Shock Tuning

@joonbug do you recall if those 3.0 coil overs and 2.5 Omega's I got from you if you modified the valving or are they at stock valving?

Thanks

 

@joonbug must be busy with work. I'm 99.9% certain the valving is stock.

 

Long time since I heard that song and way longer since I seen the video!!!

 

Thanks Warren

 

Yes. 99.7% sure. I’m almost as certain as Warren.

 

Thanks Joon!

 

This is a great thread on the tuning! Really interesting to catch the videos ( @osidepunker etc) and see these trucks perform.

With your shocks dialed in, is there a sweet spot or short range in speed where it handles over the whoops, or is it kind of broad spectrum for the setpoint?

Is there a different setting for general slow speed wheeling or will a well tuned suspension carry over into other things fairly well?

I'm looking to utilize some used/rebuilt raptor shocks at some point on a first gen DC and hope to learn more on the tuning end after.

Sorry for the Newb questions on shock tuning.

Also that engine brace is bonkers, well done!

 

IMO, there's a sweet spot for daily driving(roads/streets), and sweet spots for dirt. Definitely not broad spectrum. After re-valving the rear over ten times, with notes, driving the same roads, what may be valved awesome for one section, is terrible for another. So you'd want to valve it for the majority of the terrain you use it on.

 

Also a believer in opening up bleed holes on the piston for washboard

 

OK. Washboard is more what I'm looking for as opposed to the full on desert runner over big whoops kind of thing.

 

The last valving adjustment I did on my buggy I ran the face shim really thin (well a 20, compared to a 35-40) and the rest of the stack as a traditional pyramid. I read that allows for small bump compliance because the "crack pressure", ie minimum force, to get that first big shim to deflect is low and then you still have big shims to catch the truck for big hits. It's actually working really well, I'd even say it handles small bumps and washboard better than any of my other vehicles and that's while running ~30psi in the tires.

Not to say anyone should try that, but just to throw my anecdote in here on the topic of shock tuning and washboard compliance.

 

like this thread.... thanks for all the info

 

This is kinda what I did. In addition to the thinner large shim I added a smaller diameter shim between the face shim and the next shim in the stack to further decrease the "crack pressure" requirement. I've heard it called a flutter stack.

 

If it works, well it works. If you have things apart again take some pictures I'd like to see it.

 

These are pictures from the first revalve I did. I contacted ADS and gave them a bunch of specs and they sent me all the goods. Since then I revalved it again since it needed a lot more compression for how I was driving and that's when I did the above tweaks. At this point I think I need bigger shocks. The front is effectively a single 2.5" bypass with a 30 stack for compression and the rear is a 2.5" coilover with a 15 stack I think and a 2.5" bypass with a 35 stack. I'm not sure how far people push the valving, the front isn't bad but the rear I have the bypass tubes almost completely closed and not really getting a good ramp up in compression because of that. I don't blow through the bumps but it pretty easily gets into the first inch of bump travel. Front probably needs a 3.0" bypass, and rear needs a 3.5" realistically, especially since it doesn't have much suspension travel so not a lot of motion to ramp up compression with hits so really need the top bypass sections to get stiff fast.

But maybe I can layer another set of shims and push the 2.5s harder, not sure.









Front is different than a Tundra, but the rear is pretty similar. 48" trailing arm strapped at 24".

 

I like this buggy. Would be nice to have a lighter version of the 14 bolt for less unsprung weight but as you know its got strength and great value for kit that will take abuse.
Someone needs to build a braced housing at +100lbs less then the artec bracket format that seems to be fairly common in builds.

Not many folks talking about how a 300 lb axle versus a 600 lb+ axle transmits energy through washboard or whoops into the rest of the chassis.

The trailing arms give so much more travel than axle mounted coils and maks sense in your build, where you'd otherwise be limited by shock length, but the downfall is stiffer spring rates and more leverage on links (though they seem to handle it). I guess they're probably lighter and simpler than a stout cantilever design. With your triangulated lower trailing arms, do you feel that you might have more body roll than if you had straight lower arms? Anything you'd do different if you built it all over again?

 

Yea fabricated axles would certainly be nice, I think my front Dana 60 is like 900 lbs and the rear 10.5 is 700 lbs as I recall. Agreed the artec stuff is insanely heavy. When I started on this I didn't know much, and if I did it again would just build my own truss (even if it was all 1/4" would probably shave 30% of the weight off the Artec truss).

There's a long list of shit I'd do differently, this was my first tube chassis, first trailing arm, first V8, etc. etc. and took a long time to build, so a lot of stuff happened with little foresight how it'd affect other things. One of them being how narrow the chassis gets in the back, which forced the shocks inboard to clear, which is why the trailing arms are cranked inward so far. It actually handles really well I think. I added a rear sway bar a few months ago which helped a lot, and before that it certainly had a lot of body roll over 40mph or so but I don't know how much if any of that can be attributed to the link layout. It has 10" of up travel, a 40" tire at chest level on the back, a 32gal fuel cell over the axle, etc. so the CG isn't low by any stretch. With the rear sway bar (no front bar) the body roll is extremely tame, and I leave the bar on for crawling and it doesn't seem to make any appreciable difference (at least for my level of skill). It's surprisingly stable crawling and will do 50mph through turns happily.

I'm entering a race in northern Utah at the end of next month so pretty soon here will probably pull the shocks and fuck with ride height and springs to try and get it a bit more dialed in. It seems to hang with the IFS rigs decently well, though being such an absolutely different layout than a desert truck it's hard to compare them.

 

That thing looks great.

It's easy to cherry pick design after the fact from my comfy chair, you did well with that thing and should be proud.

The fabrication and design and putting new linkage ideas together is maybe what I enjoy the most, learning new things like the valving as well.

Any thoughts on some of the ruffstuff 9" housings with FF spindles (trussed) as alternative options holding up to what you use it for? I know Torq has an aluminum 3rd member 14B but its like $3k

 

Yea a 9" would be fine, especially with the current offering of 10"+ ring gears from Tube Works and the like. I don't think it's worth putting that much effort into this chassis though, I'd rather design a new chassis in CAD and then get it laser cut and bent and then glue it together and start fresh and take everything I've learned and dislike and apply it to the new build. Though that's a long ways out, but building lightweight axles is the point I draw the line since if I'm doing that I'd rather build brackets once for the updated suspension geometry.

And on a different note, I reached out to ADS and they said you can go a lot fatter than just double stacking 20s. I think I'll run a triple stack of 20s for my rear bypasses, and a double stack for the front bypass, and also asking if they'll sell bypass tubes since I think it might help to add a third compression zone to the rear.

 

To throw more in this thread, talking to Tyler at ADS more he actually recommended I go the opposite route I did and increase the crack pressure (he even recommended 3x 20s for the face shim) and open up the ride height bypass. He said the bypass port already effectively reduces the crack pressure, and increasing the face shim thickness will help push fluid through the bypass tubes making them more effective. And then run doubled 20s for the rest of the shims, though I could run more if need be. And then open up the ride height bypass tube to make it compliant there.

Compare this to my coilovers, which are running a flutter stack since they don't have the crack pressure work around of having the bypass tubes.

 

Heading over to youtube for shock tuning for idiots videos so I understand what your talking about.

 

I'll take more pictures with explanations when I pull the shocks apart. I just ordered a few shim packs from ADS so in a week or two will pull all the bypasses and tear them down again.

 

I recognize that gas station. One of these days I'll run into ya. Sweet build and journey getting there. Best of luck with your race up north.

 

I see your truck fairly often. I thought you had maybe moved away since it had been a few months but last week I drove by your truck if you hear the world's loudest exhaust in town it's probably me. I usually do a run out to the gap and back as my test loop (just got back actually), though I usually try to stay off the throttle as much as possible until I hit dirt since it's so god awfully loud.

 

I was working out of state for a few months. I'll be listening for ya

 

That's interesting advice from Tyler and makes sense. I haven't re-valved my bypass shocks, just the C/Os. I need to get the new (to me) truck out for a tuning session