universal air bag on short shock question

[Rollnnn]

Hey Guys,
Im hoping someone can help me out with this. I had to get custom rear short shocks made. Can i run a double bellow bag with this even though the bag is taller than the shock is at full extension? are there any problems with it?

Thanks in advance....

[mike410]

I don't see why not. As long as the bag deflated/at its minimum height is short enough to go as low as you want. If anything it helps, because if you lift the car the shock will stop at full extension and won't put any strain on the bags.

Care to share any info about the custom rear shocks?

[Rollnnn]

Thanks for the reply. I was thinking the same thing, but was just wondering about when i calibrate the system and the airs up to 100. Will it have a negative affect on anything since it wont be able to expand all the way?

What did you want to know about the shock? It's nothing big, its just has a shorter body with shorter travel. They way my rear kit is designed i cant have the shock extend too long or the tire can hit the bottom of the kit that curves under it...

[Oh Damn, it's Sam]

Thanks for the reply. I was thinking the same thing, but was just wondering about when i calibrate the system and the airs up to 100. Will it have a negative affect on anything since it wont be able to expand all the way?

Won't hurt a thing. A well-designed air suspension system doesn't have the bags at full extension at ride height anyway. If you did, your suspension wouldn't have any droop, and every time you went over a pothole, you'd be hanging the entire weight of one corner of the suspension, that brake, and that wheel and tire all off the bag. Not good.

The bag is never going to know the difference.

[Rollnnn]

ok great, thanks! Another quick question.

Does a double bellow bag ride better than a single bellow bag?

[Oh Damn, it's Sam]

Some people say so. I've never been able to find any empirical evidence to suggest so, in spite of it being common wisdom, nor can I find many people who repeat this common wisdom who are even able to articulate what they mean by "rides better." Air ride is kind of like the Catholic Church - there are a lot of "rules" and "wisdom" and "common knowledge" and no one seems to know where it came from or why it's true.

The major advantage of a double-bellows bag is the band in the middle, which helps control ballooning, meaning that the bag stays about the same diameter through its stroke. Double-bellows bags fold a little differently as they compress as well, so if you're extremely space-constrained, they're definitely the way to go. One additional advantage for most applications (although not really yours) is that double-bellows often have greater range than single-bellows.

[mike410]

Thanks for the reply. I was thinking the same thing, but was just wondering about when i calibrate the system and the airs up to 100. Will it have a negative affect on anything since it wont be able to expand all the way?

What did you want to know about the shock? It's nothing big, its just has a shorter body with shorter travel. They way my rear kit is designed i cant have the shock extend too long or the tire can hit the bottom of the kit that curves under it...

Yeah, I'm not sure how the autopilot v2 works but with e-level you can have it calibrate with the car already set to the max height setting. I did this because my rear has so much more travel than my fronts that if I let it auto adjust my settings would be uneven due to the difference in travel (without changing the height settings manually). I would think you should be able to limit it to a max psi for the front and rear before calibration. I am just guessing though. The manual should have something if you read through it.

Did you just have an existing shock shortened or a custom shock made? Who did the work? I might want shorter shocks in the rear just to shift the travel to a more usable range.

[Rollnnn]

Thanks you guys! very informative stuff and definitely helps out a lot.

Sam, Right now i have a single bellow bag installed in the rear. Ill see how this goes and maybe change to double bellow sometime down the line.

Mike,
I don't think you can set a max psi setting before calibrating or maybe i just didn't read that far into the manual. I did calibrate it though and it was fine.

I had custom shocks made. I did the prototype for the megan racing coils for my car. They just went above and beyond and helped me out with the custom shorter shock that i needed. My car is going to be at sema, so this might have helped...

[Oh Damn, it's Sam]

You shouldn't need to set a max psi during calibration anyway - the bag isn't going to give a shit, so long as the bag is capable of handling more pressure than your compressor can provide. This is an issue with sleeve-style bags that have lower pressure ratings, but bellows-style tend to be able to handle a fair bit of pressure. My SS-5s are rated to 250 psi, for example, and lots of others are in that range.

Be sure to post some pics of your setup. I'm sure other W203 people would love to see what you've come up with.

[Rollnnn]

Sam, its actually for my w209. Here are a couple pics from sema last week: