Bolt On 325iX Coilovers

[AWDBOB]

those fronts look interesting, but they don't look short enough, and I don't like the camber plate design. the stack height is too tall so you either compromise ride height or shock travel.

the set I had built by ForcedFirebird are superior IMO, and cheaper.. with Konis they ride like a dream. Bilstein can suck my nuts.

I emailed them for all of that info, I'll update when they respond.

I knew you'd dig the Konis! My Zinno car with the GC/Konis rode better than the Bilsteins/H+Rs do now.

[litu]

Funny that they used a photo of the RWD parts for that advert.

Don't need to mod the shock tower?

Yes you dont need mod those shock towers, in that kit.
There is that shock and spring separately, so in my sense, you dont need then.
But if i understand this correct, you need to strengthen towers if you use those real coils, where that spring and shock is together, becouse bmw is not designed to the use of such coil....Of course you can try it, i have seen also others use like this

Other are just used reinforced tower. I would use this x-brace, what ever they called. That i would think to use
This maybe are some tziper tzaper,

[Kershaw]

theres something sexy about true rear coil overs though. they look so... exotic

Exotic? Did you know that e21s had rear coilovers?

[ForcedFirebird]

Exotic? Did you know that e21s had rear coilovers?

That's just a Chapman strut.

Calling it a coil over would be like calling e30 front McPherson struts coil over. ;)

[Kershaw]

Which it absolutely is...? It may not be adjustable, but "coil spring over shock" is the most basic component of a macpherson strut.

I know you know a lot more about suspension design than I do, so I don't see why you're making a technically confusing statement. Maybe you can clear up my confusion.

[The Dark Side of Will]

For true coils the rear shock towers should be reinforced. A local had them on his e30 we swapped without the reinforcement and they seem to be holding up ok after a few years, but not sure I would trust them like that.

There are two schools of thought on reinforcing the shock tower:

The first school points out that it's thin fucking sheet metal held on with a couple spot welds that is known to fail under normal use.

The second school says that it totally works fine.

The reality is that you *can* run unreinforced shock towers. Of course, you are taking a substantially increased risk that you will will tear the sheet metal. (Also, since it's a weak area, leaving it unreinforced allows a bit of additional movement.)

Is there an accepted minimal reinforcement? Seam weld the cap to the tower and the tower to the frame rail? Make a new cap out of 1/8" steel tubing?

But if i understand this correct, you need to strengthen towers if you use those real coils, where that spring and shock is together, becouse bmw is not designed to the use of such coil....Of course you can try it, i have seen also others use like this

Other are just used reinforced tower. I would use this x-brace, what ever they called. That i would think to use
This maybe are some tziper tzaper,

That brace is... umm... elaborate. I've been thinking that I'd make the dual differential mounting ear/rear diff mount crossmember and shock tower reinforcement one job, which would end up with hard points to mount a brace like that. Mine would be simpler and easily removable for when I want to put something big in the trunk.

That's just a Chapman strut.

Calling it a coil over would be like calling e30 front McPherson struts coil over. ;)

Don't E21's have semi-trailing arms very similar to E30's?
In the strictest sense, I think a Chapman strut uses the axle as the control arm, thereby saving the weight of a separate control arm and the weight and complexity of a plunge mechanism in the axle.

[ForcedFirebird]

Don't E21's have semi-trailing arms very similar to E30's?
In the strictest sense, I think a Chapman strut uses the axle as the control arm, thereby saving the weight of a separate control arm and the weight and complexity of a plunge mechanism in the axle.

McPherson and Chapman are almost the same, save for the McPherson has rotational provisions Chapman does not.

http://www.automotivedictionary.org/Chapman_strut

[The Dark Side of Will]

:roll: automotivedictionary? :p ;)

Took me a bit to find a good photo... note the lack of control arm.

EDIT: Wow, that's a large photo...

http://www.scottnettleship.com/elite/carinfo.html

Also Wikipedia: https://en.wikipedia.org/wiki/Chapman_strut

[litu]

That brace is... umm... elaborate. I've been thinking that I'd make the dual differential mounting ear/rear diff mount crossmember and shock tower reinforcement one job, which would end up with hard points to mount a brace like that. Mine would be simpler and easily removable for when I want to put something big in the trunk.

That i was also thinking, some day will also make that :)

[ForcedFirebird]

:roll: automotivedictionary? :p ;)

Took me a bit to find a good photo... note the lack of control arm.

EDIT: Wow, that's a large photo...

http://www.scottnettleship.com/elite/carinfo.html

Also Wikipedia: https://en.wikipedia.org/wiki/Chapman_strut

That was his first design in 1956-7 and was scrapped the next season due to failures. He added lower wishbone to the design and still called it after himself.

Many of Chapman's ideas can still be seen in Formula One and other top-level motor sport (such as IndyCars) today.
He pioneered the use of struts as a rear suspension device. Even today, struts used in the rear of a vehicle are known as Chapman struts, while virtually identical suspension struts for the front are known as MacPherson struts that were invented 10 years earlier in 1949.

It was the fact that he was the first to use the newer (at the time) strut design in the rear of a vehicle, that was his innovation, not where the strut was attached.

[The Dark Side of Will]

Yep...

But anyway... E21's have semi-trailing arm.

[ForcedFirebird]

Doesn't matter. If it were the whole suspensions system, it would likely be called "Chapman Suspension". Anytime one mentions Chapman, it is common knowledge that it's a rear strut.

Ford, Honda, VW, Chevy, Mazda, Lotus etc all still use the term today when there's a rear strut, and Honda isn't even RWD to HAVE and axle as a suspension member.

You say tomato I say tomato.

[The Dark Side of Will]

Semi-trailing arm is NOT Chapman strut, if that's what you're implying.

[ForcedFirebird]

I am referring to the strut itself, not the suspension type it's attached to.

[JIM1inWisconsin]

coil overs

You guys are way ahead of me in terms of knowledge so help me out. Correct me where I'm wrong but it appears that for about $1700 you purchase four springs, two housings and four shocks(inserts) and all additional parts for installation? This lowers the car a bit? Are these quality parts?

Wish I known about this a few years back when doing mine trying to piece together used parts etc. What an expensive mess this job can be.