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

[jaysgottaredtop]

i recently got done with my LCA/knuckle combo (based on Def's how-to). i used knuckles which were professionally cut and TIG'd for greater steering angle. i drilled out the knuckle to 3/4" and used shims totalling ≈1.7" (≈42mm) of roll center correction. i also drilled out the tie rod pickup point to 5/8" to use a heim joint and fine tune it's drop down distance (aka bumpsteer correction) with various collars and washers. the final product looks nice and made LOTS of angle compared to stock.

the only down side is the shorter pickup point on the knuckle gives less steering leverage, making it very hard for me to steer without power steering. sooooo i converted back to stock LCAs and knuckles for the time being. i may convert back to power steering later, we'll see.

in the meantime, if someone wants to buy this setup (modded LCA's, modded s13 knuckles, outer tie rods, and all the nuts/bolts/spacers/shims/etc), PM me. i'd consider selling it all as a complete bolt-in setup and just sticking with the simplicity of my stock stuff for now.







i wish i had taken a pic when everything was installed. lotsss of angle! haha

[Motary]

Wow they dont even look modified!

I dont get overcentering right now because it is running stock caster but I do need to relocate the steering rack because it will definately overcenter once I have solved the clearence issues

Originally Posted by frifox

i30 ones are 35mm longer than s14 tie rods, which in turn are longer than s13 tie rods by 10mm (?).

The s14 has longer lower control arms so it should also have longer tie rods, but they could have just made outer ones longer too

[jaysgottaredtop]

Originally Posted by Motary

Wow they dont even look modified!

yeah, the shop did a crazy clean job of welding and grinding to make the knuckle look damn near OEM!

[Jonnie Fraz]

Originally Posted by Motary

Wow they dont even look modified!

I dont get overcentering right now because it is running stock caster but I do need to relocate the steering rack because it will definately overcenter once I have solved the clearence issues




The s14 has longer lower control arms so it should also have longer tie rods, but they could have just made outer ones longer too

Top is Z32
Bottom is S14

[Matej]

Originally Posted by jaysgottaredtop

the only down side is the shorter pickup point on the knuckle gives less steering leverage, making it very hard for me to steer without power steering. sooooo i converted back to stock LCAs and knuckles for the time being. i may convert back to power steering later, we'll see.

Have you attempted using the knuckles with stock S13/S14 LCA's?
While the shorter pickup probably did make steering a bit more difficult, if you ran a lot of negative camber thanks to those adjustable LCA's, that may have been the main culprit.

[jaysgottaredtop]

^ i tried driving around with the LCAs adjusted to roughly s14ish length. not crazy amounts of camber and toe was zeroed out. simply too hard to turn a tight corner without that leverage on the knuckle and without power steering to assist.

[Matej]

Good to know. Guess I will keep my knuckles stock for now.

[Motary]

I installed inner tie rods from that of Nissan Maxima A32, they are the same as I30. They are much longer than X-trail ones but still I have 10mm of thread engagement so I am planning to fit a rack spacer. Have any of you had problems with offset rack spacers? Removing the front crossmember seems a bit pain

I also adjusted my camber plates to max negative camber with min. caster ( rotated them toward inside), tyre looks quite flat on the ground

[STR8E180]

Originally Posted by PerilousActs

What is this from? Details?

Any reason to use those knuckles over the z32/r32 style like MotoIQ has been doing on the old XS Engineering long a-arm setup?

its the MCA time attack car from Australia

[swiftmini]

Originally Posted by Motary

I installed inner tie rods from that of Nissan Maxima A32, they are the same as I30. They are much longer than X-trail ones but still I have 10mm of thread engagement so I am planning to fit a rack spacer. Have any of you had problems with offset rack spacers? Removing the front crossmember seems a bit pain

I also adjusted my camber plates to max negative camber with min. caster ( rotated them toward inside), tyre looks quite flat on the ground

why not just make some longer?

[Motary]

It was a question of time which I didnt have. I am moving my car home back to my personal workshop, keeping it with me in the city is useless because the garage is about half a meter of space to both sides lol

Adding a spacer will also increase rack travel but I have to make a custom lower control arm and I am unsure how to proceed.

Picture of ride height and arm position:

Before:



After:





Maybe make an arm like Nigel's

[CamryOnBronze]

Alright, so here's the scoop. I installed Megan Racing roll center adjusters all around on my car a while back, basically just as a replacement for the ball joints (since I know that they do nothing to actually correct roll center.) I've decided to do something about that, and purchased some Ikeya Formula front LCAs for the car to help with the roll center and keeping the arms level to the ground.

I had hoped to score a set of Ikeya Formula RLCA, but I lost out on that deal. I am now in the market for some PBM RLCAs to correct roll center, but for another reason as well. My rear wheels that I recently had rebuilt are a bit too aggressive for my tastes, so I am planning to have the back pad shaved down 5mm to get closer to the look I want. However, I am not sure that will be enough.

I emailed PBM and found that the track width with their arms can be adjusted up to 10% in from stock (7mm), or up to 90% out (wider) from stock. If I were to adjust my rear track width inward 7mm with these arms, this would reduce the rear camber I have to run to clear the fender, correct? I found a similar situation on Joel of C's Garage's car, where they shortened his RLCA to remove some negative camber:



My other question is: I need to run different tie rod ends, such as SPL, in addtion to the Ikeya FLCA that adjust roll center, correct?

Appreciate any insight- I've done my research and am in the process of doing some more, but I would love to hear some experienced opinions.

[Motary]

1) yes
2) You need to run Ikeya tie rods aswell, psm ones for pro kit are quite similar, perhaps those could work

[SicBastard]

Motary, what kind of joint is Nigel using on the front LCA where the tension rod bolts to it?

[PoorMans180SX]

Originally Posted by CamryOnBronze

Alright, so here's the scoop. I installed Megan Racing roll center adjusters all around on my car a while back, basically just as a replacement for the ball joints (since I know that they do nothing to actually correct roll center.) I've decided to do something about that, and purchased some Ikeya Formula front LCAs for the car to help with the roll center and keeping the arms level to the ground.

I had hoped to score a set of Ikeya Formula RLCA, but I lost out on that deal. I am now in the market for some PBM RLCAs to correct roll center.

PSM rear control arms don't actually adjust roll center, because you don't really want to do it with the lower arm anyway. You'd either want to get PSM/SPL subframe risers, or their rear knuckle, although for your setup just the risers should be fine, as you're not correcting that much in the front.

[thefro526]

Originally Posted by PoorMans180SX

PSM rear control arms don't actually adjust roll center, because you don't really want to do it with the lower arm anyway. You'd either want to get PSM/SPL subframe risers, or their rear knuckle, although for your setup just the risers should be fine, as you're not correcting that much in the front.

This.

Though, the arms do come with a little (5mm?) spacer to correct a bit.

[DJPimpFlex]

What benefit would there be to a narrower rear track besides fitting wheels? How would that effect the suspension's travel? I heard a rumor that some of the top level guys have their rear track narrower than stock and I can't wrap my head around why that would be better.

[Matej]

It mainly has to do with how narrow the rear track is in proportion to how wide the front is, I believe. I know I have read an article a long time ago claiming that the narrower the rear track, the better the car will drift. Unfortunately I do not remember any of the technical explanations, just said conclusion.

That is why more and more drift cars are looking like this.

[Lutz Performance]

I would think that have a smaller rear track would help the car to swing around.

It should be the same as it is on road racing applications. great front track helps to rotate the car, so maybe they are using that instead of adding rear toe in.

ex b: more mechanical grip, so you dont have to run as big of a tire up front (i believe)

[CamryOnBronze]

Originally Posted by PoorMans180SX

PSM rear control arms don't actually adjust roll center, because you don't really want to do it with the lower arm anyway. You'd either want to get PSM/SPL subframe risers, or their rear knuckle, although for your setup just the risers should be fine, as you're not correcting that much in the front.

Wow, really? The shank on their rear lower arms looks a ton longer than the factory ball joints. Maybe I am just seeing things? The reason for my concern is that Ikeya Formula recommends running their front and rear arms together, and says you should not run only the front or only the rear. However, I do have the PBM risers out back right now, so maybe that is enough to allow me to run the Ikeya front arms alone?

Regardless, I have decided to just have the wheels modified for now, and not mess with the rear lower arm at this time. Appreciate the info and insight guys- lots of great info in here.

[thefro526]

Originally Posted by Lutz Performance

ex b: more mechanical grip, so you dont have to run as big of a tire up front (i believe)

That initiation was so weird. I can't tell if he just under-steered a ton or what, looks like his car is setup really awkwardly.

[PoorMans180SX]

Originally Posted by DJPimpFlex

What benefit would there be to a narrower rear track besides fitting wheels? How would that effect the suspension's travel? I heard a rumor that some of the top level guys have their rear track narrower than stock and I can't wrap my head around why that would be better.

It's all a big compromise depending on what you want to do or how you want the car to drive. A wider front track gives more front end lateral grip and a narrower rear does the opposite basically. Since lateral grip doesn't matter so much when you're drifting, they can shorten the track to help the car initiate.

Shortening the rear lower arms helps with dynamic camber change a little as well, at least if you don't have much roll center correction.

Originally Posted by Lutz Performance

I would think that have a smaller rear track would help the car to swing around.

It should be the same as it is on road racing applications. great front track helps to rotate the car, so maybe they are using that instead of adding rear toe in.

ex b: more mechanical grip, so you dont have to run as big of a tire up front (i believe)

Well, rear toe in is generally for more forward bite on suspension compression, and that car doesn't look like it actually has much front grip, he's throttle steering after initiation for sure. He just knows his car really well.

Originally Posted by CamryOnBronze

Wow, really? The shank on their rear lower arms looks a ton longer than the factory ball joints. Maybe I am just seeing things? The reason for my concern is that Ikeya Formula recommends running their front and rear arms together, and says you should not run only the front or only the rear. However, I do have the PBM risers out back right now, so maybe that is enough to allow me to run the Ikeya front arms alone?

Regardless, I have decided to just have the wheels modified for now, and not mess with the rear lower arm at this time. Appreciate the info and insight guys- lots of great info in here.

Yes, you'll be just fine with the risers in the rear and Ikeya's up front.

Originally Posted by thefro526

That initiation was so weird. I can't tell if he just under-steered a ton or what, looks like his car is setup really awkwardly.

Yeah man, that car looks like it would be kinda sketchy to drive unless you were doing backwards entries all the time. I'm guessing the car is setup so that it has both massive understeer and oversteer, which tends to happen when you go to extremes like that.

Also, his steering is probably so quick that he can turn the wheel that far in with a flick of the wrist probably.

Definitely looks cool, hahah. Like I said above, it's all in what you want the car to do.

[IsBettyBish]

Originally Posted by thefro526

That initiation was so weird. I can't tell if he just under-steered a ton or what, looks like his car is setup really awkwardly.

That looks like a shallow faint initiation. I see it all the time here in Japan. Especially in street drifting where the roads are narrow. That shit looks Boss to me.

[brainfood]

I think it has a lot to do with his narrow ass tires and toe out. Probably running such narrow wheels and tires and spaced so far out to get that much angle.

[240sxr]

ok so, i'm going to get an alignment

i have D-max coil overs,extended LCAs,maxima/i35 tie rods,and PBM SAK

im going to use my coils to adjust caster and the LCAs to set camber,

its mainly a drift car,with little street use,any tips on how should i set my caster,camber and toe


thx

[thefro526]

Originally Posted by IsBettyBish

That looks like a shallow faint initiation. I see it all the time here in Japan. Especially in street drifting where the roads are narrow. That shit looks Boss to me.

You're totally right.

I think what messed my head up was the bit of understeer on turn in combined with the amount of body roll he had. I'm used to cars that are way stiffer than that.

That car really make me want to reconsider my whole love of wide wheels up front, that thing looks like it has a tonne of angle and probably just has hammered fenderwells.

[Motary]

by the way, Poorman, do you sometimes update the front page? It would be quite beneficial to make a list of mods to improve roll centers, camber curves and max steering locks and perhaps use my graph of rc mod effectiveness so people would know how to improve their suspension spending a reasonable amount of money

[PoorMans180SX]

Yes, I really need to edit the first two posts. The info is quite outdated now. I'll try and get around to that next week when I have a few days off.

[Lutz Performance]

Does anyone have some spare bumper steer correction endlinks for sale?

looking to replace the ones on my hatch, but oem stuff wont cut it for more than 3-4 months

[travypoo]

Originally Posted by 240sxr

ok so, i'm going to get an alignment

i have D-max coil overs,extended LCAs,maxima/i35 tie rods,and PBM SAK

im going to use my coils to adjust caster and the LCAs to set camber,

its mainly a drift car,with little street use,any tips on how should i set my caster,camber and toe


thx

i like slight toe out up front (1/8 or less), -4.5 camber, 7 caster. rear i do 1/4 inch toe in, -0.4 camber