How I’d Build A Faster Wienermobile For The Weenie 500

Oscar Mayer Wienermobiles hit the track for the Wienie 500 as part of the Carb Day schedule at Indianapolis Motor Speedway and created some exciting action on track. My immediate thought as a racing mechanic was that I could see a way to win that race with the right set of modifications and adjustments, and I’ve decided to share my master plan to build a faster Wienermobile.

Each Wienermobile is built on a modified version of the Isuzu NPR-HD, which features a 6.6-liter Chevrolet L8T V8 engine that is rated for 350 horsepower and 425 pound-feet of torque. This engine is backed by an 8-speed 8L90 transmission. This is the first step in our grand plan to build the fastest racing Wienermobile. The easy items here are swapping the intake manifold and throwing on some headers, and giving it a tune that is more in line with a crate L8T to boost output to over 400 horsepower and increase speed for those straightaways at Indy.

That 8L90 will get hot under racing conditions, so the first move there is to install a transmission fluid thermal bypass valve in order to maximize flow to and from the transmission cooler in order to keep the transmission in an optimal shift state.

Once we’re putting down some better power, we’ll need to start looking underneath the chassis to improve handling and braking. The Wienermobile is equipped with 19.5-inch commercial steel wheels that are wrapped in 225/70R-19.5 commercial tires. These wheels are fairly heavy, and the tires are typically designed with a pretty hard compound and tread that is suited for dry and wet conditions. We can swap those wheels to 17×9 super singles, which will allow us to install performance-oriented tires.

We’ll want to keep a high load rating due to the weight of the Wienermobile but we can still find an ultra-high performance tire in that load range with a shorter and stiffer sidewall to not only offer a better compound for race track traction but also help to lower the ride height in order to optimize handling even further.

The Wienermobile is equipped with leaf springs, which limits upgrade options, but an easy change that we can complete is swapping to parabolic springs. The standard leaf springs on the Wienermobile feature a traditional leaf spring pack that causes the stacked leaf springs to slide against each other which results in friction. This type of friction results in internal resistance which is not present in something like a coil spring. A parabolic spring features a more stretched out shape which prevents this type of friction and results in a progressive spring that is much closer to the compliance levels of a coil spring. This type of spring upgrade would allow our Wienermobile to corner significantly better than our competitors.

Spring upgrades could be assisted by air suspension products that are already available on the market, or the possibility of working with a vendor like King Shocks which offers suspension kits for this chassis already. These suspension kits are typically focused on raising ride height for things like camper conversions, so the shocks would need to be customized for lowering, but they would offer far more adjustability as most of these shocks offer at least compression adjustment. These upgrades can be accompanied by camber and caster kits, which are available for this chassis in order to fine-tune the setup to be optimized for the layout at Indianapolis Motor Speedway.

Our Wienermobile can only go as fast as the brakes are able to slow down in the turns, but fortunately it is already equipped with a sizable 14.3 by 1.65 inch front rotor that offers a lot of thermal capacity but also a lot of weight so we’ll want to step down to the 11.5-inch rotor found on the standard non-HD Isuzu NPR to drop some weight on the front corners.

Our main focus when it comes to braking will be the brake pads, as we’ll want to have an appropriate compound handy when and if we do need the brakes. The Wienermobile uses a brake pad shape that is shared with the Isuzu Elf and Chevrolet Tiltmaster that isn’t found on other vehicles, so we’ll have to go to a custom build here with a company like Carbotech that can take a specific brake pad shape and apply one of their racing compounds. Once we’ve upgraded the pads we’ll also want to use some matching brake fluid in order to complete the package. As the race is short enough to basically be a qualifying run, we’ll want to pull those pads back so that the rotors can spin freely until we absolutely need to apply the brakes.

CFD study of the Wienermobile.

Courtesy of Dan Mather from Digital Engines. https://t.co/jh1R6zfEqh pic.twitter.com/hVBeJOKCBR

— Bozi Tatarevic (@BoziTatarevic) May 23, 2025

In order to take advantage of our other upgrades, we’ll want to make sure that aerodynamics are appropriately optimized, and as a first step, we’ll want to fold in the mirror to reduce drag on the sides of our Wienermobile. We’ll be so far out front that we won’t need to even look at those. The top of the hot dog, where the windshield glass meets the fiberglass skin is also another high-pressure area, and depending on what the rules allow here, we can start with basics like taping the transition or going as far as filling and sanding it in order to make it completely smooth. Since the Wienie 500 is only a two-lap race at Indianapolis Motor Speedway, we can also partially tape that lower grille in order to redirect some of the airflow.

Adding a splitter at the front of the bun and a spoiler at the rear of the bun could significantly improve downforce if allowed by the rules with a focus on the rear as the transition at the front where the hot dog meets the bun traps a decent amount of air which likely shifts the downforce percentage more towards the front.

We’ll also want to maximize our steering feel to take advantage of these modifications, so we’ll want to dig into the steering system and adjust the worm gear in order to make the steering as tight as possible. We’ll also want to adjust the tie rod ends in order to optimize the toe for left-hand turns.

Once all of our changes are completed, we’ll need to adjust our setup in order to optimize cross weight of the Wienermobile along with other setup adjustments before we put it out on track where it will surely gain more than a few tenths on the competition.

If we do this right, the competition will have a hard time catching up, and it’ll be our hotdoggers enjoying some milk (mustard?) and kissing the bricks.