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Knocking sound over uneven surfaces
- Rockhopper
- Senior Member
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- Location: Mansfield
Knocking sound over uneven surfaces
Ah, fair enough.
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- Lifer
- Posts: 11077
- Joined: Tue Feb 10, 2015 10:27 pm
Knocking sound over uneven surfaces
Yes but dampers have no effect on ride height, that's down to springs.B21 wrote: ↑Wed Mar 29, 2023 6:07 pmCorrect ..however the dampers are also different between MSport and ‘normal’..
One member here had a MSport spring inadvertently supplied instead of a stock ride height spring and the effect was very obvious visually and ride height wise..
Also springs sag with age and use which compounds any differences…
As I said could be many other factors too..
M roady...OEM CSL’s, strut brace, Remus back boxes, ZHP
MR2 MK 2
E89 35i project car...mapped 365bhp, M4 stoppers & wheels, KWV3’s, H&R front ARB, M3 front arms, strut brace Eisenmann cat back race exhaust, VRSF downpipes inbound
E89 35is
G29
MR2 MK 2
E89 35i project car...mapped 365bhp, M4 stoppers & wheels, KWV3’s, H&R front ARB, M3 front arms, strut brace Eisenmann cat back race exhaust, VRSF downpipes inbound
E89 35is
G29
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- Lifer
- Posts: 8506
- Joined: Wed Jan 20, 2021 7:20 pm
- Location: Spaldingski
Knocking sound over uneven surfaces
And weight of the occupant(s)
All good things come to those who wait. I'm really impatient which explains a lot.
F31 320i. Good car.
E89 20i Now fully dried
Z3 'free litre'. Project and a half. Complicated!
Mazda3 sold
Tatty old R56 Mini Cooper. Money pit!
F31 320i. Good car.
E89 20i Now fully dried
Z3 'free litre'. Project and a half. Complicated!
Mazda3 sold
Tatty old R56 Mini Cooper. Money pit!
- B21
- Lifer
- Posts: 5450
- Joined: Tue Oct 05, 2021 7:15 pm
- Location: In my Banana Yellow Space Shuttle...somewhere over Southern Caledonia
Knocking sound over uneven surfaces
The dampers may affect the ride height for at least two reasons…
The sports damper has a shorter stroke..so the maximum possible extension / compression is more limited..
Depending on where the spring is attached to the bottom pre load collar the spring rate of an incorrect spring may affect both preload and therefore ride height..
I’m not sure that both dampers have their bottom collars in exactly the same position relative to the bottom mount?
The sports damper has a shorter stroke..so the maximum possible extension / compression is more limited..
Depending on where the spring is attached to the bottom pre load collar the spring rate of an incorrect spring may affect both preload and therefore ride height..
I’m not sure that both dampers have their bottom collars in exactly the same position relative to the bottom mount?
We choose to go to on with this endeavour at this time and do the other things, not because they are easy, but because they are hard…
A very modified Atacama Yellow 35is
A very modified Atacama Yellow 35is
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- Lifer
- Posts: 11077
- Joined: Tue Feb 10, 2015 10:27 pm
Knocking sound over uneven surfaces
If you fit a damper for an E89, beit M sport, standard, Ohlins, KW's etc, they have no influence on ride height. If I wind my KW's up to full hardness it doesn't jack the back of the car up to look like a dragster, same for if I set them to fill softness, it doesn't squat on the ground scraping the exhaust. It's stays the same height.
M roady...OEM CSL’s, strut brace, Remus back boxes, ZHP
MR2 MK 2
E89 35i project car...mapped 365bhp, M4 stoppers & wheels, KWV3’s, H&R front ARB, M3 front arms, strut brace Eisenmann cat back race exhaust, VRSF downpipes inbound
E89 35is
G29
MR2 MK 2
E89 35i project car...mapped 365bhp, M4 stoppers & wheels, KWV3’s, H&R front ARB, M3 front arms, strut brace Eisenmann cat back race exhaust, VRSF downpipes inbound
E89 35is
G29
- B21
- Lifer
- Posts: 5450
- Joined: Tue Oct 05, 2021 7:15 pm
- Location: In my Banana Yellow Space Shuttle...somewhere over Southern Caledonia
Knocking sound over uneven surfaces
That maybe so on some of those dampers but not Ohlins R+T you can adjust the static ride height by at least 40mm if you so wish..john-e89 wrote: ↑Thu Mar 30, 2023 9:34 am If you fit a damper for an E89, beit M sport, standard, Ohlins, KW's etc, they have no influence on ride height. If I wind my KW's up to full hardness it doesn't jack the back of the car up to look like a dragster, same for if I set them to fill softness, it doesn't squat on the ground scraping the exhaust. It's stays the same height.
Ohlins suggests a ride height analogous to MSport ride height but you can vary it by quite a large amount.
I’ve changed them on mine by about 30mm at various times to see what effect they have on ride and handlimg.
https://world.ohlins.com/app/uploads/20 ... MSMP50.pdf
Refers
So in the case of Ohlins they pitch the nose down by 5mm compared to a stock MSport setting.
We choose to go to on with this endeavour at this time and do the other things, not because they are easy, but because they are hard…
A very modified Atacama Yellow 35is
A very modified Atacama Yellow 35is
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- Joined: Sun Aug 05, 2018 12:14 pm
- Location: Hershey, PA USA
Knocking sound over uneven surfaces
I had this problem and it was finally solved today. Local BMW indie mechanic found that the rear sway bar shifted to one side and came out of the bushing. Don't know how or why, but he put everything back into position and it's clunk free now.
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- Member
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Knocking sound over uneven surfaces
Check your rear anti-roll bar links. Especially if you replaced the rear springs without disengaging the hand brake.
Are you sure the noise isn't coming from the rear roof clamshell hitting the rear deck. It should sit around 3mm off the black boomerang bit that sits on the top of the boot lid.
Are you sure the noise isn't coming from the rear roof clamshell hitting the rear deck. It should sit around 3mm off the black boomerang bit that sits on the top of the boot lid.
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- Newbie
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- Joined: Sat Mar 18, 2023 10:17 pm
Knocking sound over uneven surfaces
That's not a bad shout re the clam shell. When the weather has been cold and the car has a layer of frost on it I get a really distinctive noise coming from back there, as if it's creaking/scratching and breaking the ice as the shell moves.
And looking at the shell where it meets the rear of the car, there are two blobs (as if the paint has dropped and set) on either corner which takes that part of the shell much closer to the rear shelf. Could be that those are hitting?
Is there a way to adjust this gap to 3mm? But in doing so, is there a danger that the seal won't meet and water will get in?
And looking at the shell where it meets the rear of the car, there are two blobs (as if the paint has dropped and set) on either corner which takes that part of the shell much closer to the rear shelf. Could be that those are hitting?
Is there a way to adjust this gap to 3mm? But in doing so, is there a danger that the seal won't meet and water will get in?
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- Member
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- Joined: Sun Aug 05, 2018 12:14 pm
- Location: Hershey, PA USA
Knocking sound over uneven surfaces
I had the knocking sound. Turned out to be the rear sway bar slipped to the side and out of the right side bushing.