I am still putting this together but I thought there should be an update on this information since coil-over industry has changed a lot.
Yes E28's have a coil-over suspension from the factory but it isn't adjustable.
First of all, lowering spring will probably tickle your pickle enough. Just get some Spax springs and Bilstein Sports and it will be good enough for backroads and for ride okay enough for rough city streets like Houston. If you hate yourself and track you car, camber with stock diameter springs will be a problem. In order to get over the awful -1 degrees that is allowed on E28's you will need coilovers. If you also want adjustable dampening and ride height then coilovers are for you.
If you were raised in God's country spring rates might make more sense in English, so here's a conversion. For a frame of reference, your average lowering springs for these cars are around a 250in/lb or 4.5kg/mm. Meaning the spring compresses 250in/lb for 1 inch.
https://www.redline360.com/garage/sprin ... m-to-lbsin
Popular Trends Now:
Adjusting Height without Preload:
Also note the threaded body shock is quite a common phenomenon, these days. Mainly in my opinion to save cost in manufacturing, because the shock is the most expensive part of a coil-over kit. So they just change the ends, and by keeping the shock relatively the same they can really keep cost down and mass produce them.
Clickity Clackity Shocks: People apparently like to use their shocks to change the ride instead of spring rates. It works I am not sure how it but it does work. Shocks have clicks of adjustment which I'm assuming lowers the shocks peak pressure.
Digressive Shocks: This is so your shock basically has a wastegate in a sense so it blows by pressure. This is so at lower speeds, the shock stiffens up quite a bit on low shock speeds, braking, accelerating, car pitching and diving. When you hit a rumble-strip or pothole your shock speed quickens up a lot, so to make it more comfortable as well it will cap how much the shock stiffens up. This why coilovers have gotten more comfortable.
Options for Buying Coilovers:
Buying is for you if you want don't mind a little welding and just want to have a product that will work, they all have shocks matched to the spring. Since coilovers are the new lowering springs in a way , all these brands are credible except for God Speed. Fortune Auto is your best mid level in my opinion.
God Speed: They're cheap and you can go lowz with them, supposedly their quality has improved. Their dampers can accept +/- 2K of spring rates. I wouldn't buy them.
Spring Rates: Front- 8kg Rear- 6kg
https://godspeedproject.com/bmw-5-serie ... -58mm.html
BC Racing: If we are going to be honest, these may be Taiwanese but they are your best bang for your buck on the market. You get camber plates and okay dampers for $995. There of this new style of a threaded body shock, so you don't ever gain travel. You just have the ability to adjust ride height without affecting preload. You can only go as low as how short your shock is. So you don't gain travel, I want to make that clear. You can buy these through FCPEuro and get a lifetime warranty. So $995 for a mid level coil-over with a lifetime warranty is a good deal at the end of the day. Their spring rates seem more geared to drifting and street duty.
https://www.fcpeuro.com/products/bmw-br ... e28-i-34br
Spring Rates: Front- 7kg Rear- 6kg
Fortune Auto:
These are of the same style as the God Speed and B/C with the threaded shock body. These are at least assembled in the U.S.A and you get shock dyno sheet specific to your set when you buy them. That is a nice touch, much smaller operation then B/C. You can send your shocks back for a rebuild, so serviceability is best with them in my opinion. It's around $1375 for them. Speed Academy had a video of install and a review with them.
Spring Rates: Front- 10Kg Rear- 8Kg
http://www.fortuneautosuperstore.com/fo ... eries-e28/
Broadway Static: is more for the stance crowd but the owner seems like a non ignorant man. I am sure he can set you with a road race setup. They use Fortune Auto shocks, and shorten them and valve to their rates which on E28 their base rating is 12K in the front 10K in the rear. That is stiff!
https://fortune-auto-direct.myshopify.c ... 0s-dampers
The Classic Ground Control Full Conversion: It's kind've like Snap-On you buy it for the brand name and quality product. I highly doubt it is significantly better then the others performance wise, but it's a quality product. My father had a Ground Control setup for 10 years, only had one Koni leak. This is the most expensive option, and unlike the others it does not have a threaded body shock but it has re valved Koni race dampers.
https://groundcontrolstore.com/collecti ... it-not-e34
Building Your Own Setup:
I don't think this is the way to do it anymore with price and options available. I actually really enjoy playing with suspension though. So if you want to mess around with shorter bodies and springs if you don't leave right by one of the above companies where you can stop by get a different spring or shock. Building is the most customizable way to do this unless you like waiting and shipping stuff back and forth.
Perches:
If we were in E30 land we would just buy some Koni's and Ground Control Sleeves and call it a day. Sadly, we don't own a inferior automobile and we own a 5-series. Which Koni does not supply shocks for anymore. Ground Controls kit though is stuck in 2006 and they say its only compatible with Konis. I''m assuming due to the circlip/snap-ring style of the Bilstein Sport and the damping they say is wrong. They want you to buy the full coilover kit. Their kit might fit with sports, I haven't tried it. Bimmerguy2002 had it like that, I am not sure what option he selected from their website and Lloyd with his Beige e28 also has the Ground Control kit with Bilstein Sports. So if you find Koni's this is the way to go.
https://groundcontrolstore.com/collecti ... conversion
$500 is a really good price for this kit.
Ireland Engineering sells a DIY kit as well. There's is designed for Bilstein Sports. I talked to Jeff at Ireland, didn't seem like a very customer happy man. He said Bilstein Sports in the front can handle 450 in/lb in the front.
Front: http://www.iemotorsport.com/bmw/item/e28frtcoil.html
Rear: http://www.iemotorsport.com/mm5/merchan ... ode=E29coR
Here's what I am using:
https://www.amazon.com/gp/product/B006K ... UTF8&psc=1
Front Inserts:
Before I address the shock issue, I want to say that Spec E30's recently have switched to race springs, at a 515lb spring on the front with a Bilstein Sport. They bottom out their struts consistently, because with the sports internal bump-stops you just can't go that low. Sports have less travel then a Koni. If you are staying around 300lb spring, Bilstein Sport will be perfectly adequate.
Now the biggest trouble is shocks. The only real aftermarket shocks we can get is the Bilstein sports, which everyone basically says is shit they need to be revalved specifically for every application. For the front there are a bunch of inserts other then the Billie Sport that require shortening the housing. Shortening is beneficial as you gain travel illustrated in this picture:
E30Suspension-2-1 by samleisey, on Flickr- Koni Race Insert 8610-1437
This can take the highest rate, the best choice. I am assuming it fits upper strut bearing. Source was the original Ground Control DIY thread here
http://www.truechoicekoniracingservices ... rut-insert
- 325ix Koni Sport
People use these in the E30 world and E30 shocks fit our housing they can handle 500lb/in spring rates.
https://www.bimmerworld.com/Suspension- ... 325ix.html
-MR2 Rear KYB AGX
A newcomer, and it fits only issue is that the shock shoulder is 15mm unlike the BMW 14m strut bearing. You can out new bearing in or machine shock down. It can handle high rates as well.
https://www.amazon.com/gp/product/B0006 ... 00_details
Rear Shocks:
This is very limited for a bolt in shock, compared to inserts.
Rear Shocks:
-Koni's (NLA)
-Spax Rear Shock
still available from TCD
-914 Rear Koni
This requires a lot more fab work because of the bushing, and the shock stem is different.
-E34 Koni Sport
These are sadly 1 inch taller then E28 Rear Shock.
If you can't find a rear Spax you are stuck with sport.
Spring Rates:
This topic is very subjective.
Springs can be found from a lot of sources. It is recommended to start that you have 7" springs. The front should be 400in/lb spring and rear 300in/lb spring. That is a good starting place.
I will be trying 500F and 400R and seeing how it goes. Some here recommend 10-15% higher in the rear, and I feel in the lower spring rates that is needed to get the car to rotate.
Coilover Building Threads:
(working pictures as of 12/4/18) https://www.bimmerforums.com/forum/show ... over-Setup
"Front 375 lb Eibach springs, threaded sleeves, adjuster nut, top hats, weld-on rings for the sleeves to sit on, and their street/track camber plates (made for an E30, but they fit the E28/E24 as well!), and some spacers to go in the strut housings to take up the room that is left between the E30ix struts (Koni Sports) and the bottom of the strut housings once I get them cut.
Rear sleeves, adjusters, ~200 lb springs, and top hats to work with stock upper mounts. The rear struts will be Bilstein Sports."
(Pics do not work) https://www.bimmerforums.com/forum/show ... ble-shocks
"Version 3 is with 350lbs/7" QA1 springs and rear KYB AGX adjustable shocks for a 1991 Toyota MR2."
(Pics work) https://www.bimmerforums.com/forum/show ... read/page5
"It is really simple. He already had Billy Sports for the rear, and he bought a set of Corrado front Koni's brand new. He purchased his sleeves and collars from a website online which I believe he lined in this thread. He also purchsed upper and lower mounts to match, and got his springs from GC in 550 front and 450 rear. He shortened the front housings 2" as we did with the NEX coils and then welded a collar around the housing about 5" down so that when you slide the threaded sleeve on, there is something to stop the collar. For the rears he just adjusted the removable collar to a point where his sleeve would fit and give him plenty of adjustment. Pretty easy and I like that the components are all readily available so if something goes bad, I am not on the phone with Maxspeed begging for parts that have to come from overseas."
http://www.teamdfl.com/bmw/e28/suspensi ... hocks.html
http://www.teamdfl.com/bmw/e28/suspensi ... overs.html
As of know this thread has not finished just what I have put together so far. This is just pooling everything I have researched together, please comment if you have a setup that works for you. Review of any product anything that relates to coil-overs. Please do not use this thread as a place bicker amongst one another. I also know my grammar is ass.
I still drive it on the street after doing any major work, so it still has to be street-able at least for short distances. Really liking the idea of getting the car lower (has HKS springs and B8 sports now) and stiffer in addition to having some camber. Plowing through 4 tires for a single race gets expensive...
