How to Make a Car Rear Wheel Drive
by Richard Rowe
Rear wheel drive is better than front wheel drive. Yes, there are certain situations in which front wheel drive has a slight advantage, but four wheel drive is better in almost all of them. The fact is that front wheel drive is and always has been primarily a packaging solution meant to maximize interior space while minimizing productions costs. With a bit of work and fairly minimal investment, a skilled mechanic and fabricator can make almost any car rear wheel drive simply by moving the engine and transmission to where they should have been in the first place.
Step 1
Unbolt and remove the entire front subframe assembly, including the subframe, suspension, brakes, engine and transmission. You have two options here; you can either re-use your stock powertrain and subframe/suspension or you can use one. If your engine lies aft of the axle centerline, you'll definitely need a new powertrain and its associated subframe.
Step 2
Remove your vehicle's rear seat and strip the rear interior down to expose the metal of the car body. Temporarily weld a horizontal support into place to keep the car body from twisting while you work on it. Use a reciprocating saw to cut the entire floor-pan out of the car, starting from just behind the front seats, all the way around of the perimeter of the car body, along the wheel openings and around the back of the trunk. Remove the metal cut-out.
Step 3
Align the wheels on your donor subframe/engine/transmission/suspension assembly under the rear of the car and into the space recently vacated by the floorpan. Don't worry about the track width right now, as it's easier to widen the body than to narrow the donor subframe.
Step 4
Weld or bolt the subframe to the car body, fabricating new framerails as need be from 2 by 3 inch steel tubing. Obviously, this is a gross oversimplification of a complex process, but it's not beyond the scope of an average fabricator. Affixing the subframe to the body may be as simple as cutting and trimming the old framerails and welding, or it may require fabricating an entirely new subframe from 2 by 3 steel. If you're not comfortable or experienced enough to design and fabricate such a frame, enlist the services of someone who is.
Step 5
Install a new subframe/suspension package under the front of your car. If you used the subframe/engine/transmission suspension from another car, then simply re-install your car's front subframe and suspension. If you used your car's subframe assembly, you'll need to acquire a new one from the same make/model as your car or an aftermarket Mustang II type suspension and subframe.
Step 6
Seal your new "engine bay" by fabricating a firewall from sheetmetal, placing it just ahead of the engine inside the cab of the car and extending it over the engine to just below the rear window. Plumb the engine to the radiator using a series of steel tubes, and install a fuel tank where the engine used to be. Fabricate a sheetmetal tub in the original engine bay to act as a trunk. Remember that air going through the radiator has to go out somewhere, so ventilate your hood accordingly.
Step 7
Connect the engine and transmission to their respective fluid lines and controls, including any required electrical (or electronic if you're using fuel injection) connections, coolant, fuel supply, power steering, steering linkages, shifting and throttle cables, vacuum lines and anything else you need.
References
- "Mechanics of Materials"; Russel C. Hibbeler; 2007
- "Materials Science and Engineering - An Introduction; William D. Callister; 2006
- "Race Car Chassis: Design and Construction" Forbes Aird; 1997
- "Race Car Engineering & Mechanics: Paul Van Valkenburgh; 2007
Tips
- This is a fairly basic procedure for converting a front-engine/front-drive car to mid-engine/rear-drive; the devil is in the details here, so don't expect this to be as simple as it sounds. You could easily spend a month of weekends on a conversion like this, and you're still not done dialing the suspension in, rebuilding your interior and fabricating the 100 little pieces you'll need to make the car driveable.
- If you're looking for more power on the cheap, you can't go wrong with using a subframe/engine/transmission/suspension package from the following applications: Northstar-equipped Cadillac V8s, front-drive Ford 4.6-liter V8 sedans, Nissan Maxima V6, Acura Integra/RSX VTEC inline-four.
- Don't use a MacPhereson strut rear suspension with a double A-arm front suspension like the Mustang II style. The Doube A-arm has much more grip than the strut suspension, so your car will lose grip in the back before the front. Combine this with a mid-engine setup like this and you'll wind up with an evil, oversteering mess that you won't be able to drive without spinning off the road.
Writer Bio
Richard Rowe has been writing professionally since 2007, specializing in automotive topics. He has worked as a tractor-trailer driver and mechanic, a rigger at a fire engine factory and as a race-car driver and builder. Rowe studied engineering, philosophy and American literature at Central Florida Community College.
