NASCAR engines and the 1997 Mercedes SL600 have one thing in common


NASCAR is one of America's premier motorsports. Despite its “stock car” roots, the series now uses purpose-built race cars and bespoke engines that have almost nothing in common with regular road cars. In fact, a NASCAR Ford Mustang probably has more in common with a 1997 Mercedes S-Class than a Ford Mustang street car.

We became aware of this hilarious fact thanks to the racing mechanic and Autopian employee Bozi Tatrevic. He's an experienced pit crew and knows a thing or two about race cars.

Vidframe Min Top

Vidframe Min. Below

Bozi was recently searching the NASCAR parts database and came across something interesting. These are the ignition coils approved for use in the three best NASCAR series.

There are only two ignition coils on the NASCAR approval list. There is one from McLaren Electronics Systems and the other is a Bosch part. The latter is listed under part number 0 221 504 001. “It’s part of the NASCAR parts database,” Bozi told me. “Every part used in a race car in NASCAR’s top three series must be submitted to NASCAR for approval, and once approved, it will be listed in this database.”

Type this part number into Google and you will find a ton of parts sites selling these coils for around $70 each. Because they are often used in a whole range of Mercedes-Benz models!

Screenshot 2024 04 05 150225

Screenshot 2024 04 05 150215
The Bosch P50, both with and without an integrated spark plug connector.
Mercedes Benz S-Class 1993 pictures 1 (1)
Mercedes-Benz used these ignition coils on a number of models in the mid-1990s.

This so-called P50 ignition coil was found in the Mercedes SL500 and SL600 from the mid-1990s. They used a whole range of these coils in their V8 and V12 engines. The same part was also found on several S-Class models from 1992 to 1999 and also on the E420.

As explained in Bosch documents, the P50 ignition coil was designed to mount directly to the cylinder head in a coil-on-plug configuration. In many applications it is used with a long rubber boot that connects it directly to the spark plug. However, the boot is not an integral part of the P50 coil and can instead be used as a small square model with a regular spark plug wire connecting to the output terminal.


Https Wp Content Uploads 2016 06 Rye Fr92 Wallpaper

Https Wp Content Uploads 2016 06 Rye Fr92 Wallpaper (1)
You have to squint, but they are there.

Bozi noticed that the coils were approved for NASCAR, but I wanted to see if they were actually used in real NASCAR engines. I skipped distributor-based engines because the Bosch coils are really designed for a more modern coil-per-cylinder setup. As I looked around, I found photos of the Ford FR9 engines used in NASCAR and was able to spot the Bosch coils quite easily. In photos taken by engine builder Roush Yates, they are mounted in groups of four near the air intake. From there the spark plug wires extend to the spark plugs attached to the exhaust ports.

It can be a bit confusing as the coils are attached in square brackets which obscure their shape a bit. If you want a better look, you can zoom in on this high-resolution photo from the NASCAR Hall of Fame. If you look closely you can see the small plastic tooth on the top of the coil, which is characteristic of the Bosch part.

Nascar Hall of Fame (51419092305)
via Jeffrey Hayes, CC BY-SA 2.0
Screenshot 2024 04 05 134308
via Jeffrey Hayes, CC BY-SA 2.0
Screenshot 2024 04 05 134754
Note the small tooth on the ignition coil right next to the spark plug wire connector. via Sparesbox

It appears that at least some Chevy engines in NASCAR use the same part and layout based on pictures from Engine builder Mag in 2017. I did some research on Toyota's NASCAR engine program and I assume they used the same coils in 2017.


They look like the same Bosch coils, but I can't see closely enough to be sure.

Amusingly, based on the part numbers, it appears that NASCAR only allows the Bosch P50 coil. This would prevent teams from using the Bosch P50-M, which is a special motorsport version designed to better withstand vibration damage. You can actually buy the racing parts supposedly used by the Aston Martin LMP1 racing team on eBay. If you prefer to order new, search for part number F 02U V00 869-01.

In any case, it was interesting to see that modern NASCAR engines have something in common with classic Mercedes-Benz models. The road car world has moved on beyond the P50, but it seems like Bosch has sold a lot to NASCAR teams since the part was approved in 2015.

Photo credit: Jeffrey Hayes, CC BY-SA 2.0, Sparesbox, TRD via YouTube Screenshot, RoushYates, Bosch, Mercedes-Benz