More suspension dramas

[speedyg 16]

I am fitting a bilstein streetline suspension kit to my car. The kit is suppose to lower a std 325i by 40mm. My car has the mtech suspension. I went fit the front shocks and springs and noticed that the new springs are 40mm shorter than the mtech ones(uncompressed) and also the diameter of the shock rod (the chrome bit) is smaller than the mtech one.

My questions are: Are the mtech struts different to the std 325 ones, ie is the lower perch in a different place?

Also are the shock rods a different diameter between mtech and std 325?

I've got a photo here if this helps

The new shock fits in the strut housing and the black part of the shock is the right length and diameter but when I put the new spring on I don't even need to compress the spring to get the top nut on.

I await your expert advice!

[speedyg 16]

The shock rods close up.

[speedyg 16]

The distance from the bottom of the strut to the perch weld is 300mm (as per pic), could someone with std 325 strut measure theirs?

[petone 0]

That shock rod on the "standard" shock is huge, looks more like a Ohlins shock (Not that they make them for E30 AFAIK). Are there any markings on the standard shock that might tell you otherwise? There is no way the standard 325i shock rods are that big.

As for not having to compress spring to get top nut on that is quite common with aftermarket springs. As long as it is captive when the nut is tightened up its all good.

Sorry I can't help anymore, but I'm interested to find out whether that "standard" strut is Mtech or aftermarket.

Edited November 7, 2005 by petone

[Gus 5]

that stock strut looks like a stock bilstein/boge gas shock...much thicker. im surprised your replacement ones arent the same size. as long as it has the appropriate threaded collar you will be fine. the spring wont be hard to get on, its stiffer and lower than the replacement. spring pads can be used to keep it in place, but 40mm springs are usually fine.

the "mtech" bits are nearly all the same (struts are). only bits diff suspension wise are the shocks/springs, rear sway

[petone 0]

wow, had no idea that the standard Mtech was that big, like I said, I've only seen Ohlins shocks that big.

Are Andy's J-stock shocks that big?

[speedyg 16]

The inserts are yellow bilsteins.

I don't want the car lower or much lower than the mtech height.

The kit is suppose to lower the std height 325 by 40mm so in theory it should lower the mtech by 10mm?

[Gus 5]

easiest just to put it all in, and see how you like it. a 40mm drop really is not very long....i hardly ever touch ground on mine

mike - both andys j stocks and mine are like that (essentially same shock, his just valved diff and he has funky inverted rears). my pre FL MS shocks were too, but not quite as thick

[speedyg 16]

Also as the shocks are so different the original dust cover doesn't fit either and the new shocks don't come with any?

[Gus 5]

what replacement shocks do you have? they might be the bilstein stock replacement shock (they look like stock shocks). in that case you might be better with the ones in there. they should have come with a dust cover if new. try stretching the old one, or run without it for a little while to see if you want to keep the shocks. not a huge job to change it again

[speedyg 16]

They have the code PNE-3050 on them, the old shocks are a little tired, hence the change.