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

[PoorMans180SX]

Originally Posted by GripTerror

Well they should offer an aluminum and spherical option... especially when some of us are interseted in extracting maximum performance. I mean correcting geometry is a bigger pro/gain than anything else for the most part... but going back to something that potentially heavier and binding (polyurethane) is not cool. As mmdb said though we COULD make/buy alternatively sphericals as he and I already have... but why not have a product already with that err..

Parts Shop MAX bro.

You just have to wait.

[jholman05]

Someone tell me if this sounds stupid. For the longest time now, I've been wanting to do z32 knuckles, get the stance lower sleeve for the z32's and upgrade my gr+ to gr+ pro, with the addition of the tender or "helper" spring. Also lately I've been wanting to go with the s14 subframe, but find it cumbersome to change my diff cover, find the metal offset bushings, deal with my 17x10 +22 with 275/40/17 being pushed out 5mm (s14 subframe being wider) or whatever and not adding more camber.

Does anyone know if you could carefully cut the s14 front rlca mounts off the s14 subframe, and cut the s13's off and weld the s14 mounts on the s13 subframe? To me this sounds easier than dicking with the entire s14 subframe. Or just welding tabs on myself and not even buy a s14 subframe.

Pros
-So I don't want a wider subframe becuase I'm already close on clearance with the wheels/tires with a roll and pull
-Don't want to buy more expensive offset subframe bushigns
-Have a super clean s13 subframe
-Keep my diff cover
-Keep my exhuast hanger location

Cons
-fabbing the tabs for the rlca

Also what subframe bushings does everyone recommend? I'm looking for most overall grip with little concern about noise or vibration. I've tried mmr-direct but ehh not sure if I like them, I dont think it retained factory anti-squat.

-PSM
-SPL
-Nismo
-MMR
-Oem filled or collared

Sorry if this seems just thrown out there, my mind is scrambled.

[Jonnie Fraz]

Originally Posted by jholman05

Someone tell me if this sounds stupid. For the longest time now, I've been wanting to do z32 knuckles, get the stance lower sleeve for the z32's and upgrade my gr+ to gr+ pro, with the addition of the tender or "helper" spring. Also lately I've been wanting to go with the s14 subframe, but find it cumbersome to change my diff cover, find the metal offset bushings, deal with my 17x10 +22 with 275/40/17 being pushed out 5mm (s14 subframe being wider) or whatever and not adding more camber.

Does anyone know if you could carefully cut the s14 front rlca mounts off the s14 subframe, and cut the s13's off and weld the s14 mounts on the s13 subframe? To me this sounds easier than dicking with the entire s14 subframe. Or just welding tabs on myself and not even buy a s14 subframe.

Pros
-So I don't want a wider subframe becuase I'm already close on clearance with the wheels/tires with a roll and pull
-Don't want to buy more expensive offset subframe bushigns
-Have a super clean s13 subframe
-Keep my diff cover
-Keep my exhuast hanger location

Cons
-fabbing the tabs for the rlca

Also what subframe bushings does everyone recommend? I'm looking for most overall grip with little concern about noise or vibration. I've tried mmr-direct but ehh not sure if I like them, I dont think it retained factory anti-squat.

-PSM
-SPL
-Nismo
-MMR
-Oem filled or collared

Sorry if this seems just thrown out there, my mind is scrambled.

What about Powerd by Max sub frame bushings? How much do they raise the pick up points vrs the s14 subframe? Also cutting and welding on your subframe sounds like a great idea to me.

[ballinnmiami240sx]

you just scrambled mine with that post..lol


If I gather your post correctly you want to make new mounts in the rear subframe to except s14 rlca's on to your s13 subframe but at the same location?

Arnt the rlca's the same. I had them side by side and they are almost identical. One has more metal than the other, but Im pretty sure they mount the same. Please correct me if Im wrong. I just had them at the shop side by side, but didnt actually measure them.

Or are you taking about the RLCA's mounting location at the subframe in refrence to the s14 vs. s13 subframes. I wouldnt dick with the mounting points on the subframe. I just dont really understand your reason.

[ballinnmiami240sx]

Originally Posted by GripTerror

Well they should offer an aluminum and spherical option... especially when some of us are interseted in extracting maximum performance. I mean correcting geometry is a bigger pro/gain than anything else for the most part... but going back to something that potentially heavier and binding (polyurethane) is not cool. As mmdb said though we COULD make/buy alternatively sphericals as he and I already have... but why not have a product already with that err..

And why should it be automatically 'expensive', that sounds stupid. If Nissan could bring both on a factory car, an aftermarket one should be available with little to no difference equally.

At the end of the day all we're getting is the effort of someone else who figured out how to move these points and then cast/forge/put together magically with their choice of metal/material. A. Because alot of us dont have the knowledge B. Don't have the connections.

That being said, just because its aluminum doesnt mean that it should cost automatically more on the price. Think about it... The s13 and z32 spindles are not that different just different material and fork vs bushing type. They are overall the same shit.

So true....things dont have to be expensive. i remember when there where like two people selling knuckle.....$499 + shipping. Alot of us got smart and decided there is no way it could cost that much to cut and reweld something and started making our own sets. Now they are selling at half that price because people caught on. If you are left with one company supplying a product then that company can set any price. I would think if it the product was afforable then you would make more money from quantity alone.

We all agree the rear knuckles need to be modified to correct the geometry, but no one on this board can tell you what ride height they will be running tomorrow. To sale or make a product on what if's will be kind of a waste with out adjustability. I for one run my car super low with the arms facing the sky and still managed to drive the living hell out of my car. Im I going to correct this YES!!! Making a drop spindle would help correct most of the problem.

[jholman05]

Jonnie I was under the impression PBM - PSM were the same company?

Originally Posted by ballinnmiami240sx

Or are you taking about the RLCA's mounting location at the subframe in refrence to the s14 vs. s13 subframes. I wouldnt dick with the mounting points on the subframe. I just dont really understand your reason.

That ^, basically move the rlca mounts on my s13 subframe to match that of an s14.

I come from a mini trucker/air ride back ground. I've chopped my whole frame in half and welded it back together, I think I can handle a couple little mounting tabs. Also I just pretty much totaled the front of my car and I'm in the process of replacing most everything in front of the firewall. I'd post pictures, but I don't want to clutter the thread.

Also I don't care about any rules, I just like to work on stuff. Then see if it had any improvements.

[95KA-Turbo]

If you're going to copy a subframe you might as well copy the S15 subframe, since it's better then the S14 one. I honestly am not sure what makes it better, or even what the differences are between the S13 and S14 rear subframes.

[GripTerror]

the s14 and s15 subframes are identical, to the exception of the fact that the s15 subframes are better/more braced. That is all.

[Jonnie Fraz]

Originally Posted by jholman05

Jonnie I was under the impression PBM - PSM were the same company?



That ^, basically move the rlca mounts on my s13 subframe to match that of an s14.

Correct...They are the same. Sorry, my thought is S13 sub frame vrs S14 sub frame how much higher are the pivot points. The PSM inserts move the subframe up approx .5" how much higher would you want to move it?
If you look at the PSM rear subframe they moved theirs up a bit, I would say like 2" judging by the pics.

[mmdb]

Called Ben over at driftworks. Here's more info passed down:
- the rear spindles do not keep exact stock geometry, but keeps the geometry as close as stock as possible to retain dynamic alignment settings from factory.
- the diameter of the pivot bushings are not the same as stock. This was due to the design changes required to develop the knuckle so no more usage of Def's spherical bearings.
- the front spindle's kingpin angle has changed.
- z32 rear e-brake will be a OK.

[GripTerror]

Eh so never mind def's sphericals all together then..

so did he say if theyll offer a spherical option?

What about the front i am still confused about the whole extra steering angle ordeal, I dont wana drift thatll be a problem when tracking the car lol... well in grip not drift.

They're being a bit slow to respond with all the questions they should have an faq

[mmdb]

Originally Posted by GripTerror

Eh so never mind def's sphericals all together then..

so did he say if theyll offer a spherical option?

What about the front i am still confused about the whole extra steering angle ordeal, I dont wana drift thatll be a problem when tracking the car lol... well in grip not drift.

They're being a bit slow to respond with all the questions they should have an faq

Nope. No spherical options as they thought a large portion of the folks wouldn't want them. I forgot to ask about ackerman for the front spindles... I'll ask whenever they get back to me via email... but like you said... they're pretty damn slow or maybe our emails aren't getting through to their firewall.

[kognition]

It could ruin your day on the track. Too much turn in grip isn't good. Because it's so easy to turn just a couple degrees over and the next thing is you are ice skating in a turn.

Originally Posted by GripTerror

Eh so never mind def's sphericals all together then..

so did he say if theyll offer a spherical option?

What about the front i am still confused about the whole extra steering angle ordeal, I dont wana drift thatll be a problem when tracking the car lol... well in grip not drift.

They're being a bit slow to respond with all the questions they should have an faq

[mmdb]

Originally Posted by kognition

It could ruin your day on the track. Too much turn in grip isn't good. Because it's so easy to turn just a couple degrees over and the next thing is you are ice skating in a turn.

Are you referring to the nature of modifying the roll center so much that it suddenly overloads the tire causing abrupt under and/or oversteer? I noticed that when I added 35mm of adjustment on my gp sports knuckles... Tires did not like it one bit during turn in. Sudden understeer.

[PoorMans180SX]

Originally Posted by GripTerror

And why should it be automatically 'expensive', that sounds stupid. If Nissan could bring both on a factory car, an aftermarket one should be available with little to no difference equally.

I'm sorry, I was thinking of someone CNCing aluminum drop spindles. Clearly this would cost more than making a jig and welding steel plates together.

Originally Posted by jholman05

Does anyone know if you could carefully cut the s14 front rlca mounts off the s14 subframe, and cut the s13's off and weld the s14 mounts on the s13 subframe? To me this sounds easier than dicking with the entire s14 subframe. Or just welding tabs on myself and not even buy a s14 subframe.



Also what subframe bushings does everyone recommend? I'm looking for most overall grip with little concern about noise or vibration. I've tried mmr-direct but ehh not sure if I like them, I dont think it retained factory anti-squat.

Yes, you can modify the S13 subframe to be like a S14 subframe. It's completely safe. What this does is change the squat. The S14 subframe has more squat because of the flatter angle of the LCA. You can actually just modify the S13 subframe, no need to buy an S14 one. However, it may not meet tech in some racing classes.

This is what Parts Shop MAX did on their S13. It's the orange subframe in the first post. They actually moved their pivot points farther up, giving a lot of squat and traction.

Parts Shop MAX and SPL both make great subframe bushings. SPL's can either be set to stock, or made to raise the subframe like the PSM ones do.

Originally Posted by mmdb

- the front spindle's kingpin angle has changed.

For those that don't understand, If you project a line from your top pillowball through to the bottom balljoint, then measure the angle between that line and true vertical. That's your kingpin inclination. Driftworks did this because it helps keep your wheel upright with extreme angles.



On anther subject, the Parts Shop MAX spindle is supposed to be 100% Machined. This means it would be fairly easy to make an aluminum one. There's the aluminum/spherical combo you've been looking for. Maybe I'm misunderstanding, but Here's what Dan said:

Originally Posted by Parts Shop MAX Dan

We are jigging up for some rear knuckles.
Planned features:
~100% machined steel - no casting components
~drop spindle
~pillowball replacements for all bushings
~improved strength
~independent hydrobrake caliper bracket

[jholman05]

Originally Posted by PoorMans180SX

Yes, you can modify the S13 subframe to be like a S14 subframe. It's completely safe. What this does is change the squat. The S14 subframe has more squat because of the flatter angle of the LCA. You can actually just modify the S13 subframe, no need to buy an S14 one. However, it may not meet tech in some racing classes.

This is what Parts Shop MAX did on their S13. It's the orange subframe in the first post. They actually moved their pivot points farther up, giving a lot of squat and traction.

Parts Shop MAX and SPL both make great subframe bushings. SPL's can either be set to stock, or made to raise the subframe like the PSM ones do.

Well that's what I think I'll do then, seems easier to me than with everything else. I'll be ordering either the PSM or SPL subframe bushings soon, as well as the coilover sleeves for the z32 knuckles.

Now can someone post up a few good pictures of the s14 rlca subframe mounts so I can copy them on my s13 subframe? I tried lookin on google images but wasnt getting anything worth a damn.

[ManoNegra]

Originally Posted by PoorMans180SX

I'm sorry, I was thinking of someone CNCing aluminum drop spindles. Clearly this would cost more than making a jig and welding steel plates together.

If you make it a one piece unit, it would be very difficult to machine since it
would most likely require a 5 or 7 axis machine to make them.
I think a modular assembly similar to the griggs one for mustangs is the way to go.
One piece to locate the strut and hub
one piece to locate the brake caliper.
One piece to locate the LCA balljoint and tie rod.

Machining it as a three parts assembly makes it a whole lot easier and would
bring the cost down significantly.
There is also a great deal of freedom in the design:
You need more (or less) roll center correction? Easy, just unbolt the lower part and bolt in a new one.
You want to run Evo, STi or whatever brake caliper without adapter brackets. Sure, just unbolt the stock piece and put a new one.

Yes, you can modify the S13 subframe to be like a S14 subframe. It's completely safe. What this does is change the squat. The S14 subframe has more squat because of the flatter angle of the LCA. You can actually just modify the S13 subframe, no need to buy an S14 one. However, it may not meet tech in some racing classes.

This is what Parts Shop MAX did on their S13. It's the orange subframe in the first post. They actually moved their pivot points farther up, giving a lot of squat and traction.

Parts Shop MAX and SPL both make great subframe bushings. SPL's can either be set to stock, or made to raise the subframe like the PSM ones do.

Best solution I have heard is this:
A set of solid aluminum bushings that raises the subframe,
allows to install S14 subframes into S13
and enhances the geometry, ie: maybe adds some caster, fixes the z32 upright shock binding issue in S14s, etc.

On anther subject, the Parts Shop MAX spindle is supposed to be 100% Machined. This means it would be fairly easy to make an aluminum one. There's the aluminum/spherical combo you've been looking for. Maybe I'm misunderstanding, but Here's what Dan said:

So machined steel parts but still welded on a jig?
My concern about doing it this way with aluminum is that it's difficult to get
good penetration and retain strength with aluminum.
It would require a lot of heat to get good welds and aluminum tends to distort at high temperatures.

[PoorMans180SX]

Originally Posted by jholman05

Now can someone post up a few good pictures of the s14 rlca subframe mounts so I can copy them on my s13 subframe? I tried lookin on google images but wasnt getting anything worth a damn.

Here you go (S15). You can see that the front mounts are lower:

Originally Posted by ManoNegra

If you make it a one piece unit, it would be very difficult to machine since it
would most likely require a 5 or 7 axis machine to make them.
I think a modular assembly similar to the griggs one for mustangs is the way to go.
One piece to locate the strut and hub
one piece to locate the brake caliper.
One piece to locate the LCA balljoint and tie rod

I wasn't even thinking of this. Definitely would be the way to go.

Originally Posted by ManoNegra

So machined steel parts but still welded on a jig?
My concern about doing it this way with aluminum is that it's difficult to get
good penetration and retain strength with aluminum.
It would require a lot of heat to get good welds and aluminum tends to distort at high temperatures.

Ah, this makes more sense.

[ballinnmiami240sx]

ManoNegra hit it on the head. Making something for mass production that will work for everyone would require what he stated. It would allow the nissan community to have something it has never had.

IE.





The advantage of this would be people could buy a knuckle that was aluminum, strong, and adjustable to what ever angle, ackerman, and roll center you wanted. Beleive me that this picture has been in my head for about 6 months now. I dont have access full time to a machine shop, but if I did this would be the first thing i would make.

This griggs front spindle set up it offered to the mustang road racers at a prices of $2999.95. Way more than the 240 owner would ever pay. Why can griggs do this? Well they have patents pending on that desing and are the only ones as far as i know that make something like this for the stang. I passed something like this thru stephen "95ka-turbo's head and my idea was to try to figure a way to have a 6160 billet aluminum boltable tierod piece that we could all use. This will solve bumpsteer issues and have multiple pre lenght outer tierod mounting points for "X" angle.

[ManoNegra]

Originally Posted by PoorMans180SX

I don't know what you mean here. Caster has little affect on the rear suspension, and putting an S14 subframe in an S13 is going to make your Z32 shocks fit worse.

To clarify, a well designed set of solid subframe bushings could possibly correct the problem with Z32 upright/S14 subframe binding that traditionally occurs by altering the location of the subframe.
But only by doing some R&D can we know for certain.

[GripTerror]

^SPL just released offset subframe bushings!

FYI you can fit S14/S15 subframe now into S13:

Our CNC machined T6061 aluminum subframe bushings completely replace the stock bushings to eliminate free play of the subframe relative to the chassis, reducing wheel hop and improving suspension performance. Our new version 2 solid subframe bushings is designed to allow the subframe to sit up to 1/2" closer to the chassis (raising the subframe), which will allow up to 1/2" compensation of roll center for a lowered car.

However raising the subframe will not just change roll center, it will also increase anti-squat. Therefore our subframe bushings include 1/4" slide in shims so you can quickly raise or lower the subframe in minutes, and adjust the roll center and anti-squat behavior to best fit your driving style! Our unique adjustable subframe bushings offer a completely new way to tune the suspension behavior.

Available in standard (S13 subframe onto S13 chassis, or S14/S15 subframe onto S14/S15 chassis) or offset (S14/S15 subframe onto S13 chassis or vice versa).

[ballinnmiami240sx]

outstanding!!!!! spl has always been in the fore front of development. Now someone link Kuah to this thread, so they can start making something.

[longfellow]

Originally Posted by PoorMans180SX

I don't know what you mean here. Caster has little affect on the rear suspension, and putting an S14 subframe in an S13 is going to make your Z32 shocks fit worse.

Caster has a huge affect on the rear suspension. Changing the rear traction rods length greatly affects the camber curve in the rear.

The reason Z32 uprights fit like shit in an S14 is because the shot is alot longer and run at a different angle from the uppeer mount. Z32 and S13 shocks are almost the same length. Changing subframes dosnt really do anything in relation to how the shock mounts.

[PoorMans180SX]

Originally Posted by longfellow

Caster has a huge affect on the rear suspension. Changing the rear traction rods length greatly affects the camber curve in the rear.

The reason Z32 uprights fit like shit in an S14 is because the shot is alot longer and run at a different angle from the uppeer mount. Z32 and S13 shocks are almost the same length. Changing subframes dosnt really do anything in relation to how the shock mounts.

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.

[mmdb]

Some more Driftwork info:
- installation is bolt on affair.
- knuckles are ensured to be very, very strong (I asked cause I wanted to use these on the road)
- offset spacers will be available end of January, 2010
- knuckles were designed with road racing geometry in mind. I understood this as the camber, toe, etc gains/losses remain as OEM as possible
- for road racing usage without the spacers are recommended, drift use the spacers.
- if using them for road racing purposes without the offset spacer, usage of a stock length tie road (inner and outer) maybe not be long enough. Brands such as SPL Parts/Kazama would be preferred.
- the knuckles are currently available.
- ... will post up more as I come across it.

With that said, anyone interested in a set of GP Sport Hyper Knuckles with 20mm spacer adjustments so I can try the Driftworks knuckles out? LMK

[kalypso123]

thread subscribed and bookmarked

[Def]

Originally Posted by mmdb

Some more Driftwork info:
- installation is bolt on affair.
- knuckles are ensured to be very, very strong (I asked cause I wanted to use these on the road)
- offset spacers will be available end of January, 2010
- knuckles were designed with road racing geometry in mind. I understood this as the camber, toe, etc gains/losses remain as OEM as possible
- for road racing usage without the spacers are recommended, drift use the spacers.
- if using them for road racing purposes without the offset spacer, usage of a stock length tie road (inner and outer) maybe not be long enough. Brands such as SPL Parts/Kazama would be preferred.
- the knuckles are currently available.
- ... will post up more as I come across it.

With that said, anyone interested in a set of GP Sport Hyper Knuckles with 20mm spacer adjustments so I can try the Driftworks knuckles out? LMK

So I've just got to ask. Why is everybody wanting geometry to "be like stock?"

The bumpsteer isn't bad in the rear when you lower the car, and there are a couple of ways to get the roll center back up to a reasonable height. Besides, stock geometry via a heavily revised drop spindle with a severely lowered car will probably put the roll center ABOVE the CG - which is something you don't want.

Just wanting to know if there's any real justification behind this other than "I guess stock must be the best."

[kognition]

No, i meant that when you are at certain speed and turning angle going into a corner, that the grip stops gripping, then you are ice skating straight into the gravel. So too much turning angle would not be good, unless you are a pro and can control your reflexes.

Originally Posted by mmdb

Are you referring to the nature of modifying the roll center so much that it suddenly overloads the tire causing abrupt under and/or oversteer? I noticed that when I added 35mm of adjustment on my gp sports knuckles... Tires did not like it one bit during turn in. Sudden understeer.

[mmdb]

That's a good point. Definitely don't want the roll center to be above the CG. I'm personally still bouncing the idea of using driftwork spindles in my head. Without the knowledge of where the true CG is or the RC is then it's pointless to purchase these units. I'll try to get get some measurements done this week to get a general height/location of the roll center this weekend.

In my experience, when I had about 50mm of front adjustment, the roll center was most likely to be TOO high. At the time I was running an 18" wheel with a 265/35 tires on there and I was get SUDDEN understeer during turn in. I remain a bit skeptical of how much roll center adjustment is needed, but the other side of me tells me there's only one way to find out. But of course there's a few steps to get to check whether or not it's needed.

Originally Posted by kognition

No, i meant that when you are at certain speed and turning angle going into a corner, that the grip stops gripping, then you are ice skating straight into the gravel. So too much turning angle would not be good, unless you are a pro and can control your reflexes.

Oh gotcha. Currently, as my car gets closer to the limit the fronts initially scream which is safer rather than have the rear slide out first. At that point it's nice to have adjustable sway bars to tweak and tune the rotation of the car to prevent front from washing out.

[PoorMans180SX]

Original post edited. Let me know if I missed something or said something wrong.