Lifted / off-road E30 suspension questions

[amarino]

My current car is a 1990 325i coupe, M20B25 with a 5-speed and 2.93 LSD. Stock springs and Bilstein HD struts. Had a accident in the past where it rolled on its side. Just needed some bodywork (door / fenders / hood / windshield) and it still runs great mechanically. I took it on a Lemons Rally a few years back and am wanting to do 1 or 2 of them this year as well. Some pics and history of the car here: https://www.bimmerforums.com/forum/s...3#post29555663

Doing some research into lifted / off-road E30 suspension setup. Nothing crazy like rallying or jumps, just want some extra clearance and bigger tires like Gambler 500 or Lemons style.

After a lot of searching here and Bimmerforums, I see 3 options for the front:

1. Cheapest / easiest - Strut spacers between the top of the strut mount and body.
2. Middle option - Using E34 front springs, 540i best but can also use 530i/525i. Might also need E30 M3 Control Arm Bushings to fix the caster / make the wheel sit center of the wheel well. I've also seen E46 control arms mentioned here but not sure the exact benefit. Bilstein HD shocks okay here? This is probably what I'll end up doing.
3. Expensive option - Custom coilovers with taller springs.

For the rear I really only read about using E36 or E46 rear springs from a convertible E36 or 330i / ix E46. Basically the heavier car/trim should have sniffer or taller springs.
Will the same spring pads work? Also what about shocks?


Some tire options I found that others have used in the past. Looking in size: 27 X 8.50 R 14

• General GRABBER A/T
• Maxxis MT-764 Buckshot II All-Season
• BF Goodrich All Terrain T/A KO (If you can find them, I think they only make KO2 now and thats not in 14")

[amarino]

Ended up going with my option 2 above. Could not find any of the right cars near me in the junkyards so I bought the springs off eBay.


Fronts are actually brand new from a E34 525i. $70 for the pair with free shipping. Pick-N-Pull near me charges $27 each for coil springs so not that much more and the brand new ones won't be sagging from being in use for 30 years.

Lesjofors Pair Set Of Left and Right Front Coil Springs for BMW E34 525i 89-95
https://www.ebay.com/itm/154174643855




For the rears I made a mistake and ended up with E46 M3 convertible springs which are actually shorter than this stock E30 springs. I should have gotten non-M3 springs but it looks like they're still a little bit of a lift because they're thicker / stiffer I think. They were in the $60 range as well.

Doing some more research it looks like E36 convertible non-M3 would have been the best way to go for the most lift. I had already replaced one side and was working on the other before I noticed the difference in height. Didn't want to be left with mismatch springs and didn't want to redo the work so just went forward and put other one in so the match for now.



Here is how it sits now. This is after going for a little drive and letting everything settle.

(that streak of water on the ground was after drilling a hole in the trunk to let the rain from last week drain out)


I was doing all this research and work building the car for the Lemons Rally in April. I'll probably buy tires in February or March as I don't really use the car and it would otherwise sit on the street and be a prime target for theft with brand new A/T tires. I'll then check fitment to see if I need the E30 M3 offset control arm bushing, but for now the front wheel looks pretty centered, and later alignment.

Did some other little things while in there. On the front replaced a broken ABS sensor (now my Anti-Lock light turns off) and new brake rotor and pads that already had in the garage. Rear brakes need some attention as well as a broken CV boot.

[amarino]

Finally took care of some other maintenance items for the car (new brake lines, spark plugs, distributor cap and rotor, fuel filter, air filter, etc)

Also made the big purchase of wheels finally. GENERAL GRABBER ATX 27X8.50R14 LT 95Q C1 RWL






Took it to an alignment place and they were able to fix toe that was out a little bit, but can't do anything about camber. I don't know anything about off-road suspension or how much it matters. If I wanted to I could get something like this to fix the camber, with the added benefit of lifting the body a bit.
Street Adjustable Camber Plates – E30/E28/E24/E34

https://www.iemotorsport.com/product/street-adjustable-camber-plates-e30-e28-e24/

Also looks like I shouldn't need to use the E30 M3 CAB (Control Arm Bearing) since the caster is within spec and the front wheel looks centered in the wheel well.

[amarino]

Now to the fun part of where it rubs. This is on the ground clearance between the wheel and upright.


It does rub going over speed bumps and dips. But don't really hear anything on smooth straight roads. Some spacers will probably help push it out a bit.

Passenger side (was mostly driving solo so no weight on this side)



Driver side (only hear it on speed bumps and dips)



The big one is the frame rail and this hook area. I wasn't sure if it was actually rubbing at first since it's all dirty so sprayed some primer and went for a drive and then can see that yep its rubbing. But this is only when turning at full steering lock.

[amarino]

Now for the plastic pieces. Here is where I removed the lower plastic on both sides.



This one on the passenger side is broken and flaps and rubs on the wheel during turns.



And a little bit of rubbing in the back during turns as well on the plastic that sticks out. You can see where it's rubbed clean.

[amarino]

Now if anyone is reading I do have some new questions.

I have not tried with someone in the backseat and the trunk loaded, so that might drop the rear too much and start rubbing. I saw these adjustable rear perches on Ireland Engineering's site. I wish I would have seen this sooner as I could have went this route from the beginning.
Rear Adjustable-Height Spring Perches – E30/E36/E46
https://www.iemotorsport.com/product...g-perches-e30/

I reached out to IE but they didn't have any tips on spring rates and length for the rear. I also reached out to Ground Control but they won't sell the rear perches on their own and want me to place an order before they'll talk spring length and rates.


I'm not looking to go over any jumps or rock crawling, but maybe a rallycross type auto-x in the future to try it out. Mostly off-roading on dirt roads and overlanding type stuff. Car will probably be full of camping gear and 2-3 people (sometimes 1 person in the back seat) so I assume I want something a little stiffer?


Anyone here have any thoughts on spring lengths or spring rates for the rear to get a little bit more lift and handle the weight?

Thanks!

[iansane]

I know with my truck, as soon as I put any weight in the back it drops onto it's nuts. Pretty disappointing. I think an adjustable perch and a universal Eibach-type 2.5" coil over spring would do wonders. The springs themselves are pretty cheap and you can get them in almost any weight and length you want. I'm currently using e36 vert springs and a small spacer. I'm tossing around the idea to throw airbags back there since it's a truck and has a hard time doing truck things without dragging tail. Don't forget about CV articulation. I think I'm about maxed out on droop.