Handling setup advice please
-
- Posts: 77
- Joined: Wed Jul 20, 2011 2:32 pm
Handling setup advice please
Hello, I haven’t posted for a while but have been lurking reading posts ☺
recently managed to get my Ghia onto the road after a three year restoration.
I’m looking for some advice on setting up the handling as most of it is all new so I’m working my way through the list of snags and things to set up as I put more miles on the car.
The setup is as follows;
Red9Design front suspension – dual wishbones with adjustable coilovers for height & spax adjustable shocks
Steering is Red9 rack & pinion conversion.
Rear has had an IRS conversion, plus adjustable spring plates & spax shocks to match the front. The rear torsion bar has been upgraded to a squareback one (I forget the thickness but from memory it was thicker & stiffer)
Tyre pressures – 18psi front, (175 tyres 5.5” rims)
- 28psi rear, (185 tyres 5.5” rims)
Done so far to get the car on the road;
- Rear IRS arm camber adjusted to give 0 degree camber at the rear
- Front tracking set up to give 0.5 degree toe-in
I am conscious that I haven’t set up the camber on the front yet and will be doing so this weekend with the top concentric ball joint. Not sure if the caster needs setting up yet.
The ride comfort is surprisingly good! but the car has a strange handling characteristic at the moment which is when you change direction at speed (over 40mph) it feels like there’s a delay and the rear then follows the front about ½ second later. Sort of sways changing lanes on the motorway rather than being precise.
This could be that the rear shocks are not set stiff enough compared to the fronts, but I was contemplating if a rear anti-roll bar might help tighten up the rear as the front seems a lot more planted than the rear.
Any advice would be appreciated thanks ☺
Here’s some pictures of her completed (used to have a build thread on here I must dig out &
recently managed to get my Ghia onto the road after a three year restoration.
I’m looking for some advice on setting up the handling as most of it is all new so I’m working my way through the list of snags and things to set up as I put more miles on the car.
The setup is as follows;
Red9Design front suspension – dual wishbones with adjustable coilovers for height & spax adjustable shocks
Steering is Red9 rack & pinion conversion.
Rear has had an IRS conversion, plus adjustable spring plates & spax shocks to match the front. The rear torsion bar has been upgraded to a squareback one (I forget the thickness but from memory it was thicker & stiffer)
Tyre pressures – 18psi front, (175 tyres 5.5” rims)
- 28psi rear, (185 tyres 5.5” rims)
Done so far to get the car on the road;
- Rear IRS arm camber adjusted to give 0 degree camber at the rear
- Front tracking set up to give 0.5 degree toe-in
I am conscious that I haven’t set up the camber on the front yet and will be doing so this weekend with the top concentric ball joint. Not sure if the caster needs setting up yet.
The ride comfort is surprisingly good! but the car has a strange handling characteristic at the moment which is when you change direction at speed (over 40mph) it feels like there’s a delay and the rear then follows the front about ½ second later. Sort of sways changing lanes on the motorway rather than being precise.
This could be that the rear shocks are not set stiff enough compared to the fronts, but I was contemplating if a rear anti-roll bar might help tighten up the rear as the front seems a lot more planted than the rear.
Any advice would be appreciated thanks ☺
Here’s some pictures of her completed (used to have a build thread on here I must dig out &
-
- Posts: 1925
- Joined: Wed Aug 11, 2004 6:20 am
Re: Handling setup advice please
Is your rear camber set with weight on wheels and an additional dummy weight of 100kilo in the car, and what is the rear toe?
Also. Tire pressures?
Also. Tire pressures?
-
- Posts: 77
- Joined: Wed Jul 20, 2011 2:32 pm
Re: Handling setup advice please
Tyre pressures – 18psi front, (175 tyres 5.5” rims)
- 28psi rear, (185 tyres 5.5” rims)
rear camber was measured with car on the ground, but no 100kg extra
- 28psi rear, (185 tyres 5.5” rims)
rear camber was measured with car on the ground, but no 100kg extra
- ONEBADBUG
- Posts: 213
- Joined: Wed Dec 02, 2009 9:25 pm
Re: Handling setup advice please
Might have too much toe in at the rear.
-
- Posts: 77
- Joined: Wed Jul 20, 2011 2:32 pm
Re: Handling setup advice please
Aha! something is starting to dawn on me, when I adjusted the camber by twisting the hub the holes were slotted and the hub could slide forward or back a few mm. It didn't dawn on me at the time but I guess if I push the hub towards the front of the car it gives toe-in at the rear, and if you pull it away it'll give toe-out?
I'll check the rear alignment, is toe-out by 1/2 degree the recommended setting for IRS then?
I'll check the rear alignment, is toe-out by 1/2 degree the recommended setting for IRS then?
- ONEBADBUG
- Posts: 213
- Joined: Wed Dec 02, 2009 9:25 pm
Re: Handling setup advice please
Toe out in the rear is scary, the car is really twitchy. You want a little toe in.
-
- Posts: 77
- Joined: Wed Jul 20, 2011 2:32 pm
Re: Handling setup advice please
thats what I would have thought, but this site says it should be set to toe-out; http://www.vw-resource.com/rear_suspension.html#adjust
And Aircooled.net says toe-in; http://www.aircooled.net/vw-handling-suspension-tuning/ (which sounds less scary!)
And Aircooled.net says toe-in; http://www.aircooled.net/vw-handling-suspension-tuning/ (which sounds less scary!)
-
- Posts: 1925
- Joined: Wed Aug 11, 2004 6:20 am
Re: Handling setup advice please
Excessive toe out can give a delay, then the rear goes quickly.
Slight toe out gives zero toe under accel,,and more toe out under decel (keeps rear end behind you under panic stops)
Slight toe out gives zero toe under accel,,and more toe out under decel (keeps rear end behind you under panic stops)
-
- Posts: 77
- Joined: Wed Jul 20, 2011 2:32 pm
Re: Handling setup advice please
That is exactly how I would describe it !helowrench wrote:Excessive toe out can give a delay, then the rear goes quickly.
Thanks for all the feedback guys
-
- Posts: 77
- Joined: Wed Jul 20, 2011 2:32 pm
Re: Handling setup advice please
Update: just checked the alignment by using my Dunlop gauges on the rear wheels (never done that before!) and it's showing a slight toe out of around 1/4 of a degree. But I did notice that the rear wheels at the back were at slightly different angles so I suspect I have not set each with the same toe-setting when I did the camber. (based on the fact that I didn't know it was possible )
Might combine setting this up with fitting a rear anti-roll bar at the same time seeing as it fixes to the same bolts (or could this make the situation worse?)
Might combine setting this up with fitting a rear anti-roll bar at the same time seeing as it fixes to the same bolts (or could this make the situation worse?)
-
- Posts: 7404
- Joined: Sat Mar 10, 2001 12:01 am
Re: Handling setup advice please
Half a degree of toe in on the front is quite a bit, especially for a double a arm design. What are the specs from Red9?
Steve
My Baja Build
My Baja Build
-
- Posts: 1925
- Joined: Wed Aug 11, 2004 6:20 am
Re: Handling setup advice please
When getting my baselines, the colored (I use pink) builders string gives me a nice set of straight lines to compare to.carl4x4 wrote:Update: just checked the alignment by using my Dunlop gauges on the rear wheels (never done that before!) and it's showing a slight toe out of around 1/4 of a degree. But I did notice that the rear wheels at the back were at slightly different angles so I suspect I have not set each with the same toe-setting when I did the camber. (based on the fact that I didn't know it was possible )
Might combine setting this up with fitting a rear anti-roll bar at the same time seeing as it fixes to the same bolts (or could this make the situation worse?)
Using a point on the chassis (don't use the body on Ghias) measure out accurately, and run string parallel down each side using jackstands or such to hold it.
then you can measure in to the wheel rims, front edge and back, and determine toe measurements.
(you do have to have straight rims for this, or you use an alternate procedure)
-
- Posts: 1925
- Joined: Wed Aug 11, 2004 6:20 am
Re: Handling setup advice please
BTW, I purchased a car that was originally set up for autocross. Scirocco II 16v
It had 7/8" of toe out on the rear------
I did not notice it until first drive, wow, when you turned in hard and the weight shifted, the rear steered its own way around the corner.
fast around a corner, but chewed up tires quickly for street use
reset that one using string and the shimming procedures for the rear (scirocco) got the rears down to .005 degree toe in, and 1.5 negative camber. still handles great, but imperceptible tire wear after 10k miles.
It had 7/8" of toe out on the rear------
I did not notice it until first drive, wow, when you turned in hard and the weight shifted, the rear steered its own way around the corner.
fast around a corner, but chewed up tires quickly for street use
reset that one using string and the shimming procedures for the rear (scirocco) got the rears down to .005 degree toe in, and 1.5 negative camber. still handles great, but imperceptible tire wear after 10k miles.
- Piledriver
- Moderator
- Posts: 22520
- Joined: Sat Feb 16, 2002 12:01 am
Re: Handling setup advice please
For extra fun, 50 PSI in front tires and 18 in rears...helowrench wrote:BTW, I purchased a car that was originally set up for autocross. Scirocco II 16v
It had 7/8" of toe out on the rear------
I did not notice it until first drive, wow, when you turned in hard and the weight shifted, the rear steered its own way around the corner.
fast around a corner, but chewed up tires quickly for street use
reset that one using string and the shimming procedures for the rear (scirocco) got the rears down to .005 degree toe in, and 1.5 negative camber. still handles great, but imperceptible tire wear after 10k miles.
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
-
- Posts: 1925
- Joined: Wed Aug 11, 2004 6:20 am
Re: Handling setup advice please
It already reminded me of a active rear steering car.Piledriver wrote:For extra fun, 50 PSI in front tires and 18 in rears...helowrench wrote:BTW, I purchased a car that was originally set up for autocross. Scirocco II 16v
It had 7/8" of toe out on the rear------
I did not notice it until first drive, wow, when you turned in hard and the weight shifted, the rear steered its own way around the corner.
fast around a corner, but chewed up tires quickly for street use
reset that one using string and the shimming procedures for the rear (scirocco) got the rears down to .005 degree toe in, and 1.5 negative camber. still handles great, but imperceptible tire wear after 10k miles.
and I was handing it to a first time driver... so ... no.
reset everything to a very stable config. lotso rear camber (which necessitated being extremely picky with the toe in)