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

[xska]

Originally Posted by Steve Lloyd

So what makes the S14 kit not work on an S13??

S13's inner tie rod is skinnier, where outer tie rod fits.
So to make it work on S13, you need to change to S14 inner tie rod.

[Def]

Yep, M12x1.25 (S13) vs. M14x1.5 (S14) threads on the inner tie rods.

[nieko]

is the z33 tie rod the same diameter and thread pitch as an s14? sorry for a retarted question..

[95KA-Turbo]

Yes it is.

[nieko]

just to clarify again... i know the steering rack threads are, but what about the actual tie rod end threads?

[95KA-Turbo]

mmmmmmmm, I believe so, you can contact SPL to be sure though. My car isn't at my house, so I can try and remember to check tomorrow when I go up there.

[Def]

Originally Posted by nieko

just to clarify again... i know the steering rack threads are, but what about the actual tie rod end threads?

Yes, they're the same. SPL's tie rod page explains all. Their stuff has a M14x1.5mm thread on the inner tie rod side, and you can use Z32 or Z33 inners. Z32 is like a shorter S14 tie rod.

[az_240]

I saw the stance angle kit has one of these... maybe it was already discussed but does this help with over centering?

If it doesnt it seems like the rack would over center pretty easy.

Are modified knuckles going to be the best option to keep the angle without over centering? I just picked up a hicas rack and heard things start to get scary when running both the hicas rack and knuckles but I have issues with over centering....

[nieko]

so DAN, is there ANY kind of ETA on the rear uprights?

[PoorMans180SX]

Originally Posted by az_240

I saw the stance angle kit has one of these... maybe it was already discussed but does this help with over centering?

If it doesnt it seems like the rack would over center pretty easy.

Are modified knuckles going to be the best option to keep the angle without over centering? I just picked up a hicas rack and heard things start to get scary when running both the hicas rack and knuckles but I have issues with over centering....

No, they don't help.

The only real solution for overcentering is moving your rack forward. Running less caster could help a little too if you adjust it with the tension rods.

[!Zar!]

If you put those extenders on without modified knuckles and your car is slammed, it will increase the likelihood of going over center; not help decrease it.

[xska]

Superstreet august issue has Driftspeed knuckle install/review.
It's only $250 with core exchange. But looks like it needs longer tie rod.

[PoorMans180SX]

Let's dive into the ackerman subject eh?

I know our cars have a significant ackerman affect at high lock angles, and I know the drift guys are now starting to modify their knuckles for zero ackerman, which helps them hold out long drifts across the straights.

I'm curious as to what a good setup would be for drift/grip/street car. I know BMW's have very little ackerman, and they seem to be good on the road course.

Just looking for opinions really, as everything is a compromise, and I've read several articles by reputable people, and they all seem to have different views, haha. From what I've read, reducing ackerman shouldn't hurt roadcourse performance very much, but help with contact patch and steering while sideways.

Also curious as to the ackerman on the Driftworks knuckles. mmdb? I know you love how they feel, but can you give us some front shots at full lock? You're probably the only one I know of with modified knuckles that grip drives.

[nieko]

yeah ive been reading up on ackerman too, everyone has different opinion it seems lol

please spread more info people.

correct info.

[Z33dori]

thoughts on this :

Some race cars use reverse Ackermann geometry to compensate for the large difference in slip angle between the inner and outer front tyres while cornering at high speed. The use of such geometry helps reduce tyre temperatures during high-speed cornering but compromises performance in low speed maneuvers

[!Zar!]

Here you go guys.
What is Ackerman Steering and how it affects handling.

[Def]

S13s have less than 100% Ackerman btw. I wouldn't go less for "grip" driving(I hate that term... but it's the usual here).

[DC Dan MAX USA]

Originally Posted by nieko

so DAN, is there ANY kind of ETA on the rear uprights?

Not until they are tested by our local heros.

Originally Posted by PoorMans180SX

Let's dive into the ackerman subject eh?

Theory with zero ackerman is that with tons of power you could carry your drift along a straight section very far with good front traction and in various corners you have the power to easily steer with the rear as both front tires track together, But if you did not have the power to sustain such a long high speed drift then its usefullness is limited and side effects would compromise the grip on a low power car. For most drifters, a conservative reduction in ackerman is more appropriate. The MAX Super Angle kit has adjustable ackerman depending upon the knuckle extension installation position.

[Slidin' Sam]

Originally Posted by DC Dan MAX USA

The MAX Super Angle kit has adjustable ackerman depending upon the knuckle extension installation position.

Can you please elaborate (spl) on this?

[Z33dori]

Originally Posted by Slidin' Sam

Can you please elaborate (spl) on this?

x2 plz. How much is generally need to be taken out, and what power level are you okay to go for Zero ackerman?

[PoorMans180SX]

Originally Posted by !Zar!

Here you go guys.
What is Ackerman Steering and how it affects handling.

Thanks, I never would have thought an RC article would have such an easy to understand diagram that applies to real cars, haha.

Originally Posted by DC Dan MAX USA

For most drifters, a conservative reduction in ackerman is more appropriate.

That's probably the route that I will take.

Originally Posted by Slidin' Sam

Can you please elaborate (spl) on this?

Well, if you look at that RC article, ackerman depends on how the steering arms come off the knuckle (where your tie rod ends go through). With your wheels pointed straight ahead, the arms point in towards the rear diff a little. Zero ackerman is when the arms go straight backwards towards your rear wheels.

By welding the tie rod end adapter on the PSM kit at different angles compared to the stock arm, you can change ackerman.

[kognition]

I can really respect your comment Def. From my pov, (as well as my customers). Sending out a prototype for sale into the community is a dangerous idea. I track tested my products for months before i released them for sale. And the rest is becoming history for Kognition because of it.
Design and testing both go hand in hand. And continuous design evolution with each new generation of product.

Originally Posted by Def

I'm not saying they don't test their products, but testing a product does not make up for a lack of design work on the front end.

I have no idea why S chassis guys are so willing to accept products that don't have any engineering/real design work behind them, and take "it feels better" as the "best it can get."

Don't take this the wrong way, I'm not saying PSM is not doing any due dilligence in analyzing what the end result is with their upright design. They haven't posted any, but it's just a prototype, so I am not levelling judgements at them yet.

This is more a general look at the S chassis community, and what I see as a piss poor attitude towards actually modifying their car. It's too much about flash, what's "hot" at the moment in the "scene," and not much about learning how to set your car up better and analyzing products on their technical merits.




Yes, take out some caster and that should help the positive camber gain of the inside front during a drift.

[shinobis13hb]

Front:
Tension rods: These control caster on the front suspension. Caster helps determine camber gain over the suspension stroke and how easily your car turns. This also helps “auto turn” the wheel when countersteering. The angle of the tension rod (vertical plane, front to back) also helps determine anti-dive under braking situations.


i have the energy suspension poly tension rod bushings. i noticed that the bushing are VERY large that i had to open the brake that the bushing goes into. i noticed that when i was tightening it the metal was tightening on the big ass bushing its self. could this be why my wheel doesnt want to "auto correct" and my steering feels oh so tight? thanks guys.!

[GripTerror]

Originally Posted by Def

S13s have less than 100% Ackerman btw. I wouldn't go less for "grip" driving(I hate that term... but it's the usual here).

Please elaborate

[PoorMans180SX]

Complete or 100% ackerman, is when the lines drawn from each knuckle arm intersect at the center of the rear axle (the diff).

Anything less (where the lines intersect after the diff) is less than 100%.

Zero ackerman is where the lines go straight back to the rear wheels.

Negative ackerman is where the lines go farther out than that.

[Def]

That. S13s have less than 100%.

[GripTerror]

Can you draw it (sorry lol -- but im sure it would complete the picture in my mind what you're exactly saying)

And what would be the pros/cons vs 100%, 0, negative, etc...

Grip here >_>

[PoorMans180SX]

Originally Posted by !Zar!

Here you go guys.
What is Ackerman Steering and how it affects handling.

Read that.

Basically if you're not going to be doing any drifting, I wouldn't mess with ackerman. Just like Def said.

[Slidin' Sam]

so with the max kit you can adjust ackerman by re-positioning the tie-rod holes? Should you picture this like toe-in/out?

[95KA-Turbo]

Would I be correct in saying that 'more ackerman' with toe in will give you more angle? That's what I am getting from that article.

So if 240s have less then 100% ackerman from the factory, then changing it to 100% ackerman will give you more angle?

I hope I am understanding that article correctly, it seems fairly cut and dry to me but I could be incorrectly interpreting it.


Also, I should be able to find my round about ackerman by having the car up in the air and using something straight (maybe string would work?) to make a line from my tie rod end heim joints to the rear center of the car?




I just found this program, it looks simple to use and extremely handy:

http://www.auto-ware.com/software/ccw/ccw.htm