Quick valving question

cosmo

Super Moderator
If that helps, then you can start to turn in your high speed comp. (bypass tube).
 

partybarge_pilot

Well-Known Member
Picture of assembled piston/valving in the CO?

With that light of valving it should not be harsh. Thinking you have other issues. Something like that would normally run a .015 on comp and .008reb. With 2 bleeds open and a flutter stack, it should be a sloppy pig.
 

chatter_splatter

Well-Known Member
I don't have a picture of the coilover, but the valving specs are up towards the top. It's pretty soft, but I wouldn't say sloppy. I just have no idea what other issues there could be unless it's in the bypass.
 

osidepunker

Well-Known Member
What's the science behind the double flutter on yours? Looks kinda like something Accutune would do.

You might try just the 1.8 before the fulcrum shim to reduce the crack pressure and eliminate the 1.6.

1.800 x .010
.800 x .008
1.600 x .010
.800 x .008
1.60 x .010
1.425 x .010

I think reducing the crack pressure might get the oil moving through the piston sooner and soften up the initial hit.

One guy suggested I try a flutter in the bypass for the same reason. Said the oil in the tube and the poppet has mass, so it helps to crack open the valving on the piston sooner so it doesn't have to get all of that oil moving and open the valve.

Not sure how I feel about a flutter in the bypass, but I might try it.
I don't understand the double flutter. Down South gave me the stack. DC Shocks put a flutter into the bypasses, 4.3.2 with 20s on the small shims. At this point I had 700# coils and it was pillow soft over everything and the bypasses still did a decent job of soaking up the big stuff.

BUUUT I had so much preload on the 700# that I was binding at full compression. My problem is that I made too many changes at once. I did the following all at once:

switched to 800# coils
switched bypasses to low flow pistons
removed the flutter from the bypasses

At this point I was able to take HUGE hits without bottoming out. It was still controllable over 2'-3' whoops if they had the proper spacing and I hit them at the right speed. But I had my compression tubes opened up a lot or it would get harsh over the medium stuff and pretty stiff over the small stuff. So basically my bypasses are really just working as bumps. I am working on trying to tune that out so they work properly in most of the range.

I don't see anything wrong with trying a flutter in the bypasses, but I'm still suspicious of your springs.

Picture of assembled piston/valving in the CO?

With that light of valving it should not be harsh. Thinking you have other issues. Something like that would normally run a .015 on comp and .008reb. With 2 bleeds open and a flutter stack, it should be a sloppy pig.
This is what I was thinking. Those are very light stacks for a full size truck.

I don't have a picture of the coilover, but the valving specs are up towards the top. It's pretty soft, but I wouldn't say sloppy. I just have no idea what other issues there could be unless it's in the bypass.
I think you should still look at the springs. and you can also try a flutter in the bypasses.
 

chatter_splatter

Well-Known Member
I've thought about the springs being a possibility, but the only way I can see them contributing to harshness is if the spring divider is binding and the small hits aren't enough to move it.

I have run the truck with the crossover rings down and felt the 900lb without the upper spring. It's definitely too stiff, and feels really bad. But it's a different kind of stiff. It's stiff over everything and just doesn't let the suspension travel.

The harshness I'm dealing with now is high speed, and is only really bad over rapid, successive hits.

It could be that with the soft initial spring rate I need less rebound. If the front end is packing up into the bump zone it would cause some pretty serious harshness issues. If this is the problem, more compression might fix it. I just haven't tried it yet because it seems really counter intuitive.

Another possibility is that there isn't enough high speed compression control and the tire is jouncing of the face of hard hits.

Could be a combination of these two things.

I tried turning the comp tubes all the way in just to see how it felt and hit some speed bumps and it felt very controlled. Firm, but way less of a hard impact feeling.

I think I'll lower high speed rebound a bit in the bypass, and really work on trying every possible comp setting. I'll also try raising the crossover a little like Cosmo suggested.

Wish me luck!
 

partybarge_pilot

Well-Known Member
If it's too stiff you need to open up the tubes. Putting a flutter in it really defeats the purpose of the bump zone. Low flow pistons will mask lack of valving but will also create pressure spikes like rate plates. Harsh for no good reason.
 

osidepunker

Well-Known Member
If it's too stiff you need to open up the tubes. Putting a flutter in it really defeats the purpose of the bump zone. Low flow pistons will mask lack of valving but will also create pressure spikes like rate plates. Harsh for no good reason.
Well I took my flutter out. But some guys think a flutter is ok in bypasses to keep it soft overt the little stuff so that why I asked your opinion. Thank you for explaining

As for the low flow, I understand they can cause harshness. But I had regular pistons with the largest stack I could fit and the bump zone wasn't enough so I threw on the LF pistons and they've worked really well so far. Yes, they are a little harsh over the medium stuff unless I open the tubes. But I also still have a huge stack n there, 4.3.2 all 20s. So the first thing I will try is to reduce the low speed shims and see if I can smooth it out a little over the chop.

I understand a larger shock would help me here since I'm so heavy, but its not in the cards right now. I have to work with what I have
 

chatter_splatter

Well-Known Member
Or your comp stack is to close to the top out washer making it act like a rate plate. Why photos tell a lot.

Never flutter a BP.
Here's the coilover valving:

.800 x .020

.950 x .008

1.100 x .008

1.350 x .008

1.425 x .008

1.600 x .010

Piston

1.800 x .008

.950 x .012

1.600 x .008

1.425 x .008

1.35 x .008

1.100 x .008

.950 x. 008

.800 x .020 (x2)

Top out washer


The shocks are still harsh with the comp tubes fully open. Bypass valving is 2,1/70.
 

chatter_splatter

Well-Known Member
Would it be a bad idea to do something like this and eliminate the rate plate?

800 x .020

.950 x .008

1.100 x .008

1.350 x .008

1.425 x .008

1.600 x .010

Piston

1.800 x .008

.950 x .012

1.600 x .008

1.425 x .008

1.35 x .010

1.100 x .012

.950 x. 015

.800 x 020


Could possibly eliminate high speed flow problems in the coilover and let the bypass do the high speed work.
 

partybarge_pilot

Well-Known Member
Ok, now that I have a real keyboard.

With your current stack you have .095 of space between the face shim and the top out washer.
With a .015 stack and a .093 spacer like usual, you come up with .165 between the face shim and the plate.
This is where your issues are coming in. Space it up. I have a feeling when you do this it will become to "soft". If you still feel the need for some high speed control after that, throw a .015 X 1.8 on top of the stack.

Your springs are also suspect, but not causing the high speed harshness.
 

osidepunker

Well-Known Member
Ok, now that I have a real keyboard.

With your current stack you have .095 of space between the face shim and the top out washer.
With a .015 stack and a .093 spacer like usual, you come up with .165 between the face shim and the plate.
This is where your issues are coming in. Space it up. I have a feeling when you do this it will become to "soft". If you still feel the need for some high speed control after that, throw a .015 X 1.8 on top of the stack.

Your springs are also suspect, but not causing the high speed harshness.
This is good information thank you for this. I had to go back and look at my stack sizes to make sure I wasn't getting too drastic.

Its funny, but a stack of all 12s would have a smaller "stack height" then say a stack of 15s. Does that mean the 12s will resist the hard hits more even though they would be softer over the little stuff??
 

chatter_splatter

Well-Known Member
This makes a lot of sense, and is probably why the high speed has always been so jarring on the truck.

The previous owner had the standard .008 stack on the compression side with no spacer. I changed it to a flutter and added the two .80 x .020 spacers at the end of the comp stack and it helped, but I'm thinking it was the spacers and not the flutter that made the difference.

The coilover shaft has 3 thick washers under the valving nut, and I can either move one of them to the bottom of the compression stack, or keep adding .020 washers until it fixes the issue.
 
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