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MG MGB GT V8 Factory Originals Technical - 4link, 4 bar or ladder bar rear suspension?
|Hey all, with knowing I will be replacing the rear axle this winter with a customized Ford, I am reasearching the rear suspension.|
I see 5 options.
1. Leave stock and add in a panhard bar (lower 1" or leave alone)
2. Try to modify Mustang suspension links to MG chassis
3. Install a ladderbar system with panhard and probably coil overs.
4. Install a 4bar system with panhard and probably coil-overs.
5. Install a 4link system with panhard., and probably coild overs.
4bar and 4 link are basically the same, just bar is welded rods and link is adjustable tie-rod type bars.
My performance mentality makes me lean toward making a 4link system, why build it if not adjustable?? plus it would be more tolerant to haveing a link a touch shorter or longer as it could be adjusted via the tie rod ends.. The systems I have seen look very "simple" and straightforward to put together, just a matter of modifying design to MGB chassis and re-inforcing the chassis in appropriate locations..
|Just for jollies, what do the Camaros and Firebirds that you say can beat you use?|
|I am not sure what the GM cars use, but the Mustangs use a 4link set-up, wihtout panhard, and coil springs. Thier links are set-up diagnoally which is why no panhard. I am going to try and get a look under a stang and see if there is a way to adapt the stock mustang links to the MGB chassis, that would be REALLY nice as then I could take advantage of the large Stang aftermarket parts selection..|
|Where are the Mustang springs located relative to the axle? You may have to remove the fuel tank and invade the boot when fitting the springs order to get adequate suspension movement, as well as strenghthening the area to which the springs and shocks attach to the body. Remember that the percentage of unsprung weight will be much higher in your B than in the Mustang with the same setup.|
To add a little to what George has said I think some reinforcement of the floor where the springs mount will be essential.
With the leaf springs the weight at the rear is spread over 4 points and with a coil spring arrangement the weight is now spread over two points.
For what is is worth my thoughts are to opt for choice 5 since this will be the most straightforward to install, adjust and properly arranged should give results comparable to a full independent set up.
The loads for braking and accelleration are fed into the sill areas either side and the links aill allow fine tuning for rapid launches when needed.
This also leaves the battery box(es) un disturbed and , if there is enough clearance behind the diff casing , the fuel tank as well.
If you use coil springs my suggestion would be to mount them ahead of the rear axle centreline on the lower link with gas shocks inside (coil overs in other words), the panhard rod parallel to the rear axle centreline but at the level of the lower link and arrange a triangular bracket welded to the lower part of the main chassis leg behind the rear axle.
The weight of the links, springs, shocks are all within the wheelbase and only the panhard rod is outside but since it is anchored at one end only a percentage needs to be figured as unsprung weight.
This will feed the vertical loads into the body just ahead of the diaphragm panel dividing the boot(trunk) from the cabin.
If you want to get fancy you can feed the loads into a roll bar and the mount the roll bar to be welded or bolted to the sills just behind the seats.
The upper links will need to be mounted to the chassis where it begins to rise over the rear axle but some welded bracketry there would be easy enough to arrange.
Remember to allow for roll in your calculations so the whole axle does not bind solid.
Sounds like a great idea to me and I would be very interested in how you develop it.
If I can help further please post back,
Thanks for tall the idea. A few of them I did not grasp yet in terms of locations, but I will take this with me when I got out to look under the car..
I was/am also looking toward the #5 option if I do anything.. Thanks for you tip on the front mounted coils. I will probably mount it to the axle itself, as I would have the upper and lower links directly above each other..
Look at examples of each at: (In his rear suspension section)
|Larry...Hawkes Cars offers a complete independent hookup using Ford Sierra pieces, I believe....its available through the MGOC or Doug Jackson in California...accomplishes virtually the same thing you're trying to do...|
Thanks, but IRS and 4link are quite different. I want to retain the "live axle" format, but get it more rigidly located for better power transfer and wider tires. I am affraid to even look at the price of that Sierra set-up, I have heard a few thousand for a IRS is the norm. OUCH! :-)
But do you have a link?
|Doug Jackson is at mgbmga.com.|
|true, live & independent are different but for what you're suggesting, you might as well go all the way...currently, I have an MGC rear end with anti-tramp bars, composite springs, tube shocks, & panhard bar...were I to go any farther, I'd go independent|
|I just saw a Ford 8.8 rear axle kit installed|
in a Ford Focus to make it a rear wheel drive
with a 302cid Ford engine for power. The kit is
made by Kugel Komponents. Pics at:
This article was in HCI Hot Compact & Imports magazine,Vol.3,#8, October 2002. It had some nice shots of the rear suspension with coil overs.
This could possibly be a method to put an 8.8
in an MGB. The rear axle would need narrowing. If
the upper stabilizer bar attachments could be used
for the 8.8 upper links, the lower part could be
handled like the Focus. Putting in the coil overs
would take the most rework! Lots of welding and
battery relocation. Just a thought. I have not
really investigated it thoroughly.
I am putting a narrowed 8.8 rear axle in an
MGB. I had it narrowed by Moser. I trimmed off
the upper link mounts and as much cast iron as I
could to lighten the axle. I had Fast Cars, Inc.
(Ted Lathrop) make up some conventional spring
pads to accept the stock MGB rear springs and
put a 3.55 gear in it.
Thanks for the link to art morrison's site too. Some good pics there and what he has in the second one is basically what I was trying to cover above.
A picture being worth a thousand words etc!
Yep , totally agree there about putting the links above each other for the best geometry and if you opt for this then the coils and shocks need to be located elsewhere ; either behind or on top of the rear axle as you said.
If you weld an extra bracket to the axle housing to form a step at the level of the lower link then this will give you the maximum amount of height for the coilovers and the loads should end up going into the step in the boot panel the spare tyre buts up against, or into the chassis as it sweeps up over the rear axle.
One point would be to keep the Panhard rod as long as possible to minimise lateral displacement of the body relative to the rear axle on bump and droop.
Keep posting this is getting better by the day!
Yeah it will be allot of work, no doubt there, I just like to drag the car and have had all my drag friends steer me pretty hard away from IRS as it can be very hard ot tune effectively to the track and get rid of the twisting. That and it would require 8 links rather than 4 heh. I will look at Dougs set-up though just in case, the way things change around here you never know..
I saw those cars, Man woud I like one of those!!! I never looked at the rear suspension much, but I will go back and look again. I think I ave decided pretty much to go with the 8.8" as well, coming from the factory with Posi is just to nice to pass up. How much did Moser get you for to shorten the axles?
I was thinking similar, put the links just inboard of the normal springs to gain a touch of inboard wheel clearance, then shocks as close to that as possible, attached from the bottom front side of the axle. Panhard in their someplace..
It's a shame you ruled out option 6, the IRS. I would like to see someone try using the 8.8 IRS from a Ford Thunderbird/Cougar or even a Mustang Cobra.
Did you know that Ford developed an IRS for the very first Mustangs? Interesting:
This is right up your alley:
|Just ALLOT of work to do that Carl, plain and simple.. that would probably be as much to more work than the actual V8 conversion! :-P It is intrguiging for my road car, but until I know I can have a drag car, I will stick with live rear on it..|
This thread was discussed between 01/09/2002 and 04/09/2002
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