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Fooling around at the rear.....

Posted: Wed Jun 07, 2006 4:38 am
by Murray
So hopefully my title will get JK's & Barry's attention :lol:

Here's my story:86 GTV6 2.5L used for street and track.
Current suspension setup: Koni yellows all around,Shankle sport suspension setup with 27mm front anti-roll bar 25.5mm rear anti roll bar stock front torsion bars (I'm too lazy to upgrade to 27mm :evil: ) rear Sport ? springs.
Currently my car's track handling is very neutral and balanced so I figured I'd screw it up :twisted:
I've read here and elsewhere that some people remove the rear swaybar on the track so I decided to disconnect mine to see what happened.On the street it certainly softens up the rear but on bad roads I find it allows a little too much movement.I haven't tracked it yet but I feel like the rear end would take a better "set" and probably take a bit of time off a lap ?
So my question is if I reconnect it but use longer link bolts (my bars are connected to Dedion differently than stock) such that the bar is only coming into play at more radical angles of body lean will I likely strike a reasonable compromise between to stiff and too soft or am I likely to screw up my transition from no roll to full roll ?

Posted: Wed Jun 07, 2006 5:36 am
by Mats
Increasing the link length will have very, very limited effect (and really not the way you think, only during breaking and accelerating).
You will for sure notice a bigger difference if you vary the amount of fuel in the tank.

Better to move attachment point on the bar to make the leverage arm longer/shorter, that makes the AR-bar softer/stiffer over all.
If you do remove the rear bar and you had a good balance before you will get understeer...

Posted: Wed Jun 07, 2006 6:00 am
by Maurizio
An easy way of stiffening up the backside would be a hard connection of the backside ar bar. With some sort of uniball (or derative) as link.

Posted: Wed Jun 07, 2006 6:56 am
by Jim K
You may notice track improvement in the wet if you disconnect it and thats about it. There are rear bars (I don't remember who sells them) with different link attachment points along the two arms, THERE you could experiment, as Mats says short or long links in your existing setup would do almost nothing.
Me and Barry have something to do with rear-ends?? I can see Greece having unjustly earned the reputation (if you think its justified, you must have some...proof you'd like to share,heheh! :oops:) But Nigeria...?? Hmmm, maybe you're right, them buggers are always up to no good, hell, I use surgical gloves when I type letters to the guy! Can't be too careful, y'know! :lol:
Jim K.

Posted: Wed Jun 07, 2006 9:53 am
by Murray
Ok thanks guys,knew you'd have a good answer.I'll leave things alone for now and order a new bar from Andy at Performatek this winter.He sells the bars with selectable mounting holes.

Rear ends of cars only JK :lol: you must have read something else into my wording :D

Posted: Wed Jun 07, 2006 10:10 am
by Mats
Hard bar with selectable mounting holes? :shock:

Posted: Wed Jun 07, 2006 10:32 am
by x-rad
Murray:

where is that rear torsion bar from???a retailer??

Posted: Wed Jun 07, 2006 1:09 pm
by Murray
Mats what is about that design that concerns you ?

x-rad that image is from http://www.performatek.com/frOnlineCatalog.htm Perfomatek's website.Andy has all kinds of good stuff for transaxle cars.

Posted: Wed Jun 07, 2006 1:30 pm
by Mats
Murray wrote:Mats what is about that design that concerns you ?
Read what I wrote again but this time think dirty.

No, dirtier!!!

That's right.... 8)

Posted: Wed Jun 07, 2006 9:47 pm
by Mezevenf
Mats wrote:
Murray wrote:Mats what is about that design that concerns you ?
Read what I wrote again but this time think dirty.

No, dirtier!!!

That's right.... 8)
Haha, thats so wrong.

Posted: Wed Jun 07, 2006 10:06 pm
by Micke
Murray,

What is your goal? I have ahard time understanding what you aim for. If the balance is right like you write, it WILL NOT improve by just playing with the rear AR bar.

If your car doesn't have a LSD there is a gain in a soft rear end. This increased traction in acceleration from curves then come of the cost of increased US in general.

If you want to play, I'd say the starting point is decent front springs and then tune the balance neutral with the bars.

Posted: Wed Jun 07, 2006 10:40 pm
by Maurizio
What is your goal?
People have the need to change something to prove that theory and real life is the same. :wink:


Had disconnected the back side ar bar for the ring trip in the wet a few weeks ago. And even after a few 100m from my driveway I already disliked the added understeer, but so much safer in the rain.

Posted: Wed Jun 07, 2006 11:20 pm
by Micke
I do not have an AR bar in the rear at all. But then I compensated it with stiffer springs of course.

Now, I'll move the rear RC some 3-5 cm lower and need stiffer springs stll (Start with 520 lbs)

Posted: Thu Jun 08, 2006 2:07 am
by Murray
Read what I wrote again but this time think dirty
Mats my problem was I was actually thinking clean/normal thoughts at that moment.It was just temporary.I'm OK now :lol:

Micke basically Maurizio explained why I'm exploring this.Well balanced cars are not necessarily the fastest around the track.I'm fed up with getting my butt kicked by modern FWD cars particularly Hondas (my son's) :twisted: so I'm trying out different theories and learning.You're right that step #1 with my current setup is to increase my front spring-rate which I will do next winter.