Leaf Springs....

kaBOOMn

kaBOOMn

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Joined
Jun 29, 2006
Messages
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Location
Adelaide, South Australia
No this is not another Corvette argument thread rehash (tho funny pics with leafsprings are appreciated!)

O.K my, Uh project

http://forums.finalgear.com/post-your-car/kabooms-uh-project-23969/

Having a little trouble with the rear suspension design, mostly due to the fact the ideas I had weigh too much. The rear suspension consists of a pair of Subaru WRX rear lower paralell links and a pair of trailing arms (or links) to control the toe.....oh and I'm using a Subaru Forrester GT rear upright/caliper

I was thinking (and have been thinking) why not use a transverse leaf spring (only 1!!!!) like a corvette....its light and simple, and I don't need a upper control arm to keep the rear wheels camber in check....

Talk me out of it guys....what have missed?

edit:

Ooops wrong section....uh mods can we move this into general automotive?
 
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-Packaging can be problematic; the leaf must span from one side of the car to the other. This can limit applications where the drivetrain, or another part, is in the way.
-Materials expense. Steel coils are commodity items.
-Cost of modification. Due to the specialized design and packaging, changing spring rates would require a custom unit. Coil springs in various sizes and rates are available very inexpensively.
-Prone to damage.
 
Kaboom, I think its a great idea. I would get a diagram of a corvettes rear suspension and base it on that.

Leonidae said:
-Packaging can be problematic; the leaf must span from one side of the car to the other. This can limit applications where the drivetrain, or another part, is in the way.
-Materials expense. Steel coils are commodity items.
-Cost of modification. Due to the specialized design and packaging, changing spring rates would require a custom unit. Coil springs in various sizes and rates are available very inexpensively.
-Prone to damage.
Click to expand...

What? Prone to damage? Please elaborate.
 
well, the composite leafsprings atleast.. they dislike heat and chemical substances according wiki.
 
kaBOOMn said:
I was thinking (and have been thinking) why not use a transverse leaf spring (only 1!!!!) like a corvette....its light and simple, and I don't need a upper control arm to keep the rear wheels camber in check....
Click to expand...

Ok, and how do you plan to control camber then?
 
The project will forever be mocked for having lolspringz. I rest my case.
 
It's not all bad - at least he doesn't have pushrods.
 
Leonidae said:
-Packaging can be problematic; the leaf must span from one side of the car to the other. This can limit applications where the drivetrain, or another part, is in the way.
-Materials expense. Steel coils are commodity items.
-Cost of modification. Due to the specialized design and packaging, changing spring rates would require a custom unit. Coil springs in various sizes and rates are available very inexpensively.
-Prone to damage.
Click to expand...

Well the spanning issue really isn't a problem, since we are crossing over the gearbox.....um actually I'll have to check if you clear the Turbo dump pipe. If I could find my digital camera (or was home) I'd show you a happy snap :(

I wasn't concerned about getting a custom leaf set; We use coilovers on other cars, and it works out around $250AUD a pair. From memory I belive getting a single set leaf is around $150....that info was second hand off a customer of mine....I'll have to double check that figure....

The two main issues here are cost and assembly time. This isn't intended to be a one off (part of the design brief was a 225 hour fab time) so it a little bit harder than normal here....

Posmo said:
The project will forever be mocked for having lolspringz. I rest my case.
Click to expand...

*sadly* :(

When you start really looking into car design (I mean the gritty part) a lot of ideas that "normal" car people mock. I already cop enough flak for the choice of engine...

I think someone was talking about camber control, yes I suppose you would have a camber change between full droop and full bump. I'll have to look up what the Corvette does.

I do have a set of fully adjustable spax coilovers for the rear of the car, I was just playing with ideas to make the whole fabrication process cheaper. My boss thinks I'm barking mad for even considering it....oh well (maybe thats the reason hes the boss!)

Dsemaj said:
It's not all bad - at least he doesn't have pushrods.
Click to expand...

Well a few people are upset that I don't! haha

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Just a quick update, I now have just under a year to finish the car, since its a part Uni project I don't get my degree till I finish it....so the project won't die...haha!

I had to change engine, the STi engine got ditched, and now have a slightly tamer EJ20 Turbo. Erm, things are moving along quite well, hopefully we'll be driving (as a frame) next month
 
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Is this your chassis?

s900000.jpg
 
So you would essentially be using parallel lower links, trailing arms, and a transverse leaf-spring for the upper. How about a pair of cantilevered coil-overs? Be much easier to fine tune the suspension that way, and there would be less chance of one wheel effecting the other on bump. Depending on the geometry, you can orient them any way you like (longitudinal, lateral, diagonal, or whatever lends itself best for packaging) If you can design the linkage, it would be hardly more expensive. Just my idea.
 
kaBOOMn said:
I was thinking (and have been thinking) why not use a transverse leaf spring (only 1!!!!) like a corvette....its light and simple, and I don't need a upper control arm to keep the rear wheels camber in check....
Click to expand...

You still would need a UCA, you definitely don't want a swing axle. Just use a strut suspension and that'll simplifiy everything, as you won't need the UCA and you can use a simple coilover setup.
 
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