Originally Posted by PoorMans180SX (Post 3209841)

They were talking about the URAS ones, which are a different design and less quality.

Driftworks designed theirs to be better.

I'll quote:

Originally Posted by Def (Post 3210092)

It doesn't matter how much "better" they design the materials, that part still puts the steering rack into bending when it wasn't designed to handle that(inner tie rods pivot, and it doesn't locate the front spindle at all, so no bending). The rack might handle it for a bit, but I imagine the seals aren't up for that kind of beating.

Originally Posted by mmdb (Post 3210838)

Another FYI (sorry i know). I'm using the GP Sports Hyper knuckle right now, and because it spaces the lower control arm and the spindle it added a bit of negative camber. It's likely that during compression the front suspension cambers inward, and by fixing the roll center it's added much negative camber. This could take a toll if your camber plates are out of adjustment which doesn't allow you to run less negative camber. Currently I'm stuck running 1.8' negative camber and out of adjustment.

Originally Posted by Sport Compact Car

On MacPherson strut-equipped cars, the wheel will gain negative camber under roll as long as the lower control arm is positioned less than 90 degrees relative to the strut axis. Unfortunately, many enthusiasts with MacPherson strut-equipped cars lower their cars too much and make this angle greater than 90 degrees. Beyond 90 degrees, the suspension will gain positive camber instead of negative as it compresses, significantly compromising grip

http://i24.photobucket.com/albums/c2...iondiagram.jpg

Originally Posted by PoorMans180SX (Post 3210912)

Found this in a Sport Compact Car article:



I don't know why it would be a problem, as gaining negative camber in a corner is good. Do you mean if you have already adjusted your camber plates to run a lot of negative camber, then correct your roll center, your car will run too much camber in corners?

Originally Posted by white92_s13 (Post 3210649)

MY idea.....?
take a stock knuckle off. take a pre measured chunck out. not much. and then heat it with a torch and weld it back together. shortening the knuckle with increase the leverage and gain more angle?

Originally Posted by Jonnie Fraz (Post 3210943)

This is a great graphic! I remember reading this series in SCC back before the mag went to shit.
This also explains why I have seen some of these super low cars running retarded front camber. That would also get the angle below 90.
I like changing the pick-up points better, but to each is own. Please keep filling this thread with great info.
One thing that I keep thinking about is with suspention set-ups as stiff as have been discussed earlier what kind of compession travel are we talking about?

Originally Posted by VIPDRFT (Post 3211106)

I stumbled upon this. They make knuckles that look like the Driftworks ones. Flame away.

Originally Posted by VIPDRFT (Post 3211106)

I stumbled upon this. They make knuckles that look like the Driftworks ones. Flame away.

Originally Posted by 95KA-Turbo (Post 3211692)

I have a friend stationed in the UK, I don't see why he couldn't get the spindles shipped to him, then ship them out through the base USPS and get very reasonable rates on shipping.

Originally Posted by 95KA-Turbo (Post 3212158)

No, at most those give 1/3-1/2 inch of adjustment.

The only ones that actually do anything are the top of the line Moonface ones....IMO 1/2 inch of adjustment isn't worth 450 bucks.

Originally Posted by d0pe240 (Post 3212183)

yeh they didnt look long enough, like how your setup is. how much do you think your set up cost, just for the roll center adjusters?

Originally Posted by articdragon192 (Post 3212278)

Pardon my ignorance, but what does overcentering mean? And why is it bad?

Originally Posted by 95KA-Turbo (Post 3212324)

That will give you an alignment.

Tie rods adjust toe, but if you space them down to be flat you'll correct bump steer.
Tension rods adjust caster
RUCAs adjust rear camber
Toe rods....adjust toe out back, haha.


The only way to adjust the roll center is to modify the ball joints on the LCAs.

Originally Posted by 95KA-Turbo (Post 3212352)

The BEST thing to do would be to buy a modified spindle to correct the roll center some, while making the geometry of the other arms proper as well AND buying an adjustable LCA so you can control everything.

I am pretty sure the ikeya arms don't adjust enough for a completely slammed car without some other form of adjustment as well.

Originally Posted by udon! (Post 3212434)

fuck this is compricated.


what about this:

Ikeya Formula - Roll Center Adjuster Pillow Lower Arms Kit - Nengun Performance

Originally Posted by PoorMans180SX (Post 3212467)

Those are just adjustable lower control arms. Those will give you probably 15mm of roll center correction. On a slammed car, a new RCA knuckle is needed. This is why there's so much excitement over the Driftworks and PSM knuckles.

Originally Posted by udon! (Post 3212469)

wait are you talking about the pbm super angle kit?

Originally Posted by GripTerror (Post 3212620)

you know this thread makes me happy.. not just that we're finally getting more readily available solutions to fix our screwed up geometry but... the fact that zilvia is asking about suspension geometry and not slamming their car LOL :D

My only concern is getting rid of polyurethane or getting them to make spherical bearings version. As well as having the option for a z32 spindle for those of us that run z32 fork style shocks in the back.

Originally Posted by 95KA-Turbo (Post 3212619)

Those can't be Z33 rear uprights. They don't even remotely look like that and don't remotely have the same suspension set up as a S chassis car.

Z33:

http://www.meganracing.com/uploadIma...DSC04985x8.jpg

http://img.mudah.my/images/75/7503669951.jpg

vs

S15:

http://www.dragsport.com/issue/2008/...1108/s15-3.jpg

You can see the same hump in the above picture that the modified spindle has on it. They just cut/welded on the stock S-chassis spindles.


This is what I want to do:

http://www.dragsport.com/issue/2007/...0707/s15-5.jpg

Which is another S15 time attack car, they are just using Z32 uprights.

Originally Posted by PoorMans180SX (Post 3212562)

Have any shots of the whole rear setup?

Since all the arms are JIC, I'm going to guess the JIC/Hankook S15?

If that's true, I'm stoked to find out more details if you have them. That car is amazing! Probably my biggest single piece of inspiration.

Originally Posted by kognition (Post 3212792)

The car is no longer here in the states, i think it is in Australia or back in Japan.
http://kognitiondesign.com/rear-left.jpg

Originally Posted by GripTerror (Post 3212743)

You know we can wait for driftworks' response to all our concerns.

Then again PBM/PSM will have it stateside no doubt AND with spherical bearings (screw polyurethane... i dont want any bushings/binding/whatever in my track car).

Originally Posted by PoorMans180SX (Post 3212536)

My bad, I should have specified. The PSM REAR drop knuckles/spindles that they are making.

Happy New Year!

Originally Posted by udon! (Post 3212912)

oh ok, so do you use the super angle kit and the rear knuckles?

what do you use for the front

Originally Posted by SoSideways (Post 3212918)

The fronts aren't roll center corrected.

They are mainly made for more angle without using aftermarket tie rod ends like the SPL Parts tie rod ends.

Originally Posted by PoorMans180SX (Post 3212932)

Yeah Udon, PSM's front knuckles are not roll center adjusting. They just adjust for bump steer (tie rods).

That's why everyone is in for the Driftworks. Look on the first post. See how the hubs are moved up in the front knuckles (towards the shock mounting bolt holes)?

Originally Posted by roboticnissan (Post 3212968)

so you would put the driftworks knuckles above the psm ones becuz they adjust for roll center?? and with the psm front knuckles you will get increased bump steer with out other suspension like tie rods???

Originally Posted by Toadstool (Post 3213001)

Originally Posted by Teknolust72 (Post 3213022)

My friend was the race mechanic for the JIC S15 last year, and he mentioned they also raised their entire steering rack by drilling out new position holes for the steering rack brackets.

Originally Posted by Jonnie Fraz (Post 3213162)

Formula D Rules, etc, etc.

Originally Posted by PoorMans180SX (Post 3213366)

Well, looks like I won't ever be competing in Forumula D. Oh well, I never did like FD.

I can see the modification thing, but no strengthening? I think that's kinda stupid.

Made some changes to the OG post.

Originally Posted by Jonnie Fraz (Post 3213454)

I hear ya! I am really not following the re-enforcing the subframe rule.
Tons of people out there running modded subframes, as well as the S14 subframe in the S13 chassis or s15 subframe in the S14.
Now the rules do state that you can get an exception from Formula D, but the pick up points can not be moved more than an inch.

Originally Posted by PoorMans180SX (Post 3213457)

Hahaha, so how does that make sense? The pickup points can't be modified, but then they can?

Pretty dumb.

Clearly the front pickups were modified on the JIC S15. They must have got an exception.

Originally Posted by PoorMans180SX (Post 3212932)

Yeah Udon, PSM's front knuckles are not roll center adjusting. They just adjust for bump steer (tie rods).

That's why everyone is in for the Driftworks. Look on the first post. See how the hubs are moved up in the front knuckles (towards the shock mounting bolt holes)?

Originally Posted by udon! (Post 3213533)

GOT IT! so basically if youre car is fucking slammed with driftworks or psm knucklesyou may not have perfect roll center, but its going to be ALOT better than stock knuckles because on the driftworks/psm knuckles the part that hooks up to the links is much lower than stock.

is that right?

Originally Posted by udon! (Post 3213541)

how does a tension rod work?
how does a traction rod work?

can you guys show me pics of these installed?

Originally Posted by PDM Racing

Adjustable TC Rods are crucial to increase positive caster on Nissans. Caster is a very good alignment quality to induce into your Nissan, as this allows you to reduce your static camber more, yet when the car turns in, negative camber will increase which generates higher cornering ability. Translation: less inner tire wear when the car is driving in a straight line which is over 85% of the time, yet when it comes time to corner, your car will have enough caster to create good negative camber to make your car feel like it’s cornering on rails. Also, having adjustable caster means you can equalize caster from left to right on your Nissan to maximize turning performance both left and right. (On our Hunter computerized alignment rack, we notice it’s common to see 240SX’s with left to right caster specs out by as much as 1.5 degrees. Some are from curbing accidents, others are off-balance straight from Nissan Japan!) By adding adjustable TC Rods, you ensure your car will corner equally fast turning left, or turning right.

The TC Rod is the ONLY arm that locates the bottom control arm on the 240SX. When a car is under severe braking from 100 mph, the force on that TC Rod is the most extreme force that any single suspension component will experience. So replacing the stock TC Rod bushings with a spherical bearing, will ensure under braking your front end will not shimmy or wander as caster and toe will change from the TC Rod bushing flexing back and forth. For example, many of our 300ZX customers complain of brake shimmy and thinking the rotor is the culprit, they have their rotors turned. Most often, the culprit is a worn OEM TC Rod bushing which is a viscous filled rubber membrane, which is good for comfort and compliance, but makes for a terrible locator for an arm that sees such severe duty. Over time, the stock outer membrane wears from repeated force, heat and oils. Quite often we see cars come into our shop with completely blown-open TC Rod bushings.

Originally Posted by PDM Racing

The forward traction link arms locate the rear spindle assembly, and controls the forward and aft movement of the rear upper suspension assembly on independent rear suspension (IRS) cars as the suspension moves through its’ engineered movement. While the stock stamped steel arms works fine for most applications, it’s when you drastically lower the car for race or drift, that there needs to be arm adjustment for setting the rear bump steer.

Bump steer, in short, is the change in toe settings a suspension has as it moves through it’s compression and rebound cycles. Nissan Engineers designed toe in under compression which is safer than toe out, but for optimum settings, racers like to have control of bump steer to dial in the amount of toe change their race cars will encounter as it goes over bumps and dips on the course. Cars that are “nervous” or “twitchy” are often ones that have bad bump steer, so the car literally steers itself as the car goes into a bump. While not as critical as the rear toe links or upper rear control arms, Battle Version Rear Forward Traction Link Arms will complete your rear suspension by positively locating the rear spindle for very minimal rear suspension for and aft flex. For those that know how to plot your rear bump steer, this allows these racers to properly set up the rear suspension to their personal tastes.

Originally Posted by udon! (Post 3213621)

yaya. thats pretty much the last n00b shiz i didnt really know about. kinda was embarrassed to ask...

Originally Posted by PerilousActs (Post 3213627)

Does anyone have any books on suspension to recommend? This could be nice for us suspension noobs to learn from. :) Maybe websites covering the basics?

Originally Posted by PoorMans180SX (Post 3213457)

Hahaha, so how does that make sense? The pickup points can't be modified, but then they can?

Pretty dumb.

Clearly the front pickups were modified on the JIC S15. They must have got an exception.

Originally Posted by PerilousActs (Post 3213627)

Does anyone have any books on suspension to recommend? This could be nice for us suspension noobs to learn from. :) Maybe websites covering the basics?

Originally Posted by Jonnie Fraz (Post 3214110)

More Formula D rules

Originally Posted by Jonnie Fraz (Post 3214110)

Like Mike said the rules last year were allowing modification of the pick up points. It was like 1.5" in all directions if I remember correctly.

The new exception rule states:
8.3.8 Provisions for vehicles with Vehicle Identification numbers 0-129
Competition vehicles with VID numbers 0-129 can opt for exemption from
sections 8.1.1.1, 8.3.1, 8.3.2, 8.3.3, and 8.3.4.
In such case the following is true:
• Previously approved modifications of the firewall, subframe and
transmission tunnel, as indicted in the vehicles technical record are
allowed.
• Suspension pick-up points may be moved to within 1” of the OEM
location
• Stock hubs must be used.
“Pre 130” vehicles wishing not to use the 8.3.8 exemption must request a
new VID.

As for the member modification...The way I am interpeting it is that the sub frame may be modified, but can not be compleatly cut in in half, as to retain stock dimentions side to side.
For instance this sub frame...
http://dangdrifters.com/images/dang%20sub.jpg
would be illegal since it had been cut compleatly into three parts and welded back together, but if you did not cut the front plane and just cut out the rack mounting and moved it, then it would be legal.
The only reason I can figure that they went with this is to keep competitors from widening the pick up points.

Originally Posted by Toadstool (Post 3214521)

This is 1 piece I cut the center out and moved it... so it would be "legal" as f last years rules... I think. its sectioned. not fully cut. FYI

Originally Posted by Def (Post 3215645)

That's similar to an E36/E46 rear suspension(BMW) - most of those guys just raise up the subframe as much as possible and call it good in the rear.

In our cars, the roll center doesn't drop as quickly in the rear as the front, so a huge amount of correction is not needed back there like the front.