[Tambohamilton]

Originally Posted by Biginboca

I’m now running the standard e9x front spring perch (p/n 31336759452) which gives plenty of clearance for the Dinan Camber Plates nuts.

As far as ride height, it’s actually not ideal for what I want. I’d actually like to run the car flat to maybe even a bit of negative rake. I know shirmer likes the cars set up like this, and I have been taking a lot of cues from their builds this year.

I will say I like the front height where it is because #daily but the rear about ~10mm lower would be fine by me. From what I have researched these cars seem to handle best with zero to slight negative rake.

It arrived where it is now because the rake increased a bit after weight reduction because more of the weight loss was from the rear (lithium battery took 45lbs off the rear and rear seat delete took 40lbs off the rear). Most of the other mods were even reductions front to rear.

I cut the rear springs a bit when I did the rear uniballs and that seemed to get me back to about factory rake. At this point without doing coilovers (which I don’t really want to do yet) only way I know to take the rear down a bit more is cut the springs a little more, which I would prefer not to do because this increases the spring rate, or maybe try some of those adjustable rear springs/perches. I need to check the spring rates on those but I might be doing that next if they are in the 500-550 lb/inch range.

Thought it looked odd. Those perches are for Xd cars, not RWD. Not sure what the differences are, other than the RWD ones being aluminium rather than steel (which I think those are?). I believe the correct part is 31336764093.

Yeah, that's true about the rake. In my opinion it's not just having the rear a bit lower than the front, but the front also has a point where going lower isn't very constructive. The rear however can go very low without the suspension getting weird.

[Biginboca]

Originally Posted by Tambohamilton

Thought it looked odd. Those perches are for Xd cars, not RWD. Not sure what the differences are, other than the RWD ones being aluminium rather than steel (which I think those are?). I believe the correct part is 31336764093.

Yeah, that's true about the rake. In my opinion it's not just having the rear a bit lower than the front, but the front also has a point where going lower isn't very constructive. The rear however can go very low without the suspension getting weird.

Yea these perches are steel. Not sure what the difference is either between these and rwd ones. I didn’t even realize I’d ordered x drive perches I guess when I was shopping the strut mounts I just grabbed the part number off the same diagram. I guess that’s good… the parts will match each other

I did find this thread comparing them but nothing concrete here…

https://www.e90post.com/forums/showthread.php?t=1350276

What’s funny is ECS tuning shows the black ones as compatible with X Drive and RWD cars on their page.

[Tambohamilton]

Haha, yeah they can be friends under there. Just from looking at it, I'd guess that the Xd perches are a little shallower. You haven't had any issue with those nuts from the camber plates, where I didn't have clearance for a cap head bolt!

P.S. You HAVE to replace them with the aluminium ones NOW, because lb/oz/g

[Biginboca]

Originally Posted by Tambohamilton

Haha, yeah they can be friends under there. Just from looking at it, I'd guess that the Xd perches are a little shallower. You haven't had any issue with those nuts from the camber plates, where I didn't have clearance for a cap head bolt!

P.S. You HAVE to replace them with the aluminium ones NOW, because lb/oz/g

Yea for sure lol. I actually found the difference just now. The rwd e92 strut has a conical shape where it meets the perch and the aluminum perch has a conical shaped seat attached to mate. The X Drive struts are flat at the seat and meet flat to the black spring perch. So probably I should have run the aluminum perch cause it had the taper but the taper isn’t steep enough that I think the strut will punch through or anything so I’m going to leave it alone for now.





The next thing I would like to address is the rake though. I already had that on my mind but since you noticed it, well now it’s definitely become more important

[Tambohamilton]

I am not your normal observer - I didn't just notice it, I was looking for it

I recently replaced the rear springs in mine, to lower it a bit. I went from F3 (e91 330d non-sport) to D4 (stock sport spring from an e93) IIRC. Both essentially the same rate from my measurements and calcs, but the latter lowered the car some 20mm. I now have something like the factory rake again, but approximately sport ride height, with performance front springs and ~-2.2deg front camber.

I don't think there are any OE rear springs which will match what you're looking for, but if you want any input on where *I think* you should aim for I'll be happy to stick my oar in

[Biginboca]

Originally Posted by Tambohamilton

I am not your normal observer - I didn't just notice it, I was looking for it

I recently replaced the rear springs in mine, to lower it a bit. I went from F3 (e91 330d non-sport) to D4 (stock sport spring from an e93) IIRC. Both essentially the same rate from my measurements and calcs, but the latter lowered the car some 20mm. I now have something like the factory rake again, but approximately sport ride height, with performance front springs and ~-2.2deg front camber.

I don't think there are any OE rear springs which will match what you're looking for, but if you want any input on where *I think* you should aim for I'll be happy to stick my oar in

Paddle away! I can’t find the rates on those K&W Height Adjustable Springs so I’m leaning towards another rear spring trim lol

My current rear rate is 505lb/in

[Tambohamilton]

Know the front and rear axle weights of your car? What are the front spring codes (Tx), or rate? What sway bars do you run? You've got an LSD, right? What bump stops do you run? What are your current ride heights, measured the BMW way?

Sorry for the barrage of questions!

[Biginboca]

Originally Posted by Tambohamilton

Know the front and rear axle weights of your car? What are the front spring codes (Tx), or rate? What sway bars do you run? You've got an LSD, right? What bump stops do you run? What are your current ride heights, measured the BMW way?

Sorry for the barrage of questions!

I’ll answer as best I can tomorrow thats a lot of info lol

[Tambohamilton]

I know, sorry. With that plus knowing the suspension geometry, we can calculate 'magic number', which is a basic way of comparing the front and rear suspension setup.

[Biginboca]

Originally Posted by Tambohamilton

I know, sorry. With that plus knowing the suspension geometry, we can calculate 'magic number', which is a basic way of comparing the front and rear suspension setup.

After thinking about it some more I think I’m just going to cut the rear springs a bit more. Looking at this:



The M3 has a larger front to rear spring rate difference and a firmer rear spring than I do. I have BMW performance springs, oem e92m3 swaybars, and a LSD… so firming up the rear a bit would get me more in line with those M3 rates.

And then even if I ended up 600lb/in or more after a huge cut (larger than I intend to make) I’ll still be in a similar frequency ratio fr/rr as the M3 with the same swaybars and an lsd. (I believe the BMW performance suspension keeps the rear rate lower vs M3 due to the assumption that the car it’s going on doesn’t have a lsd.)

Plus this won’t cost any money lol. My long term goal is to run coilovers when these dampers are shot so spending money on new rear springs is buying more parts I would be stripping off in the next year or 2.

While I’m in there I think I’ll add some of the Dinan (or Monroe) mounts. I think these would keep the shock travel longer?

[Tambohamilton]

Yeah, I hear you on the cost...

I'd want to run the numbers if I were you though; that is also free!

I'm surprised the M3 rear rate is so low there. I'd expect much more like 600-650... But I think you should still aim not to not increase the rear rate too much. I dunno. I'm clueless without some numbers to throw at the situation!

[Biginboca]

More progress today. I wanted to adjust the rear ride height (thank you @Tambohamilton ) and add more rear camber also. At my last track day I spent some time chasing a N52 E90 and could not catch the guy in the turns. We chatted and he was running -3.5 front and -2.5 rear camber on 255/35 r888 tires square. So I’m stepping up my game going to run the same camber now and run 255 square tires allowed by the new camber settings.

While I was in there making adjustments I installed some new rear shock mounts, the uppers are the Monroe everyone seems to love and the lowers are the Turner Monoball mounts.







And I cut 3” off the ends of each rear spring to lower the rear 7/16” on each side.



Really love how it came out this is with 1/2 tank of gas:

[Tambohamilton]

I've spent most of the weekend so far swearing at my crumby bushing press/puller...thrown Meyle ball joints into the rear trailing arms, and swapped to M3 upper arms. 8 rubber mounts out, 6 balls + 2 rubber in. I'm going to replace the camber arm joints with OE parts soon too. Then I just need to decide what to do with the toe arms...

I feel like my suspension has progressed heaps recently! Isn't it funny how there's always something else to upgrade/fix/improve though?

[bmw335ie90]

Originally Posted by CalvinNismo

I know this information is a bit late for you Biginboca, but the E85/E86 Z4 top mounts have a 10mm lower stack height than the regular E9X non-M top mounts. Could've saved a few millimetres of grinding!

So if you combine Dinan camber plates and z4 strut top mounts it will lower the front suspension 4 mm? (6 mm increase from camber plates and 10 mm reduction from top mounts). You have confirmed the z4 top mounts work with e90 strut and reduce front height by 10mm? I cant find any information online so I just want to confirm this because that would be a perfect combo for me.

[Biginboca]

Originally Posted by Tambohamilton

I've spent most of the weekend so far swearing at my crumby bushing press/puller...thrown Meyle ball joints into the rear trailing arms, and swapped to M3 upper arms. 8 rubber mounts out, 6 balls + 2 rubber in. I'm going to replace the camber arm joints with OE parts soon too. Then I just need to decide what to do with the toe arms...

I feel like my suspension has progressed heaps recently! Isn't it funny how there's always something else to upgrade/fix/improve though?

That’s a ton of work! Why are you keeping the rubber bushings on the camber arm? I replaced those with the bimmerworld camber bearing kit.

That camber arm bushing at the subframe side is such a huge pita! I think it took me as long to replace those 2 camber arm bushings as it did to do the entire rest of the joints put together.

[Tambohamilton]

That doesn't bode well! The trailing arm ones have been bad enough!

Keeping them rubber, because £££. This is sort of just a refresh; I'm just upgrading where I can justify the cost. Also if it's good enough for the M3, it's probably fit for my usage on an E91 diesel.

[CalvinNismo]

Originally Posted by bmw335ie90

So if you combine Dinan camber plates and z4 strut top mounts it will lower the front suspension 4 mm? (6 mm increase from camber plates and 10 mm reduction from top mounts). You have confirmed the z4 top mounts work with e90 strut and reduce front height by 10mm? I cant find any information online so I just want to confirm this because that would be a perfect combo for me.

You would be correct in that you'd have a 4mm drop with the Dinan plates and the Z4 top mounts. I haven't fitted them myself, but here is my information source:

https://www.babybmw.net/forum/viewtopic.php?t=132985

[IMG]https://uploads.tapatalk-cdn.com/202...314b438ece.jpg[/IMG]

[Tambohamilton]

Originally Posted by Tambohamilton

Here's my source on strut mount info:
https://www.e90-forum.de/forum/threa...er#post1510042

This post has all you need to know about the top mounts.

[Tambohamilton]

Originally Posted by Biginboca

That camber arm bushing at the subframe side is such a huge pita! I think it took me as long to replace those 2 camber arm bushings as it did to do the entire rest of the joints put together.

Well. I see now what the issue is! Snapped the stud bar on my puller twice last night, trying to get a bushing out. Ended up ripping the centre out if it instead, and using a larger stud bar to get the sleeve out. Side note; it's insane how far you can deflect 14 year old stock bushings before they start to delaminate or fail! Hopefully my bushing compressor will show up today so I can have a go at getting the new one in. The ball joints are comparatively simple!

[Biginboca]

Originally Posted by Tambohamilton

Well. I see now what the issue is! Snapped the stud bar on my puller twice last night, trying to get a bushing out. Ended up ripping the centre out if it instead, and using a larger stud bar to get the sleeve out. Side note; it's insane how far you can deflect 14 year old stock bushings before they start to delaminate or fail! Hopefully my bushing compressor will show up today so I can have a go at getting the new one in. The ball joints are comparatively simple!

I posted this earlier in this thread where I detailed my uniball install but going to put it here again because maybe it would be helpful…

I had to make a cup to press them out you really need something 50.5mm in diameter. I used a threaded rod from Lowe’s and what worked for me best was when there was so much tension on the rod it felt like it was about to snap I tapped the subframe around the bushing area with a BFH* and then was able to get 2-3 more turns before it got super tight again. So it was extremely slow going. Pressing the new Bimmerworld uniball housings in the Camber Arm subframe locations was easy and I used retaining compound to hold them in place.

*Big Frigging Hammer in case anyone doesn’t know

[Tambohamilton]

Yeah it was too late for me to go hitting stuff when I got that far, unfortunately. I'd normally go for hitting the end of the puller in the direction I want the bushing to move.

On side 2 I'm now having the issue where 50mm is too small. But I've already broken the centre out of the bushing, so I think in the morning I'll just collapse the outer ring inwards, and take it out that way. The new bushings sure go in super easy by comparison!

Also I seem to have torn one of the Meyle ball joint gaiters, so I need to source a new gaiter from somewhere...no way I'm installing a new one - it's in a damn awkward location!

[roastbeef]

Originally Posted by Guy Fieri

Sorry to beat a dead horse but after wasting a lot of time trying to figure out how to retrofit these shock tower braces to my E90, I found out that the E90 M3 doesn't even have them.

sorry to crash the thread, but i have a set for sale.


https://www.e90post.com/forums/showthread.php?t=1838569