Author Topic: ideas for rear end set up  (Read 15523 times)

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dehne

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ideas for rear end set up
« on: September 21, 2010, 09:54:24 PM »
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
now
1x 85 mdl road 90
2013 Giulietta 1.4
2015 Launch Edition Giulietta
Past
Multiple Alfa 90’s, Alfetta’s and 147’s

wankski

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Re: ideas for rear end set up
« Reply #1 on: September 26, 2010, 11:29:42 AM »
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

JOHN G

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Re: ideas for rear end set up
« Reply #2 on: September 26, 2010, 01:41:05 PM »
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
 
Present
ALFA 75 3.0
BMW X5 M


Past
Alfa  75 3.0 qv Potenziata (Black) Concours
Alfa GTV6 GP 3.0
Alfa GTV6 GP 2.5 Concours
Alfa GTV6 SA 3.3 AHMotorsport 250Hp ATW (Grey)
Alfa GTV6 3.0 (Black)

dehne

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Re: ideas for rear end set up
« Reply #3 on: September 26, 2010, 02:03:55 PM »
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
now
1x 85 mdl road 90
2013 Giulietta 1.4
2015 Launch Edition Giulietta
Past
Multiple Alfa 90’s, Alfetta’s and 147’s

wankski

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Re: ideas for rear end set up
« Reply #4 on: September 26, 2010, 09:01:16 PM »
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...
« Last Edit: September 26, 2010, 09:19:52 PM by wankski »

Sheldon McIntosh

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Re: ideas for rear end set up
« Reply #5 on: September 26, 2010, 09:31:45 PM »
prob going for neg 2 on the rear as it is easy to do

Really?  How are you going to do it? 

JOHN G

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Re: ideas for rear end set up
« Reply #6 on: September 27, 2010, 03:10:24 AM »

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
Present
ALFA 75 3.0
BMW X5 M


Past
Alfa  75 3.0 qv Potenziata (Black) Concours
Alfa GTV6 GP 3.0
Alfa GTV6 GP 2.5 Concours
Alfa GTV6 SA 3.3 AHMotorsport 250Hp ATW (Grey)
Alfa GTV6 3.0 (Black)

Sheldon McIntosh

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Re: ideas for rear end set up
« Reply #7 on: September 27, 2010, 08:12:43 AM »
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.

Anthony Miller

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Re: ideas for rear end set up
« Reply #8 on: September 27, 2010, 09:15:06 AM »
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
Now-  '99 156 2.5l V6 (rosso)
         '88 75 3.0l V6 (grigio)
Then- '81 Giulietta 2.0l transplant (ol whitey)
         '82 Giulietta 2.0l transplant (ol brownie)
         '82 Giulietta 2.0l TS transplant (ol red)

JOHN G

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Re: ideas for rear end set up
« Reply #9 on: September 27, 2010, 12:55:32 PM »
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
Present
ALFA 75 3.0
BMW X5 M


Past
Alfa  75 3.0 qv Potenziata (Black) Concours
Alfa GTV6 GP 3.0
Alfa GTV6 GP 2.5 Concours
Alfa GTV6 SA 3.3 AHMotorsport 250Hp ATW (Grey)
Alfa GTV6 3.0 (Black)

BradGTV

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Re: ideas for rear end set up
« Reply #10 on: September 27, 2010, 05:24:28 PM »
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
79 gtv sr20, 83 gtv, 83 gtv6 3.0, 75 ts x 3, 85 gtv, 76 gt, 91 164, Subey L Series, S13 silvia, Bmw e30 318i, VT SS 6spd

JOHN G

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Re: ideas for rear end set up
« Reply #11 on: September 27, 2010, 08:28:01 PM »


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.
Present
ALFA 75 3.0
BMW X5 M


Past
Alfa  75 3.0 qv Potenziata (Black) Concours
Alfa GTV6 GP 3.0
Alfa GTV6 GP 2.5 Concours
Alfa GTV6 SA 3.3 AHMotorsport 250Hp ATW (Grey)
Alfa GTV6 3.0 (Black)

BradGTV

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Re: ideas for rear end set up
« Reply #12 on: September 27, 2010, 09:40:47 PM »
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
« Last Edit: September 27, 2010, 09:46:26 PM by BradGTV »
79 gtv sr20, 83 gtv, 83 gtv6 3.0, 75 ts x 3, 85 gtv, 76 gt, 91 164, Subey L Series, S13 silvia, Bmw e30 318i, VT SS 6spd

MD

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Re: ideas for rear end set up
« Reply #13 on: October 03, 2010, 10:30:38 AM »
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
Transaxle Alfas Haul More Arse.

dehne

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Re: ideas for rear end set up
« Reply #14 on: October 03, 2010, 11:44:33 AM »
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
now
1x 85 mdl road 90
2013 Giulietta 1.4
2015 Launch Edition Giulietta
Past
Multiple Alfa 90’s, Alfetta’s and 147’s