RWD vs AWD in Drag Racing

In factory form, the Camaro SS includes a posi-trac differential, which allows both rear wheels to be powered at once.

For a long time, drag racing has been led by the rear wheel drive (RWD) platforms. From the ’50s through the ’90s, everything was rear wheel drive. As recently as the mid-’90s, things have started to change. All-wheel drive (AWD) cars have made quite an impact on the drag racing world. From Subarus, to Mitsubishis, and now the Nissan GT-R, a lot of cars running at the strip have power going to all four wheels.

Which is better, and why?

In traditional RWD drag racing, the car would be set up with two key components: drag radial tires and a locking differential. With a good burnout before heading down the 1320, most RWD cars can gain traction efficiently and be propelled down the track.

For spring and summer, the RWD reigns as king, until heavy rains begin to shower down. Rain isn’t that big of a deal; however, certain power levels and mod combinations make driving in the rain more dangerous. Stalls, cams and anything but street tires will only add danger to the mix.

 

RWD Pros

1. A locking differential and a pair of slicks goes a long way towards traction and low E.T.s

RWD vs AWD in Drag Racing
In factory form, the Camaro SS includes a posi-trac differential, which allows both rear wheels to be powered at once.

2. Gear changes, transmission changes and other driveline related upgrades, mods or repairs are inexpensive compared to an AWD car. The parts availability is almost unlimited, as are the choices. F-Bodies run anything from the T-56 manual to the 4L60E automatic in stock form, and upgrade to the 4L80E or TH400. Rear ends are swapped out to either the GM 12 Bolt, Ford 8.8”, or Ford 9” rear ends. Dana 60s are available as well.

RWD vs AWD in Drag Racing
This page, taken out of Motive Gear’s catalog, shows the choices for the popular Ford 9” rear differential. Gear changes can shave tenths of seconds off E.T.s, as well as be tailored to the car’s purpose.

3. Since it’s RWD, power goes through the transmission, driveshaft and rear differential. All three components are designed to handle high loads of abuse, and can be easily upgraded to handle more. Having only three major components in the drivetrain limits the number of parts that can break.

RWD vs AWD in Drag Racing
This simple diagram shows the basic components of a RWD system. Courtesy of Drivespark.com

4. RWD systems contain fewer components and thus weigh less and have less powertrain loss.

5. RWD platforms are usually cheaper to enter.

 

RWD Cons

1. Can’t use street tires efficiently at the track. Maximum gains in lowering the E.T. are through slicks and suspension mods.

2. Can’t launch without slicks compared to AWD.

3. Inclement weather is a nuisance and is inadvisable to drive in with street legal drag tires.

4. Because so much attention is given to traction at the rear wheels, set-ups become limited when trying to compete in auto-cross, drag racing or drifting. Each style of racing must be set up differently.

5. High horsepower applications can become difficult to handle on the street.

Enter the all-wheel drive platforms. Although most are imports and have engines smaller than 5.0L, these cars are more than capable of putting low numbers at the finish line due to their turbocharged engines and their ability to power all four wheels. To add insult to injury, some AWD cars can run low 11s on street tires. Let’s compare in terms of economic feasibility, ease of modification and adaptability.

For a daily driven street car, the AWD becomes more sensible. Driving a RWD V8 through the snow-covered streets of the north can be a hassle, if not dangerous. Getting stuck and spinning out of control are only two of the common dangers. In the AWD, inclement weather does not pose as an issue.

 

AWD Pros

1. Better launch, even on street tires.

2. Safer in all types of weather.

3. Some weigh less than RWD cars, and have smaller engines.

4. Handling can be absurd, in a good way.

5. Factory turbocharged engines in AWD cars can sustain a lot of aftermarket abuse.

For a drag car, the AWD might seem like the better option. Launching on all four wheels as opposed to two seems like a logical choice, but the AWD platform has its setbacks.

 

AWD Cons

1. AWD systems are only as strong as their weakest link. Most systems are composed of a transmission, transfer case, rear differential and front differential. Instead of the RWD’s transmission and rear differential power path, the AWD complicates things by having power routed to all four wheels. Most AWD systems were not intended for high horsepower and drag strip abuse. Finding “affordable” upgrades becomes a challenge. There is also the issue of not being able to change gears at the track, nor is there an endless amount of options available. Most AWD transmissions are specific to the vehicle for which they were built. AWD parts on cars are a lot smaller than those found on SUVs.

RWD vs AWD in Drag Racing
Subaru’s transmission/center/front differential all in one. Although effective at factory levels, parts can only handle so much power, thus making this unit the car’s weakest link.

2. AWD systems lose more power through the drivetrain as opposed to RWD. Typically, RWD power loss is around the 15% mark, whether through a manual or automatic transmission. For AWD systems, 20-25% losses through the drivetrain are standard. It takes more to produce more, and for some the setback is too much.

RWD vs AWD in Drag Racing
Note the drivetrain setup in the Nissan GT-R. Although all four wheels are powered, the power from the engine must run down a driveshaft to the transmission, which is connected to the rear differential, and then runs a separate driveshaft to the front differential. 20-25% of the engine’s power is lost in this transfer.

3. AWD options are limited, and are normally found in imports. Audi Quattro, BMX x, Subarus, Mitsubishi EVO and the Nissan GT-R are all imported. The only domestic AWD cars are the Dodge Charger R/T (5.7L) and Challenger GT (3.6L). With such a heavy curb weight, any import is bound to be faster than these 4,000lbs (or heavier) cars.

4. Not everyone has an AWD car, so you have to pay the “not everyone has it” price tag. Only so many companies will offer upgraded and race ready transmissions, differentials, transfer cases and axles.

5. Most AWD platforms are more expensive to enter compared to other cars with the same power that are RWD.

 

So, which one is better?

To be completely honest, it all comes down to personal preference and available money on hand. If you desire to have any car that can run 11s in the ¼ mile and maintain street manners, the cheapest route would be a RWD car. The hassle that comes with it would be changing wheels and tires at the track, while upgrading the suspension for drag use only. A 4th Gen F-Body, Mustang GT or Cobra (’03-’04) can easily get the numbers you desire. Junkyard engine builds, salvaged rear ends and DIY transmission builds are common. People have built 600 RWHP+ cars through junkyard parts as opposed to crate engines!

If AWD is something you’d like, go for it. The problems that will arise are going to be drivetrain and powertrain related. With most AWD cars, your options are limited, and you have to use what is available to you. Since most performance-based AWD cars are turbocharged, the hassles of turbo ownership come along with them. Finding parts is going to hurt your wallet and your abilities. Most AWD cars do not have such luxurious options for differential gear changes, transmission gear changes etc. The junkyards also charge a premium on any AWD parts; engines, transmissions, etc.

There isn’t a definitive answer to which is better. The driver has more to do with what the car can do than anything else. If RWD is your thing, stick with it. If turbocharged AWD cars is your thing, then stick with that.

Dollar per E.T. reduction, RWD cars will continue to dominate the drag strip. The availability of the cars, parts and modifications lower the cost of the platform.

Yes, a Nissan GT-R can run 11s (even reportedly 10s) in the ¼ mile in stock form. The cost of such a car? MSRP for the 2017 model starts at $109,900. If you can’t take any RWD car produced before 2017 with a budget of $109,900 and hit 11s in the ¼ mile, you’re in the wrong place.

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