Removed front roll bar

[jardon]

I disconnected one of the drop links to see what happened - I have front and rear IPD bars running with BC coilovers,1.5 degrees front negative camber, 1.0 degree of rear neg camber and some toe in front and rear.

The result so far is much better traction and far less wheelspin in all conditions - this was my aim. I feared it would roll all over the place and be scarily tail happy but up to now it seems relatively tame. It is noticeably more settled on rough surfaces and doesn't want to ££££ a wheel anymore on speed bumps taken at an angle.

With the bar attached I get a lot of traction loss at any front/rear damper settings from full hard to full soft. For sensible dive and roll control I was running the front dampers at 15 clicks (of 30) from full hard with the bar - less than 10 from full hard gets too jittery on my local roads to be enjoyable. At the same 15 from hard setting with the bar disconnected there was noticeably more front roll so I notched it up 4 clicks. Now very little roll (still more than with bar attached) but much more settled.

The traction difference has made me smile where previously I was cursing not getting power down in anything below 4th. My brain tells me this is probably illegal, may catch me out in the wet with snap oversteer and just sounds plain wrong. My experience of it is that the ride is comfier even at harder damper settings, the car pulls out of corners and in a straight line much better, is more composed overall and even with some fairly aggressive provocation the back end stays put. It "feels right".

On Tims advice I have bought a used 2001 23mm front bar off a 2.0t S60 to swap for the IPD one but even so I don't want to fit it. The IPD bar (25mm) is 40% stiffer than the stock one so I will get better traction if I swap but I think that with the stiffness of coilovers up front it is really driveable without. The IPD front bar with my set up is far from how I want it - I can't believe I drove the car with just the front one for ages, it must have been awful.

Tim has firmly suggested I should fit the stock bar so in time that's what I'll do but I'd be interested in anybodys comments as we all rush out and buy these things without thinking sometimes (I did). Lets face it my HIDs/Carbotechs are not strictly legal but that doesn't make them dangerous - that's how I'm viewing the disconnected roll bar in the context of good roll control with coilovers..

Interesting link on the effect of roll bar thickness on stiffness (stiffness is proportional to thickness to the power 4).

http://www.balancemotorsport.co.uk/s...Whiteline.html

eg: 23mm 23*23*23*23=279841
25mm 25*25*25*25=390625

so 390625/279841~1.4 ie: 40% stiffer.

I have notified my insurance company and they are happy with a deleted front bar. MOT should be fine with total removal but will fail if just a disconnected drop link.

As stock it was Front - 23mm, Rear - 21mm.

IPD was Front 25mm, Rear - 22mm but I didn't like it.

I currently run Front - NIL, Rear - 22mm.

I don't fancy running the front 23mm bar with the IPD 22mm bar but I have found this:

http://www.ultraracing.my/Bars.asp?ID=3811

It's a 25mm rear bar and I am very tempted as it may complement the stock front bar nicely. Where would be cheapest?

[p fandango]

Johnny Tempest noticed an improvement when he disconnected his front roll bar on his race car, again thats with coil-overs. I've just been looking at the UR racing rear bars for BT, they do 23mm while IPD do 22mm (not sure whats stock). For your UR racing stuff phone 01213742185

[jardon]

Johnny Tempest noticed an improvement when he disconnected his front roll bar on his race car, again thats with coil-overs. I've just been looking at the UR racing rear bars for BT, they do 23mm while IPD do 22mm (not sure whats stock). For your UR racing stuff phone 01213742185

Thanks for that - I have a front UR strut brace but that was a T5D5 group buy so was relatively cheap. Knowing what you have planned for BT I would fit the stiffest rear bar available and stock or nothing on the front - the caveat being that your choice of spring/damper rate will have an effect.

[AndysR]

Johnny Tempest noticed an improvement when he disconnected his front roll bar on his race car, again thats with coil-overs. I've just been looking at the UR racing rear bars for BT, they do 23mm while IPD do 22mm (not sure whats stock). For your UR racing stuff phone 01213742185

Stock rear roll bar was 22mm on mine but the make up of the bar is different on the IPD one compared with the stock one which allows for less flex....

[p fandango]

Thanks for that - I have a front UR strut brace but that was a T5D5 group buy so was relatively cheap. Knowing what you have planned for BT I would fit the stiffest rear bar available and stock or nothing on the front - the caveat being that your choice of spring/damper rate will have an effect.

i was very impressed with UR's prices, i paid £250 for all 4 underbody braces on BT which didn't think was bad (did collect). With my driving style i always got on well with the standard balance, i always brake late into the corner & the back comes round. I'll have a mess & see once she's on the road, with the new coil-overs the balance is going to be totally different now anyway

[Al115]

Interesting, Jardon - thanks for sharing. I'm not surprised - I've done the whole "stiffen everything up" thing too, and the results weren't always good. Never thought of removing the front ARB completely, though!

[JT]

ok, having read this and done a bit of video editing,
hopefully you can see what having 900lb springs on the front and an IPD anti-roll does for the car round the corners.Its not great to say the least! the car is just bouncing on the springs as they are too strong and the ARB is just making things worse.

http://youtu.be/uBQpUmWp4fU

the next clip is with the same springs,but the ARB has been disconnected.

http://youtu.be/pxMPLTDaSj8

It makes quite a big difference,hopefully you can see that?
I now have have 700lb springs on the front,but as yet have not tested these. I might refit the standard ARB,but if it starts bouncing again...........it'll come off!

[Al115]

Nice illustration!

[mitchyboy01]

ok, having read this and done a bit of video editing,
hopefully you can see what having 900lb springs on the front and an IPD anti-roll does for the car round the corners.Its not great to say the least! the car is just bouncing on the springs as they are too strong and the ARB is just making things worse.

http://youtu.be/uBQpUmWp4fU

the next clip is with the same springs,but the ARB has been disconnected.

http://youtu.be/pxMPLTDaSj8

It makes quite a big difference,hopefully you can see that?
I now have have 700lb springs on the front,but as yet have not tested these. I might refit the standard ARB,but if it starts bouncing again...........it'll come off!

Bye bye E30!!

[jardon]

ok, having read this and done a bit of video editing,
hopefully you can see what having 900lb springs on the front and an IPD anti-roll does for the car round the corners.Its not great to say the least! the car is just bouncing on the springs as they are too strong and the ARB is just making things worse.

http://youtu.be/uBQpUmWp4fU

the next clip is with the same springs,but the ARB has been disconnected.

http://youtu.be/pxMPLTDaSj8

It makes quite a big difference,hopefully you can see that?
I now have have 700lb springs on the front,but as yet have not tested these. I might refit the standard ARB,but if it starts bouncing again...........it'll come off!

Excellent video - thanks!!


900lb!!!

I suspect your 700lb fronts will help with traction significantly especially on more uneven tracks (I have 2 days track experience so laugh at me if you like). I really don't know whether the front ARB is required with that much roll stiffness but as you say experimentation is the key.

[JT]

well i hope the 700's do what I want.

but yes,trial and error, but every set up is different.
there are not 2 cars,drivers or tracks that are the same, so what works for one.........blah blah blah! lol

[t5_monkey]

I've heard it said don't bother changing the front ARB on a FWD car.....

Depends on your driving style too.... personally I like it smooth and hard