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

[longfellow]

Originally Posted by PoorMans180SX

Deleted that post. Don't know what I was thinking.

I'm thinking about doing some serious editing to the first posts to include more technical information on the front and rear suspension.

Again, thanks to everyone who is contributing, I think we have some awesome stuff going on here, and I'm definitely enjoying the learning!

I PMed Kuah the link to this thread.

Haha no worries, if you get the S13 and S14 FSM's go into the body section and it will give you measurements for the chassis itself and I think it might cover the subframes but I cant remember. That kinda helps in relation to over geometry for the chassis and suspension.

I know from experience about the S14/Z32 set up because its on my car right now. I kinda regret doing it and sadly I tossed my stock uprights. For an S14 its not really worth the effort unless you can cut the shock mount off and relocate it so it dosnt sit at such a terrible angle. I've already torn my Nismo shock bushing. Spherical bearing would help some but the mounting bracket for the coil-over actually hits the upright and there isnt much you can do about it.

So I suggest to people with S14's to not do Z32 uprights unless you want to figure out how to re-work the mounts.

[Def]

Originally Posted by longfellow

Haha no worries, if you get the S13 and S14 FSM's go into the body section and it will give you measurements for the chassis itself and I think it might cover the subframes but I cant remember. That kinda helps in relation to over geometry for the chassis and suspension.

I know from experience about the S14/Z32 set up because its on my car right now. I kinda regret doing it and sadly I tossed my stock uprights. For an S14 its not really worth the effort unless you can cut the shock mount off and relocate it so it dosnt sit at such a terrible angle. I've already torn my Nismo shock bushing. Spherical bearing would help some but the mounting bracket for the coil-over actually hits the upright and there isnt much you can do about it.

So I suggest to people with S14's to not do Z32 uprights unless you want to figure out how to re-work the mounts.

You just need some slight clearancing of the shock mount on the upright with spherical bearings to keep from getting contact from what I hear.

[longfellow]

With any type of rubber bushing thats pretty much out of the question, I had to grind down part of my shock mount and the coilover bracket to get it to where it wouldnt hit. Also the lower the car is the worse the angle gets.

I was hoping the Sphericals would make the difference. But I'm not going to find out first hand because there a better solution. KW V3's

On a new note, Is there any measurements that would be a good idea to take when I shave my subframe bushings? I plan on bring the subframe pretty much directly to the frame with maybe a 1/16" shim. I also plan on making a few shims in difference sizes so I can raise and lower the subframe up to 1/2 like the SPL kit.

[nissankat]

^^ The sphericals will not solve the problem. I was running the spl sphericals in the z32 knuckles on my s14 and they would still bind under compression. They actually bent the mounts on the bottom of the coilovers and caused one of the shocks to blow. My car handled so much better after getting rid of the z32 knuckles and eliminating the bind.

[ballinnmiami240sx]

I just installed a set of these on a buddies car and the z32 rear to shock mount is horrible. It does weight a ton less!!!!!

[GripTerror]

Basically the bottom line benefit of running z32 spindle IS weight loss and that's 8lbs PER corner. Which is frickin awesome. Imagine people bickering about wheels weighing 1lb up and down... put that into perspective.

[95KA-Turbo]

Yeah, when I get the car moving I am going to get the rear shock mount cut and welded so it will be at the right angle when I get the toe arm mount corrected.

[Def]

Originally Posted by nissankat

^^ The sphericals will not solve the problem. I was running the spl sphericals in the z32 knuckles on my s14 and they would still bind under compression. They actually bent the mounts on the bottom of the coilovers and caused one of the shocks to blow. My car handled so much better after getting rid of the z32 knuckles and eliminating the bind.

They need a smaller diameter misalignment bushing, and then some clearancing on the spindle.

You save a little over 6 lbs per side going with Z32 rear spindles over stock iron ones.

[GripTerror]

i believe when i had it on scale it was 8lbs.. but whatever 6-8... either way incredible unsprung savings !

[longfellow]

Originally Posted by GripTerror

Basically the bottom line benefit of running z32 spindle IS weight loss and that's 8lbs PER corner. Which is frickin awesome. Imagine people bickering about wheels weighing 1lb up and down... put that into perspective.

Wheels create centrifical inertia, 1lb extra rotating is alot different than 1lb going up and down a few inch's. So saveing 1lb per wheel is a huge gain. It affects the suspension movement, gearing, braking and turning. Which is alot more to consider.

So put that into perspective.

And I restate that if you have an S14 its not worth the aggervation to run Z32 uprights. I plan on switching back to stock uprights as soon as I can find some.

[Def]

Originally Posted by GripTerror

i believe when i had it on scale it was 8lbs.. but whatever 6-8... either way incredible unsprung savings !

I saw about 6.7 lbs, but yea, it's quite a bit when you multiply that by two.

Unsprung weight is unsprung weight. Yea, it might not rotate, but it's pretty damn big.

[longfellow]

I'd rather spend the money on shocks that work then uprights that dont.

KW V3's have changed my mind about how I want my suspension set up. And you cant run them with Z32 uprights.

[GripTerror]

So basically is it going to present the same problem on an s13 that has an s14 subframe and z32 spindle?

[Steve Lloyd]

It shouldn't. The Z32 and S13 have the same shock length, so the angle is essentially the same between the Z32 and S13(at least from what I've read). Adding the subframe will only shorten the travel length(if you use the bushings to set the subframe against the chassis)

The S14 shocks are longer and that's what creates the slight binding......

[longfellow]

What steve said. Though I said the exact same thing on the last page.

I'll take a picture tomarrow and post it to show you just how bad it is. The lower you go the worse it gets.

[Def]

Originally Posted by GripTerror

So basically is it going to present the same problem on an s13 that has an s14 subframe and z32 spindle?

S14s have a weird angle with Z32 spindles due to position of the top shock mounting. An S13/Z32 are roughly the same with shock mounting, and changing the subframe from S13 to S14 doesn't affect this at all.

In short - it's fine. I run Z32 spindles with an S14 rear subframe in an S13 and the misalignment is almost zero.

[GripTerror]

Oooh okay, so its about the strut tower placing... interesting. Well that clears that up. Thanks for sharing that.

Hmm... does the position of the shock have any other effects? Anyone ever wonder that (if at all). Like in the front moving the shock mount backwards would be like running positive caster.. just a random thought that befell me now that you mention that... or whichever way the shock is mounted for that matter.

[white92_s13]

ok so i had a chance to modify some corolla knuckles!






these were a test set we made. boxed lower control arms, and cut stock p/s knuckles. we didnt go to crazy short, but by the way they came out they should provide good angle!

also we did measure both sides and made them equal, and we heated the knuckles red hot, beveled the 2 pieces and fully welded it. Had a Professional welder do the work!

[ballinnmiami240sx]

The knuckles dont need to be red hot. They should be heated to about 400* and then you can start welding. So I was told. Look good.





Driver Steve angerman when he was running my knuckles.

[longfellow]

Originally Posted by GripTerror

Oooh okay, so its about the strut tower placing... interesting. Well that clears that up. Thanks for sharing that.

Hmm... does the position of the shock have any other effects? Anyone ever wonder that (if at all). Like in the front moving the shock mount backwards would be like running positive caster.. just a random thought that befell me now that you mention that... or whichever way the shock is mounted for that matter.

Rear caster is controlled mostly by the traction arm (thats why it points forward). As far as I can tell its the only arm that will allow for any sort of forward/backward adjustment.

The reason why the front shock can change castor angle is because its bolted to the entire top of the upright with only the LCA and Tie rod for other attactment locations. So when you move the top of the shock forwards/backwards it moves the entire upright forwards or backwards with it.

The rear upright is a 5 link set up and has 4 arms bolted to it along with the shock, so changing the position of the top mount wont do very much especially since its on the bottom and towards the back. Thats why the top of the rear shocks just piviot in place using a spherical bearing instead of running a camber plate.

[EDacIouSX]

Originally Posted by s0apgun

you definitely don't need to modify suspension pick up points or steering angle or even give a shit about roll center to do drifting

90% of the people looking to do these mods still don't have the driver skill to require them

so true, cause i know i don't have the skill. but then again do you want to learn how to play basketball with a flat basketball or a basketball that's inflated... but then you can always argue that you can learn how to play with a worn out inflated basketball oh well i guess my point fails haha.

[KA24DESOneThree]

Originally Posted by PoorMans180SX

In the aftermarket arms catagory; SPL adjustable front and rear lower control arms:
[snip]
In my opinion, these are the best parts for the money. There are a myriad of choices though, including Ikeya Formula (Megan Racing makes knock-off ones), Battle version, Driftworks, Orange Tree, etc, etc.
[snip]

Good post.

The last picture is one I took of my car a couple years ago. I still had FNs, stock uprights and stock rear brakes back then, heh.

I have the SPL FLCAs and RLCAs. They were never fully set up; I had an idea of what I was doing but never measured all the pickups for optimum setup. Now they're all worn out and feel wiggly.

In my opinion, as someone who has run on them, they're OK. They require some initial modification to fit (mostly clearancing holes for tension rod studs and end link brackets) and are relatively cheaply made.

My gripe with nearly everything available in the aftermarket is that they use crappy spherical bearings and rod ends. These arms are no exception; while the bearings are good for a while, all it takes is a few thousand miles and they're toast. I understand that the parts are manufactured for racing purposes and really aren't meant for daily driving use (I think I have about 15k or so on mine), but just by looking at the housing you can tell the bearings are junk. To be fair, if SPL had them made they'd actually be worth a damn.

Can I outdrive these parts? No, but they give me a level of adjustability (should I choose to use it ) and purpose that's hard to argue with. The clarity of the chassis' intent is why I installed them... the car telegraphs what it likes and doesn't like so much better without any play.

Damn youse guys, now I want to go play with the Nissan even though I have a broken BMW and a Miata with an exhaust manifold leak. Maybe I should just say "fuck politics, I'm picking up Chassis Engineering again."

I've been out of the game for so long, I don't know where to pick up again. The car just sits in the parking lot at work and gets driven maybe 20 miles every two weeks, but life finally caught up with the bank account and I can't spend what's necessary on the car.

[PoorMans180SX]

Originally Posted by KA24DESOneThree

Good post.


In my opinion, as someone who has run on them, they're OK. They require some initial modification to fit (mostly clearancing holes for tension rod studs and end link brackets) and are relatively cheaply made.

My gripe with nearly everything available in the aftermarket is that they use crappy spherical bearings and rod ends. These arms are no exception; while the bearings are good for a while, all it takes is a few thousand miles and they're toast. I understand that the parts are manufactured for racing purposes and really aren't meant for daily driving use (I think I have about 15k or so on mine), but just by looking at the housing you can tell the bearings are junk. To be fair, if SPL had them made they'd actually be worth a damn.

Strange, I thought SPL uses QA1 rod ends? Maybe not on their lower arms?

Also, Kuah PMed me and said that he's thinking about putting some serious R&D into drop knuckles, because there is so much interest (aka this thread).

[95KA-Turbo]

I was under the impression the SPL LCAs were just rebranded 'JDM' pieces, much like their version 1 arms were. I cannot find the link to the Japanese page that uses the same picture.

I know all of the new version arms from SPL are completely done in house. I am sure the sale of the LCAs has not been as good as the basic alignment arms so I wouldn't be surprised - nor would I blame Kuah for not doing his own version of them.

[KA24DESOneThree]

All of SPL's own parts are the business. High quality throughout, and they use very nice QA1 rod ends that have lasted quite a long time (and have been very precise) on a "street" car. That's why I said "if SPL had them made, they'd actually be worth a damn."

Kuah and the team are committed to producing quality products, and I support them 100%. They've been nothing but an asset to the community; without them I wouldn't be where I am today, mod-wise.

Some of the stuff they import and sell, though, doesn't have the same thought and quality they put toward their own parts. It's a shame, but at the same time high quality adjustable LCAs are expensive to develop and R&D, so I cannot blame them. There are only a few people who see the point in spending huge amounts of money on control arms.

Kuah has corrected me on this before, and I think I've got it right that the LCAs they sell are Nams.

[PoorMans180SX]

Ah, that makes sense. Well maybe with all this renewed interest in the good stuff, he'll develop something new.

PSM is also supposed to be developing their own lower control arms eventually.

[GripTerror]

its about time spl came up with their own solution to these things other than the NAMS arms which imo are way too overpriced like wth

[longfellow]

I wonder how hard it'd be to make drop spindles like these:



These are made by LG Motorsports for C5 vettes. I think with enough practice on my Milling machine I could make something like that. I might give it a go over summer when I have more time. Not saying they'd be perfect but I think I could make something that works well enough.

[GripTerror]

Do it

Actually I was just looking at drop spindles from some race site yesterday I think it was for DSMs... they were making many applications... what a fool... i forgot to bookmark it... i should still have it in my history on the computer at work. I am sure if there was enough interest we could have some made by a variety of people.

I really think SPL should jump on this... it would make s chassis cars one step up for sure... plus z32 would benefit and a number of other nissan/inifiniti cars.

[longfellow]

I'd like to see some one make them as well. I need to track down some front uprights so I can take measurements. Might make a trip out to the junk yard this weekend.

Time to brush up on my solidworks as well.