156 GTA rear roll bar on 2.5 V6

Has anyone tried it?
I believe the rear roll bar of the 156 GTA is around 3mm greater diameter than standard and will therefore make the back end of a standard 156 stiffer. This supposedly reduces the tendancy for the V6 version to understeer and makes it a little more 'chuckable'.

I heard of one guy who did this mod and found it made the cornering of the V6 better. Has anyone else tried it though, I'm just trying to get some subjective opinion before trying it out. The rear roll bar is fairly easy to fit by the look of it so I may give it a go.

It has been covered quite a few times - have a search for GTA ARB

Andy,

Mine is for sale if you are interested - 156 GTA rear anti roll bar.

Regards,

Edward.

Hi Edward,

Could be interested in that. Where abouts in Bristol are you? I'm only down in Congresbury, 15 miles south of Bristol. PM me with a price if you would please.

Cheers, Andy.
P.S. How many miles has 'it' done by the way?

I've got one on mine. (Standard 2.5 on the front)

I can't really comment on the difference its made as I put it on when I built my car - I've never driven it without it on. I can nly compare it with my old 2.5 V6 which had the same coilovers on it:

I'd say don't do it. Not unless you're going to do the front roll bar too. With the GTA rear bar on it I think, contrary to expectation, it understeers more as a result.

Hi Andy,

I am in Clevedon which is only about 5 miles from you, as you know. I will PM you shortly with a price.

Chris155,

Interesting thought, but I always thought that anything you did to increase rear roll stiffness (geometry remaining the same) would result in less understeer. As you say your experience sounds contrary to expectation. I guess there is only one way to find out.

It doesn't look too hard to change so if I don't like the results it wouldn't take much to change it back. Watch this space......

It'll be intereesting to see what you make of it. The problem is I raised the ride height on the front when I swapped the suspension over to my current V6. I also moved the battery to the boot so it kind of clouds things.

Either way, where you would expect my old 2.5 to lift off oversteer, the 3.2 just understeers. I don't think the weight difference between the 2 engines is that signicant. I don't really understand it TBH.

Oh its an easy swap BTW.

For what its worth stiffening my rear ARB to a whiteline extra heavy duty one (16mm->20mm differnce) totally transformed my cars handling, and made it way more responsive under cornering plus conclusively quicker lap times.

This would be the normally expected result for most I would say.

Originally Posted by AndyL

Chris155,

Interesting thought, but I always thought that anything you did to increase rear roll stiffness (geometry remaining the same) would result in less understeer. As you say your experience sounds contrary to expectation. I guess there is only one way to find out.

It doesn't look too hard to change so if I don't like the results it wouldn't take much to change it back. Watch this space......

Ahh I would say that is it
The 3.2 height hugely affects handling.

Dropping my car 30mm from road height to trackday height is worth the guts of a second a lap for me (> 2min lap).
I was too lazy to actually drop the car at one track day recently and the car was very understeery in comaprison to normal.

I dropped it back down for the next track day and it was just super..

The closer you can get that big hog of an engine to the ground the quicker you can throw the front into a corner which also helps to encourge the back to break free a little.

Originally Posted by Chris155

It'll be intereesting to see what you make of it. The problem is I raised the ride height on the front when I swapped the suspension over to my current V6. I also moved the battery to the boot so it kind of clouds things.

Either way, where you would expect my old 2.5 to lift off oversteer, the 3.2 just understeers. I don't think the weight difference between the 2 engines is that signicant. I don't really understand it TBH.

The thing is..... Whilst I raised the front ride height in comparison to the rear I actually dropped the car 10mm. It was a PITA on the road. I think I had it too low as it was hitting the bump stops all the time.

I then raised it 20mm so its now comparable in terms of ride height with a friends car on Konis.

Apparently the relative roll centre heights for front and rear axles affect balance significantly so I guess this would at least partly explain what you saw.

RE the bumpstops - The joys of the standard dampers - eh!

Originally Posted by Chris155

The thing is..... Whilst I raised the front ride height in comparison to the rear I actually dropped the car 10mm. It was a PITA on the road. I think I had it too low as it was hitting the bump stops all the time.

I then raised it 20mm so its now comparable in terms of ride height with a friends car on Konis.

They're coilovers......

I see what you're saying about the ride height though. Problem is, it looked like a dragster!