hi all
im starting to do some rear end work on the 90, which includes putting a lsd diff in (happy that the diff centre just slots in to the box without changing my gear ratios) so im thinking of what camber to put on, lower the roll centre, whilst it out put sloted and maybe drilled rotors on already have koni's have standard springs but have cut them so there shorter(have worked well so far not sure what benifits will be if i get bigger ones) and im also putting in a strap that goes inside the spring area so it will not let the rear end lift anymore than what the spring sits at at a stationry position,
does anyone have any other ideas
what kind of bushing do you have on the de dion? powerflex or similar would probably do, but many rave reviews re: sz spherical ball bushing
Dehne
Have you considered the following?
As Wankski said ....
The main De Dion mount at the front of the triangle connects to the car with a giant rubber bushing. This bushing is critical and should be replaced with either a polyurethane bushing, or an Alfa SZ bearing. (I have a poly one for sale in poly ) ;)
A serious track car will benefit from chassis strengthening.
Cambered Dedion tube. The Alfa SZ has 3/4 of a degree of negative camber at the rear wheels. This increases cornering power. Although the Dedion tube keeps the wheels perfectly perpendicular to the ground during hard cornering, the tire itself will deform slightly and lean over. The slight negative camber helps cancel this out. If your car is a pure track car, this is a good modification. For a street car it will result in increase tire wear and slightly increased braking distance.
Fom Greg Gordon's site
John
i had not even thought about putting new bushes/rubbers in (thanks guys)
straps will be easy to do as have already got the stuff for them and 2 mates have done it to their cars already
prob going for neg 2 on the rear as it is easy to do
have order my vented/groved rear disks so hoping to get started on the mods soon then hopefully once all is done and tested ill will finally get to a aroca track day
cool....
may i ask what the bushing situation is on the rest of the car?
I know u are focusing on the rear, but if anything the forward castor arms on the 116 type platform is even more critical and often goes bad... also what u choose for this could help u decide on the de dion bushing...
the stock unit is a large foamy type rubber that is almost certainly half gone... improving your suspension is pointless when half the control bushings are missing...
u have two options there too... 1) poly bushing - this is cheapest and easiest...plug and play... 2) 105 ball joint, threaded onto the control rod and 2 holes drilled into the body to anchor the joint - this involves more work, but not expensive, and of course totally eliminates play...
i would suggest if you go poly for the front castors u go poly on the de dion and likewise for ball joints... in both cases the poly option will be cheaper and easier to fit...
tip with the poly de dion bushing. lube the ID not the whole bushing...
Quote from: dehne on September 26, 2010, 02:03:55 PM
prob going for neg 2 on the rear as it is easy to do
Really? How are you going to do it?
The easiest way is to cut the tube (not all the way through) about 10cm from the middle and bend the center down.
Angles you will have to work out by yourself but anything between 1 to 4 degrees depending on tires and type of driving.
Look out for toe changes too, they tend to be not so straight from the factory (or 25 years of driving).
John
I'm aware of the technique, I've just never heard it described as easy is all. You've got plenty of spare tubes I suppose though dehne, so you may as well give it a go. This seems like the kind of mod that would be very easy to screw up on the first go.
John G, if you're going to copy and paste someone elses text from another forum, you should at least acknowledge it. At least change the spelling to Aus English anyway. ;)
I see you changed the original '15 years' to 25 years though.
I know it's major engineering work but height adjustable spring mounts and outboard brakes should be considered especially if you are going to the trouble of adjustable roll center and neg camber
Hi Sheldon
I know Mats he won't try and sue me he will just get a bigger head than he already has.I usually do acknowlege the writer of the posts but last night I was tired... Legally I am not bound to but ethically I should. ;)
Dehne
I was first told about the De Dion method about 20 years ago by Tom Zat as the guys said outboard brakes very good Zat used 164 calipers Beninca used mercedes discs clamped by Commodore slide-type calipers on his Targa car.Lenz from Alfagtv6.com fitting 75 V6 Front brakes at the dedion, hydraulic handbrake, wilwood adjuster, gta 305mm 4pot brembo front, 25.4mm BMW master, http://www.alfagtv6.com/phpBB3/viewtopic.php?f=3&t=880
Since the Alfa SZ every transaxle owner who wants to improve handling should duplicate the mods to the level of the SZ and then there is the RS racing gear to consider.
John
choderboy - very intersting set up, was a space made up for where the rotors were originally? is the rear wheel offset effected with the addition of the rotors?
cheers, brad
Nice work Choderboy!
Well worth the unsprung weight and the loss of the handbrake.
But I have read on the ALFABB.COM you can fit a motor cycle caliper to one of the rear outboard calipers or fit a drift lock up set up.
John.
thanks for the info.
im considering doing this modification to my track car, but not sure if its really worth it as its not a full on race car as such.
machining the spacers and making the caliper adapters wont cost anything as i can do myself. so its really upto if its worth it performance wise as oposed to cost. but as you say great upgrade for a race car but for a track car that will go out once or twice a month and 100% speed is not required is it nessiscary?
what is required to do the roll centre modification?
cheers, brad
Here's one for ya. Turns a transaxle into a box behind the engine when the power is over the top and breaks the tranny.It's on ebay at the mo.
http://cgi.ebay.co.uk/T5-GEARBOX-fit-RWD-ALFA-V6-LSD-/280566109743?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item41530b162f (http://cgi.ebay.co.uk/T5-GEARBOX-fit-RWD-ALFA-V6-LSD-/280566109743?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item41530b162f)
hi all
wow you guys have been busy posting i have not read it all yet but will today/now just thought i would say thanks first
hi sheldon
the father inlaw is going to do the roll centre change for me as he has done a few in his time he showed me how to do it before but i prefer someone who has accuatly done it, and yes have a few spare rear ends so im going to do 2 of them never hurts to have a spare one modified and ready to go, what camber do you have on urs,
as for all the other guys that have comented on this subject thanks heaps and i think i will look into a few other options, and i will start ordering all new poly bushes soon and do the whole car just want to get the rear done before dec for my next play,
as for ur post MD the father inlaw is going to build a new race car from scratch using alfa 90 running gear with a mid mount engine so this could certainly help him, will have to look at it further though may not suit his needs
will keep posted as i go on
Quote from: dehne on October 04, 2010, 09:58:04 AM
hi sheldon
the father inlaw is going to do the roll centre change for me as he has done a few in his time he showed me how to do it before but i prefer someone who has accuatly done it, and yes have a few spare rear ends so im going to do 2 of them never hurts to have a spare one modified and ready to go, what camber do you have on urs,
Ah okay, there's where the confusion is. Changing the roll-centre has no effect on camber. You need to cut-and-shut the tube to change camber (or apply heat apparently). Neither of which sound like an easy job.
changing roll center and camber at same time pointless doing 1 with out the other
have ordered new poly bushes for every thing as well as braided brake lines for only $140 pretty happy with that
hoping to get everything soon so i can get it finished