This is the roll center, suspension pickup, and steering angle modification thread.

[ka-titties]

Originally Posted by Def

Well, not like next week. But I've modeled the front suspension's geometry. It's every bit as bad as you'd suspect from just looking at it. Started designing the bits, then I've got to do a stress analysis on everything, then get the bits machined/plated etc. etc. Long process to make something that's not some Chinese ripoff of an existing piece, so patience young one... haha

someone enjoyed dynamic systems in college... lol. i'm more of a thermal fluids person myself.

[Tearlessj]

Originally Posted by Jonnie Fraz

Def never goes into anything without figuring it out first. I can only imagine how nice this is going to be.
Is this what you are looking to do?


More pics here
Patience young grasshopper....when you can snatch the ball joint then you will truly ready.

My friend and I are going to attempt to make these this summer. He has made some for a few open wheel karts before, so it shouldn't be too difficult.

I'll let you guys know how it goes.

[!Zar!]

Originally Posted by SoSideways

Well, if I would have known the SPL Parts bits spaced almost 2", I wouldn't have spent the money on making my own stuff.

Way to go internet, for providing insight into a common product that everyone seem to have bought!

Doesn't Kuah suggest not using max correction because it places too much stress on the shank though?

[GunmetalSR]

Originally Posted by S14DB

$ 1,995

ewwwwwww my testicles jus twisted when i read this....ahh well the price for amazing quality
now someone make something like this for the s14 or ill end up ordering driftworks spindles

[SoSideways]

Originally Posted by !Zar!

Doesn't Kuah suggest not using max correction because it places too much stress on the shank though?

I think he was talking about the steering arm on the knuckle, but he could be talking about the shank too.

I'm using a grade 8 bolt there, which is quite near the type of shank he is providing in his current version of the tie rod ends in terms of tensile strength (IIRC his shanks are rated at 160ksi and the grade 8 bolt is rated at 150ksi), and also the bolt is a bit bigger around where it goes through the knuckle, as there is no taper.

So really... the only way to find out is just to go on track and beat the shit out of these to see how they hold up.

Originally Posted by GunmetalSR

ewwwwwww my testicles jus twisted when i read this....ahh well the price for amazing quality
now someone make something like this for the s14 or ill end up ordering driftworks spindles

$1995 is not that bad for a pair of modular CNC'd aluminum knuckle, actually.

Have you seen some of the stuff for the Mustangs and Corvettes? Talk about expensive...

[GunmetalSR]

Originally Posted by SoSideways

$1995 is not that bad for a pair of modular CNC'd aluminum knuckle, actually.

Have you seen some of the stuff for the Mustangs and Corvettes? Talk about expensive...

nah but i guess ill do some more research and check this out...

[[email protected]]

Originally Posted by Pandapants

Thank you. Those 2 spacers per end, they're .25" each right? Is 2 the maximum you can fit per end?

As Nieko mentioned, there are 3 spacers provided, 1 thick cone shaped spacer that is 0.75" thick, and 2 thin spacers that are 0.25" thick each.

Originally Posted by SoSideways

I think he was talking about the steering arm on the knuckle, but he could be talking about the shank too.

I'm using a grade 8 bolt there, which is quite near the type of shank he is providing in his current version of the tie rod ends in terms of tensile strength (IIRC his shanks are rated at 160ksi and the grade 8 bolt is rated at 150ksi), and also the bolt is a bit bigger around where it goes through the knuckle, as there is no taper.

Our shanks are heat treated 9310 alloy, and are rated at 190ksi. In addition to the tensile strength, the 9310 alloy is chosen for its impact strength over 4XXX alloys.

The maximum stress occurs when the tie rod end hits the lower arm, that amount of torque about the pivot can be enormous when the car slams into full lock (when drifting), or when the car hits a bump/dip at full lock.

[atutt]

Originally Posted by GunmetalSR

ewwwwwww my testicles jus twisted when i read this....ahh well the price for amazing quality
now someone make something like this for the s14 or ill end up ordering driftworks spindles

I'm slowly, but surely, working on something for the S14. Along with all it's supporting arms and what not.
Unfortunately having a full time job, as well as doing chassis work on the side doesn't leave me with as much time as I'd like.

I'm hoping to have everything ready by winter. As, everything will be getting track tested this year.
I won't be doing the testing. Some with MUCh more experience then me will be doing the testing, lol

[95KA-Turbo]

Originally Posted by SoSideways

Well, if I would have known the SPL Parts bits spaced almost 2", I wouldn't have spent the money on making my own stuff.

Way to go internet, for providing insight into a common product that everyone seem to have bought!



And yes, I am fucking pissed off, because after spending so much fucking money into this setup, I might as well make it work.

2" of spacing, ladies and gentlemen, seem to be impossible, because of the stock ball joint angle, aka the KPI.

This past weekend, I basically spend a better part of 4 hours going over everything I did up front, and making all sorts of combination of adjustments to try and make things work.

Everytime, it comes down to either the spherical bearing binding up on the FLCA, or the spherical bearing up top on the camber plate binding up.

And just so everyone is clear, I've just been messing with the driver's side front suspension, that way when everything is sorted on this side, I can just do it once on the passenger side and be done with it.

I have taken the spring off of the coilover up front, and the only thing I put back on so I could bolt the knuckle back on is the lower bracket, not even a collar to lock it down, because I wanted the whole coilover to pivot with the knuckle with the least amount of force so I could see how things are doing without using much effort, as I had to keep putting the wheel on and jacking the suspension up, then turn the wheel left and right, etc.

The end result is that, either the spacer on the FLCA spherical bearing runs into the bearing mounting cup (that has been opened up via a stepped drill to 1-3/8" and chamfered) when rotated back, as if you're trying to make a left turn, or it doesn't bind at the spherical bearing part, but the nut that holds the camber plate to the coilover binds/bottoms out on the bearing cup up at the camber plate.

I've tried to put the tension rod above and below the FLCA so that the FLCA would be tilted differently to allow for a little more wiggle room at the spherical bearing, but mounting the tension rod on the bottom, and thus rotating the FLCA back a little bit seem to give more room for the spherical bearing to rotate front to back than mounting the tension rod on top will do.

I should also mention that, this whole process has been done with the 3/4" nut tightened by hand on the knuckle, on the count that I was trying different amount of spacing by ways of using shims and washers.

I also played with the FLCA length to see if it would give me a little more breathing room at the spherical bearing, due to the shittastic ball joint angle, and thus far, it seems the longer the lower arm is, the more centered the bolt/spacers will be within the bearing cup when it's at operating height.

I'm honestly so exhausted and tired with this whole setup, and have spent so much money on it for it to not work, that I am about to commit myself into a mental institute, because quite honestly, I just don't see this setup working.

Before anyone says, "what about aftermarket knuckles like the MA Motorsports Awesometron 5000 knuckles?"

I already thought of that, and while yes, those will be awesome with the tie rods being in play, I am having issues of binding at the FLCA without even involving the tie rod!!!!

Which means, even with those knuckles, it will bind at the same exact spot.

All because of the massive KPI angle.

Quite honestly, I just don't see this setup working. At least not with the ride height that I wanted to have, which is to barely tuck the tread on some 215/40/17 tires up front, or actually, soon to be 245/35/17s up front.

And yes, I've even tried to use less spacing than 2", and it still binded at the spherical bearing. Actually, binded much worse.

Which brings me to question just how exactly was it possible for guys with stock FLCAs and stock tie rods to slam their cars and not break anything, much less for everything to still work?

Granted, I've inspected the stock front suspension components left when I took everything off, and everything was busted. Both inner tie rods were busted and loose at the ball joints, and the outter tie rod ends were also busted at the ball joints. The stock FLCA ball joints were loose as well.



I don't know.

At this point, I am really, really, REALLY DISAPPOINTED in how this didn't work out.

Unless I'm missing something obvious that I am not seeing because I'm pretty much tunnel visioned on this whole thing.

Anyone else got any ideas?

I know it will not do you any good with the spindles you have now, but switching to a 5/8" bolt...or the tapered shank I am using...you can run 3/4 to 5/8 misalignment spacers, which will give you more room before it binds.

I have to put my misalignment spacers in before I can see if they'll bind (it doesn't look like it will), but aside from building some flat control arms I don't see how you could avoid the binding you're experiencing with your set up.

[PoorMans180SX]

Originally Posted by SoSideways

2" of spacing, ladies and gentlemen, seem to be impossible, because of the stock ball joint angle, aka the KPI.

Sucks to hear that man. I know how much of a bummer that must be to have put all that work in and have it not turn out well.

Has anyone thought of chopping up some Z32 rears and moving the center hub part up? I know it would involve making a jig and adding some extra aluminum here and there, but it seems possible to me. You could make everything smooth afterwards and probably be just as strong as stock.

I mean, have you seen all the stress raising edges and casting lines on those things?

[Def]

Originally Posted by PoorMans180SX

Sucks to hear that man. I know how much of a bummer that must be to have put all that work in and have it not turn out well.

Has anyone thought of chopping up some Z32 rears and moving the center hub part up? I know it would involve making a jig and adding some extra aluminum here and there, but it seems possible to me. You could make everything smooth afterwards and probably be just as strong as stock.

I mean, have you seen all the stress raising edges and casting lines on those things?

You could do that, but with all that effort it'd be easier to just make some new ones really.

Honestly, the rear roll center isn't a huge deal unless you're really low. I think some RLCA are the most that need to be used to help move that up some beyond some bushings which bring the subframe up to the chassis of the car like SPL v2's.

[PoorMans180SX]

Originally Posted by Def

You could do that, but with all that effort it'd be easier to just make some new ones really.

Honestly, the rear roll center isn't a huge deal unless you're really low. I think some RLCA are the most that need to be used to help move that up some beyond some bushings which bring the subframe up to the chassis of the car like SPL v2's.

Man, as much as I trust what you say, it's hard to believe. Say I tuck tire on 17's or 18's. The control arms are at pretty intense angles. At that point, don't you need more correction?

[mmdb]

Originally Posted by PoorMans180SX

Man, as much as I trust what you say, it's hard to believe. Say I tuck tire on 17's or 18's. The control arms are at pretty intense angles. At that point, don't you need more correction?

I think he's just saying he'll get around to it after he gets the fronts done. I do think the rears are gonna be harder to do since it adds more pickup points and hub spacing issues. I'd figure he'd just use the DW ones as a template... j/k!

Since I've used the Moonface roll center adjusters, the GP Sports hyper spindles, and now the DW front spindles without the rear spindles at the time, I would foresee the rears being needed. Having only the front modification vastly improves stability by eliminating much roll, which ultimately enhances driver confidence, but at a price. I noticed how quickly the fronts were loaded. At the limit the fronts would wash out, but upon corner exit the rear would slide out. Now following with the rear roll center adjustment, I felt the car held higher cornering G's and upon corner exit the car held very well as I was able to power out of the corner much harder. Having the fronts is great, but also having that important balance is priceless. If not now, I figure someone (DEF) will make one in the future. Just my thoughts.

[Def]

Originally Posted by PoorMans180SX

Man, as much as I trust what you say, it's hard to believe. Say I tuck tire on 17's or 18's. The control arms are at pretty intense angles. At that point, don't you need more correction?

I have zero gap between my stock fenders and 255/40-17s. With SPL v2 subframe bushings and no spacers I have about parallel, maybe slightly upward(going inwards) angled RLCA.

If you're going to go another inch lower or so(don't see how you can realistically go much lower and still have your car handle worth a crap), then some RLCA can help correct the roll center some. Maybe rear uprights have some benefit, but the problem isn't NEAR as big as the front, as the roll center probably drops at about half the rate when lowering the car(rear vs. front).

The rear is a bit more complex as well, as I don't buy just making things "stock but raised up some" is the right way to do it. It'd probably be more extensive machining, so more expensive than a set of fronts as well... I do think some RLCA might be an option in the future.

Just not thinking it's a big deal for our cars.

[PoorMans180SX]

Originally Posted by Def

I have zero gap between my stock fenders and 255/40-17s. With SPL v2 subframe bushings and no spacers I have about parallel, maybe slightly upward(going inwards) angled RLCA.

If you're going to go another inch lower or so(don't see how you can realistically go much lower and still have your car handle worth a crap), then some RLCA can help correct the roll center some. Maybe rear uprights have some benefit, but the problem isn't NEAR as big as the front, as the roll center probably drops at about half the rate when lowering the car(rear vs. front).

The rear is a bit more complex as well, as I don't buy just making things "stock but raised up some" is the right way to do it. It'd probably be more extensive machining, so more expensive than a set of fronts as well... I do think some RLCA might be an option in the future.

Just not thinking it's a big deal for our cars.

That makes sense. Sometime I would like to see where the actual roll centers and centers of gravity are so that the the mass axis and roll axis could be compared, but we've already discussed how time-consuming this is. Maybe someday I will get to it, or someone else.

[Def]

Originally Posted by Jonnie Fraz

Def never goes into anything without figuring it out first. I can only imagine how nice this is going to be.
Is this what you are looking to do?


More pics here
Patience young grasshopper....when you can snatch the ball joint then you will truly ready.

Similar.. but better. That tie rod mounting bracket is a total POS.

[Gnnr]

Wiisass should come chime in this thread. He's also a suspension guru and engineer if I'm not mistaken.

[Def]

Originally Posted by drftwerks

1/65867586758
not bad.

What does it matter what everybody else is.

What are your credentials if you're going to come in here and start shit?

I'm guessing you're just another hard parker based on your tone, but I'd love to be proven wrong.

So what can you bring to the discussion?

[PoorMans180SX]

Originally Posted by Gnnr

Wiisass should come chime in this thread. He's also a suspension guru and engineer if I'm not mistaken.

Oh yeah, I haven't seen him post around here in forever. Someone who knows where he is should link him in.

[Def]

Originally Posted by OptionZero

def, should I get SPL tie rods and ends, or do i wait to give you money

My crystal ball says waiting is a good idea if you want to correct your front geometry to any large extent.

[atutt]

Originally Posted by PoorMans180SX

Sucks to hear that man. I know how much of a bummer that must be to have put all that work in and have it not turn out well.

Has anyone thought of chopping up some Z32 rears and moving the center hub part up? I know it would involve making a jig and adding some extra aluminum here and there, but it seems possible to me. You could make everything smooth afterwards and probably be just as strong as stock.

I mean, have you seen all the stress raising edges and casting lines on those things?

The issue with that is, if I understand what you mean correctly. Aluminum isn't like steels. Where the weld is more often stronger than the parent material. Aluminum is usually slightly weaker or as strong as the parent material.
The problem with is you've likely just created additional stress points. And should the weld not be clean or there is a fault in the weld.
It would almost split right down the centre.

It would probably be a better idea to use a set of iron knuckles if you wanted to do that.

[SoSideways]

Originally Posted by [email protected]

As Nieko mentioned, there are 3 spacers provided, 1 thick cone shaped spacer that is 0.75" thick, and 2 thin spacers that are 0.25" thick each.



Our shanks are heat treated 9310 alloy, and are rated at 190ksi. In addition to the tensile strength, the 9310 alloy is chosen for its impact strength over 4XXX alloys.

The maximum stress occurs when the tie rod end hits the lower arm, that amount of torque about the pivot can be enormous when the car slams into full lock (when drifting), or when the car hits a bump/dip at full lock.

Thanks for clearing that up Kuah!

And honestly, if I had known all this to begin with, I probably would have just bought your tie rod ends to begin with and not worried about making my own for the extra spacing, since my goal of 2" could have been done without spending the extra money I did spend on making these and now am going through the headaches of making it all work.

Originally Posted by 95KA-Turbo

I know it will not do you any good with the spindles you have now, but switching to a 5/8" bolt...or the tapered shank I am using...you can run 3/4 to 5/8 misalignment spacers, which will give you more room before it binds.

I have to put my misalignment spacers in before I can see if they'll bind (it doesn't look like it will), but aside from building some flat control arms I don't see how you could avoid the binding you're experiencing with your set up.

Well, since I'm using some of those shims on the bottom to keep the bolt head away from the bearing mount cup, which acts as a misalignment spacer of sorts (thanks for suggesting that Def!).

At the top, it's just the 1.25" DOM tubing on top of the bearing, then the machined down GS spacer, which is machined down to .75" or so, for a total of 2" of spacing.

When the spacer binds onto the bearing cup, the shims on the bottom also bottom out on the C-Clip, so basically, it binds top and bottom.

Now, again, I haven't tightened everything down, so for all I know, there might be a chance that the bearing would rotate within the cup itself when everything is tightened down, giving me that extra little bit of rotation, although it is unlikely.

Last night was a bit busy so I didn't get to work on the car (had a BBQ w/ the wife instead, after modifying my grill for more airflow so the charcoal don't die out after like 5 minutes of lighting it initially lol), but tonight should be a little better for me, time wise.

Just got the shims from McMaster yesterday, so I'll be able to play with the spacing some more on these arms.

[Jonnie Fraz]

Originally Posted by Def

Similar.. but better. That tie rod mounting bracket is a total POS.

I am sure somthing awesome will be comming our way! Ok I am not sure this has been covered, so forgive my question if it has.

Why are the spindle and the ball joint mount not perpendicular to one another like they are in the MSI upright? I know we are comparing Nissan to Subaru, but it seems that when we start lowering the cars the angle becomes more apparent. I guess it is the kingpin inclination angle (KIA) that I am refering to. I do understand that we need some for high speed stability, but I have never seen it addressed by any aftermarket companies with either arms, knuckles or both. Maybe it is way too complex to start monkeying around with.

[SoSideways]

Which upright/ball joint mount are you referring to Jonnie?

[Jonnie Fraz]

If you look at the pics of the Subaru /MSI upright the lower ball joint seems to be perpendicular to spindle. On the other hand the S chassis uprights the spindle is not perpendicular to ball joint or am I mistaken?

[SoSideways]

On the S-Chassis, at least with the stock lower arm and stock knuckles (spindles, uprights, etc., whatever you wanna call it ), the ball joint is mounted to the knuckles in a perpendicular way.

It's just that on the S-chassis knuckles, the section where the ball joint mounts to the knuckle is on an angle to accommodate for the ball joint, which is mounted on the angled part of the lower arm.

Did I answer your question or did I still miss something?

[Razi]

I think his question is why it is like that, and why it's not like the Subaru's.

[SoSideways]

You're gonna have to ask Nissan that.

But I'm guessing it has to do with the huge KPI angle that Nissan was going for, which really hampers things when you start lowering the car and the such.

[Jonnie Fraz]

Originally Posted by Razi

I think his question is why it is like that, and why it's not like the Subaru's.

Exactly! I am wondering first why the massive KIA? What is the benifit? and Why if we are inclined to lower our cars that the aftermarket has not gone with a lower KIA through adjusted knuckles and lower control arms?

[SoSideways]

I think the high KPI angle and the caster help to give the negative camber when the wheel is turned in, and positive camber when the wheel is turned out.

Other than that, I can't really think of a reason why there would be such a high KPI angle.