SHOCK EXPERT HELP

ranman5608

ranman5608

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I have a 2.5 14" coil over and a 3.0 16" bypass on the back of my car. both shocks are set up for 90* at bump. but at full extension un strapped i will use all 16" of the stroke on the BP and only 12" of the stroke on the CO. I have about 5* left in the safe zone on my cvs so more droop is easily accomplished. the bypass is an actual 16" stroke shock. not an 18" de stroked.
so my questions are as follows.
1 can i run an 18" stroke shaft in the 16" shock or will it hit the cap at bump?
2 would removing one of the shaft spacers get me closer or is allowing the piston to travel past the reservoir port a no no.
3 am i wasting my time for an extra 2-3" of droop.

thank you for sharing your wisdom.
 

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With the coilover fully drooped, what are the CV angles? You might not have more droop available.
 
at full droop im at 20.5* so I have a few more degrees in the safe range
 
ranman5608 said:
at full droop im at 20.5* so I have a few more degrees in the safe range
Click to expand...
Derp, you had that in your first post.

There's going to be a lot of finagling to get more travel, especially with the bypass. I don't think you can run a longer shock shaft in that BP. How do things look at full bump? Can you fit a longer bodied bypass (18") with the same mounts?

Either way it goes, since the BP is the limiting factor, this won't be cheap.
 
The bypass and co at full bump are both on there rubber stoppers. I did some more measuring and since I’m running an outboard hub the cv isn’t the limiting factor it’s actually the axle hitting the trailing arm I would be able to get maybe another 1” of droop but I’m not sure that’s worth it. Oh well
 
ranman5608 said:
The bypass and co at full bump are both on there rubber stoppers. I did some more measuring and since I’m running an outboard hub the cv isn’t the limiting factor it’s actually the axle hitting the trailing arm I would be able to get maybe another 1” of droop but I’m not sure that’s worth it. Oh well
Click to expand...
Yeah, since they're equal at full bump, you'd have to rework one of the mounts to lengthen the BP (longer rod end like @Jtmoney714 says would be easiest). Lot of work for an inch...

But, some of us would kill for that extra inch. :ROFLMAO:
 
Rockwood said:
Yeah, since they're equal at full bump, you'd have to rework one of the mounts to lengthen the BP (longer rod end like @Jtmoney714 says would be easiest). Lot of work for an inch...

But, some of us would kill for that extra inch. :ROFLMAO:
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thats what im thinking haha.

what kind of rear wheel travel numbers have you experienced as an average?
 
ranman5608 said:
thats what im thinking haha.

what kind of rear wheel travel numbers have you experienced as an average?
Click to expand...
Long travel buggies are usually around 16-18" of real travel. Most important part, to me, is using all of the bypass shock. The rest can be tuned in. What's the complaint you have that triggered this? :D
 
I was having an issue with going over the real tight side to side chatter bumps in the back only. the rear suspension would essentially lock up in the really fast turnover low speed stuff even with the bypasses wide open on all the tubes but would perform well in larger whoops. so I've built a spring rate calculator and have the car coiled perfectly now (I think it was too light for the sprung corner weights i came up with). I then started measuring wheel travel and where the car was sitting compared to shock stroke and everything was calculated off of 14" coil over travel which threw the percentage off. so now its right at 66%. utilizing 12" of co stroke. I then started getting into the shocks I had a #30 shim stack in the coil over and a 3,3,2,1 shim stack in the bypass. so I'm going to try 0 valving in the coil over and run a 2,2,2,1 stack in the bypass to see if i can get the first few inches of droop and compression to be much smoother. If this makes any sense.

calculator attached
 
Lock up as in pack up and bottom, or lock up as in it wouldn't move at all for the chatter?

30's pretty light already. Is there a flutter stack in the CO or bypass?


This has a pretty good writeup on basics to solve high vs low speed issues. Removing all valving from the CO is a valid tactic, I'm just not a fan of losing that extra heat capacity. Bypasses are position sensitive with the screws, not speed sensitive (though all the way open should allow enough fluid flow). The overall damping is adjusted with the screws in the zone, high and low speed. If you need to fix speed issues, that's in the stacks.
 
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By locking up I mean stiffen up enough to violently shake the car side to side. The best way I can describe it would be a steering dampener. I would have to either hammer down and get over the top of them and just take it or slow down drastically maybe down to 5 mph and also just take it.

when I bought the coil overs I had my buddy put the 30 stack in it because since I had the bypasses I figured a little help would be ok. So we went with the lightest full stack on fox's sheet. Nothing fancy no flutter stack or anything like that.

Ill read through that now
 
ranman5608 said:
any one ever do a flutter stack in a bypass?
Click to expand...
I always do, bypass tube are position sensitive, flutter stack is velocity sensitive. Flutter stack is the only way I've found to make the chop/washboard better. The shock tuning needs to be good everywhere else first tho, Flutter stack should be the last thing you do.
 
Looney Duner said:
I always do, bypass tube are position sensitive, flutter stack is velocity sensitive. Flutter stack is the only way I've found to make the chop/washboard better. The shock tuning needs to be good everywhere else first tho, Flutter stack should be the last thing you do.
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Makes total sense. What’s a good starting point you like to go with in a flutter? And do you do both comp and rebound
 
ranman5608 said:
Makes total sense. What’s a good starting point you like to go with in a flutter? And do you do both comp and rebound
Click to expand...
I don't know how the numbers work on fox shims, I've always run king. But start by putting a small diameter shim between the largest and 2nd one down, on the comp side only. You can adjust how it reacts by changing the diameter and thickness of the small shim. I usually start with a .008 or .010 then adjust accordingly. If you make the shim thicker it will have more effect. Google flutter stack, there is a lot of info out there, with pictures and such to help. You can also run a partial stack, 3 shims, thin ones on top of your normal stack, it will run on the lighter stack until a bigger hit, then get into the heavy stack. Many different ways of going about it. My last 2 cars were absolutely brutal in the chop, after a few different stacks it's almost perfect.
 
Right on thank you all for the help I can’t wait to get back out to see how all of the changes I’ve made work
 
old stack configuration when i was getting the "lock"
#30 stack in 2.5 coil over compression and rebound
1.8 od .008
1.6 od .008
1.425 od .008
1.350 od .008
1.1 od .008
.950 od .008
.800 od .008

3,3,2,1 stack in 3.0 bypass compression side
3x 2 od .015
3x 1.8 od .015
2x 1.6 od .015
1.425 od .015
1.350 od .015
1.1 od .015
2x .950 od .015

#90 stack in 3.0 bypass rebound side
1.80 od .015
1.6 od .015
1.425 od .015
1.350 od .015
1.1 od .015
.950 od .015

new stack coil over
no valving

new stack bypass rebound remained the same compression as follows
2x 2 od .015
2x 1.8 od .015
2x 1.6 od .015
1.425 od .015
1.350 od .015
1.1 od .015
2x .950 od .015
 
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