[thakid22]

FYI: The Dinan Rear Suspension Strut Mount Kit does eliminate the rear bounce common to non M3 E9x models.

The cost was $100 and included the mounts for both rear shocks.
To date, this has been my cars most impressive mod.

There was debate on whether or not the Dinan mounts could reduce/cure rear bounce. I just wanted to let everyone know, yes, they can and did for me.

2006 330i Sport Package

[e90ben]

Thats pretty cool

Just to confirm youre talking about the mid-corner hit a bump feeling?

Or

Something else?

[dbudh001]

Would like to know myself

[thakid22]

Yes. This eliminates the pogo action you get at the rear when you hit bumps while cornering. WTF was BMW thinking?? More incentive to pony up for the M3?

[gtaccord]

You talking about this?

http://dinancars.com/product/d110-00...ries&mid=1013/

[CALWATERBOY]

Originally Posted by thakid22

Yes. This eliminates the pogo action you get at the rear when you hit bumps while cornering. WTF was BMW thinking?? More incentive to pony up for the M3?

Attractive - if I read Dinan right, allows 1 cm add'l shock travel before bump stops. That may affect shock life and gotta wonder about suspension component issues for out of spec travel, but maybe the problems don't exist.

However. Pogo from hitting bump stops is spaced farther out, but is not gone, technically. And those water bed stock bushings are still just that. Oy! Improved spring/shock combo and M3 bushings still just as desired. So's LSD + M3 sway.

[mlifxs]

doesn't this mod cause the rear shock shaft to sit slightly higher, relative to the shock body? If so, might be good for a lowered car?

[DrRobert]

Originally Posted by thakid22

To date, this has been my cars most impressive mod.

What other suspension mods does your car have?

[thakid22]

Originally Posted by gtaccord

You talking about this?

http://dinancars.com/product/d110-00...ries&mid=1013/

Yes. Those units right there. They are worth every (somewhat overpriced) penny of their $100 cost.

[thakid22]

Originally Posted by DrRobert

What other suspension mods does your car have?

Meyle HD Tie Rod Ends
Meyle HD Control Arms
Bilstein HD Shocks
Koni FSD Shocks (replaced by Bilsteins)
Goodyear Eagle Sport A/S Tires

[thakid22]

Originally Posted by CALWATERBOY

Attractive - if I read Dinan right, allows 1 cm add'l shock travel before bump stops. That may affect shock life and gotta wonder about suspension component issues for out of spec travel, but maybe the problems don't exist.

However. Pogo from hitting bump stops is spaced farther out, but is not gone, technically. And those water bed stock bushings are still just that. Oy! Improved spring/shock combo and M3 bushings still just as desired. So's LSD + M3 sway.

I don't doubt the effectiveness nor desirability of the M3 bushings.
I just point out that there is an alternative to the labored, expensive, special tools required, M3 bushing install.

These Dinan units can be installed in 45 minutes or less and adequately quelled the annoying rear bounce.

Keep in mind, my car has the N52, so I was never producing enough power to get the rear subframe out of sorts during spirited cornering under power. I imagine the N54, with its massive low end torque, could present a few challenges to the rear end during high power cornering.

But on my 330i this has not been an issue. The rear is rock solid under all dynamic situations.

Eventually, I'll step up and try M3 rear bushings. I love to DIY, but don't look forward to dropping the subframe. I'll definitely pay my Indy to tackle that job.

There's also a huge lower shock mount bushing that the shock/shft bolts to on the lower control arm. I've searched high and low. No one makes a stiffer replacement for that mount. But I can see where we could benefit from replacing it with a better bushing too.

Originally Posted by thakid22

There's also a huge lower shock mount bushing that the shock/shft bolts to on the lower control arm. I've searched high and low. No one makes a stiffer replacement for that mount. But I can see where we could benefit from replacing it with a better bushing too.

How much stiffer do you want it to be? The OEM piece is already hard as a rock. Almost no difference between the new one I put in and the one I took out w/ ~56k miles on it.

[ajsalida]

Originally Posted by thakid22

I don't doubt the effectiveness nor desirability of the M3 bushings.
I just point out that there is an alternative to the labored, expensive, special tools required, M3 bushing install.

These Dinan units can be installed in 45 minutes or less and adequately quelled the annoying rear bounce.

Keep in mind, my car has the N52, so I was never producing enough power to get the rear subframe out of sorts during spirited cornering under power. I imagine the N54, with its massive low end torque, could present a few challenges to the rear end during high power cornering.

But on my 330i this has not been an issue. The rear is rock solid under all dynamic situations.

Eventually, I'll step up and try M3 rear bushings. I love to DIY, but don't look forward to dropping the subframe. I'll definitely pay my Indy to tackle that job.

There's also a huge lower shock mount bushing that the shock/shft bolts to on the lower control arm. I've searched high and low. No one makes a stiffer replacement for that mount. But I can see where we could benefit from replacing it with a better bushing too.

OK enough already. Shock mounts are not an alternative to M3 rear subframe bushings. If your shock mounts were blown or old, sure replace them and the rear will feel better. Esp when fitting new shocks. But it is in no way related to or a replacement for M3 subframe bushings.

I am glad you fixed a problem with your rear suspension but you did not fix all problems. Furthermore you don't appear have the shocks/springs/tires/sway bars/WHP/WTQ etc or other mods yet that would make the rear subframe bushings obvious as a weak point.

[andrey_gta]

Wow. Interesting discovery.


I upgraded my rear arms to //M and found it reduced some hop too

[zhp43867]

Originally Posted by ajsalida

OK enough already. Shock mounts are not an alternative to M3 rear subframe bushings. If your shock mounts were blown or old, sure replace them and the rear will feel better. Esp when fitting new shocks. But it is in no way related to or a replacement for M3 subframe bushings.

I am glad you fixed a problem with your rear suspension but you did not fix all problems. Furthermore you don't appear have the shocks/springs/tires/sway bars/WHP/WTQ etc or other mods yet that would make the rear subframe bushings obvious as a weak point.

No, enough of your attitude already.

You can feel the bounce on a completely stock 325i. I will eventually do both the M3 bushings and the Dinan shock mounts, and it's good to know that the Dinan shock mounts help to mitigate the bounce problem. Just that correction alone may be enough for most people, and that's what OP is stating.

[ajsalida]

Originally Posted by zhp43867

No, enough of your attitude already.

You can feel the bounce on a completely stock 325i. I will eventually do both the M3 bushings and the Dinan shock mounts, and it's good to know that the Dinan shock mounts help to mitigate the bounce problem. Just that correction alone may be enough for most people, and that's what OP is stating.

Carry on. If you think new shock mounts on an old car fix or replace subframe bushings be my guest.

[zhp43867]

Originally Posted by ajsalida

Carry on. If you think new shock mounts on an old car fix or replace subframe bushings be my guest.

You have serious reading comprehension issues.

[ajsalida]

Originally Posted by zhp43867

You have serious reading comprehension issues.

Nope, don't think so. OP had some rear bounce due to worn shock mounts. Had nothing to do with rear subframe bushings, totally unrelated. Probably had nothing to do with DINAN or "extra travel" fixing it either.

There is a lot of rubber and therefore compliance in rear e9x suspension. Over time some of that ages and gets weak. However some of it was weak from new. Shock mounts are an example of the former, subframe bushings the latter.

Eventually you want to replace ALL of it. Replacing one piece of the puzzle does not fix all the other pieces. That also does not mean you can't notice improvement after fixing one piece. But if you drive your car in a manner which makes the rear subframe bushing weakness apparent, or have other suspension mods that end up making the RSB the weak link, slapping in some DINAN shock mounts will not do you any good, which is what I wrote if you had bothered to read it.

edit: and in fact, stiffening up other parts of the suspension makes the RSB weakness MORE apparent. So somebody who truly is having issues with RSB will make them worse by putting something stiffer into the system. It is all about RELATIVE compliance of pieces and if you get too far off on any one piece things deteriorate pretty fast. OP likely had worn/weak or improperly installed upper shock mounts, which caused a problem unrelated to RSB's.

[DrRobert]

I wonder if these shock mounts OP is referring to would benefit someone who already has the M3 SF bushings and other suspension bits.

[zhp43867]

Originally Posted by ajsalida

Nope, don't think so. OP had some rear bounce due to worn shock mounts. Had nothing to do with rear subframe bushings, totally unrelated. Probably had nothing to do with DINAN or "extra travel" fixing it either.

There is a lot of rubber and therefore compliance in rear e9x suspension. Over time some of that ages and gets weak. However some of it was weak from new. Shock mounts are an example of the former, subframe bushings the latter.

Eventually you want to replace ALL of it. Replacing one piece of the puzzle does not fix all the other pieces. That also does not mean you can't notice improvement after fixing one piece. But if you drive your car in a manner which makes the rear subframe bushing weakness apparent, or have other suspension mods that end up making the RSB the weak link, slapping in some DINAN shock mounts will not do you any good, which is what I wrote if you had bothered to read it.

edit: and in fact, stiffening up other parts of the suspension makes the RSB weakness MORE apparent. So somebody who truly is having issues with RSB will make them worse by putting something stiffer into the system. It is all about RELATIVE compliance of pieces and if you get too far off on any one piece things deteriorate pretty fast. OP likely had worn/weak or improperly installed upper shock mounts, which caused a problem unrelated to RSB's.

I don't disagree with what you say in theory. However, replacing E90 RSMs with stiffer units has been previously documented to reduce the "E90 bounce" in cars that were very unlikely to have worn stock RSMs.

http://www.1addicts.com/forums/showthread.php?t=383796

I never said the Dinan RSMs fix the problem, moreover that they seem to contribute to the overall fix. You told me that if I thought Dinan RSMs fix all the suspension problems, I should stuff it. Ironically, I never said that.

I'll be moving on now. Didn't intend to be sucked into an argument (or suck you into one).

[thakid22]

Originally Posted by ajsalida

OK enough already. Shock mounts are not an alternative to M3 rear subframe bushings. If your shock mounts were blown or old, sure replace them and the rear will feel better. Esp when fitting new shocks. But it is in no way related to or a replacement for M3 subframe bushings.

I am glad you fixed a problem with your rear suspension but you did not fix all problems. Furthermore you don't appear have the shocks/springs/tires/sway bars/WHP/WTQ etc or other mods yet that would make the rear subframe bushings obvious as a weak point.

Agreed. My only problem with the E9x rear suspension is the rear bounce on bumps.
During my research to remedy this bounce, the rear subframe bushings have been repeatedly fingered as the culprit. Many a thread, said the only way to get rid of the bounce is via M3 rear bushings.

This thread is simply here to state that the bounce can be fixed without the m3 parts. Hallelujah!
Let me my make myself clear, though. The M3 rear subframe mounts do indeed offer additional benefits beyond the alleviation of bounce.

I am just ecstatic that the horrid bounce is gone.

M3 bushings may one day find a home at my rear subframe, as I love making upgrades.
Mind you, there is still room left on the table for improvement. You'll have to forgive my overzealous enthusiasm for these Dinan mounts, though. They took the one single thing I hated most about the E9x platform and fixed it expertly. That bounce is ridiculous.
Anyway, that's neither here nor there, as it is gone now. I digress.

[thakid22]

Originally Posted by ajsalida

Nope, don't think so. OP had some rear bounce due to worn shock mounts. Had nothing to do with rear subframe bushings, totally unrelated. Probably had nothing to do with DINAN or "extra travel" fixing it either.

There is a lot of rubber and therefore compliance in rear e9x suspension. Over time some of that ages and gets weak. However some of it was weak from new. Shock mounts are an example of the former, subframe bushings the latter.

Eventually you want to replace ALL of it. Replacing one piece of the puzzle does not fix all the other pieces. That also does not mean you can't notice improvement after fixing one piece. But if you drive your car in a manner which makes the rear subframe bushing weakness apparent, or have other suspension mods that end up making the RSB the weak link, slapping in some DINAN shock mounts will not do you any good, which is what I wrote if you had bothered to read it.

edit: and in fact, stiffening up other parts of the suspension makes the RSB weakness MORE apparent. So somebody who truly is having issues with RSB will make them worse by putting something stiffer into the system. It is all about RELATIVE compliance of pieces and if you get too far off on any one piece things deteriorate pretty fast. OP likely had worn/weak or improperly installed upper shock mounts, which caused a problem unrelated to RSB's.

My shocks and stock upper and lower shock bushings were BRAND NEW.
I tried koni fsd first, whilst adding new BMW strut mounts.
The bounce was there, but better than with the blown BMW shocks that the konis replaced.
Still not good enough though, so I switched to bilstein HD shocks.
Initially the bilsteins are very stiff. They rode like crap, but there was damn near no body movement over road imperfections. The rear bounce was gone too! But, as the bilsteins broke in, the shocks got more civilized, but allowed more body motion. After break in was complete the ride quality was phenomenal, but the all too familiar rear bounce was back.
This now, was with new BMW upper and lower strut mounts. The whole setup felt very OEM BMW like, just smoother. Even the bounce felt OEM.

I swapped in the Dinan mounts, BOOM! No more bounce.

Take that however you must, or not at all. The Dinan mounts worked for my application.
Were they not supposed to?

Everyone else I talked to that personally has these installed, got the same results. That's what made me give them a try.
I'm glad I did.