The car... 1985 524 TD. 5 series
The driving... enthusiastic street driving. Probably no track time. But I wanna get rid of the 35 year old "floaty" ride. No longer an executive car. If I can take it past the handling of the M5, I will.
I think this is gonna take more than sway bars!
I guess I should mention... it's not a diesel any more.
It's got a 400hp LS. Lol!!
Put the diesel back (I'm weird and have two of those)
Gaz or ground control coilovers are great. Stick with 16" wheels or smaller, don't go nuts with spring rate and enjoy supreme handling.
In reply to Cactus :
Haha. Yeah, the diesel is NOT going back!
Replace all the bushings. The lower control arms benefit from upgraded bushings without voids - I think the E32 ones fit, but they might need to be altered slightly. Fill the rear subframe bushing voids with Window-Weld. Rear trailing arms are better with polyurethane, if you're willing to live with the slight increase in harshness. Poly for the sway bars.
Koni or Bilstein, whatever you prefer. I had Bilsteins, but if I were to do it again I'd go Koni.
If you like the ride of Bilstein's they're readily available and work well with H&R sport springs. That's a really nice setup for the street that will handle very well but the car will still take all the crap you will find along the way. With stock style springs you are very limited with the front camber as there just isn't room to lean the struts in. That is fine on the street but if you want to hit a track or autocross you'll be all over the outside shoulders of the front tires. The rear doesn't have a problem with negative camber lol, if you drop the back more than what you would go with a set of sport springs you should really weld in an adjustable setup so you can dial in the toe and camber back there to reasonable settings.
Cactus's recommendation is good as well if you want to take the car further and those setups would allow a lot more camber in the front. 16" wheels are the way to go, 16 x 7 or 16 x 8 work well and 205/55R16 or 225/50R16 are available in most performance tires. The E38 16 x 8 style 5's are very affordable and look good on the car (I'm up to 9 of these wheels with an average price of $40 CAD/wheel for my track tires), you will likely need a 5-10 mm spacer in the front though with a 225/5oR16.
For your usage stay away from any of the BC/Fortune etc. style coilovers, the shock travel is very limited in those setups and will not work that great in my experience on the street.
02Pilot said:Replace all the bushings. The lower control arms benefit from upgraded bushings without voids - I think the E32 ones fit, but they might need to be altered slightly. Fill the rear subframe bushing voids with Window-Weld. Rear trailing arms are better with polyurethane, if you're willing to live with the slight increase in harshness. Poly for the sway bars.
Koni or Bilstein, whatever you prefer. I had Bilsteins, but if I were to do it again I'd go Koni.
These cars have lower control arms and thrust/upper control arms in the front, lower control arms are fine but the thrust arms (which run towards the rear and what 02Pilot is referring to) definitely have stock bushings that fail all to often causing problems when you brake mainly. Take a look at those for sure and see if the PO has done anything there and what the condition of them is like. The old school upgrade was to modify E32 bushings but I think Meyle might make an upgraded part now. I personally run the Moosehead Engineering poly/spherical bearing setup in the thrust arms but they might be too much for you.
Poly rear subframe bushings aren't a bad idea but you'll likely hear the diff more if it is making any noise, if the current ones are in good shape filling them like 02Pilot says will be easier than replacing and make an improvement. Trailing arm bushing are not under built in these cars like they are in an E12 or an E30, the stock ones are likely just fine and allow the trailing arms to move the way they were designed to with the pitman arms (make sure those are in good shape too, they are referred to as dog bones sometimes and help control the trailing arms). I just replaced my trailing arm bushings with stock and I push my car hard on track, for the street they are more than enough.
Sadly there is not an off the shelf Koni option for these cars, they did one way back in the day but not anymore.
Since we are talking about suspension we might as well bring up steering, these cars unfortunately don't use rack and pinion so it's a bit of work to get that system tight on center (don't bother off center as that isn't possible but you won't feel it). Make sure there is no play in any ball joint in the front at all, if there's play throw it away. The pitman arm bushing in the front also makes a big difference, I think by 85 they were using the larger diameter bushing which is good as they used that same part all the way through the E38 and E39 (including the M5). Buy the OEM pitman arm bushing! They are cheap and are much better than something like a URO part (if you have an earlier arm with the small bushing though you can buy the URO arm and swap out the bushing for the OEM one). The steering box can be adjusted and if it has never been done it will likely make a big difference, just make small increments on that one and then test, you don't want to go too far as that will cause damage, tightness and the steering will not return to center. Lastly there is a U-joint that can be replaced in the column as well as making sure the nut under the dash that adjusts tension for the telescoping column is just tight enough that you can still adjust it but there is no play. After all of that the steering is decently tight and nice, but not as nice as a rack.
Have fun!
The best lower control arms you can get are off an 8 series. They use spherical bearings, and the arms are aluminum.
What happens to the suspension when the wheels get bigger than 16"?
I'm not clear why this would effect the suspension and handling negatively. If anything, I'd assume the shorter sidewalls would be an improvement...
The car is currently on 17's, wearing 235/45/ZR17's.
I just sold my E28 with some serious suspension investments.
Here is the build thread for the car that I recently sold: https://www.mye28.com/viewtopic.php?f=7&t=148033
In reply to adam525i :
Clearly it's been a while since I fooled around with E28s. Thanks for the corrections/clarifications.
Besides the link pointofdeparture posted above, also check the Tech Talk and Tech FAQ sections at https://www.mye28.com. Member CEK over there has a build thread on his S54 powered car that is good too, although it's sort of an ultimate, no expenses spared build and I don't know if you want to go that far: https://www.mye28.com/viewtopic.php?f=7&t=137105
The FAQ and tech article section over at http://www.m535i.org/main.html is another good resource. That website hasn't been updated for a long time but the information is still valid.
A common failure point on these cars is the bracket on the subframe that bolts to the bottom of the steering box breaks loose. Ed Raether sells a simple and elegant repair kit for this problem at http://www.mwrench.com (click on the e24 steering fix button to see the instructions, e24s and e28s share the same suspension.) I think it cost me $55 when I bought one years ago, email him for current pricing and availability. It's a worthwhile upgrade even if yours hasn't cracked yet.
Shawn D's wheel and tire database is another good resource to figure out what size tires and wheels to run: http://www.scrappycrow.com/e28wheelstires/e28wheelstires.html Scroll down the page to where you can download the spreadsheet in Excel format. The general consensus has always been that 16" tires are the best combination of ride and handling, but lots of guys run 17" without issues and good 16" performance tires can be harder to find these days.
SVreX (Forum Supporter) said:What happens to the suspension when the wheels get bigger than 16"?
I'm not clear why this would effect the suspension and handling negatively. If anything, I'd assume the shorter sidewalls would be an improvement...
The car is currently on 17's, wearing 235/45/ZR17's.
E28s already ride like crap when you start messing with the suspension and going to larger wheels with lower profile tires makes that even worse with the increase in unsprung weight and decrease in tire sidewall. My car had a teeth-shattering ride and my setup was not NEARLY as hardcore as you can make these cars.
Since 16's clear the best off-the-shelf big brake option and you are not building a track car, 16's will preserve a degree of comfort that you would eliminate with sporty suspension and 17's. Skipping the spherical UCA/LCA bushings in favor of uprated rubber parts (E32 bushings, Meyle HD, etc) may also help in this regard.
There is nothing inherently wrong with 17's but if I were to do it all over again I probably would have run 16's as I would've appreciated a little more street comfort.
I think everything important has been covered already. I enjoyed the car with stiff tires and stockish suspension. It let the car move but stopped the awful sidewall flex feeling from the high profile tires.
I may have a set of koni sport shocks with coilovers sleeves and 2.5" springs from my e28 days if you are in Florida.
H&r + Bilstein made for an awesome sport street setup on E36, I'd assume it would be similarly good on an e28.
My challenge 7 series was the fastest bmw in autox at the challenge (beating e30s and e36s) with stock springs cut a bit and bilsteins. That car had a lot of shared designs with the e28, in the rear I actually used e28 shocks. Now, I also had a7s... But the big girl could dance.
In reply to ojannen :
Any idea of the spring rates?
I may be interested, if you are willing to ship
I really liked how my E28 535is handled on H&R springs with Billy sports. The tittyjiggle of the Bilstiens got a little tiresome so if I were to do it again I would probably go Koni.
That car always surprised me. I really miss it.
Trent said:I really liked how my E28 535is handled on H&R springs with Billy sports. The tittyjiggle of the Bilstiens got a little tiresome so if I were to do it again I would probably go Koni.
That car always surprised me. I really miss it.
Upvoted for "tittyjiggle of the Bilstiens" lol
I've got two cars with front subframes with 400,000 km on them and no problems with the steering box mounts which always surprised me more than anything. Both of those cars see/saw track and autocross as well as salt and winters so they haven't been babied either but I know from following Mye28 that the failure is not uncommon. At some point I will reinforce mine just for piece of mind, it would be a stupid way to end the weekend at the track.
Also, this thread is lacking picks of the new ride! Here's mine at Mosport last year.
In reply to adam525i :
Please stop. I can only get so erect.
In reply to adam525i :
You're right!
Car looks really nice! You will probably want to replace the factory "Comfort" BarcaLounger seats with factory sport seats or something that has actual bolsters if you plan to go around corners at all though 
Love it! Looks like a wolf in sheep's clothing right now and really clean.
In reply to adam525i :
I'm a big fan of good sleepers, and this one checks those boxes.
I adore it. Although a set of 16s would tick the boxes for me.
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