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

[Motary]

Originally Posted by DC Dan MAX USA

So you can get today from Parts Shop MAX up to 62 degrees of angle and the lowest usefull ackerman down to 9.5% difference at lock, 45mm roll center correction, OEM bump steer, quick steering....For $400
Or a kit that may cost $1200 to get a few more degrees angle, zero ackerman plus 11 more mm roll center?
If the second option is what makes your heart pump guys, if seeing zero ackerman really makes you want to throw 3x the money at a kit that does that, let me know and I'll totally make this happen for you.

Now let me hit you with some knowledge about a must have new product that will NOT break your bank:

Wisefab kit:
waterjet cut lower control arm with joints
strut relocating top mounts
new tie rods
knuckle bolt-on block

1700$ (Price in Estonia will be 1050€ plus 20% VAT)

Parts shop MAX parts for that lock:
Knuckle mod - 400$
Shipping the knuckles - 100$
Bump stop - 50$
ikeya inner tie rods - 150$
outer tie rods ( SPL ) - 230 $
pro control arm with tension rod - 550$
+ modifying inner fenders

~1480$

The cost difference - 220$

The wisefab kit is not adjustable as much because it is only for drifting and you do not need to adjust everything if it is setup perfectly from the box with predetermined settings like toe and ride height, plus it has 3 selections for ackermann, don't bring it down before it is even released and tested by the public

That aluminum rack holder is very neat!

[nathanong87]

My buddy John Hammond will be buying some of those wise fab knuckles

[John Hammond]

I sure will

[DC Dan MAX USA]

paypal [email protected] $50 to reserve your set of SREB, for January delivery - shipping is free.

Thanks guys.

I have not tested the offset ITR/rack spacers on my car yet...because I dont need them, I dont overcenter, my caster is too low for them.
And you certainly cant combo those two items without having the ITR hit the LCA mounting bolt.
Its really performing amazingly lately with all the new product, such a blast, so satisfying to get in and stand on it all day letting the suspension and steering parts do their job = )

However we are running some ITR/rack spacers on Ross Pettys car with good results - he loves loads of caster. Everyone has their own opinion, thats why its mind blowing to not have adjustable alignment. Everyone has different levels of power requiring different settings and for FD they change the settings at every track. Didnt the video say that you have to purchase additional parts to add ackerman to the wisefab kit?

I dont recommend SPL outer tie rods or any tie rod end with an exposed bearing.

[Tearlessj]

I think there is still too little known about the Wisefab kit to be throwing around judgement.

[Motary]

Originally Posted by DC Dan MAX USA

Didnt the video say that you have to purchase additional parts to add ackerman to the wisefab kit?

I dont recommend SPL outer tie rods or any tie rod end with an exposed bearing.

Pre-order ones get them for free, that is ending after 2nd week of January.

Don't most competition cars run exposed rod end bearings? I am currently making my own arms for rear and use rubber boots like this:

[TheRealSy90]

Would it be okay to use the offset rack spacers with a modified front subframe that moves the rack 1" forward like this one?

[DC Dan MAX USA]

True. Pro cars can afford to replace the bearings more often than privateers.

Im guessing you dont need the SREB if you have 1 inch rack forward, thats a lot (depending on the knuckle and settings).
SREB was designed with not having to cut and weld in mind.

[codyace]

Originally Posted by DC Dan MAX USA

Are you measuring between the ball joint and the knuckle to get that measurement? The question is what's the difference between stock length and yours, not overall distance.

I always assumed that those numbers of correction were just measuring how far you space the lower ball joint down, as IMO (and I think with most of these numbers is that there isn't a true accurate or repeatable way to measure it it this side of a chassis program. Sure I guess you could measure certain suspension points and graph it out on paper, and plot your instant centers and true movement of RC on the centerline and all of that jazz...however that leaves a fair range of error IMO, especially when accuratly measuring the downward angle of upper strut mounts when initially determining instant centers.

And with that all considered above, I am also under the impression that a control arm level with the ground allows for an almost spot on 'roll center' for a car? That is it provides an acceptable height of RC from the ground, while also keeping it close to the actual car center of gravity. To me overly correcting roll center can in fact put it way too low, and really increase that distance of RC vs CoG (which is also important).

Again, just some musings. I mean there is a fair range of acceptable 'RC'...I just don't see how adding anymore than your estimate of my 25mm of RC adjustment helping a car with already flat control arms. I'm not trying to be a hater, just curious...I know how grassroots drift guys are quick to accept whatever they are told, whereas the grassroots grip guys think about a it a little more, so I do excuse my constant questioning...it's not doubting it's more curiosity.

Originally Posted by DC Dan MAX USA

I dont recommend SPL outer tie rods or any tie rod end with an exposed bearing.

Couldn't that easily be fixed with some little rubber booties from Tractor Supply Company (or similar) (or like the ones Motary posted above). Performance wise I can't see how they could be recommended against for something so easily fixed. With that said, I know of PLENTY of farm equipment that had many years of strong service outside with oldschool rod ends and bearings, that still work and are great...I really can't see how leaving a PTFE lined and self cleaning bearing out in the open on a road car is really going to fail in a normal track and service life.

[PoorMans180SX]

Well codyace, your first question was "How are yours better than mine".

Thus, the statement that more roll center correction is available. This would obviously be for cars that are lower than yours.

The ackerman changes are necessary for a double duty car as well, and quicksteer is actually nice on the roadcourse.

[DC Dan MAX USA]

OEM tie rod end, 2 reasons:

I recommend buying the cheaper part that lasts longer like MOOG tie rod ends which simply come with a boot thats made for it. I would caution that if a boot does not fit perfect you could retain moisture in it and thats bad too. (from my experience) Aftermarket tie rod ends get fine dust inside and slowly grind themselves loose, more on the tie rod ends than anywhere else because its the steering movement plus suspension movement double duty whereas other parts with exposed bearings...RLCA for example is just the suspension motion. Obviously super steering angle makes this worse.

We setup our knuckle to work with the OEM style rod ends so the bumpsteer adjustment that some people may need from an aftermarket exposed bearing tie rod end is not necessary for combining with our knuckle.

RC:

Yes we can all agree that the easy rule of thumb is that if your arms are pointing up you're suspension performance is in trouble and if they are flat thats way better.

[az_240]

Just to give an idea of how long the SPL outer tie bearings last I had mine for about 10k daily driven before they started developing a small amount of play. You can get replacements for about $30 (a pair) when they wear out.

Those eccentric rack spacers are nice. It's about time someone made them for a reasonable price..... sucks I just had my crossmember modified 20mm forward like Sy90....

Any idea how far these eccentric rack spacers move the rack forward?

[codyace]

Originally Posted by PoorMans180SX

Well codyace, your first question was "How are yours better than mine".

Thus, the statement that more roll center correction is available. This would obviously be for cars that are lower than yours.

Wait a second:

- I measured my 'correction' buy measuring how much I moved the arm down, and was told it was wrong...but now we're saying that's how PSM does it as well?

-I admitted I was potentially wrong in how I measured it, however offered the reasoning being that in order to really measure true 'Roll Correction' you'd need to professionally plot the suspension points, discover instant centers, and then obviously draw their intersection with car centerline to deliver a roll center. I understand how to 'really' measure it, but was under the impression that most measured it by ball joint spacing vs actual measurment.

So I'll re-ask my question: how are we all 'actually' measuring it?


FWIW: If performance is at the heart of these products (which we all can probably agree these things are aimed at the the guys who are serious about these cars)....and even if these knuckles are correcting roll center almost 2 inches....wouldn't we all agree that the actual roll center is still below the ground, and that we should maybe be more focused at total setup than debating things that most guys couldn't even discern from in a set of knuckles?

Originally Posted by PoorMans180SX

The ackerman changes are necessary for a double duty car as well, and quicksteer is actually nice on the roadcourse.

While I do not know your track experience, I've driven *plenty* of different cars on track, and starting to have some more autocross experience too. I can assure you that a stock 240 centers itself pretty well for a road race oriented car as it does come with a fair amount of caster for a production based cars. I can also confirm that my personal car comes back to center so easily and so quickly (which I've also heard in compliment from many other people who have driven my car hard or on track) that I almost find it hard to believe that any more is possible from the setup.

Edit: I guess my point here is, once you drive a bunch of cars, you begin to really appreciate how well a 240 works in a 'quick steer' aspect. It's not a Ferarri, and never will be a porsche, but for me it's hard to hinge on small things like that when it's already vastly better.




So with that all said, wouldn't better be a subjective answer? Without a doubt a welded knuckle is a nice solution, but to write it off as all encompassing is a bit unfair, especially with correction numbers and emphasis on stuff that could be overcome with more track time for 90% of the prospective buyers out there.


(I wish I could type less sometimes, I'm just not smart enough)

[codyace]

Originally Posted by DC Dan MAX USA

Aftermarket tie rod ends get fine dust inside and slowly grind themselves loose, more on the tie rod ends than anywhere else because its the steering movement plus suspension movement double duty whereas other parts with exposed bearings...RLCA for example is just the suspension motion. Obviously super steering angle makes this worse.

We setup our knuckle to work with the OEM style rod ends so the bumpsteer adjustment that some people may need from an aftermarket exposed bearing tie rod end is not necessary for combining with our knuckle.

Total durability is obviously in the favor of the OEM style setup, but in that same regard wouldn't we also agree that on the performance end of things, changing a rod end every 10k-15k (btw mine are in that range now without a lick of rust, play, or apparent wear) if need be is a small price to pay? To me I'd rather have the spherical rod end end for alignments sake when making adjustments vs the ball joint tie rod ends?


Either way that does save some good cash on the big end by having the knuckle make the correction vs the tie rod end itself...which I think we all know is often a 'weak spot' with some of the lesserbands. I know if the SPL shaft busts I can get a new one for free, or drill it out and put a big bolt in and call it a day.

[95KA-Turbo]

Codyace....you just measure the distance between your spindle and your LCA, then subtract that from the distance between the spindle and LCA of a stock 240 (which I believe is somewhere around 3/4 of an inch), then you know how much you've dropped your outer pivot point.

[Howie Felter Snatch]

What is this a pissing contest on SPL tie rod ends? Really?

I just clean them off every month or so with WD40 like Kuah recommends and NO PROBLEMS what-so-ever.. Been around a year now and all is still good. I needed to get the misalignment in check and it's been a charm not to have my steering wheel steer itself when hitting bumps or dips on the road when driving hard.

Sure OEM style is more reliable.. Anything OEM is more reliable, even suspension arms.. But sorry, the OEM stuff didn't have the functionality I needed.. So for what it is, its not that bad.

[YannG]

great thread...a lot of usefull information!

[PoorMans180SX]

Originally Posted by codyace

Wait a second:

- I measured my 'correction' buy measuring how much I moved the arm down, and was told it was wrong...but now we're saying that's how PSM does it as well?

Yours:



PSM's:



Obviously you can see there is more correction there. By changing the angle of the lower arm, you directly effect roll center. I get your point that the 45mm drop is not linear to a 45mm raise of roll center height, however, it's still more drop of the outer pivot, thus more raising of the roll center.

Originally Posted by codyace

FWIW: If performance is at the heart of these products (which we all can probably agree these things are aimed at the the guys who are serious about these cars)....and even if these knuckles are correcting roll center almost 2 inches....wouldn't we all agree that the actual roll center is still below the ground, and that we should maybe be more focused at total setup than debating things that most guys couldn't even discern from in a set of knuckles?

On a low car, 45mm correction can make the difference between gaining positive camber on suspension compression and gaining negative camber on compression. That is a huge difference and will be felt regardless of the type of driving. Less front body motion increases driver confidence most of the time as well.

A relatively low car will have messed up it's roll axis angle vs. mass axis angle as well, which causes increased understeer; more correction helps that as well.

Originally Posted by codyace

While I do not know your track experience, I've driven *plenty* of different cars on track, and starting to have some more autocross experience too. I can assure you that a stock 240 centers itself pretty well for a road race oriented car as it does come with a fair amount of caster for a production based cars. I can also confirm that my personal car comes back to center so easily and so quickly (which I've also heard in compliment from many other people who have driven my car hard or on track) that I almost find it hard to believe that any more is possible from the setup.

I apologize, I should have clarified what I meant by "quicksteer". I mean the fact that the steering wheel now goes from lock-to-lock in 2.5 turns instead of the stock 3. So I guess I should have said the "quicker steering ratio" is nice.

Conclusion: Your knuckle setup is probably just fine for your setup, and perfectly functional. Things change when you go lower or have a road course/ drift car.

[Motary]

Originally Posted by codyace

So I'll re-ask my question: how are we all 'actually' measuring it?

I measured all the suspension points and entered them into susprog3d, the software costs 300 AUD which is very reasonable, around the same cost as a pair of aftermarket suspension arms. In the front it was 175mm underground and in the rear it was 87mm above ground. At college the lector said that around 50 in front and 100 in the rear would be good. Rears has to be higher so you can use softer springs to achieve better traction while retaining same lateral stiffness. That is the theory.

About the front lower control being flat to the ground, I think what you guys mean is that chassis and knuckle pickup points should be at same height, they aren't with a flat arm because the balljoint is a little higher.

This is how the suspension looks like when we improved it in susprog for 2.68 degrees of camber change when body roll is 4 degrees, never mind the epic bump steer, but it is for good comparrison how the arm used to be:



You will notice the angle of the strut axis has also been changed, from 5 to 15 degrees if I remember correctly

I don't personally like the way roll center is raised with the long ball joints, It's much better to raise chassis pickup points or lower knuckle pickup point

I will do a full post with measurements to get close to ( i.e not account measuring errors ) this kind of performance in the near future

btw, what is the reason behind putting a 2nd bearing on the tension rod? The one between tension rod and control arm, what are the advantages?

[DC Dan MAX USA]

Originally Posted by Motary

The cost difference - 220$
don't bring it down before it is even released and tested by the public

Yes you could set up the MAX mods in that combination to make it as expensive as possible, or you can have this setup for $500 as just one example, and get on track with your extra dollars going to entry fee and tires.

There is so many combinations with the MAX pro knuckle.

And there is one wisefab package with ackerman choice and without alignment choices, no choice to make the kit less expensive by mixing it with the end users existing investment in parts, no choice for different width and offset wheel fitments?
Maybe people will love not having to think about their choices and they will be pumped on plopping down some cash for the full setup. Or maybe not, everyone buys one thing at a time from me, rarely in full sets.

Dont get me wrong by pointing out the differences, Im very happy its not a cheap copy of what we do. For our sport this is addition is fantastic! We need more companies investing in R&D to supply ORIGINAL parts that were not previously available to the end users. The thought and time that went into wisefab's unique package is commendable and deserves serious consideration from enthusiasts who want to spend more money and less time testing different alignment settings. Job well done!

Originally Posted by Motary

what is the reason behind putting a 2nd bearing on the tension rod? The one between tension rod and control arm, what are the advantages?

Its not a bearing, its a solid steel rod end. Its function is to create an A-arm when locked down. To change caster, you simply loosen this solid rod end thats through bolted to the double shear LCA bracket. It pivots as the tension rod is adjusted and when the setting is finalized you lock everything down.

[SicBastard]

Originally Posted by Motary

Wisefab kit:
waterjet cut lower control arm with joints
strut relocating top mounts
new tie rods
knuckle bolt-on block

1700$ (Price in Estonia will be 1050€ plus 20% VAT)

That much engineering and that much money invested in a new suspension system that still doesn't have a 1:1 camber-gain:roll is insane. If wisefab really wants to engineer an improvement on current s-chassis offerings they should be building a dual-unequal A arm kit like the griggs and agent47 kits (also around $2000).

[SicBastard]

Originally Posted by Motary

...we improved it in susprog for 2.68 degrees of camber change when body roll is 4 degrees




I don't personally like the way roll center is raised with the long ball joints, It's much better to raise chassis pickup points or lower knuckle pickup point

There is absolutely no difference to the camber curves or roll center whether you lower you LCA/ball joint via a lower knuckle or longer ball joint shaft. It might look a little jankey, but the car doesn't care.

And I've modeled moving the LCA mounting point up, surprisingly it does next to nothing for roll center.

Increasing the the angle of the strut axis is an elegant solution, but then you either need a fabricated knuckle or modified strut housing to prevent excessive camber. And by the point you're doing that much work, you're better off just building a double A arm set up.

[Motary]

Originally Posted by SicBastard

There is absolutely no difference to the camber curves or roll center whether you lower you LCA/ball joint via a lower knuckle or longer ball joint shaft. It might look a little jankey, but the car doesn't care.

And I've modeled moving the LCA mounting point up, surprisingly it does next to nothing for roll center.

Increasing the the angle of the strut axis is an elegant solution, but then you either need a fabricated knuckle or modified strut housing to prevent excessive camber. And by the point you're doing that much work, you're better off just building a double A arm set up.

It is not that much work, set top mount plate on max camber and modify the strut's mounting bracket to get the camber back to normal and play with camber settings by changing the length of the lower control arm.
Moving the chassis mounting point up by 10-20 mm does very little that is true, clearance is a realistic issue that was not taken into account when solving this task.

[SicBastard]

Hey Motary,

if, "...we improved it in susprog for 2.68 degrees of camber change when body roll is 4 degrees"

I hate to ask, but do you remember how bad stock was?

[Motary]

You guys feel free to ask anything I love the development of S chassis suspension lately and try to help out as much as I can.

4 degrees of body roll in my s13 made camber from -2 to 3,30 degrees, making it a total of 5,3 degrees.



PS! There are a lot of bugs with my calculations and I need to fix them. I will put this info back when it is fixed

[/FONT]

[PoorMans180SX]

Good stuff Motary, thank you!

[SicBastard]

Epic post Bro!

Isn't it true that you can get just a touch of camber gain if at static ride height your ball joints are lower than your chassis mount points?

Also what was your base line ride height either in ground clearance, or ground to one of the LCA chassis mount points.

and again , epic post!

[Motary]

Originally Posted by SicBastard

Epic post Bro!

Isn't it true that you can get just a touch of camber gain if at static ride height your ball joints are lower than your chassis mount points?

Also what was your base line ride height either in ground clearance, or ground to one of the LCA chassis mount points.

and again , epic post!

I measured ride height from front fender's vinyl stripe's lower line that was closest to the wheel. I also made some mistakes that I have been pointed out ..

No camber gain: Because the top of the vertical strut is mounted rigidly to the body structure, MacPherson struts do not provide camber gain -- the wheels lose camber as the body leans. You can compensate to some degree by designing the suspension with a few degrees of static negative camber (that is, aligning the wheels so that the upper halves are tilted slightly inward when the car is level), but too much negative camber causes uneven tire wear. The only way to prevent camber loss is to use stiffer springs and/or anti-roll bars to reduce body lean, which results in a stiffer ride. It's possible to make a MacPherson strut car handle very well, as Porsche, Volkswagen, and BMW have repeatedly demonstrated, but it compromises ride quality more than would be the case with a double-wishbone suspension

link to reference

[SicBastard]

Originally Posted by Motary

I measured ride height from front fender's vinyl stripe's lower line that was closest to the wheel. I also made some mistakes that I have been pointed out here.. I will do this on Monday since I can only do this at college.

Check out post #385 on page 13 of my build thread in my sig. I did some modeling in performance trends roll center program and posted the results there, along with some ideas you might find interesting.

[Motary]

Ideal camber curves have about 1 degree of camber gain per degree of roll.

This is true for cornering, but cars also have to brake on race tracks, so it is good to optimise it a bit, for 2 degrees of body roll, 1 degree of camber gain