Fett Bro's Air Cannister 2's

[woolyviper]

I think it has to be brought up again that the only thing the reservoir is going to do is change the spring rate. It's equivalent to changing a spring on a traditional shock. I think putting a stock float on a shock dyno and then doing some real world testing is the only way to prove performance add-ons. Anyone got access to a shock dyno?

 

[arteeex]

Yes. My dyno has electric start and reverse.

 

[ahicks]

I think it has to be brought up again that the only thing the reservoir is going to do is change the spring rate. It's equivalent to changing a spring on a traditional shock. I think putting a stock float on a shock dyno and then doing some real world testing is the only way to prove performance add-ons. Anyone got access to a shock dyno?

Dyno results fine for some (engineering types), but my "seat of the pants" dyno says that the properly tuned resi can let the spring rate increase slightly - without the proportionally increased harshness you might expect to go with that - in the upper parts of the suspension stroke - when compared to a non air resi equipped shock. In fact, my butt dyno would show a harshness decrease with the properly tuned resi install (as compared to without).

Maybe that's just me...

 

[woolyviper]

i'm gonna run the fb2 cannisters on my RTX and see what happens. I like that the fox floats ramp up, but i want them to ramp up deeper in the stroke.

 

[ahicks]

i'm gonna run the fb2 cannisters on my RTX and see what happens. I like that the fox floats ramp up, but i want them to ramp up deeper in the stroke.

I think you're on the right track. I think that's exactly what you'll see. As one that can't seem to leave well enough alone, I thought I'd like a little control over when and how much that happens. That's why I went the adjustable route?

 

[ralger]

>i'm not questioning your graphs (you're obviously smarter than i am), but wouldn't your x axis have to show the resultant volume with the intial volume built in (example start at 13 and add 10% your resultant would be 14.3), thus moving the curve further out vs. the stock volumes?<

You are absolutely correct. I started them that way, but the curve would end at 1.3 in3 (where the shock would bottom out) instead of zero; I decided is was easier to compare vs. stock by shifting the curves to only show the volume change in the shock (ie. shock travel) not the total volume in the shock and resi.

 

[woolyviper]

You are absolutely correct. I started them that way, but the curve would end at 1.3 in3 (where the shock would bottom out) instead of zero; I decided is was easier to compare vs. stock by shifting the curves to only show the volume change in the shock (ie. shock travel) not the total volume in the shock and resi.

i kind of figured that but wasn't sure - nice graphs by the way - this thread should be made a sticky, as this is going to keep coming up with the genesis of "air sprung" shocks.

 

[TurboJamie]

I have been throwing this air cannister idea around for a while now. Not that I own a sled with air shocks anymore just my train of thought might help your decision.

Just because you increase the volume of at you are still at the same pressure. This cannot change how the shock reacts. If there was some way that the extra air chamber was empty and the air in the sock was bled back and fourth it would make a change. But IMO the chamber would have to be empy to do anything which its not its full of air. The same exact pressure that is inside the shock to be exact so where is the air going when the shock is compressed? No where! IMO the cannister cannot make a difference. That is ofcourse my opinion.

 

[arteeex]

I have been throwing this air cannister idea around for a while now. Not that I own a sled with air shocks anymore just my train of thought might help your decision.

Just because you increase the volume of at you are still at the same pressure. This cannot change how the shock reacts. If there was some way that the extra air chamber was empty and the air in the sock was bled back and fourth it would make a change. But IMO the chamber would have to be empy to do anything which its not its full of air. The same exact pressure that is inside the shock to be exact so where is the air going when the shock is compressed? No where! IMO the cannister cannot make a difference. That is ofcourse my opinion.

The Ideal Gas Law and Boyle's Law kinda of works against you on this one.

 

[ahicks]

I have been throwing this air cannister idea around for a while now. Not that I own a sled with air shocks anymore just my train of thought might help your decision.

Just because you increase the volume of at you are still at the same pressure. This cannot change how the shock reacts. If there was some way that the extra air chamber was empty and the air in the sock was bled back and fourth it would make a change. But IMO the chamber would have to be empy to do anything which its not its full of air. The same exact pressure that is inside the shock to be exact so where is the air going when the shock is compressed? No where! IMO the cannister cannot make a difference. That is ofcourse my opinion.

Would combustion ratio/pressure remain the same if you increased the size of the combustion chamber? As mentioned, you'll see more difference as the shock approaches full compression. As you suspect, the shocks performance won't change much with/without the resi while fully extended.

 

[TurboJamie]

My 08 RTX rode like crap with or without the cannisters. I guess I would have to see a drastic difference in the shocks performance to justify the purchase of the cannisters again. I ran the hygear ones with the bleed control screw to adjust the chamber to shock transfer speed.

 

[ahicks]

My 08 RTX rode like crap with or without the cannisters. I guess I would have to see a drastic difference in the shocks performance to justify the purchase of the cannisters again. I ran the hygear ones with the bleed control screw to adjust the chamber to shock transfer speed.

Rode like crap after a revalve, or before? I don't think the resi's are a very good substitute for a good revalve - especially they way they come set up for chatter bumps - or not set up, depending on how you're looking at it!

 

[TurboJamie]

Yeah I would like to see what a revalve does for a float, mine were not. I wasn't even aware of a revalve at the time. i did try a set of Evol X's last winter and they were sweet!

 

[NyTrOMaNIaC]

Sooooo, the TRUE QUESTION.... Air cannister 1's (4% increase in volume) or Air Cannister 2's (16% increase in volume) ???

 

[ahicks]

My best guess-
As mentioned, I personally run a low front end. Out of a fear that 16% may be too much, I'd go for the smaller one. Somebody running 65+ might want the larger.