RA23 Loves to oversteer!

[jabbatron]

..........

[George]

btw very interesting thing about volvo diff that fits the RA23. Just fot the case you don't know yet, there's a variety of locking diffs available for Volvo, all rated at some $450 usd

[jabbatron]

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[George]

I've recently installed one
http://www.eaton.com/EatonCom/Produc...troitTruetrac/

as you can see Eaton makes several diff types not to mention other makes. Each model comes in many types to fit different rear ends. I have a 1994-1998 volvo 940 rear end, so I searched Ebay for something "dana 30 detroit truetrac". Since Dana 30 is common as a Jeep front axle unit I then searched among the items found for the unit specifically made for Volvo rear end (which would take more power).

Also note that earlier (pre-1991) Volvos came with slightly different diffs, so for example to fit such a diff in say Volvo240 you would need some machining on the diff. Anyway you will also need two new differential bearings and adjusting shims.

p/s Volvo diffs also come in two types depending on final drive ratio (3.73 up and others).
p/p/s a diff can't make any noise when driving straight, but wrong adjusting shims can

[jabbatron]

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[Rodger]

My suggestion is to take the rear bar off. The first thing I would do before anything else.

The rear bar effects the bump response, hitting a bump mid corner inside wheel or worse the outside wheel causes the bar to transfer that movement across the diff trying to pick up the other wheel hopping it up off the road.

TAs and RAs need really stiff fronts with a lot of castor (3-4 positive) and camber (depending on tyre grip, 1.5 street hard tyre to 3.5-4 negative, super soft) and softish rear springs and shocks. Front ride height about one inch higher than rear. Your car looks a little high in the rear.
It should not need to be any lower than a point where the panhard is parallel to the road and the front has the control arms also parallel to the road.

Once the bar is off try different tyre pressures. Front 34-40psi, rear 32-36psi. Rears a couple of psi lower can be used to absorb those mid corner sharp bumps and allow some tyre roll and heat generation in the rear tyres.

Do not yet suspect worn bushes. However do take it to a good suspension place and have them bumped and forced around to look for broken rubbers.

Also assume not, by replacing the OEM rubber bushes with poly will improve the rear handling. There is a lot to be said about the OEM rubber and alot of maintenance to keep the poly bushes from binding up over a short period of use.

Regards

Rodger

[jabbatron]

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[Rodger]

Ok Damien.

I'll waffle on again sligtly off topic but also could be relavent to others.

Leave the ride height where it is then as that slightly sagged look is about right, opposed to the slightly jacked up look. Hmm more weight in the back, that would effectively make the shocks and springs feel softer and give more straight line grip and absorb the bumps better but......!
Castor for most of us is increased by winding on the castor rods as far as they can pulling the wheel as far forward as possible and making them the same left to right. It will need to be wheel aligned as the change in castor changes the toe. More castor will make the steering feel heavier but will allow the wheels to self centre quicker allowing you to move into opposite lock correction sooner.

The extra castor will help you clear the tyre on the inner stone guard if it now rubs but when wound on as far as possible it would now foul the front lower corner. A straight tangent cut with hacksaw down from the arch to a point 60mm further forward from the corner should give the clearance.

The trick as I mentioned is to keep poly bushes from binding. The grease supplied with them is to allow the inner tube spacer to rotate freely on the inner surface of the bush. The tube should be tightly held by the bolt and the bolt tight on the bracket and neither should move. Trouble is with this design, the grease is forced out or corrupted by water, dirt, rust over a short time and the bush quickly becomes bound up making for a non working suspension joint.
Rubber has a shear property that allows it to sheer witout falling apart this is why the bush is bound to both the outer tube and the inner tube,allowing the joint to rotate with little resistance where as poly compounds do not have this property and if bound will tear apart. A car's suspension has not got enough leaverage and force to tear a poly bush apart so all that happens is the suspension joints stop rotating.

I'd suggest for a road/street car obtain OEM bushes. For a competition car go with poly and maintain them by greasing for each event.

Regards

Rodger

[bigmat]

Take it to a suspension shop and get the whole lot checked out. It doesn't sound like there's anything fundamentally wrong with the make up of your setup and looking at the rear bar, i ran at least that thick on my 23 (18mm from memory?). It sounds like something is worn or out of alignment and causing the ugly weight transfer.

Your tyres are definitely shite.

i agree with justen. i have had the same problems as you and the way to fix it is get all new suspension and tyres im sorry but thats the truth. these cars handle like puss on old bushes and shit tyres. dont band aid fix as you will regret it. look at some of the other cars on here with 200kw plus first gens and the only ones doing it safe are the ones who have put the money into and didnt cut corners. good luck and see a suspension shop

cheers mat

[jabbatron]

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[thechuckster]

just out of interest, what camber, toe and castor are you running on the front?

[bigmat]

im not having a go buddy but it sounds like your having problems and people are telling you to go to a suspension shop because we cant see your bushes, we dont know if your running stock or aftermarket mixup of suspension products and if the car is old and had nothing done to it in the last five years eg ovehaul the problem will be hard to fix on a forum. best bet take it somewhere where they know what there doing spend $100 on some sound advice. my opinion.

cheers mat

[bigmat]

My suggestion is to take the rear bar off. The first thing I would do before anything else.

The rear bar effects the bump response, hitting a bump mid corner inside wheel or worse the outside wheel causes the bar to transfer that movement across the diff trying to pick up the other wheel hopping it up off the road.

TAs and RAs need really stiff fronts with a lot of castor (3-4 positive) and camber (depending on tyre grip, 1.5 street hard tyre to 3.5-4 negative, super soft) and softish rear springs and shocks. Front ride height about one inch higher than rear. Your car looks a little high in the rear.
It should not need to be any lower than a point where the panhard is parallel to the road and the front has the control arms also parallel to the road.

Once the bar is off try different tyre pressures. Front 34-40psi, rear 32-36psi. Rears a couple of psi lower can be used to absorb those mid corner sharp bumps and allow some tyre roll and heat generation in the rear tyres.

Do not yet suspect worn bushes. However do take it to a good suspension place and have them bumped and forced around to look for broken rubbers.

Also assume not, by replacing the OEM rubber bushes with poly will improve the rear handling. There is a lot to be said about the OEM rubber and alot of maintenance to keep the poly bushes from binding up over a short period of use.

Regards

Rodger

by the way this is sound advice and i recommend what he has said. cheers mat

[andrew_mx83]

the ole pedders $14 28 point steering and suspension safety check is fucken tops, i have done it a couple of times when i decided it was not worth getting changed and jacking the car up for $14.

they will tell you whats wrong, quote you something stupid to fix it then you smile politely and go fix it yourself for nix

[sheepers]

i don't have time to read through the whole thread but if it hasn't been mentioned before then ill say it now.
make the back of the car lower than the front. it will change the car more drastically in one move than anything else you do to it.
i had exactly the same problem and this fixed it straight away.

once you've done this then you can actually drive it round a corner and start to tune the rest of the suspension.

sheepers.