After a nice little break last week, I’m back! Now that law finals are over and my third semester has begun, I’ve had a bit of time to get back into a shop and do some good ol’ fashioned wrenching again. This brings me to this week’s topic: rear-wheel drive conversions! Settle in for a good one this week, I’m going to walk you through the what, why, and how, and share my thoughts post-conversion of my own AWD car to fun mode. Let’s dive in.

What are RWD Conversion kits? Generally speaking, these can be done in a few ways. They can be homebrewed with your original axle ends and a welder (for center diff cars) or, they can use specific axle delete kits that cap the spindle on the inboard side to hold the wheel bearing assembly together. This is what I recently did with Rennline’s latest kit for the 996/997 and what we offer here for many popular Audi platforms, like the B8/8.5 S4 and B5. Whichever way you do it, you’re effectively eliminating the front axles and sending 100% of your power to the rear wheels. But why?

Depending on your platform, you can have a number of reasons to make this swap. First, even if you’re only deleting the axles, you’re removing weight. Less weight means less work for your engine to move your car, which means you feel some more power. Second, you’re removing resistance and allowing more of that power to transmit to the wheels rather than be lost in ‘driving’ the other two wheels. Again, that equates to a punchier feel when you mash the go pedal. Third, you’re taking away some of the work your front wheels need to do, which lets them dedicate their operation to strictly traction and steering rather than a powered assembly. Less work means less wear, better mileage, and a more “pure” driving experience. 

More than those technical reasons, though, is the fun to be had. Whether you have an LSD (best case) or an open diff, the balance of the car changes for the better. Sharper turn-in response, a bias to oversteer, and a more planted feeling is what you can expect from a RWD conversion. I know this sounds counter-intuitive, but hear me out. In stock or close-to-stock horsepower applications, the AWD tends to be more of a hindrance. I can tell you firsthand with my 996 C4 that the way it felt in the corners before the swap can only be described as “pushy.” It didn’t feel like I was rotating my way through the corners like an E46 M3 (the car’s arguably biggest competitor) and it just felt detached. The steering felt heavy, but not in a responsive way. Like it was fighting the added resistance and weight in every corner. It didn’t add confidence, either, as it made some low-traction events slightly unpredictable. The car just wouldn’t rotate with the throttle the way you’d expect it to, especially with a rear-engine layout. It just felt… backward.

Now how does that compare to something like an Audi, which notoriously has the engine hanging over the nose like a pendulum? In our experience, that front weight still makes it have a tendency to understeer a bit, but with the RWD conversion, it significantly improves the balance of the car. The ability to swing a big, heavy, sedan through the corners offers a hysterically fun and surprisingly predictable experience. That said, you’ll want either a sport diff or welded open diff to truly take advantage of this kit.

Now, onto the kits themselves. Pictured is the most recent work I’ve done on my 996. Rennline’s spindle caps are par for the course here, which are basically what they sound like. These caps, as I mentioned, take the place of your front axle in the spindle to hold the bearing assembly together. In doing so, in this application, I was able to remove the front axles, front diff, torque tube, and driveshaft assembly for an overall weight saving of 80 pounds. However, this setup is a bit different than the ECS kits for your Audi. If you have a 996/997 or later-model Porsche C4/C4s/Turbo, you’ll be able to do just what I did. If you have an Audi, you have a slightly different procedure.

The ECS kits allow you to do relatively the same thing, but with the transmission itself being the front diff case, you won’t be able to delete that. Additionally, some applications like the B8 S4 and C7 S6 require a center differential delete that we also have available. This setup will do exactly what I did, but remove weight from the center of the car rather than the front and allow all your power to go to the rear differential (as god intended). 

So what will it take for you to do this swap? Why don’t I let actions speak for themselves? Enjoy some hooning action by the R&D team featuring Mike Day and Kevin Ferraro hooning the recently RWD converted B8.5 S4 around our lot here:

Now that you’ve seen what it can do (with the right driver), all that’s left is to make the argument for you to consider swapping your AWD Porsche or Audi to elitism. For one thing, the driving experience change is entirely positive. I felt instantly more connected to a car that I would already describe as damn-near telepathic. With the front wheels only doing the steering, for the first time driving up the mountain roads to my little rural town here in Vermont, I felt truly engaged. It makes you think more, but in a good way, about your steering and footwork. The car sheds speed more predictably, it feels tighter in the corners, the steering feels more nimble, the rear feels more planted, and the overall joy behind the wheel is just greater in general. 

I originally purchased a C4 because I intended to drive it year-round, which I haven’t in my three years of ownership. Additionally, to get the options I wanted, it was much easier to find a C4 in the color, package, and specs than it was to find a C2. So, I had to go with the C4. After a few years of ownership, and driving a friend’s identical C2, I knew that the AWD was more of a burden than a benefit. For you Audi folks, you only have the Quattro option, which is fine and all, but if you aren’t out snow plowing with it or taking it up a desert canyon off-road, the AWD isn’t necessary. You’ll have more fun and a better experience behind the wheel with the front dedicated to steering and the rear dedicated to power delivery. 

B8/8.5 A4, S4, S5 and C7 S6/S7 RWD Kits

B5/B6/B7 A4 + S4 RWD Kits

B5 A4 Up To 2001 RWD Kits

996/997 C4/C4S/Turbo RWD Kits

So, the only thing left to do is take the plunge and go full-on fun mode. We already offer the RWD kits for your B8/8.5 S4 and A4, B5 A4 and S4, B6 A4 and S4, B7 A4 and S4, and C7 S6 and S7. And brand new from Rennline (install instructions coming soon) will be the kits for your 996/997 C4/C4s/Turbo. If your model isn’t listed here, let us know so we can get to work on it or take an angle grinder to your axles, cap them off, and go have some fun. You deserve it.