A change to Honda’s exhaust configuration that was first spotted in pre-season testing has made the cut for the Indy 500 and beyond.

IndyCar’s engine rules allow its engine suppliers to develop new exhaust systems each year, with two provisos. First, the altered exhaust design must be submitted for homologation by the series no later than 30 days before the first race, and while the brands can use the old or new exhaust prior to the Indy 500, whichever version is deployed at Indy must be used for the rest of the year.

Honda Performance Development elected to install its 2020 exhaust configuration to open the season while making use of the extra time to have its 2021 design mass produced to supply the 17 Indy 500 entries making use of its 2.2-liter twin-turbo V6 engines.

With the start of practice at the Speedway on Tuesday, Honda’s decision was obvious as the twin-pipe arrangement last seen in testing replaced the old single-pipe design on display from Round 1 at Barber Motorsports Park through last weekend’s Indy Grand Prix.

Chevy took a different approach, bringing its new exhausts with curved sculpted outlets into service at the beginning of the championship.

It was no surprise both Chevy and Honda declined to speak about their respective exhaust developments for the Indy 500, and the change for Honda is the only outwardly visible difference between the dueling engine packages with the bodywork installed.

Honda’s return to individual engine and turbocharger wastegate exhaust outlets sprouting from each bank makes for an interesting trip down Dallara DW12 Memory Lane. (All images by the author.)

Starting with what’s on display this week, take a look at Honda’s treatment with the smaller wastegate exhaust pipe on the inside the bigger pipe leading from the cylinder head to the turbo and out through the sidepod.

Another look at the new Honda configuration with independent engine and wastegate exhaust pipes.

In the four races prior to the Indy 500, Honda used its 2020 exhaust which fed the wastegate into the main pipe to create a single outlet.

Here’s another look at the combined layout, with the wastegate pipe visible, along with the beaded welds attaching it to the main outlet.