[Mk2] [Generic] anti roll bars

[bolton]

hi goin to get some whiteline arb's soon to go with my superstreets and polly bushes!
Should i get one jus for the front or do the rear as well?
Im after a good road car which doesnt skip round corners! Lol!
Cheers

[dantheman]

that depends on what you are trying to achieve. buying one and not the other wont stop it skipping round corners, that will be how your super streets cope with the change in anti roll bar.

adding more antiroll at the rear will move the car towards understeer
adding more antiroll on the front will move the car towards oversteer
adding both will probably keep the balance aproximately the same, though there will be a change depending on percentage increases.

so make a decision based on how much understeer/oversteer you want, and then adjust your superstreets to handle the change

[Race Idiot]

I'm pretty sure the whitelines are adjustable so you can taylor them to how you like the car.

[ashley]

that depends on what you are trying to achieve. buying one and not the other wont stop it skipping round corners, that will be how your super streets cope with the change in anti roll bar.

adding more antiroll at the rear will move the car towards understeer
adding more antiroll on the front will move the car towards oversteer
adding both will probably keep the balance aproximately the same, though there will be a change depending on percentage increases.

so make a decision based on how much understeer/oversteer you want, and then adjust your superstreets to handle the change

Not saying you are wrong- but I thought increasing the rear ARB stiffness compared to the front increased over steer?

And yes- Whiteline ARB's are adjustable

[tarmac terrorist]

i run whitelines on mine & fulll poly bush kit, front are on middle setting & rear full hard setting works for me but i do have other chassis & suspension modes as well

full spec
1)whitle line arbs front & rear
2) full poly bush kit
3) apex (bc) coil overs
4) cusco front strut brace
5) cusco rear strut brace
6) ultra racing full front under cradle
7) ultra racing inner wing braces
front arm under brace(runs just under radiator)
& soon hopefully to change all arms to pillar ball tiens

[ashley]

I also have whitelines set on full stiffness at the rear, and medium at the front: car handles really nicely. The only other mods are poly bushes, yellow billies and s-tech lowering springs.

[filthy]

I agree with ashman, that in most cases increasing rear roll stiffness (i.e. thicker rear arb with standard from arb) will give more oversteer.
And the opposite effect is generally true if stiffening the front roll stiffness only.
For road cars you should change both front and rear as a pair to avoid introducing extreme handling characteristics.
I think Whiteline sell both non-adjustable and adjustable arbs.
The TRD arbs are also available and are non-adjustable.

[djpkins]

When changing them and undoing the original nuts/bolts be carefull not to snap them...a good good soak overnight in wd40 or similar...the rears are hard to get to and require you dropping the cross beam to gain access to the nuts so you or your mechanic be carefull man.

[bolton]

Thanks for all the advise everyone!
What sort of money new or secondhand do these go for?
Cheers

[dantheman]

regarding the oversteering explanation i gave and people disagreeing, i am simply going by the facts:

-lateral weight transfer at an axle reduces that axles ability to corner, as one heavily loaded wheel, and one lightly loaded wheel has less grip than 50/50 does due to tyre characteristics
-antiroll bars reduce body roll, which reduces lateral weight transfer
-based on this, less weight transfer (caused by adding a stronger ARB) at the rear will increase rear grip compared to the front
-more grip at the rear than the front means the front will exceed grip levels first, causing understeer.

im not saying this will always be the case, there are many other suspension factors affecting antiroll moment, but theoretically my explanation is true

[filthy]

The point that you haven't included is not so much the transfer of load from side to side but transfer from front to rear or vice versa.

Increasing the rear roll stiffness without increasing the front is like putting stiffer coil springs on the rear. The result is that some of the load on the loaded front wheel is transferred to the rear during cornering giving more grip at the loaded front and less grip at the loaded rear - nearly always results in more oversteer on an MR2.

If you want to read more, there are an excellent set of books written by the late Carrol Smith, "Tune to Win" and "Prepare to Win" being the earliest two books and are the most readable. These were invaluable when I used to race single seaters and explains important aspects of roll centres and other suspension geometry changes.

[djpkins]

Filthy...god man...Thats what I love about IMOC..there is always someone in the know

[dantheman]

right i looked into this (asked my lecturer) and heres as much info as i could get on anti roll bars:

if you were to add a stiffer ARB on the rear, this would shift the % of lateral weight transfer between the front and rear rearwards. this is best explained in the context of springs. say you have 2 springs next to each other, both the same height, one is twice as stiff as the other. a plank is put on top and a force applied. in order to achieve 5mm of deflection in both springs, enough force must be applied to deflect the stiffer spring 5mm. this force will be twice as much as on the weaker spring. therefore the stiffer spring takes more of the load.

therefore if a stiffer ARB is added on the rear, it will take more of the lateral weight transfer of the car, reducing the grip at the rear and increasing the grip at the front. this will cause oversteer.

adding stiffer ARBs front and rear that are an equal % increase will have no affect at all on overall cornering ability. it will not affect understeer, and it will not increase the maximum achievable cornering accelerations.
body roll is not a bad thing as such. reducing body roll will speed up the amount of time it takes to create maximum weight transfer when cornering, as the body takes less time to travel to its equilibrium. if when the body rolls, the roll centre gets higher or moves laterally, this will reduce the predictability of the cars handling.

however adding stronger ARBs can increase jacking effects. if an antiroll moment is created when the body tries to roll, there will be a downward force felt by the body on the inside caused by the ARB, and an upward force at the outside. there is weight transfer, the force at the outside is bigger and the suspension is stiff. it will therefore resist compression and has the overall effect of lifting the body up, increasing the centre of gravity, the roll centre height, increases lateral weight transfer and so reduces overall grip.

so in summary, ARBs real purpose is to change understeer characteristics, or reduce excessive bodyroll, but stiffening them in an attempt to increase performance wont work....

phew that felt like an essay....

[ashley]

I thought stiffer ARBs means less body roll = less lateral weight transfer = higher cornering force can be experienced before grip is lost?

[dantheman]

centre of gravity is normally at its highest point when static, when the body rolls the C.G rotates around the roll centre heading slightly towards the ground but also towards the side, causing weight transfer.

but reducing body roll will not reduce overall weight transfer. overall weight transfer is purely the result of the C.G not being at the same height as the contact patch, therefore causing a roll moment during cornering because of the inertia

[ashley]

Yeah- sorry, I'm being dumb...I think you're right: ARBs simply allow you to influence the split of which outside tyres take how much of the cornering force: front or back.

[Mr2_NA]

So stock for rear, poly on the front to reduce the likely hood of spinning and increase understeer?

Or does it not work like that?

On subject still, drop links. As they attach to the arb what role do they play?

I still have standard on my rears but with coilover struts. Should I look to upgrade these as they do need replacing.


and FYI, just found this on a google search...

Droplinks for the MR2 :

Toyota seem to like charging silly amount for the Drop links on the MR2. If you find yourself in need of new ones the follwing items are a straight swap.

(To fit the front of the car)
QLS3308S - Rear BMW mini link arms - 10.04+vat each

(To Fit the rear of the car)
FDL6447 - Front Volvo S40 (96) arms (the Mitsubishi Carisma also has the same part) - 13.68+vat each

[bolton]

Yeah wats the ideal combo?

[ashley]

The 'ideal' combo has to be adjustable ARBs front and rear, then you can tweak the car to behave as you want it to depending on conditions...just my opinion though of course...

[Mr2_NA]

I might just get mine finished then take it to someone who knows the know.

Too many dangerous corners here with no speed limits so don't fancy extreme understeer at 60 with a 200ft drop on teh otherside nor do I want oversteer, i'd prefer to see where im crashing

See what its like when i've ordered the new bushes.