B.I. Official e34 lowering, new suspension, wheels, and thrust arms!

[HDhandyman]

Stephen, I'll chime in here if I may. I think you have the terminology wrong on the word "strut". The strut is the device that holds the shock and spring in place. I've never heard of someone replacing it unless it's been bent in an accident, but I've heard of deliberately bending this baby to give you more camber on the front wheels.



Being a s advocate here. Why go for lowered springs anyway? The camber at the rear will be increase (more negative camber) causing the inside of the tyres to wear faster which can only be fixed by rotating the tyres more often which will have to come off the wheels or install eccentric bushings in the trailing arms which is very time consuming job. What are you doing for strut mounts at the front?

Also with a lowered front spring, it maybe so long that you cannot get your floor jack under the front crossmember when jacking up the car (thats what happened to me). Not a major deal just a bit annoying.

As for the thrust arm bushings, I think Scott H is right, the m5 ones are the ones to get. I asked about this on here with limited responses (I was curious also).

http://www.bimmer.info/forum/showthread.php?t=17705

The reason being, your going to upgrage the bush from normal to 750i, so why stop in the middle ground?

Maybe this article can also state that you can't have your cake and eat it also. Meaning any upgrade that contributes to a "more sportier feel" or stiffer ride will contribute to an increase in noise, vechile, harshness. You will feel more bumps in the road and it won't be as comfortable to ride on. I'm going to finish this off and get out of here; what are you doing for swaybars?

Thanks BigKriss. Like I said, I'm a new guy here as well. So, thanks for the strut info and words on lowering springs. I don't know what to do about sway bars, what should I do? Why don't you tell us about why you did what you did to your car, and do you know other options for people who don't want to lose that cushy ride? I noticed that cool track video that you have--are all your mods for track time?

Thanks, again!

[BigKriss]

Sorry mate, I added a bit more information in there. I'm setting up the car to be as stiff as possible. I will take any tradeoff in comfort for an increase concering speed. Of course the car can get uncomfortable over harsh roads but I've lived with it so far even though 99.9999+% of my driving is on the street. It also depends on how you want the car to handle, I mean understeer or oversteer. I only upgraded the front swaybar becasue I thought the rear one would be too hard to install myself - I was wrong. Understeer (losing grip on the front wheels) is a lot easier to control than oversteer.

I e-mailed Brett Anderson from Koala Motorsports a along time ago, he suggested to leave the front bar (23mm) as is and replace the rear bar with one from the e34 3.8L touring? (20mm and largest OEM available), which is slightly over us$100 from BMA. I would imagine this setup to give you some controllable oversteer at wide open throttle, but I can't say from experience.

You will find the largest swaybars around made by manufacturers in the USA and anywhere worldwide are 27mm for the front and 20mm on the rear. Adjustable ones are good becasue you can then fine tune the handling characteristics of the car. Personally I'll evenutally get a 22mm adjustable rear custom made one made by Whiteline in Australia, were my front bar comes from. This will mean a +2mm (front and rear increase over the larqest OEM bars). Most of the swaybar bushes with aftermarket bars are polyurethane and have to be lubed occasionally (with special paste provided) or else they squeak but I haven't experience this yet.

If you don't want to lose that cushy ride, stick with OEM stock everything, but I would still install the m5 thrust arm bushes because worn thrust arm bushes are a major complaint of the dreaded 50-60 shimmy!

[Scott H]

the strut housing is what holds it

Stephen, I'll chime in here if I may. I think you have the terminology wrong on the word "strut". The strut is the device that holds the shock and spring in place. I've never heard of someone replacing it unless it's been bent in an accident, but I've heard of deliberately bending this baby to give you more camber on the front wheels.

[BigKriss]

Scott, I always thought the picture what I showed was the strut, item 1 and the shock absorber goes inside that.

the strut housing is what holds it

[Scott H]

the front is called a strut when it's an insert type with spring surrounding it, and it acts as a rotational point for the steering

the rear is called a shock because it is fixed and bolted to the rear trailing arm

Scott, I always thought the picture what I showed was the strut, item 1 and the shock absorber goes inside that.

[Bill R.]

The strut refers to the type of front suspension which is a macpherson strut design which basically means that strut/shock/spring assembly replaces what would have been a upper control arm and shock assy. This macpherson strut becomes an integral part of the front end. A number of cars have started using this setup due to costs,weight savings, simplicity, the term strut refers to the whole unit, the strut insert is what you used to think of as a shock absorber. These can come as an insert which goes inside the strut assy. or they can come as a complete strut unit , housing and shock all one piece, you can't take this type apart and replace the shock insert you have to replace the whole unit. Many cars are this way, the bmw's have a replaceable insert in them Wikipedia has a somewhat accurate description here of the macpherson strut front end

The rear suspension is also a mcpherson strut type , only its a called a chapman strut, Colin Chapman of lotus fame, mr. cheap and light himself came up with this modification of the macpherson strut for the front and adapted it to the rear suspension of his cars. Technically these are still called inserts on the rears and its still a strut type suspension since its acts as a member of the entire suspension not just as a shock absorber.

These mcpherson and chapman struts were all intended as cheaper lighter more cost effective replacements for the traditional double wishbone suspension that most of your exotics still use such as the corvette and ferrari's.

the front is called a strut when it's an insert type with spring surrounding it, and it acts as a rotational point for the steering

the rear is called a shock because it is fixed and bolted to the rear trailing arm

[Anthony (M5 in Calgary)]

Also, the shock absorber is properly called a damper. The spring is what absorbs the shock, the damper controls its oscillations.

[Bill R.]

page is fairly accurate and current or is a lot of this no longer used?
Here

Also, the shock absorber is properly called a damper. The spring is what absorbs the shock, the damper controls its oscillations.

[Scott H]

I was just trying to get the point across that the insert was the strut, not the housing itself......

This thread is going to be about correcting a lot of misinformation....

The strut refers to the type of front suspension which is a macpherson strut design which basically means that strut/shock/spring assembly replaces what would have been a upper control arm and shock assy......

[BigKriss]

Well, I don't mean to get any more enemies on here that I already have and I don't think it's arguing over semantics however I looked over my notes from when I was studying last year and all mechanics in NSW are taught that on a McPherson strut design that the "insert" in the shock absorber and the "strut housing" is just known as the strut. I'll show you what the text book says;


Another example;

I was just trying to get the point across that the insert was the strut, not the housing itself......

This thread is going to be about correcting a lot of misinformation....