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Striker2237 · 03-23-2015, 07:27 PM

So I spent Friday and the weekend re-constructing my exhaust for better flow and velocity. I decided to gut the pre-cats and install a wideband O2 sensor (For the engine to be able to give me an exact fuel trim readout) to go along with the other upgrades. Considering the pre-cats we never installed as part of the original emissions system I felt fine gutting them....though I still kinda feel bad about killing two high-flow cats but I wasn't about to do THAT much welding lol!

Anyhow I reset my ECU at 2pm today prior to the test drive and WOW! My MPG on my normal route went from 10.4 to 12.7! The ECU still hasn't fully gotten used to the new setup but preliminary readings from the tuner are showing a 20% fuel trim reduction over the old setup that is definitely reflected in the MPG.

As a side benefit the power is up slightly and the sound of the cam is much more clear and angry without the pre-cats in the stream anymore. Main cat is still providing more than enough emissions filtering to be both legal and safe, well to be honest its about 17% better according to the voltage variance compared to the stock one. Not bad for a High-flow "racing only" Cat!

03-23-2015, 07:27 PM	#1 (permalink)
Striker2237 EcoModding Apprentice Join Date: Dec 2014 Location: Ohio Posts: 174 Silver Magnum - '03 Dodge Ram 1500 Laramie 90 day: 11.43 mpg (US) Thanks: 11 Thanked 11 Times in 10 Posts	Big mpg jump! So I spent Friday and the weekend re-constructing my exhaust for better flow and velocity. I decided to gut the pre-cats and install a wideband O2 sensor (For the engine to be able to give me an exact fuel trim readout) to go along with the other upgrades. Considering the pre-cats we never installed as part of the original emissions system I felt fine gutting them....though I still kinda feel bad about killing two high-flow cats but I wasn't about to do THAT much welding lol! Anyhow I reset my ECU at 2pm today prior to the test drive and WOW! My MPG on my normal route went from 10.4 to 12.7! The ECU still hasn't fully gotten used to the new setup but preliminary readings from the tuner are showing a 20% fuel trim reduction over the old setup that is definitely reflected in the MPG. As a side benefit the power is up slightly and the sound of the cam is much more clear and angry without the pre-cats in the stream anymore. Main cat is still providing more than enough emissions filtering to be both legal and safe, well to be honest its about 17% better according to the voltage variance compared to the stock one. Not bad for a High-flow "racing only" Cat!