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

[jaysgottaredtop]

Originally Posted by PoorMans180SX

One of the best pics I've found of the S13 rear wisefab kit, from Nigel Colfers page:

The articulation on those LCA heim joints doeeeeeeee

[Matej]

That thing looks as if it is held together by spiderwebs.

[PoorMans180SX]

Originally Posted by Matej

That thing looks as if it is held together by spiderwebs.

It's crazy right? I haven't heard of any failures on the TONS of cars that are currently equipped with the kit in professional series.

I guess that's what a good FEA analysis gets you.

[Matej]

Originally Posted by PoorMans180SX

It's crazy right? I haven't heard of any failures on the TONS of cars that are currently equipped with the kit in professional series.

I guess that's what a good FEA analysis gets you.

Cannot tell if this is sarcasm. For all I know it may be tougher than Bilbo's mithril-coat.

[PoorMans180SX]

Hahah sorry, I was not being sarcastic. I have not heard of any failures to date.

The cars that I know have the kit:

Jack Shannahan
Nigel Colfer
Juha Rintanen (S14 test car)
Odi Bachkis
Kalashnikov
James Deane
Kenneth Moen
Dmitry Illyuk (original test car)
Christer Halvorsen
Max Tvardovskiy
Alex Golovnya

I'm sure there are more.

[powahh]

Originally Posted by PoorMans180SX

Hahah sorry, I was not being sarcastic. I have not heard of any failures to date.

The cars that I know have the kit:

Jack Shannahan
Nigel Colfer
Juha Rintanen (S14 test car)
Odi Bachkis
Kalashnikov
James Deane
Kenneth Moen
Dmitry Illyuk (original test car)
Christer Halvorsen
Max Tvardovskiy
Alex Golovnya

I'm sure there are more.

Joon Maeng, bent it to crap in LB though

[TheRealSy90]

Tuerck has it on his FRS if that matters. Also Forrest Wang switched from PBM front kit to a Wisefab front kit on his FD S14. Can't find the pic of the setup at the moment but I was it on facebook earlier today.

[PoorMans180SX]

Motary isn't messing around.

[QUOTE=Motary;5620613]




/QUOTE]

[koukistylejdm]

thanks to the Genius who started that thread with tie rod lenghts on first page

[Purestock240]

Whats an ideal ackerman for drifting? right now I'm making a set of spindles for my weekend track day car and they are tacked up at 46degrees in and 38 out. I keep hearing that you want none for drifting. can anyone chime in?

[PoorMans180SX]

Originally Posted by Purestock240

Whats an ideal ackerman for drifting? right now I'm making a set of spindles for my weekend track day car and they are tacked up at 46degrees in and 38 out. I keep hearing that you want none for drifting. can anyone chime in?

It somewhat depends on how you like it. Some people like some ackerman because it helps self steer/steering feel a little. Others prefer zero. Most professionals are moving to zero because it allows them to maintain speed better.

[motoxris]

We like 5-7 to make snappier transitions

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[motoxris]

Which I feel is more fun and looks better.

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[Purestock240]

Originally Posted by PoorMans180SX

It somewhat depends on how you like it. Some people like some ackerman because it helps self steer/steering feel a little. Others prefer zero. Most professionals are moving to zero because it allows them to maintain speed better.

Originally Posted by motoxris

We like 5-7 to make snappier transitions

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thanks for the responses, I was having a hard time picturing in my head how ackerman would affect a car thats countersteering.

I tacked up my left side and now have 52 degrees turning left and 44 turning right, I'm going to tweak it and try to get 50 and 45 as I'm pretty close to rubbing and don't want to get the balljoint-tierod end-steering rack too close to straight. what do you think about those angles? its not a competitive car, I just want to have fun at track days. those angles are measured off of straight and with the rack centered there is zero toe.

when you say 5-7 degrees ackerman, thats just the different side to side right. so say 53 out and 46 in would be 7 degrees of ackerman? all I can find online is diagrams of how ackerman works and nothing on how its usually measured.

[derass]

Originally Posted by Purestock240

thanks for the responses, I was having a hard time picturing in my head how ackerman would affect a car thats countersteering.

When a vehicle is counter steered and drifting around a corner, a high ackerman angle causes the trailing tire to scrub, as it is not pointed in the same direction as the leading tire. Low ackerman is beneficial in drifting because it reduces this difference and therefore, amount of tire scrub, allowing for higher speeds and reduced front tire wear.

[motoxris]

Ackerman is is usually measured and full lock. Unless your car has some toe, it will have zero ackerman when pointed straight. So our cars go 5-7 degrees at over 65 degrees of lock. So at 45 or 50 degrees lock it can be different on our cars. We just haven't taken the time with oir current set ups to fimd ackerman through out the entire steering range.

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[Matej]

This may have been posted somewhere in this thread before, but what is the travel distance of the steering rack?

[Motary]

Originally Posted by Matej

This may have been posted somewhere in this thread before, but what is the travel distance of the steering rack?

According to FSM it is 66mm for S13, 68,5 for S14. Some S13 racks also have 68mm of travel.

[Matej]

Thank you. That is travel from center to side, I presume? So 132-136mm side to side.

I am adapting a manual rack which is supposed to have 127mm of travel, so I was trying to calculate if I would need knuckles just to have stock steering. Though those numbers seem pretty close.

[derass]

This is from the S13 FSM

[cbh148]

Originally Posted by PoorMans180SX

To me it looks like the car spins because you come off throttle too abruptly, transferring weight to the front, which is all kinds of soft and mushy according to your setup above.

You need tension rods and a Stealth Custom Fab tension rod brace. Those two combined with some modified FLCA with heims on the crossmember pickup points, would put your cars light years ahead of where they are now. Seriously it will blow you away with how improved the steering becomes. Even a solid SCF strut tower brace would help.

Thanks for the help. Again, I have CircuitSports tension rods, and although I know they're not the greatest, they're still rock solid and far better than the blown out stock crap that was in there before. And the control arms are brand new Dorman arms from RockAuto, so the bushings and balljoints are brand new as well.

What gets me is that the car felt ok about a year ago when I was still CA18 and just barely tucking tire on 16's. But it seemed like when I brought the car down to tuck tire that the "mystery-phantom-front-brakes-applying-themselves-while-sideways" effect started.

I think I'm gonna give the Cor-Integration setup a try. Hopefully the car will still be daily-able with the extended FLCA's, chopped knuckles, and steering rack relocated crossmember. Seems like a good bargain compared to the PBM stuff, and unless I'm missing something, I believe they have nearly identical specs (roll center correction amount, bump steer correction amount, steering angle, etc).

[motoxris]

Cor Integration doea quality work. Cant go wrong with that.

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[jaysgottaredtop]

Originally Posted by cbh148

But it seemed like when I brought the car down to tuck tire that the "mystery-phantom-front-brakes-applying-themselves-while-sideways" effect started.

Are you sure you aren't rubbing your tires on your fender wells? Because that's what it sounds like.

[cbh148]

See, that's what I thought. But although it does rub the fenders, I don't see/hear any inner wheel well rubbing going on (unless it's happening and I'm just somehow missing it). I was banking on the idea that it must be drastically improper rollcenter/ackerman/bumpsteer causing my front wheels to fight each other and essentially "brake" themselves and induce the pro-spin attitude my car has while sideways, just not sure why it would be only in slower drifts like in the videos I posted on the last page.

[PoorMans180SX]

Originally Posted by cbh148

See, that's what I thought. But although it does rub the fenders, I don't see/hear any inner wheel well rubbing going on (unless it's happening and I'm just somehow missing it). I was banking on the idea that it must be drastically improper rollcenter/ackerman/bumpsteer causing my front wheels to fight each other and essentially "brake" themselves and induce the pro-spin attitude my car has while sideways, just not sure why it would be only in slower drifts like in the videos I posted on the last page.

Seriously, this same thing would happen to me before I got a tension rod brace. Not sure on the cause, but that cured it for me.

_________________________

On a another note, I apologize for not updating the original page with all the latest and greatest, my car and job have been consuming my life lately. I'll try and get after it this weekend.

[Black R]

Originally Posted by cbh148

See, that's what I thought. But although it does rub the fenders, I don't see/hear any inner wheel well rubbing going on (unless it's happening and I'm just somehow missing it). I was banking on the idea that it must be drastically improper rollcenter/ackerman/bumpsteer causing my front wheels to fight each other and essentially "brake" themselves and induce the pro-spin attitude my car has while sideways, just not sure why it would be only in slower drifts like in the videos I posted on the last page.

Ackerman?

That's certainly a possibility...

[powahh]

Anyone on here runs 0 ackerman and about 8 degrees of caster and about 8 of camber? I've heard good things about this setup, I guess i just have to try it out.

I want more feel out of steering, I know i chose the wrong car, but Im trying to improve the feel and make snappy transitions, and have max contact at near full lock.

[PoorMans180SX]

8 degrees of camber sounds horrible. S-chassis have tons of steering feel? 8 degrees of caster certainly isn't going to give you contact patch at lock.

To me it sounds like a band aid setup.

You've really gotta figure out what you want out of the car/what you want your style to be. Stockish angle 2003 style sliding, big entry snappy transitions (with not much front grip), or modern high-angle high-grip sliding. Then choose your front setup from there. Trying to compromise too much just leads to an understeering pig that's hard to control.

That's my 3.5 cents anyway.

[Bink Industries]

Originally Posted by powahh

Anyone on here runs 0 ackerman and about 8 degrees of caster and about 8 of camber? I've heard good things about this setup, I guess i just have to try it out.

I want more feel out of steering, I know i chose the wrong car, but Im trying to improve the feel and make snappy transitions, and have max contact at near full lock.

try 9 degrees of caster
5.5 to 6 degrees camber
play with spacers to get your scrub slightly positive and you should be good. you may have issues with your scrub being incorrect. it can slow transitions and give less feedback

[derass]

I would think that with a 0 Ackerman setup, you should be trying to take advantage of the fact that the trailing wheel is not scrubbing at full lock and maximize it's contact patch. I've found that -4* camber is the sweet spot, flat contact patch on the leading tire without being excessive. Combine this with a factory caster setting (5* ?), as I've always found that level of caster to provide good self-steer/centering.

Mind you, I do have some ackerman with my knuckles, so I have not tried to dial out camber and caster, as doing so would increase the trailing tire contact patch and therfore scrub.