Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum - This is the roll center, suspension pickup, and steering angle modification thread.

- Tech Talk (#/f/forumdisplay.php?f=8)

Everyone has different driving style, most guys also don't run 295s up front anything that can make the front come alive more/be more responsive = welcome. Also I am going with that custom manual steering rack setup from the nico group buy. So faster = win. I think HICAS rack is too slow, the non-hicas sucks ass.

Hicas rack = 2.5 turns lock to lock.

Standard rack = 3 turns lock to lock.

Standard rack + PSM SAK = 2.5 turns lock to lock. (On close hole)

Hicas rack + PSM SAK = 2 turns lock to lock.

295's and a manual rack? Sounds like you're going to be getting a work out.

I work out :squintd: I like my cars manual, standard, raw, not assisted and alpha just like me hahaha jk

poormannn

i have non-hicas rack, and on the close hole, its 1.5 turns bro lololol

Your car is 1.5 turns from all the way left, to all the way right?

OH! NO!

i get a little less than 1.5 each way...

so almost 3 all the way i guess

Hahaha, yeah, that's what "lock to lock" means.

You probably have 1.25 each way, which would be 2.5 "lock to lock". At least that's what PSM says it should be.

The steering response and weight changed drastically when I changed from a 235 to a 255. I cant imagine what a 295 would be like.

Just found this pic. GT300 s15
http://www.gt300.no/images/bilder/7E6_8a.jpg
http://www.gt300.no/images/bilder/EAE_12a.jpg
http://www.gt300.no/images/bilder/943_10a.jpg
http://www.gt300.no/images/bilder/29B_10a.jpg

Coilover mounts on this thing are crazy.

More pics on gt300.no if anyone wants to see more. They have pretty detailed pics of everything on that car.

That's called a pull rod suspension setup. The rod going from the upper a-arm "pulls" on a bellcrank that gives a different motion ratio to the damper. Pretty trick space frame setup up front.

That is absolutely sexual and I spy Bilsteins, no taiwain/china crap HAHA, take that jdm hellaflush fanboys!:fawkd:

Quote:

Originally Posted by SoSideways (Post 3598802)

A lot of those points I have already covered with my reports, so I guess it's true even for arms of different design.

Take note people.

So far, I've noticed 3 definite things that is true between all the different types of FLCA designs:

1) if you are low, the FLCAs have to be quite long to place the ball joint/spherical bearing/rod ends in their optimal range.

2) if you are low, the tie rods themselves have to be pretty long. Tein S-chassis tie rods I know for a fact should be long enough for the job, if you pair them up with the SPL tie rod ends. I think the Ikeya Formula tie rods will be long enough too, from the measurements that Dan gave me awhile back.

3) if you space the FLCAs too much, there will come a point where the arm itself (if it uses a spherical bearing) or the rod end will come into contact with the brake rotor.

4) if you have too much angle, you will hit the tension rods

5) if you have too much angle, you will hit the tie rods, and/or hit the brake caliper bracket in the wheel well and the lip on the frame.

I would state it differently:
1. FLCA needs to be really long after you alter the roll center because the knuckle's LCA mount angle puts the LCA end joint towards the brake rotor.
2. if you reduce the ackerman your tie rod has to be much longer, customers say their tein tie rods dont work with our SAK. Ikeya formula rods are long enough and our new less expensive then ikea rods are very long (and cheaper)
If you pair aftermarket rod ends they better not have any spacers on them, so we just prefer OEM s14 spec.
3. If you space down the LCA knuckle mount using the OEM KPI you cant go more than about 25mm. If you want more, you have to change the KPI angle to be more vertically oriented to clear the brake rotor.
4. If the ackerman is too low you will hit the tension rods.
5. Correct but hitting the wheel on things is easily helped by adding a wheel spacer. (I had to add 20mm on my old setup to accomodate the new angle, and I dont hit the tie rod, or frame, and the brake bracket can be easily moved by using one bolt to mount it.

Quote:

Originally Posted by PoorMans180SX (Post 3598819)

BTW, PSM makes tie rods (inner and outer) now as well.
http://www.gtfactory.jp/cms/e107_fil...0_p1070276.jpg

We dont have them for sale yet but will very soon, thats the pic of the production quality prototype MAX original tie rod we are testing now. Super F'ing long and strong but in a collision situation you are covered because the factory has tested bending them in 180 degrees without breaking and we're going to have a great price on these.

here is view of the rear.
http://www.gtfactory.jp/cms/e107_fil...2_p1070287.jpg
you can see that with our sway bar mounted so high it will keep the maximum ground clearance for the bottom of the link
http://www.gtfactory.jp/cms/e107_fil...2_p1070288.jpg
http://www.gtfactory.jp/cms/e107_fil...2_p1070289.jpg
http://www.gtfactory.jp/cms/e107_fil...2_p1070291.jpg
http://www.gtfactory.jp/cms/e107_fil...2_p1070297.jpg
http://www.gtfactory.jp/cms/e107_fil...2_p1070299.jpg
a view with the car on the ground
http://www.gtfactory.jp/cms/e107_fil...2_p1070308.jpg
and finally the front while on the ground
http://www.gtfactory.jp/cms/e107_fil...2_p1070306.jpg

.........as far as dialing in our parts for grip and setting up the knuckles for only faster steering and not more angle its really no problem at all. We'd be happy to do it that way if you wish, just need to specify your desired use when ordering the knuckle service.

= )

You guys keep using the term kingpin inclination for why the arm runs into the brake rotor. That doesn't really have anything to do with it, since the KPI is an imaginary line from the top strut pivot to the lower ball joint. The ridiculous angle relative to horizontal that the stock uprights have for the ball joint mount is the problem. It's at a far more aggressive angle than the KPI is on a lowered car. Maybe it's closer on a sky high stock S chassis, but I tend to think of that as one of the engineer's goof's on our suspension.

Quote:

Originally Posted by DC Dan MAX USA (Post 3599407)

I would state it differently:
1. FLCA needs to be really long after you alter the roll center because the KPI puts the LCA end joint towards the brake rotor.
2. if you reduce the ackerman your tie rod has to be much longer, customers say their tein tie rods dont work with our SAK. Ikeya formula rods are long enough and our new less expensive then ikea rods are very long (and cheaper)
If you pair aftermarket rod ends they better not have any spacers on them, so we just prefer OEM s14 spec.
3. If you space down the LCA knuckle mount using the OEM KPI you cant go more than about 25mm. If you want more, you have to change the KPI angle to be more vertically oriented to clear the brake rotor.
4. If the ackerman is too low you will hit the tension rods.
5. Correct but hitting the wheel on things is easily helped by adding a wheel spacer. (I had to add 20mm on my old setup to accomodate the new angle, and I dont hit the tie rod, or frame, and the brake bracket can be easily moved by using one bolt to mount it.

We dont have them for sale yet but will very soon, thats the pic of the production quality prototype MAX original tie rod we are testing now. Super F'ing long and strong but in a collision situation you are covered because the factory has tested bending them in 180 degrees without breaking and we're going to have a great price on these.

.........as far as dialing in our parts for grip and setting up the knuckles for only faster steering and not more angle its really no problem at all. We'd be happy to do it that way if you wish, just need to specify your desired use when ordering the knuckle service.

= )

So the question is when can we expect the front and rear arm? And how much? These can be used with standard knuckles?

Quote:

Originally Posted by Def (Post 3599425)

Yeah but the angle on these PBM front arms have a much less severe angle than the stock FLCAs' angle, so I'm sure it will accommodate the lower guys' setup.

I would love to get these PBM arms but I'm quite tapped out and my setup works just fine after I got all the links out of it.

Going to be working on the passenger side all weekend so hopefully I will have a report on these soon for you guys.

Quote:

Originally Posted by Def (Post 3599425)

KPI is an imaginary line from the top strut pivot to the lower ball joint.

http://www.optimumg.com/OptimumGWebS...ges/CD_KPI.jpg
what you described as KPI is the steering axis line?
I dunno what you want to call that taper rod angle (is there a better term?) but im sure you all understand
It looks like it follows the steering axis or KPI angle more or less to me.

I suppose the above statement could be changed to say
1. FLCA needs to be really long after you alter the roll center because the knuckle's LCA mount angle puts the LCA end joint towards the brake rotor.

Quote:

Originally Posted by slider2828 (Post 3599448)

So the question is when can we expect the front and rear arm? And how much? These can be used with standard knuckles?

no one knows till its in production.
yes they can be used with an unmodified knuckle.

I have mad respect for PBM and what they are doing, they are developing parts that will benefit us all. I felt the same when Kuah was on the frontline of putting out quality products, but since seeing this stuff from PBM I am sold. I mean at first I was like meh more shiney jdm parts... but this... this is something else :)

My other concern I'd like to address is scrub radius, as I have mucho grande low offset/wide front wheels...

Overall all this is quite promising woohoo

i love this thread so much but at the same time i hate it cuz im broke

btw im looking for someone than can do me a favor. for my S13, looking for someone to fab front and rear control arms wit 3/4 spherical bearing.

PM me priced shipped. if you have some extra arms laying around that way i dont have to send mine. like what i said im broke so if you know what i mean and help a brotha out.

Quote:

Originally Posted by PoorMans180SX (Post 3598942)

It's a damn shame converting a Mustang performance rack isn't so easy :( Trust me, I've tried :(

Quote:

Originally Posted by GripTerror (Post 3599692)

Unfortunately you just can't do much with the scrub radius on our cars. I've got some adjustability in the front uprights I'm designing that increases/decreases the scrub radius about 3/8", and that's a pretty big change on the upright/upper strut mount to achieve that. Just hard to change the angle that much with keeping everything else the same.

Quote:

Originally Posted by PoorMans180SX (Post 3598942)

Oh and the group buy cnc manual rack will have 2.4 lock to lock but it's a whole other ball game, no slush fluid, completely sealed unit. There is also a drift option for more angle (ha ha ha, you guys want to fly backwards moore angle everywheeere) and any lock to lock, ratio can be chosen. According to the thread info the rx7 guys were happy with the 2.4 lock to lock option hence the choice.

Also depending on how things go, I might opt for the column mounted EPS option, also available from the same company. They've put it together. It won't destroy feel or anything and it's speed sensitive, so only when needed will it become active and can be turned off. Shouldn't decrease any of the quality of feedback, control, precision. Again totally different ball game than slush fluid.

This should be fun hehe. I'll only need a steering wheel like this lmao, who wants to turn pshhh :D:

http://www.virtualr.net/wp-content/g...151/wheel3.jpg

Then all I'll need is an electronic differential lool

Quote:

Originally Posted by Def (Post 3599859)

Hmm, it's a bish on our cars to run wide tires, lucky the stang and vette guys. However I'm not giving up :D How will you achieve this? Any diagrams or prototypes yet of your design? These are exciting times for 240 owners :)

I'm putting inserts in the upper strut hole mount.

^Cool

And this is a nice link!:

Wheel Alignment Explained

I was reading it and it kind of opens my eyes a bit but I am still trying to fully understand what will be the better or ideal setting with larger tires with a lower offset on our cars.

From what I understood running more negative camber from the upper strut mount would alter the scrub radius, and then of course lower or higher offset... and adjusting camber from the LCA/spindle?

Dan, the parts look really good. Are you on 18's up front? Looks like you have room for the 25mm shank as far as the wheel goes?

And for the rear, it doesn't look like you're going to be able to combine the drop knuckles with the 25mm adjuster lower shanks eh? Pretty close to the wheel already.

time for 19" rears lol

Quote:

Originally Posted by Def (Post 3599859)

I can't wait for you to get these done; waiting patientlly

Quote:

Originally Posted by cheeky14 (Post 3600859)

I can't wait for you to get these done; waiting patientlly

They're 95% designed. I've just slowed down on it as I don't know if there's much of a market there. But I guess I'm almost done, so I might as well finish it up.

BTW - projected weight savings in just the upright is about 4-5 lbs(need a more firm weight on the hub I'm using to nail it down).

Is is still going to be a combo with a FLCA, or just the knuckle/hub combo?

it's a complete front kit he's putting together everything has to be changed in order to be adjustable/modular/etc... stock lcas are a fail

i learned a lot from this