Converstion Kit

[MuscleProbe]

Does anyone know if there is a Rear Wheel Drive Converstion kit out there for a Ford Probe.

[2.2 Straight six]

Yes, custom fabrication.

It'll cost a small fortune, not particularly worth it unless you want to turn it into a Pro Stock.

[curtis73]

No such thing as a kit. You have to fabricate a driveshaft tunnel, a trans tunnel, and fabricate an entire cage, design, fabricate, and fully support a complete rear axle setup, not to mention cut the trunk floor to fit an articulating axle. FWD unibody cars aren't designed for the torsional stress of a RWD configuration. The only times I've ever seen FWD converted to RWD they didn't actually use the car itself. They fabricated an entire custom tube frame and cage, then put a custom built fiberglass body on top of it so that it resembled the original car. Funny car racers often do this; Chevy will sponsor them in a Cavalier, so they build a complete race vehicle and put Cavalier-like body panels on it.

They cost somewhere north of $2-3 million

You could do it for less by just hacking up and caging what you have. We put an engine, roll cage, custom suspension, transmission, and paint in a 71 El Camino (already RWD) at the shop. The tally is currently in the $28k range. Figure on doubling that at least to do it right.

[2.2 Straight six]

I've seen it done before by friends who work at a custom fabrication shop. But usually the car needs a full roll cage, seal welding and the cage has to be tied into the strut towers and firewall and stuff. Not a small job by any means.

A friend has converted his Volvo V40 to 4-wheel drive, there's no roll cage but it has a hell of a lot of chassis bracing. it's entirely seam welded, has subframe connectors, strut braces (that also go to the firewalls) and a great deal of other welding and bracing.

[MuscleProbe]

The reason for it is am going to be putting a small V8 into my Probe and of course need to convert it to rear wheel drive. I am thinking this is going to be quite the project. So in order to make this possible i am going to have to put a roll cage into the car for it to be able to work? Any specific spots where i need to connect the roll cage to the car?

[curtis73]

Everywhere

Unibody cars like your probe get their strength because of carefully geometric shaped sheet metal. Think of it like a sheet of aluminum foil. Alone its insanely weak. If you crunch it up in a ball, its very rigid. All the folds and triangulation are what make it strong. If you cut the wrong piece, your car could collapse under its own weight... seriously. Its not likely, but just for giggles sometime, cut the roof off of a Plymouth Reliant or other K-car. About half the way through the cut, the sawzall blade will get hopelessly jammed as the car will have collapsed on it.

Older V8 RWD cars typically have a full frame made out of heavy channel steel. You can remove the entire body and still have a rigid car.

The other thing you need to worry about is that a FWD car has the entire drivetrain in one unit. The engine, tranny, and wheels all are one modular type unit. They bolt into the car and the car becomes simply a trailer. The car only needs to support its own weight. If you put a RWD axle in that car, you'll have an engine and tranny twisting one way, and a rear axle twisting the other way. One good blip of the throttle and you might find all of your windows randomly exploding as the body twists. There are RWD unibody cars, but they are designed by multi-million dollar computers operated by MIT doctoral graduates that take three years to develop the body for its application. There is no way a guy in his garage can duplicate that kind of engineering with hope and a welder.

The other thing you'll need to accomplish is some serious body modification. You'll be replacing a transverse engine measuring about 18" front to back with a V8 mounted longitudinally that measures about 40" front to back. Then you'll have to find space to put a radiator that will cool all that heavy iron. Measure your current radiator, then consider that the stock radiator for most V8s is 30" x 19" and about 4" thick. You'll have to completely redesign a suspension to handle the 450-lb engine you'll be putting in place of the 250-lb lightweight you're taking out.

Then you need to fabricate a transmission tunnel, a driveshaft tunnel, and a complete rear subframe capable of handling V8 torque without ripping out the thin sheet-steel rear unibody. Think about it, your car is currently designed to carry 1500 lbs on its rear axle. After the swap, you'll still have 1500 lbs, but it will also have to deal with (taking into consideration the gear multiplication) up to 4500 lb-ft of torque just itching to rip your sheet metal frame to shreds.... that's assuming you have the engineering accumen to design a proper geometry for a rear suspension.

Then you'll have to take into consideration the fact that the front suspension in your car can't operate without the driveshafts in place. That means a complete redesign. And since front suspensions are one of the most complicated of all, its not just a guess and hope game. Read "Race Car Vehicle Dynamics" by Milliken. Its a 900 page engineering textbook that is a good start. If you read and understand all of it, then you can start the long road of math to designing a front suspension. When you get your probe all apart and realize that it is a big pile of sheet steel under there and you have nowhere to attach a suspension, that will be a whole new can of worms.

Please know that I'm not busting chops, I'm just giving it to you straight. As an automotive customizer/hotrodder myself, I've done some pretty wacky things with cars, but converting a FWD to RWD is probably the toughest of them all. I'll try anything... except what you are doing. You also have to realize that for the $75,000 you'll spend on doing it right you could own several Lotuses, or about 30 5.0 Mustang GTs, or a couple used Ferarris. And, when you're done, you'll have a Ford Probe that's worth $3000. Not a good return on your investment.

Again, not busting chops, but if you have the knowledge and talent to accomplish this task, you would also know that it just isn't feasible. In my line of work at the custom shop, its my job to take what the customer HAS and turn it into what they WANT, so I'm the master of making weird stuff happen. I don't hesitate for a second making custom modifications to some of the most delicate systems on a car... but I wouldn't touch this one with a 40 foot pole. You're talking loco. There's a reason its not done. There's a fine line between uncommon and impossible.

I do, however applaud your desire to take what you have and make it into what you want... that is the very essence of hotrodding. I just think there are more feasible ways of getting your goal... like trading your probe for a 5.0 mustang

[GreyGoose006]

or a camaro...
(stupid mustangs)







JOKING!!!
acutally, i really like the 90-92 fox bodies.
the earlier ones looked a bit funny, but the 91 and 92 especially, looked damn good.

[self-defence]

Hey everyone,

I'm sorry for just butting in to this conversation but since it is about converting a FWD into a RWD I'm all ears.
Anyway about a year back I bought my first US car (I've wanted one for a long time) a 98 Chrysler Cirrus. And I absolutely love the car. It's got only one drawback that I don't like, that it's a FWD. If it was a RWD I think it would be the perfect car for me.
Anyway one day I was thinking would it be possible to convert this FWD Cirrus to a RWD and the more I thought about it I realized most of the things curtis73 wrote. Until I attender a US car rally and meet a guy who had a Playmouth Prowler about the same year as my Cirrus.
Anyway the things that I noticed about my car was that the drive tunnel in the middle of the car would probably be big enough to accommodate a drive shaft (a friend has a RWD and the d. tunnel is about the same size). After sitting in the Prowler for a few minutes I started thinking that the center console, where the gear shifter, emergency breake are, is very similar to the one on my car. Anyway after that I started reading about the Prowler and I think that the gearboxes (acording to wikipedia) might be similar but I'm not sure about the engine.
Anyway I started thinking if the gearboxes seem to be similar and maybe the engins too and since the Prowler is a RWD would it be possible to connect a Prowlers drive shaft to my gear box and converte it into a RWD?
Or maybe the gearbox and drive shaft would fit. I mean I know there would be some modifications necesery but I'm thinking since the cars have a similar system it would be a bit easier or would it?

Anyway let me just stress I know that it would not be easy to get a different car that is RWD and that I'm just playing with the idea. So any information form if and how this would be done it would make my day. Since maybe some day I just might go for it but probably not.

Thanks and bye

[curtis73]

Absolutely not. Completely different clean sheet designs. The engine in your Cirrus is mounted transversely (side to side) and the engine in the prowler is longitudinal (front to back). The transmissions, engine mounts, suspension.... everything is completely different. You couldn't use prowler parts to make it RWD any more than you could use Ferrari parts.

Sorry, same exact boat as MuscleProbe.

[self-defence]

Thanks curtis73. Thought as much but had to ask some experts anyway.
But I still love the car drives grate but I guess I'm getting myself a corvette for summer.

Bye and thanks

[oldblu65]

There is a company in California that makes a kit to install a 5.0 L into a Focus ! There is still some fabrication involved and is not a novice project for sure ! Sorry , I can't recall the company's name right at the moment ! If you're really interested , I probably could find the info for you . I know you mentioned a Probe so this may be of no interest to you . Let me know ! P.S. -- I just entered " v8 Focus " into search and several hits came up . Not sure if any of them are the same one I was talking about but they have info ! Try it !