Who runs shortened bilsteins with their coilovers?

[LJ851]

This is one of the most confusing threads I have ever read.

No kidding.

Lets take the insert out of the picture for a second. What limits the front suspension travel on E30 is the gland nut on top of the strut tube hitting the upper spring mount (hat).

If you want to go low and have the suspension have some upward travel you will need a shorter strut housing. A 1 inch shorter housing will gain you (wait for it) 1 inch of additional up travel.

Now lets bring the insert back into the picture. On an inverted strut design (bilstein) the yellow outer shell just guides the insert and also holds it in the housing. The insert assembly is designed to bottom out (hit the bump stops) before the strut housing hits the upper spring hat.

If you shorten the outer shell 1 inch to fit in your inch shorter strut housing, the functional insert has not been changed at all and will bottom out at exactly the same place as before thus not allowing you to use the extra potential travel created by the shorter housing.

The female portion of the bilstein insert is at the top and bolted to your strut bearing. The male portion is attached to the bottom of the strut housing. There is a bumpstop at the bottom of the insert. The wheel, strut housing, bumpstop and male rod can move upward until the bumpstop contacts the female portion of the insert.

If you want to go lower or have more up travel the female portion of the insert will have to be shortened. Shortening the female portion 1 inch will allow the strut housing to travel 1 inch further up (lower) and since the droop is limited by the female portion, the wheel at full extension will be 1 inch higher as well (less droop)

Now since the male rod is still the same length as original and it can now go into the female section of the insert 1 extra inch it is probable that it will mechanically bottom out in the upper female portion of the strut insert and that would damage the valving and render the insert useless.

To avoid this the male rod can be shortened to put the piston (valve) back to a stroke area that is safe. Lets say we shorten it 1 inch. This does not allow any more upward travel additional to the 1 inch gained by shortening the female portion but since the bottom of the strut housing is attached to the rod it will reduce the extension (droop) another 1 inch.



Thats how i see it anyway.



Short attention span r3v version:

How do i gain 1 inch of suspension up travel on the front of my E30 with bilsteins ?

Problem 1: strut housing bottoms out on spring hat.

Solution: shorten strut housing 1 inch.

Problem2: the insert sticks out of my shortened strut housing.

Solution: shorten the outer (yellow) shell of the insert 1 inch.

Problem 3: insert bottoms out internally.

Solution: Shorten the female (chrome) portion of the insert 1 inch to gain 1 inch up travel and shorten the male portion 1 inch to restore peace inside the insert. This will reduce the extension and total travel by 2 inches.

[mbonanni]

Besides for the fact that you would need a spacer. Why not get it the same length that you plan on shortening he housings? Making it shorter and running a spacer gets you nothing extra, it's just what people do because the shocks we run are that short from the factory.

My vote is get the shaft 1" shorter then the stand tube, get the stand tube .5-1" shorter and shorten the housings to match. You'll have 1.5-2" more travel then stock but you'll still be able to raise it if the need comes.

The benefit of getting the strut shorter than needed would allow me future adjustment. If I want to go shorter later, but I cant because I'm maxxed on the coils, then I could shorten the spaced and housing, but I am dropping this idea. I will get the strut shortened the same as my housing.


If I understand this party correctly you are saying get the shaft shortened 2", then the stand tube 1" shorter?

Lj, what you said is what bilstein told me except in a simpler way. I believe I am confusing people because I am using different terminology for the same parts of the strut.

My idea for right now is short the shaft 2", the stand tube 2", and the housing 2". This will automatically give me a 2" drop with the same amount as upward and downward travel as stock. (If I am fully understanding this).

Thanks for the help guys. I am a total noon when it comes to suspension. I am learning though, slowly.

[E30SPDFRK]

If I understand this party correctly you are saying get the shaft shortened 2", then the stand tube 1" shorter?

Correct. And the reasoning behind that is that the chrome shaft of the Bilsteins doesn't fully compress into the stand tube. I went from stock shocks all the way down to 1" shorter housings with Bilsteins while leaving the spring at the same height on the adjuster and the car was the same height. The shaft wouldn't compress in all the way and bottomed out an inch higher than the stock shock. I would have needed to shorten the housings 2" to get the advantage of 1" over factory.

If you went from stock height Bilsteins to shorter Bilsteins in 1" shorter housings you would get an extra inch, but your car would have started out at a higher height.

The benefit of getting the strut shorter than needed would allow me future adjustment. If I want to go shorter later, but I cant because I'm maxxed on the coils, then I could shorten the spaced and housing, but I am dropping this idea. I will get the strut shortened the same as my housing.


My idea for right now is short the shaft 2", the stand tube 2", and the housing 2". This will automatically give me a 2" drop with the same amount as upward and downward travel as stock. (If I am fully understanding this).

I really don't think you are ever going to want more than 1.5" shorter housings with full travel-modded Bilsteins. My strut housings are 2 5/8" shorter and my strut shafts are 1.5" shorter, and the bottom inch of my adjuster is useless. I'm halfway down up front in my sig. The 1.5" shorter shaft is too much as well, as the shaft can compress about 1/4" into the stand tube.

[mbonanni]

Correct. And the reasoning behind that is that the chrome shaft of the Bilsteins doesn't fully compress into the stand tube. I went from stock shocks all the way down to 1" shorter housings with Bilsteins while leaving the spring at the same height on the adjuster and the car was the same height. The shaft wouldn't compress in all the way and bottomed out an inch higher than the stock shock. I would have needed to shorten the housings 2" to get the advantage of 1" over factory.

If you went from stock height Bilsteins to shorter Bilsteins in 1" shorter housings you would get an extra inch, but your car would have started out at a higher height.


I really don't think you are ever going to want more than 1.5" shorter housings with full travel-modded Bilsteins. My strut housings are 2 5/8" shorter and my strut shafts are 1.5" shorter, and the bottom inch of my adjuster is useless. I'm halfway down up front in my sig. The 1.5" shorter shaft is too much as well, as the shaft can compress about 1/4" into the stand tube.

I do not get why I should shorten the piston more than the tube. Bilstein tells me not to, as it can cause problems.

If you say 2" on the housing will be too much then I figure 1.5" on piston 1.5" on tube, then 1.5" on housing will be good enough.

[Link]

Wow, that is very complicated, but I feel you guys are getting somewhere.

Lets say I want to have my car as low as Bryon (e30spdfrk) using iX Bilstein HDs, would I shorten my strut tubes 1.5 in and run a 1.5 inch spacer. (I am told the ix bilstein hds are 3 inch shorter than stock)

Does anyone have a measurement of a stock front insert fully compressed and fully "up"?

[mbonanni]

PLEASE PLEASE PLEASE PLEASE PLEASE call Juan at bilstein.

He helped me more than this whole thread. It seemed as if there was a lot of conflicting information in here, or different terms being used etc.

[nando]

let's just put it this way, if you run ix HD's (revalved to your spring rates, which is surprisingly inexpensive, albiet time consuming) you will not have any travel issues, at all.

1.5" shorter housings and 1.5" spacer isn't a bad idea, because effectively the 3" shorter ix housing gives you 1.5" less travel (in both directions). at least if I understand completely what bilstein told me over the phone, which isn't neccesarily to be taken for granted. if you go too far one way, you might gain more compression and lose droop (for example), or taken to the other extreme, not gain enough compression for the effort of fabrication.

[mbonanni]

Call Juan

[nando]

PLEASE PLEASE PLEASE PLEASE PLEASE call Juan at bilstein.

He helped me more than this whole thread. It seemed as if there was a lot of conflicting information in here, or different terms being used etc.

agreed.

it's hard to get ahold of them but once you do, just spend the hour or so required over the phone and put all the questions to rest. leave a message, they *will* get back to you and they will also be very helpful. I think because the prices are so reasonable, they are also swamped. It took about 6 weeks from me sending them in to having them back in my hands.

If you get them revalved to your coilover spring rates (which you really should) just beware: they are going to be STIFF. meaning, fucking AWESOME from a performance standpoint. Quite literally it will handle amazingly, and responsively. but, on the other hand, you will feel the painted lines when you drive over a crosswalk and it will shake your teeth out when you cross over expansion joints on a freeway overpass. I am not exaggerating. I do not take my wife out in my car for a reason....

Quite literally the blank faceplate I have over my radio slot *exploded* off my dash when I hit an expansion joint on the I5 near Seattle. Fuck me that hurt. But the handling becomes extremely responsive and predictable: give 50% input, get 50% back. Give 100% input, get 100% back, etc. and that's supposedly the "street" valving. Don't even think about asking for the race valving if it's a street car. I can't even imagine how painful that would be!

if you want a soft compliant ride (and equally numb handling) stick with Koni. if you want razor sharp response at a lower price, Bilstein is the way to go.

[mbonanni]

Nando, what rates did you get yours revalved to?

[nando]

500f/600r

Juan told me they were good for +/- 20% of the spec'd rates (meaning, the 500# fronts would work fine for 400-600# springs). they would also work for even higher rates but the ride might be a bit too bouncy for street use.

I'm very happy with the result but also torn. I'm looking at options on what I can do to take some of the "edge" off. From lower spring rates to rubber isolators in the front strut mounts (I also have GC camber plates). the snow tires help a lot but that's only 4 months a year. our roads here are generally good except the last 1 mile to my house, which is basically a gravel road (it's asphalt, but hasn't been maintained in 20 years, so it's really awful, even in a stock modern family sedan). out of my ~10-12 daily driven miles that last 1 mile of road really makes me think I should buy a Toyota Camry or something. LOL.

(but no, really, I'd rather cut my balls off)

also, my 3 year old son thinks my E30 is cooler than my wife's car, and that's all that really matters in life, right? ;)

[mbonanni]

OKay, I got mine for 500f/700r Well Juan said he will call withing a few days.

[nando]

OKay, I got mine for 500f/700r Well Juan said he will call withing a few days.

I dunno if it will be a few days, but he always called me back and was extremely helpful.

not like the usual tech shop you call, where they treat you like an idiot and won't give you what you already know you need because they think they know everything. They definitely know their shit (and way more than I do) but I also felt like I was treated like an equal car enthusiast, which was refreshing coming from a big faceless corporation.

even when I asked about cut bump stops, I was expecting "OMG you idiot you can't do that", but basically he said he does it on his own cars and told me exactly what I needed to know to do it effectively and properly without a condescending attitude.

[mbonanni]

well they have had them since the 19th of last month. He recently told me (a couple days ago) that he will be calling me in 10 days and then he will start the machining process which will take a few days.

He did say that the price might be a little higher is they need to replace things along the way, which kind of bummed me (cost extra $100 about), but No matter what they will be cheaper than a set of brand new non-revalved ones.

[nando]

I doubt they'll have to replace anything. They tell everyone that, it's just a common disclosure.

usually it takes so long because you're in a long queue. once they've actually taken them off their shelf for machine work, it goes pretty fast and they ship it right away, no BS.