rear transverse leaf springs

Hi I'm hoping you are the most experienced with transverse leaf spring suspensions.

I want a very light setup on the back of my opel gt. It has trailing arms connected to the solid axle but installing a transaxle in the back is my main goal to better distribute the weight and second goal is to keep it very light.

I could use a very heavy Corvette or a little lighter Volvo suspension but I'm hoping you could suggest something that I could connect to use as the rear suspension in a rwd. I'm going to use a Porsche 924 transaxle.

The opel gt looks like a baby Corvette and I want to say it has a baby c6 drivetrain.

The car is less than 1000lbs without the drivetrain. It's very important that I won't increase the weight too much or I would need to increase the size of the engine, then torque tube, then...

I'm hoping with all of your experience you can help to tell me what parts would work the best.

 

The Opel GT,was design with really good factory suspension, just fix it if broken,,,The coil springs were even very high tech progressive springs in GT.
Stop! ,learn about the car as built.
To often,cars are redesigned { I was going to say that another ,way,an stop my first thought.} by those who have none, or near no understanding of a design,they want to do another way. Take the time n learn...Save $ n your time,plus a car.

 

The car couldn't keep the car planted back when it had 87hp and 110ft-lbs torque. There were links to help and am sure a torsion bar would be even better but only European versions got the better setup. Canadian versions didn't. I could keep it mediocre for standards 50 years ago but adding 3 times the power would turn it into a death trap. Since you don't know this, I am not going to take your advice.

Moving weight to the back, as I said, would give it even better handling.

You seem like a purist and I respect your love for wanting to keep your old car, old. I am changing this to corner on rails. I am rebuilding it into something that resembles what it would be like if it was a new car today. If you don't have comments that are helping, please don't tell me it's good enough when in reality it wasn't.

You could have helped, like another person, suggested I use a straight axle on a beetle transaxle so I could keep the original setup but add sway and torsion bars at least so I won't end up having to rebuild it right after finishing it.

I hope anyone else will keep their, keep it stock, comments to themselves. Cutting the fenders to weld in widebody fenders, newer suspension with composite leaf springs, different engine, switch to transaxle in rear...all new interior with electric ac and all the power options I could install.

I wanted to keep it as possible but for creature comforts, I know I will need to add more power to compensate. I will try to keep it under 2000lbs. Changing to poly carbonate instead of gl*** and replacing parts with aluminum or carbon fiber like the hood and inside of the doors will help save weight. I don't have a lot of money but I can wait for good deals.

Thanks for the ...advice?

 

This is what I do for a living. I design racecar suspension.

First step, purchase a $4k+ software package and familiarize yourself with it. You can replicate the results with pen and paper if you know the formulas. Or you could use a cheaper package, but most of them only have coil spring suspensions, not leaf springs.

Next step, collect any OEM parts you want to use, like the differential or transaxle, rear uprights, axle stubs, and create skeletal models of them in the software along with a model of the front suspension, the pickup points on the ch***is, and approximate center of gravity.
Build an understanding of what sorts of changes to the geometry result in what sort of change to the performance. What does raising the rear roll center do to your car? What about adding some anti-squat? Does the transverse leaf spring you are considering add some non-adjustable anti-sway affect?
Then design the arms to work with your calculations and build in some adjustment for alignment.

One of many, a custom rear subframe and arms with pushrod coilovers using Thunderbird uprights in the back of a V8 powered Miata.


Or, you could keep it simple and just build a solid axle with a three-link and a Watts link. Like my old Lotus. That's an early RX7 GXL axle in there. If you wanted lighter you could get an aluminum Speedway axle.


And the front end of that car has adjustable roll center in addition to alignment.


If you narrow down your question, you might get a better answer.

 

Well I don't have the money to put into buying software but there are many online websites that help with calculations and show different options.

The rx7 suspension has really helped to give me ideas about what I can adapt. A jag xj6 with a single tube on top can give me 2 bolts points and adapt the trailing rods for bolt points as well.

I've started to like the dedion setup. Even though it's not a true independent, it gives the best of both worlds.

Looking at a Porsche 928, the transaxle is perfect for what I want to do and the suspension gave me ideaa. The rear has shocks on an extreme angle but with the shocks straight in a coilover configuration where the stock springs are, the stock shock placement would work well as a multilink.

Keeping the solid axle throws me for a loop. I could bolt an adapter from a t5 transmission directly bolted to the axle but that would mean the transmission will pivot when the axle goes over bumps. The stock half torque tube from the yoke does this so theoretically using the transmission in place of the torque tube might work??

In stock form there is a driveshaft behind the transmission that allows play for pivoting at the yoke. Since the transmission is moving back, it would be engine, bellhousing, longer driveshaft, yoke with cut torque tube welded to adapter plate, to front of transmission, to solid rear axle.

I'm not trying to be a know it all and I'm on this sight asking questions and trying to run it by people that know 99.9% more than I do.

I don't like to get told I can't do something just because. Bring an older woman I've been told by men that I don't know anything so do lnt even try. That being said I do appreciate any advice that is helpful in my pursuit of my goals. I'm not nearly as experienced as those on here and it's very difficult to read between the lines when some information is left out. I'd rather someone explain it in detail like talking to a child than ***uming I know what they are saying and ending up spending the day or week researching to figure out exactly what was said.

I read my post and it does sound like I'm being a #$_& up troll in some ways. I was going to put "but" I have no excuse for it. I have big dreams for this car and I will slowly put the car back together using what parts are there and replace what's necessary to get it back in the road. After that it will be an ongoing project of ideas and squashing them when they are too difficult, expensive, or doesn't make sense when I remind myself it's a daily driver going to car meets, not a race car.

I have an idea from a few dragsters recommending the adapter between a transmission and solid rear axle. It sounds easy but since they are spending seconds in their cars in flat surfaces, it might not work as well in a car going over speed bumps and potholes.

If I go with CV or u-joint for a differential than I have no choice to change to another suspension. After figuring out how I can make the stock work better, I'm back to the original question, what will be a simple suspension that I could adapt from another car?

Last night I dreamed of cutting the stock axle in half so I could have a the differential bolted above it and put the CV axles through the ends so I could keep it fairly stock.

I decided to stop until I find someone, anyone, that knows more about suspension before I end up with wrecking my dream car.

If I haven't made it clear enough, I need help and will take advice in a more mature fashion, humility and without the chip on my shoulder. I will ask questions instead of making statements and I thank everyone for their input. I apologize if I came of as a known it all and ask for forgiveness for not doing this earlier.