Basic Valving Theory

Welcome to DezertRangers
Join the community. Register today for all the benefits of membership.
Register

FasterNU

Mega Member
Jun 28, 2006
7,773
1,196
113
San Diego
^^ trying to think in my head how that would work on those 2.0's... cavitation city with an air-spring basically? LOL

And yup, I as well have always rebuilt shocks with bottom out IFP method. Swear that's how Fox said to rebuild my BP's on their documentation too?
 

84prerunner

2:AM Fabrication
Feb 7, 2008
21,697
244
63
Covina CA
^^ trying to think in my head how that would work on those 2.0's... cavitation city with an air-spring basically? LOL

And yup, I as well have always rebuilt shocks with bottom out IFP method. Swear that's how Fox said to rebuild my BP's on their documentation too?
Idea is to limit cavitation. When cavitation occurs the IFP plunged further than it ever should. With it only an inch off the end cap it can’t plunge very far before the pressure becomes hundreds of PSI hopefully limiting the the cavitation.

same concept as running really high n2 pressure without the constant stiction on seals.
 
  • Like
Reactions: partybarge_pilot

Do Dah

Senior Member
May 13, 2012
277
98
28
^^ trying to think in my head how that would work on those 2.0's... cavitation city with an air-spring basically? LOL

And yup, I as well have always rebuilt shocks with bottom out IFP method. Swear that's how Fox said to rebuild my BP's on their documentation too?
2.0s should always have 6" foam bump stops for back up.
 

FasterNU

Mega Member
Jun 28, 2006
7,773
1,196
113
San Diego
Idea is to limit cavitation. When cavitation occurs the IFP plunged further than it ever should. With it only an inch off the end cap it can’t plunge very far before the pressure becomes hundreds of PSI hopefully limiting the the cavitation.

same concept as running really high n2 pressure without the constant stiction on seals.

That is what I am grappling with. With such a low pressure... and top mounted reservoir... wouldn't that shit just cavitate until it moved the IFP enough to ramp that pressure up??? As in wouldn't it feel kind of dead at first?

This is where I would LOVE to see a clear shock body/ressy on a shock dyno

I always just cranked up pressure like you said. Never really seemed to have any apparent stiction issues. I mean, it's not light like a mountain bike...
 

Horunner

Senior Member
Aug 10, 2014
1,690
1,540
113
Yucaipa, CA
That is what I am grappling with. With such a low pressure... and top mounted reservoir... wouldn't that shit just cavitate until it moved the IFP enough to ramp that pressure up??? As in wouldn't it feel kind of dead at first?

This is where I would LOVE to see a clear shock body/ressy on a shock dyno

I always just cranked up pressure like you said. Never really seemed to have any apparent stiction issues. I mean, it's not light like a mountain bike...
If it’s only 1.5” off the n2 side the pressure is going to ramp up stupid fast compared to 200psi with the IFP 5” of n2 side. The psi may be the same while fully compressed but it won’t have as quick of a ramp up. I have no idea how this combats cavitation, I’d assume it would make it worse. But I’m also no engineer with a striped hat.
 

84prerunner

2:AM Fabrication
Feb 7, 2008
21,697
244
63
Covina CA
That is what I am grappling with. With such a low pressure... and top mounted reservoir... wouldn't that shit just cavitate until it moved the IFP enough to ramp that pressure up??? As in wouldn't it feel kind of dead at first?

This is where I would LOVE to see a clear shock body/ressy on a shock dyno

I always just cranked up pressure like you said. Never really seemed to have any apparent stiction issues. I mean, it's not light like a mountain bike...
I never played with pressure on that vehicle, I set it up, it was worlds better than it was out of the box so it never got touched again.
i don’t remember the numbers but at ride height pressure is well over 100psi, can’t imagine what the spike is like on a hard hit. I’d run more pressure, but I don’t think the 2.0 performance series Fox resi and shaft can take much more.
 
Nov 9, 2008
682
367
63
Carolina South
I've got a question. It may be stupid or even already answered in this thread but I couldn't find it. When filling the shocks with oil and pressurizing them how does how much oil and or N2 affect the performance of the shocks?
I know springs support the ride height of the vehicle and shock shims determine the speed at which the piston moves in the shock body.
But how does the N2 pressure affect the shock performance?
And how does the amount of oil in the reservoir affect shock performance?

Sent from my HD1907 using Tapatalk
 

Horunner

Senior Member
Aug 10, 2014
1,690
1,540
113
Yucaipa, CA
I've got a question. It may be stupid or even already answered in this thread but I couldn't find it. When filling the shocks with oil and pressurizing them how does how much oil and or N2 affect the performance of the shocks?
I know springs support the ride height of the vehicle and shock shims determine the speed at which the piston moves in the shock body.
But how does the N2 pressure affect the shock performance?
And how does the amount of oil in the reservoir affect shock performance?

Sent from my HD1907 using Tapatalk
Oil volume helps with cooling and amount of oil vs n2 in the resi determines how quickly the pressure ramps up in the resi. More oil=more heat dissipation but a quicker ramp up in pressure and vice versa
 

Latest posts

Today's birthdays

New Threads

New Classifieds

latest desert trips

Member Builds