot harsher.
Lumpy roads are ok, ie, country lanes etc, but pothole/broken surfaces like you find in some urban areas where they spent money on big lumps of tarmac instead of making the road smooth... yuck.
Still creaking lots at the back. Gonna jack it up tomorrow and have a go at spraying this GT85/PTFE stuff in there and see what happens...
Dave
Won't be that bad Dave, springs were £170 fitting was easy, did them myself, will get my mate to sort alignment, Powerflex bushings were £130, Just means i will have to remover front springs from shocks again, instead of doing it in one go to start with! so will be only £890
All the best Colin.
All the best Colin.Those rear bushes are a pain...
I guess if you can get labour cheap/free that is great... that is where my £300 extra came from
In any case, at least with new everything, you should have a firm BUT very well controlled and specified setup that you can tweak somewhat through the dampers!
I'd do it but the prices of Z4 M's these days is making me think I'm better off just upgrading than doing too much to mine
Dave
I guess if you can get labour cheap/free that is great... that is where my £300 extra came from
In any case, at least with new everything, you should have a firm BUT very well controlled and specified setup that you can tweak somewhat through the dampers!
I'd do it but the prices of Z4 M's these days is making me think I'm better off just upgrading than doing too much to mine
Dave