My new arb (homemade)
Turbo Mini Forums

Hi have been busy making this arb, "losely based" on the miglia types…utilising Ø30/2 mm SS tubing, 40x8 mm blades
Waiting for M8 motorsport quality rose joints from mcgill, they probably used "royal snail"

Don´t know if it will make me faster, but it was good fun to make:)

//marcus

internationally known as "big" swede

2mm wall is pretty thick and being stainless too I can't help wounder if it will be too stiff, can it twist at all?

Edited by Jimster on 28th Jan, 2008.

Team Racing

internationally known as "big" swede

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

i dont think it will go through enough cycles outside its natural frequency to cause any problems with work hardening.

in fact i dont think its going to go through any cycles at all looking at the size of it,

it'll certainy reduce rear end grip,lol.

carl

Edited by fastcarl on 28th Jan, 2008.

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

well maybe it´s a bit stiff then, i could always cut it near the blades and try out a smaller diameter tube…any recomendations?

Will a lighter engine up front claim for stiffer arb?

By the way got my rose joints today!

cheers for all your inputs!
//marcus

internationally known as "big" swede

thats v sexy looking marcus

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

If its too stiff, regardless of the weight of the engine, surely you're just gonna lift the rear inside wheel on hard cornering - as the weight transfers to the outside wheel and compresses the suspension, the ARB is just gonna pull the inside wheel up into the arch and off the floor.

Personally, i would have used something between 12 and 15mm solid mild steel bar - that way it will have a degree of flexibility and will be able to twist a bit more. You'll still have the stability that an ARB gives you, but it won't be so forgiving that it constantly lifts the inside wheel.

That being said, if you watch the Miglia's closely, on hard cornering they lift an inside wheel every time and still get a lot of grip - although there's a lot more goes into their suspension setup than what you'd normally have on a road car.

Just as a further pointer - do you plan on fabricating some sort of ARB for the front? Personally I've never seen the point of having ARB on the back and not the front. Otherwise, the front can still roll which will either promote flexing in the shell, or if you have a very stiff cage in the car, rear inside wheel lift as previously mentioned.

Edited by Coupe on 28th Jan, 2008.

Try it and see what happens, that the only way to find out

Looks like mine is near 23mm solid bar in stiffness …thats stiff as the girl sad!
Nic, will give it a good go in a big parking lot, test the maximum adjustments, if there is no difference i guess it´s to stiff! Maybe have a friend filming aswell, just like the pros…

Thanks Coupe for the very informative answer, will probably make a front one aswell…

I actually read through all this before i designed the "stiff one", can´t be that smart can i?

"For example a 31.75mm (1¼ “) by 1.24mm (0.049”) tube bar is the equivalent of a
23.0mm solid bar, this solid bar has an OD which is 72.6% (23/31.75 x 100) of the tube
OD, and an increase in weight of 71.5% over the tube bar.
Another example is a 25.4mm by 6.35mm tube will act like a 25.0 mm solid bar as in
torsion and bending (swaybar)."

full pdf:
http://www.whiteline.com.au/docs/bulletins...d%20Swaybar.pdf

internationally known as "big" swede

Looks great anyway.
Btw is that big jar thing connected to the fuel pump a swirl pot?
Only just learned what that is about an hour ago

Warning:Stig in Training

Looks like a filter to me.

internationally known as "big" swede

jacked the car up under one of the rear wheels, 1,5 cm difference to the opposite side, stiff!
Having an 22mm/2mm bar mild steel laying around – shall i give it a go or go even thinner?

//marcus

internationally known as "big" swede

how does it handle?

internationally known as "big" swede

Might not be much help but my other non mini car has a solid arb of about 23mm in thickness on the front (it's longer than yours, think it has longer arms on it and it is poly bush mounted so that might soften it up a bit). Its pretty stiff (I haven't driven the car yet though) but we're talking a 1300kg car here with a V8 up front. So what I'm trying to say is if that is stiff on my car you can pretty much say it will be OTT for the rear of a mini! Also happens to be a whiteline like in your link:).

I would seriously try something like 12mm solid diameter bar like I previously mentioned.

Coupe, My thinking is that an anti roll bar is to do what it says, reduce body roll. On hard cornering the inside rear wheel will lift with, but the arb will be stopping the body roll and hence the outside wheel will be kept at the correct angle for the tyre to give maximum grip. I don't see that lifting a wheel on the inside has much, if any effect on cornering grip.

Also the anti roll bar on the rear will be doing a lot to keep the front wheels on the ground. The anti roll affect is to stop the loaded wheel moving into the arch, if this is on the rear then the front will be flatter. I agree that a stiffer chassis will help this, but the basic mini is well up for taking advantage of this.

There is a whole list of cars that do this. If you think that keeping the inside rear wheel on the floor is important than keeping the loaded wheel at the correct angle or the driven wheels on the floor, then you don't want to even go near an anti roll bar. With the experience I have had of anti roll bars on the hillclimber I am still undecided as to whether they have much benefit or not. Wil thinks they are great though.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

I've never seen one in the boot before, nice ONE

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

does eoll matter on the front with fwd as you dont want to be unloading one of thhe front wheels

I think the design is fine, just needs tuning. Yes ARBs can be too stiff. I still hold that the rear ARB has a good effect on the stability of the front though.

As wolfie points out though one on the front is not much good, well unless you have an LSD.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

in college tutor kinda descibed the arb when in action will lift a wheel but with the mass being over the front not too much lift will occure instead the front of the car likly to "squat" weather than happens in practice is a different matter all together.

when i was at rockingham rally few weeks back running no ARB (as iv never had one) going round corners the front would loose drive by lifting off, if the ARB wasnt working correctly i wouldnt like to think how often that would happen
Im sure if a ARB which was designed well it wouldnt suffer the problems but that would be largly dependent on other factors, chassis, sus' geometry and stiffness. If a car has very stiff suspension alot of force has to compress them before it starts to make the car "squat" keeping wheel in contact

David.

The basic point of an ARB is to allow stiff suspension in roll but suppleness of ride.

Moderm cars use ARBs sucessfully as they have good ride and handling. Minis have shit ride quality and no real need for ARBs on the road.

On the track however the suspension is not so hard, and as you lower the car it gets softer (because of the way the top are works). And with big sticky slicks on you get lots of roll. The front ARB on the TT really stiffens up the front, this basically causes understeer, but the rear ARB can be adjusted to compensate.

Works well for me, but Ben's not convinced (even though he totally destroyed our previous record at Curborough this year in a VERY driveable car)

Fastest 998 mini in the world? 13.05 1/4 mile 106mph