Front ARB thickness

[peter holst]

found a ARB from a dedra integrale at last (24mm). I now need to kvow the thickness of the original alfa 155 Q4 front ARB so I?m sure to get the right one

[AlfaJack]

I can measure it later on as my car is up on axle stands at the moment.

[Steve Webb]

I thought the Q4 ARB was 22mm, I've got a dedra ARB one on my car as its a quick and easy upgrade.

Fit a strut brace and Dedra integrale ARB and the front end of the car feels much more positive.

Steve

[arjunior45]

narrow body is 23mm and wide body is 22mm. Just measured both.
1 or 2 mm of difference wont give you such an improvement, I believe.

@ Steve
which is the dia from the front ARB you use? Are all the Grale's ARB {16V - Evo1 - Evo2} with the same dia?

Nick

[Steve Webb]

Remember that the stiffness of the ARB is going to depend on the cross sectional area, so seemingly small increases in diameter are going to cause larger % increases in stiffness.

22mm diameter cross section = 22/7 * 22? (pi x r?) = 1520mm?

24mm diameter = 22/7 * 24? = 1810mm?

1810/1520 = 1.19

The 24mm diameter ARB offers an approx 20% increase in stiffness over the 22mm ARB

A little simplified but thats the general gist of it.

And the 24mm ARB is from a Dedra Integrale not a Delta Integrale.

[arjunior45]

Thanks Steve,

is the Dedra's Integrale front ARB a direct replacement?

Nick

[wrinx]

And the 24mm ARB is from a Dedra Integrale not a Delta Integrale.

Interesting....unfortunately not many (if any!) of those in the UK :(

wrinx

[T M Oren]

I see on my WB.
Changing the ARB must be lots of work.

[arjunior45]

I see on my WB.
Changing the ARB must be lots of work.

it is quite a work to replace the arb, but the oem one is too soft - especially the one form the wb. Q4 bends too much in the corners and a arb from a Dedra Integrale is going to be my next mod!

Nick

[T M Oren]

Ok.
Thanks for the info.

[jimnielsen]

I am going to have some new ARB's made both for the front and rear of the car to go with the D2 suspension. Any suggestions as to the best diameter for a Q4 that is ONLY used on the track?

I am going to take the original ARB's into a local suspension company and get them basically 'copied' in thicker materials.

JimN~

[peter holst]

Hi Jim!

Is it possible to make an extra set - I would be greatful for that.

maybe is is possible to make the front ARB adjustabel.
think 26 mm would be enough then.

[jimnielsen]

Peter, I will find out when the time comes for you if I can have another set made and what the cost would be. so you think 26mm for the front.. what about the rear?

I think I will have them made non adjustable, I think that to make adjustable ones that actually work, you would have to do a redesign of the system with different mount points etc.

[peter holst]

hi jim!

do you have any idea about when that is?

just founf out that the eiibach fornt ARB for the 2.0 alfa 155 is 26 mm so i think 26 mm is not enough for the Q4.

as for the back I don?t know

[jimnielsen]

could be a while - I have No idea at all as to when the D2 suspension will ship - and I won't be taking the ARB's out till then.

jim.

[WhizzMan]

Eibachs and whiteline are *really* stiff so you should be doing just fine with 26mm. Be aware that the balance between front and rear (over- and understeer) is partially controlled with the balance between the ARBs. If you put a stiffer rear ARB on, you'll get more grip on the front and vice versa. Just changing the front will make the car even more going into oversteer than it does now, so you might want to make some different sizes for the rear to get the balance right. (I'm assuming the rear ARB is more easy to swap out here)

[peter holst]

I have now given up having made a custom front ARB so I am going to use the one from an dedra Integrale.
Q: the weelbase of the widebody is 2 cm longer than my narrowbody. how can I be sure that the arb from the dedra fits?

[cuore_sportivo_155]

all suspension parts are shared between the widebody and narrowbody cars, the difference in trackwidth is due to a different offset on the wheels (ET = Einpress Tiefe or something very similar), the arbs excepted and possibly dampers excepted. But even those are interchangeable.

The wheelbase is the same for all 155's IMO, 100" or 2.54m

[wrinx]

Yes, as far as I know the extra track is just the wheel offset and 5mm spacers!

wrinx

[Q4Jan]

Suspension arms at the back definitaly not interchangable between sb and wb!
I once damaged one and the one i bought turned out to be a sb one.

wich is shorter... So the rear wheel came very much inside on the botom part.

[cuore_sportivo_155]

well, whaddaya know... did the arb fit the sb arm?

[arjunior45]

Yes, as far as I know the extra track is just the wheel offset and 5mm spacers!

wrinx

saying this, the 5mm spacers, you answered a question I always wanted to ask!
Do you know if there were spacers at the wb's front wheels too and how many mm?

Nick

[wrinx]

Sorry, I was only talking about the front wheels...they were definitely fitted with 5mm spacers from the factory, in fact they can still be bought from Alfa.

Rear wheels are a bit unknown...some reports that cars had spacers on all four wheels, some say not.

wrinx

[arjunior45]

On mine are missing both front and rear and with Speedline rims is quite ugly - mostly for the rear wheels.

Nick.

[Q4Jan]

well, whaddaya know... did the arb fit the sb arm?
Not sure if this has to be removed.

Everything was fitted before i saw the car.
Including arb i guess.

The wheel offset made the mechanics look kinda silly.
The car was lifted on the bridge because putting force on the wheel like that was not a good idea.