2.5" maximum valving

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partybarge_pilot

Uno mas Cervesa!
May 14, 2004
9,343
230
63
Easton, KS
#3
The question should be how much valving in a resi out the top shock, diameter is not really a factor.

.015's on comp is the most I would run for a durable consistent set-up. You can run more than that buy cranking up the N2 pressure, but it's still going to cavitate and will eventually cook the oil and start hurting the seals and backing o-ring if your shock has one. How long all this tale depends on how hard you are pushing it. For a mall crawler that gets the occasional sweet jump, go for it. You want to run the B1k or run main at Barstow all day, you need to add another shock........

Now if you have something like the Bilstien ACV valve, you can get way more tricky, but I would not run those in the rear.
 

FasterNU

Mega Member
Jun 28, 2006
6,439
86
48
42
San Diego
#4
The question should be how much valving in a resi out the top shock, diameter is not really a factor.

.015's on comp is the most I would run for a durable consistent set-up. You can run more than that buy cranking up the N2 pressure, but it's still going to cavitate and will eventually cook the oil and start hurting the seals and backing o-ring if your shock has one. How long all this tale depends on how hard you are pushing it. For a mall crawler that gets the occasional sweet jump, go for it. You want to run the B1k or run main at Barstow all day, you need to add another shock........

Now if you have something like the Bilstien ACV valve, you can get way more tricky, but I would not run those in the rear.
Yea, top mounted resi is the problem. I would assume you can get more out of a 3" coil over because the reservoir is a larger diameter, right? (more surface area for N2 pressure)

I have run a rate plate with .028 distance in a single 2.5 coil over. That's probably the most "valving" I have run. But it's really just a choke point if you think about it... because it is only really "stiff valving" with high shaft speed events. And like barge said... I was running 330 PSI..... and shit would get hot pretty quick if you were shredding the gnar in Plaster city.

BroDaddy has some doubled up .020's in the stack too.. but also has a small flutter. Also has the King compression adjusters.

Wish I had see through shocks I could video. I'm sure it's cavitation city in there. LOL
 

marcytech

Mega Member
Mar 16, 2011
5,736
82
48
#5
kevin can better tell you what we had in the front of my silverado but it was hefty. lots of doubled up 15s. we ended up switching the resi to a 3.0 race series resi cuz they can handle more nitrogen. i think we were loading 300 or 350 psi in there
 

partybarge_pilot

Uno mas Cervesa!
May 14, 2004
9,343
230
63
Easton, KS
#6
Yea, top mounted resi is the problem. I would assume you can get more out of a 3" coil over because the reservoir is a larger diameter, right? (more surface area for N2 pressure)
Well, yes, but it never really works out that way in reality.

Say you went from 2.5's to 3.0's on a Tacoma. You would not be using the same shim stacks as the would be to much. The lighter stacks needed for the large piston would not cavitate as much.......

Now if you move up to a F150 that weights 6500#'s your going to need bigger stacks in those shocks and you cavitation problem is right back.

Also, piston to resi diameter is pretty even ratio regardless of size. Unless you get into Blackhawks.............
 

oorracing

<span style="color: orange;">DR Mod</span>
Jan 15, 2006
10,500
40
48
Long Beach Ca
#7
A total of 12 shims on compression in a 2.5” King Prerunner series shock with a big king race series resi. 350psi in that sucker and it would rip down sand highway! Which if anyone has been to Club Glam lately, they know that those whoops are pretty big. A compression adjuster woulda helped but it was out of budget, so we put foam shaft bumps on there We poor folk make do with what we got laying around!


Sent from my iPhone using Tapatalk
 

FasterNU

Mega Member
Jun 28, 2006
6,439
86
48
42
San Diego
#8
Well, yes, but it never really works out that way in reality.

Say you went from 2.5's to 3.0's on a Tacoma. You would not be using the same shim stacks as the would be to much. The lighter stacks needed for the large piston would not cavitate as much.......

Now if you move up to a F150 that weights 6500#'s your going to need bigger stacks in those shocks and you cavitation problem is right back.

Also, piston to resi diameter is pretty even ratio regardless of size. Unless you get into Blackhawks.............
Yea, makes sense ..... and no kidding...the Blackhawks have HUGE resi's!! Like almost coffee can sized.
 

FasterNU

Mega Member
Jun 28, 2006
6,439
86
48
42
San Diego
#9
A total of 12 shims on compression in a 2.5&#8221; King Prerunner series shock with a big king race series resi. 350psi in that sucker and it would rip down sand highway! Which if anyone has been to Club Glam lately, they know that those whoops are pretty big. A compression adjuster woulda helped but it was out of budget, so we put foam shaft bumps on there We poor folk make do with what we got laying around!


Sent from my iPhone using Tapatalk
12x what though? Doubled up 15's?
 
Apr 24, 2006
11,975
27
48
32
Simi Valley, CA
#10
Three shims on compression is all you need... well that and a rate plate.

Another way to help cativation is restrict the flow to the resi with a smaller diameter hose or if you have the funds, buy a new resi with an ACV valve or a compression adjuster. Fox compression adjuster with the high/low adjusters works really well. I'd say well enough that you MIGHT be content with only running a single shock.
 

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