Challenger SRT Hellcat
I have not posted or even come to this forum in a very long time (years). It's ironic on the day I came back I had an alert you mentioned me. I still have my 2015 Hellcat but went back to my 60s/70s Mopars. I recently bought a 70 Challenger 440 RT which has my interest currently. Anyway, I think the reason the reverse is 2.90 is because Dodge doesn't expect anyone to do hard launches in reverse, so it does not matter. As to the 2.66 in the Mustang, Ford was probably being less conservative. The 2.26 stock Hellcat 1st gear is exactly the same ratio as the then production Viper transmission if I recall so I assume they repurposed it for the added strength. Take care and good luck with your car.Forum user @charger440rt summarized it nicely in this thread: “I assume Dodge went with a 2.26 in 1st to increase the torque capacity on the transmission, as the choice of 1st gear ratio is directly proportional to what a trans can ultimately withstand.” That explanation makes sense to me, however it doesn’t explain how the 2.90 reverse gear is OK, or the 2.66 1st gear in the 2013 Mustang GT-500 with a 625 lb-ft engine, so maybe we’ll never know for sure why the M6 Hellcat came with the 2.26 1st gear set.