Full hydro steering, unequal length tie rods causing major handling problems?

[TBItoy]

The power beyond port is just a "return" port - when you're not steering, it is the main return port.

When you are steering, the flow coming back from the ram goes out the T port.

There should be no issue with having them tee'd together. (unless there is a restriction in your return line or something causing backpressure... Did your burned up pump fill the filter with metal?)

 

[urbex]

If you don't touch the wheel, you could "theoretically" drive it in a straight line at 100mph without anything moving in the hydraulic system.

Which would be great, if every road out there was dead flat, straight, and level, lol. The non load reactive was a plus for me, as one of my primary reasons for wanting to go to some level of power steering was to restrain a rock hit from ripping the steering wheel out of my hands, which was brutal on the stock Samurai steering. I figured going non load reactive was the full extreme on the other end, which was perfect, and worst case scenario it would just require a bit more attention to steering off trail.

No tech to add, but I've got my DE ram offset probably 6" and run only 2-3* caster and mine runs fine up to 50 mph. It's a little twitchy but I attribute it to being a fast orbital and crappy tires for that speed.

Wish I had more help to offer, but I don't think the offset ram is the culprit here.

Knowing other people have successfully run something that offset without major issue is actually a big help in narrowing down where exactly the problem lies. I figured I'd be a bit twitchy too being a 2.5 turns lock to lock setup, just not nearly this bad, lol.

As I've mentioned before, this is all new stuff to me, so I'm facing a bunch of unknowns. I realize changing so much at once (axles, suspension and steering all at the same time) isn't great for troubleshooting purposes, but then it also seems silly to attempt to get mechanical steering to work on a 4 link like this knowing it wasn't going to be the final setup anyways.

The power beyond port is just a "return" port - when you're not steering, it is the main return port.

When you are steering, the flow coming back from the ram goes out the T port.

There should be no issue with having them tee'd together. (unless there is a restriction in your return line or something causing backpressure... Did your burned up pump fill the filter with metal?)

Doesn't appear to be a clogged filter, I don't feel like it's losing the power part of the power steering at all, system bleeds out quick, and I can see a healthy flow of fluid going through the reservoir at idle. It seemed more like I just had the pressure safety valve lock in full bypass on the old pump rather than a metal failure, but I never cracked it open to verify either. I just grabbed another off a parts car, slapped it in, and kept going.

Regardless, probably wouldn't hurt to pick up a new filter from Napa either just to play it safe.

 

[Bebop]

Knowing other people have successfully run something that offset without major issue is actually a big help in narrowing down where exactly the problem lies. I figured I'd be a bit twitchy too being a 2.5 turns lock to lock setup, just not nearly this bad, lol.

My rig is 2.6 turns lock to lock and I had it at 80 ish MPH and it was totally controllable.

 

[urbex]

Ended up getting called into work today, so didn't have a bunch of time to play in the garage. I didn't have the steel I thought I did to make the alignment bars, so I just said screw it, screwed the tie rods all the way in on both sides and ended up with obvious toe in without measuring it.

That made it better...

Then I verified wheelbase left/right, and that was good. Found that, just as I suspected earlier, the axle was off center left/right about 3/4", and fixed that. Put more caster in, and that made it better.

Something told me to check coilover pressure, and oops, apparently I forgot to charge them after putting this all together. Putting 200psi of nitrogen in made a hell of a good difference there, lol

Unfortunetly, it also jacked the ride height up considerably. I built the front end for 4" up/8" down, and how I'm exactly the opposite - 8" shaft showing. I had initially guessed on what my final corner weights were going to be, and apparently I guessed way high, though based on this, I'm currently running approx 250lbs unsprung weight, which seems really low, even given that it's on a Samurai chassis.

I'm set up now on 95/175 springs, and based on the charts, I should be running more like a 70/100. Though I want to finish getting all the tube up front, winch back in, etc before deciding that.

So it's night and day better than it was, but still not quite all the way there.... Obviously, I still need to get in there and actually measure what I have for toe and caster. But could being way oversprung in the front contribute to this as well?

 

[Lil ugly]

could being way oversprung in the front contribute to this as well?

It could play a factor. Much like a vehicle whose struts are worn out or a spring is broken. I am curious though why your ride height changed with a nitrogen charge. You are running coilovers, the springs carry the weight, the rest is just a shock, it dampens the movement but does not carry the weight of the vehicle like a strut does. I can see different pressures giving you fits as the damping effect would be way off from side to side.

 

[Bebop]

It could play a factor. Much like a vehicle whose struts are worn out or a spring is broken. I am curious though why your ride height changed with a nitrogen charge. You are running coilovers, the springs carry the weight, the rest is just a shock, it dampens the movement but does not carry the weight of the vehicle like a strut does. I can see different pressures giving you fits as the damping effect would be way off from side to side.

Hmmmm nope.
The nitrogen absolutely carries some of the weight.

The shock shaft acts exactly like a hydraulic ram. Nitrogen pressure x surface area = force.
At 200PSI, a 7/8" OD shaft carries about 120lbs.

Since you fill the shocks at 200 PSI at full droop, when you're at ride height, the nitrogen pressure is even higher, thus driving the force from the shaft higher.

 

[Lil ugly]

The nitrogen gas is there to keep a consistent pressure on the shock oil. This helps prevent cavitation and aeration, which happen when shock oil essentially boils in the low pressure areas of the piston during compression and rebound, which releases gases into the oil. Nitrogen is used because it's still compressible like air, but is more consistent when temperature changes. If you keep enough pressure on a fluid, you can prevent it from boiling and becoming a gas, much like how the water in your engine doesn't boil because it's under pressure. A majority of the time when you feel your non-pressurized shocks fade or act like there is a space of nothing, it's because of cavitation and aeration which makes the oil an inconsistent fluid. So the pressure from the nitrogen and dividing piston prevents the foaming you see happen in non-pressurized shocks.

I respectfully disagree. the above quote is from one of the engineers at King Shocks. The nitrogen does not carry load in a coilover, not to be confused with an airshock or strut like an ORI where it does do the work in conjuction with the oil etc.

 

[urbex]

Every day I'm learning more and more about this stuff...I do seem to recall that I couldn't compress the shock body when it was charged without springs before. I just went out and grabbed one of the spares, and did a quick test with it, without springs installed. Empty, it's easy to compress the full stroke. Charged to 100psi, closed off the nitrogen cylinder, but left the hose and gauge attached, with the fill adapter holding the fill valve open.

Pushed down on the shock, and watched the pressure go up to roughly 150psi. It was fairly difficult to compress, and I couldn't get the full 12" of stroke out of it. Got maybe to 8" or so. Charged it to 200psi, and now I can't get more than about an inch of compression out of it just with my body weight.

I'm not claiming one way or the other, but it at least appears that the nitrogen charge is supporting some of the weight. Maybe it's just a lot more obvious on my overgrown featherweight go-kart of a rig than on the more typical 5,000lb+ rigs?

Went back and forth in my head a lot last night, and decided my wisest choice at this point is to finish building out the front tube work, cage, etc before making a spring swap out, as I'm still really just guessing on what my final chassis weight is going to be. I don't _think_ it's going to go up more than a few hundred pounds at this point, but I figure it's not like I'm gonna be running trails until I finish it all out anyways, so I might as well wait to pick up more springs.

But it's at least close enough on the alignment side of things that I feel fairly confident that I'm not going to have to make major chassis/suspension changes, so I can keep moving forward on it now.

 

[urbex]

Oops..appeared I double posted.

 

[Bebop]

I respectfully disagree. the above quote is from one of the engineers at King Shocks. The nitrogen does not carry load in a coilover, not to be confused with an airshock or strut like an ORI where it does do the work in conjuction with the oil etc.

IDK what to tell you man...

Come down to my shop, I'll give you a bottle of nitrogen and let you play with shocks in real life so you can draw your own conclusions.

Went back and forth in my head a lot last night, and decided my wisest choice at this point is to finish building out the front tube work, cage, etc before making a spring swap out, as I'm still really just guessing on what my final chassis weight is going to be. I don't _think_ it's going to go up more than a few hundred pounds at this point, but I figure it's not like I'm gonna be running trails until I finish it all out anyways, so I might as well wait to pick up more springs.

Smart.
But 95/175 is still a heavy rate for a samurai. Even if it has a cage.

 

[TBItoy]

I respectfully disagree. the above quote is from one of the engineers at King Shocks. The nitrogen does not carry load in a coilover, not to be confused with an airshock or strut like an ORI where it does do the work in conjuction with the oil etc.

Well he was wrong... Pretty hard to argue with volume...

Physics and whatnot.

He was describing the purpose of of the n2 charge in a shock, but if you try to shove a metal rod into sealed container, it WILL increase the the pressure and "push back". An uncharged shock will not push the rod out (extend) on it's own, a charged shock will.

 

[RustyC]

I respectfully disagree. the above quote is from one of the engineers at King Shocks. The nitrogen does not carry load in a coilover, not to be confused with an airshock or strut like an ORI where it does do the work in conjuction with the oil etc.

I disagree with this as well. I have charged shocks from 0 psi/kpa to 200 psi-1378 kpa and the vehicle height will raise.
The King engineer may have been trying to focus on coil-over spring function vs an air shock. I would have had to hear the conversion to agree differently.

 

[Lil ugly]

Not to siderail the OP's thread on his steering issue, but I have run used coil overs, air shocks, and ORIs. The only ones that changed my ride height when charged or not was the air shocks and ORIs. I have never run a light weight rig like a samurai so maybe they react differently to the amount of weight in them, IDK.

 

[urbex]

Smart.
But 95/175 is still a heavy rate for a samurai. Even if it has a cage.

It's not so much that I feel that those springs were the appropriate ones to choose, rather than it came about as a grossly inaccurate guesstimation of what the sprung weight was going to be when I started this build. I read a bunch of posts on various forums of people running 175lb single coils, or something like a 150/175 dual rate coilover, and when I initially did the chassis weight check using the bathroom scale method, I was coming up with roughly 400lbs/corner. I figured by the time the rest of the steel was in, I'd be around 500-600lbs/corner, and the 175lb lower seemed to be in the ballpart.

Then build out enough to drop the chassis on the springs, measure sag to determine true corner weight, and choose the upper based on that...which is how I ended up with the 95lb upper after seeing my then corner weights coming in WAY lower than I expected. Even as it was, the 95/175 ended up with a ride height 2" higher than I wanted, even without having the coilovers charged.

Not to siderail the OP's thread on his steering issue, but I have run used coil overs, air shocks, and ORIs. The only ones that changed my ride height when charged or not was the air shocks and ORIs. I have never run a light weight rig like a samurai so maybe they react differently to the amount of weight in them, IDK.

Siderails are just fine in my book...it appears that this is all related in one way or another anyways. I wouldn't have expected this much of a change from charging them, but then the only point of reference I have other wise is something like common gas charged shocks. They're definitely harder to compress to install, but I've never had them noticeably change ride height. But then, that's also a heck of a lot less volume compared to these coilovers too.

If my last round of math was correct, and I really AM hovering around 250lbs corner weight, I can see where adding another 120lbs of "spring" can make a heck of a difference (I say "spring" in quotes as I realize that it's not really the same as the coils, or an air shock..I just can't think of a better word at the moment, lol). Though the other side of this is that the spring calculators are telling me I going to need something like a 65/95 combo, and the lowest rate coils I've seen so far is 80lb, though an 80 over 80 would get pretty close. That's the other part of why I'm waiting until I finish the build to get springs, considering my last couple rounds of guesstimating future weight have been way off...

 

[Bebop]

Not to siderail the OP's thread on his steering issue, but I have run used coil overs, air shocks, and ORIs. The only ones that changed my ride height when charged or not was the air shocks and ORIs. I have never run a light weight rig like a samurai so maybe they react differently to the amount of weight in them, IDK.

See my post above. It makes a big difference in my 4500lbs buggy.

Then build out enough to drop the chassis on the springs, measure sag to determine true corner weight, and choose the upper based on that...which is how I ended up with the 95lb upper after seeing my then corner weights coming in WAY lower than I expected. Even as it was, the 95/175 ended up with a ride height 2" higher than I wanted, even without having the coilovers charged.

The springs will settle a little bit after you ride some too. But not 3" or so.

 

[87TPIYJ]

I tried to pull the specs for that valve and came up empty handed. What is the CM^3/rev for that valve? How many turns are you getting from lock to lock?

 

[urbex]

I tried to pull the specs for that valve and came up empty handed. What is the CM^3/rev for that valve? How many turns are you getting from lock to lock?

I have the catalog for it around here somewhere....100cm3/6.1ci. Ended up being roughly 2.5 turns lock to lock.

 

[ridered3]

@urbex any luck figuring this out?