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-   -   This is the roll center, suspension pickup, and steering angle modification thread. (#/f/showthread.php?t=296725)

xpertsnowcarver 04-26-2010 12:46 PM

In regards to the DriftWorks knuckles for the front and rear, would they be suitable for road racing? I apologize if this has been answered. There is just such an overwelming amount of awesome in here that I just want to make sure that I am understanding correctly.

I understand that the pivot points between the FLCA and Tie Rod are closer, causing the inner facing wheel (pointing towards inner radius of a corner) to have more angle inward than the outer wheel. (As much as 5deg difference.)

I believe, since I do not have my roll centers modified, that my outer wheel has more angle inward than my inner wheel. (Really bad right?)

Is having the inner wheel with more angle inward more beneficial for road racing? I'm picturing my car in a corner, accounting for the weight of the vehicle on the outside, and it seems that I would benefit. I just want to confirm that I am thinking correctly.

Or, would I incorporate the Offset Rack Spacers they make so that the directions of the wheel are identical?

Lastly, would combining the DriftWorks knuckles with Moonface roll center adjusters be overkill?

SicBastard 04-26-2010 12:46 PM

So you're dropping the tie rod link, but not raising the spindle? I understand that half of these knuckles are for drifting, but a little extra effort for the better camber curves would help entry speed.

xpertsnowcarver 04-26-2010 12:50 PM

^^Who me?? No. I want everything to be symmetric and ideal for road racing.

SicBastard 04-26-2010 01:04 PM

no, in response to kpr and billspear

SoSideways 04-26-2010 02:07 PM

Those guys are basically just cutting up the stock knuckles and rewelding them with the arms that the tie rods bolt up to being shorter and with a "flatter" angle, thus allowing the knuckles to be able to spin around more before they touch the FLCA as the tie rods pull them in.

Because of that, there is just not enough material to cut up and reweld on the back side where the FLCAs would bolt up to, thus not able to add any roll center correction in that sense.

To correct roll center with stock or stock-like knuckles, the most cost effective way to do it would be to do what Def did and modify Godpseed FLCAs and do it up that way.

Or you could take out the stock ball joints in your stock FLCAs and weld in spherical bearing cups and put spherical bearings there, then use a 3/4" bolt in place of the ball joint or the tapered stud. Makes life a million times easier.

Then all you'd have to worry about at that point would be the tie rod ends.

ManoNegra 04-26-2010 11:35 PM

Quote:

Originally Posted by xpertsnowcarver (Post 3412552)
In regards to the DriftWorks knuckles for the front and rear, would they be suitable for road racing? I apologize if this has been answered. There is just such an overwelming amount of awesome in here that I just want to make sure that I am understanding correctly.

Or, would I incorporate the Offset Rack Spacers they make so that the directions of the wheel are identical?

They were *cough* 'developed' *cough* for drifting but do address roll center
Jimmy mostly tracks his car so he would be the best person to ask
once his knuckles are done
on that note, Mike started making the one-off bushings for them
I'll try post up some pics tomorrow

Joel, stay away from those rack spacers, that's some scary shit

aren't you an engineer? Design me a structurally sound modular aluminum upright
kind of like the ones on the Sierra Sierra Time Attack Evo
and I'll be your best friend :bow:

http://photos.motoiq.com/MotoIQ/Feat...2_2TLxp-X2.jpg

mmdb 04-27-2010 12:02 AM

Quote:

Originally Posted by xpertsnowcarver (Post 3412552)
In regards to the DriftWorks knuckles for the front and rear, would they be suitable for road racing? I apologize if this has been answered. There is just such an overwelming amount of awesome in here that I just want to make sure that I am understanding correctly.

I would highly recommend a roll center adjuster similar to what the Driftwork spindles achieves. I like them a lot (front only right now) not only because they add a sharper feel with much, much less roll, but also because the steering arm was modified. THis decreases the steering ratio which I found beneficial during turn in (arms aren't crossed up) and during oversteer correction (fast steering ratio helps a lot with reaction).


Quote:

Originally Posted by xpertsnowcarver (Post 3412552)
Lastly, would combining the DriftWorks knuckles with Moonface roll center adjusters be overkill?

The amount of correction the Driftworks knuckles is plenty. Addition of the Moonface roll center adjuster is overkill. BUt doesn't hurt to try if you're curious, just your wallet.

ManoNegra 04-27-2010 08:13 AM

The first of the custom bushings for the Driftworks rear knuckles

http://img132.imageshack.us/img132/7...mbushing01.jpg

http://img132.imageshack.us/img132/7...mbushing02.jpg

http://img297.imageshack.us/img297/5...mbushing03.jpg

SicBastard 04-27-2010 08:52 AM

Are the driftworks rear knuckles made out of aluminum?

longfellow 04-27-2010 09:02 AM

No they're steel.

GripTerror 04-27-2010 09:11 AM

With the light rekindled, engineers jump in and make stuff for us :)

xpertsnowcarver 04-27-2010 09:55 AM

Quote:

Originally Posted by ManoNegra (Post 3413709)
They were *cough* 'developed' *cough* for drifting but do address roll center
Jimmy mostly tracks his car so he would be the best person to ask
once his knuckles are done
on that note, Mike started making the one-off bushings for them
I'll try post up some pics tomorrow

Joel, stay away from those rack spacers, that's some scary shit

aren't you an engineer? Design me a structurally sound modular aluminum upright
kind of like the ones on the Sierra Sierra Time Attack Evo
and I'll be your best friend :bow:

http://photos.motoiq.com/MotoIQ/Feat...2_2TLxp-X2.jpg

Which Jimmy are you talking about? I know more than one on here.

Yea, I wasn't looking forward to using those. I'm sure they cause a lot of stress at the joints.

Lol! Man, if I had a Mill, let alone access to one, then yes, I would make some kind of forged upright. I began designing one, but I became too busy with other things.

Quote:

Originally Posted by mmdb (Post 3413753)
I would highly recommend a roll center adjuster similar to what the Driftwork spindles achieves. I like them a lot (front only right now) not only because they add a sharper feel with much, much less roll, but also because the steering arm was modified. THis decreases the steering ratio which I found beneficial during turn in (arms aren't crossed up) and during oversteer correction (fast steering ratio helps a lot with reaction).

The amount of correction the Driftworks knuckles is plenty. Addition of the Moonface roll center adjuster is overkill. BUt doesn't hurt to try if you're curious, just your wallet.

Uggh... They are expensive..

racepar1 04-27-2010 10:02 AM

Quote:

Originally Posted by ManoNegra (Post 3413709)
Joel, stay away from those rack spacers, that's some scary shit

aren't you an engineer? Design me a structurally sound modular aluminum upright
kind of like the ones on the Sierra Sierra Time Attack Evo
and I'll be your best friend :bow:

http://photos.motoiq.com/MotoIQ/Feat...2_2TLxp-X2.jpg

:wackit:

Sorry, I just messed my pants a little.

Ya, make those and I'll be your best friend too.

:yum:

GripTerror 04-27-2010 10:04 AM

Me three .

ManoNegra 04-27-2010 10:36 AM

Quote:

Originally Posted by xpertsnowcarver (Post 3414248)
Which Jimmy are you talking about? I know more than one on here.

Jimmy <--> mmdb


Quote:

Lol! Man, if I had a Mill, let alone access to one, then yes, I would make some kind of forged upright. I began designing one, but I became too busy with other things.

Uggh... They are expensive..
I just need a well thought out design, leave the rest to me

xpertsnowcarver 04-27-2010 01:08 PM

Quote:

Originally Posted by ManoNegra (Post 3414352)
Jimmy <--> mmdb

I just need a well thought out design, leave the rest to me

OOOHH YEA! I forgot. That's another Jimmy. I'll bug him right now.

Oh, well that's not too hard. Do you have the SolidWorks program? If not, it's cool, I can send you drawings in PDF format.

wacko2 04-27-2010 03:47 PM

that for all the info

Z33dori 04-27-2010 10:16 PM

So me and my friend were having a debate on how you want your leading wheel while your at full lock. He thinks that you would want your wheel to still roll over to positive so that it will pull the car in that direction, based off the fact of your wheel always pulls to the side that is most positive while driving straight.

I think that you would want the wheel to roll flat. I based this off setups that run lots of static negative camber with higher than stock caster. B/c this will put you closer to 0 then if u had less, correct.

So which is right?
Flat>
http://farm3.static.flickr.com/2719/...d3d57bb1_o.jpg
or more towards positive>
http://farm3.static.flickr.com/2692/...e7890ec5_o.jpg

SoSideways 04-28-2010 07:38 AM

Probably a personal preference thing there...

Some might like it to be flat, some might like it to be more positive.

PoorMans180SX 04-28-2010 12:15 PM

Flat gives you much more grip. You have to think, basically that is the only wheel steering your car at that much angle. The weight is on that side, and the other tire is going to go up on it's side too.

Static camber will not change your steering axis inclination unless you dial it in using the lower mounts on your coils. Think about how your wheel moves around your shock.

Caster will make the wheel roll over onto it's edge more because the shock is more angled.

Now you can modify all these things, but be careful, you have to take into account ackerman and scrub radius as well, so be smart if you're going to do it.

mikerbike 04-28-2010 08:54 PM

So, I tried those modified knuckles like Bilspeer and KPR and LOVED them. I didn't remove the stops on my control arms, so I didn't gain much angle (some) but the steering response is what I would consider "amazing". Now I have both of my S13s equipped with them. Yeah, love them.

95KA-Turbo 04-29-2010 11:51 PM

Sorry if this was mentioned somewhere, I didn't relook through the thread.....but D-Max makes knuckles now:

http://www.dmax-cs.com/knuckle/n1.jpg

D-MAX ƒVƒ‡[ƒg ƒiƒbƒNƒ‹@Ø‚êÅ*pƒAƒbƒv | ƒGƒAƒ‚Ȃǂ̃hƒÅ*ƒtƒgƒ`ƒ…[ƒ“ƒp[ƒc

Looks like they have a nice bumpsteer correcting dip in them too.

SoSideways 04-30-2010 07:53 AM

They definitely do have some nice bumpsteer correction built into those.

But for dudes like you and me, Def, mmdb, Codyace, and Otto, we're also using roll center correcting FLCAs, so just that little bit of bumpsteer correction from those knuckles are still not enough to totally eliminate bumpsteer.

You would still need the adjustable tie rod ends.

Z33dori 04-30-2010 10:18 AM

by adj you mean like the Kazama and stance "angle" tie rod ends?


And do knuckles increase caster, or is it just the added steering angle rolls so much futher?
http://www.dmax-cs.com/knuckle/t.jpg

SoSideways 04-30-2010 10:41 AM

Caster is controlled by the T/C rods normally, as your knuckles rotate on the ball joints (or spherical bearings) on the FLCAs, so no, those knuckles that are basically just stock ones that are cut and rewelded do not change your caster at all.

And by adjustable, yes, I mean like the Kazama or Stance tie rod ends, although those don't have nearly the amount of adjustments that the SPL Parts ones will give you.

xpinoyxmk 04-30-2010 12:01 PM

Sorry dont know if its been covered either but Dmax tie rod ends and the turning up angle adaptor info pls.

Pandapants 04-30-2010 12:06 PM

What about peak performance outers?
Their shank looks comparable in size to the spl
but at a fraction of the price and compatible with s14 inners.

I was looking through the nissan road racing forum mentioned earlier,
and many were saying that roll center adjusters like moonface and greddy
don't really change roll center "b/c of the location of the pivot point."
Are there any pictures out there with either of these products next to a stock balljoint to compare the location of the pivot points?

PoorMans180SX 04-30-2010 12:12 PM

Quote:

Originally Posted by Z33dori (Post 3420262)
by adj you mean like the Kazama and stance "angle" tie rod ends?


And do knuckles increase caster, or is it just the added steering angle rolls so much futher?

Another reason I'll be getting Driftworks knuckles. The steering axis inclination is modified to keep the tire flat when at extreme angles. Check it:

http://i24.photobucket.com/albums/c2.../cars/ukd6.jpg

http://i24.photobucket.com/albums/c2...lSantapod3.jpg

Z33dori 04-30-2010 12:15 PM

Quote:

Originally Posted by PoorMans180SX (Post 3420471)
Another reason I'll be getting Driftworks knuckles. The steering axis inclination is modified to keep the tire flat when at extreme angles. Check it:

http://i24.photobucket.com/albums/c2.../cars/ukd6.jpg

http://i24.photobucket.com/albums/c2...lSantapod3.jpg

thank you so much i was trying to find pix like that last night to prove that they keep flat.

much appreciated. Yea the more i look into those geomaster knuckles the more they are worth the heavy price.

PoorMans180SX 04-30-2010 12:15 PM

Quote:

Originally Posted by Pandapants (Post 3420456)
What about peak performance outers?
Their shank looks comparable in size to the spl
but at a fraction of the price and compatible with s14 inners.

I was looking through the nissan road racing forum mentioned earlier,
and many were saying that roll center adjusters like moonface and greddy
don't really change roll center "b/c of the location of the pivot point."
Are there any pictures out there with either of these products next to a stock balljoint to compare the location of the pivot points?

Look on the first page. Sunline racing ball joints actually have a longer shank.

I'm sure peak performance outers are very high-quality. SPL's are compatible with S14 inners, they just like to tell you they're not so that you buy inners from them.


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