I Review a 2021 RAM 3500 High Output Cummins Turbo Diesel engine and explain the mechanical differences between the standard output and the high output Cummins engine. The 6.7 HO Cummins is posting 420 hp and an industry leading 1075 lb-ft or torque giving you the most powerful pickup truck engine to date.

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I hope everyone had a great weekend! my good friend Ryan at back roads garage let me gets my hands on his beautiful 2021 RAM 3500 with the High Output 6.7 Cummins. I figured it would be a cool video just talking about why and how the HO Cummins is more powerful then the standard output.

So the fourth gen RAM HD trucks had a variety of power outputs coming from the 6.7 Cummins. most notably was the manual transmission option leaving you with ONLY 660 lb-ft of torque vs a truck with the Aisin transmission could reach up to 930 lb-ft of torque. so even in the last generation of ram truck there were variations in power outputs.

in 2019 Cummins beefed up the 6.7 platform to be able to handle over 1000 lb-ft of torque. they strengthen the block, made the mean bearing caps stronger, main bearing cap bolts are thicker. the crankshaft is stronger, connecting rods are stronger. piston wrist pins are thicker and stronger. so this engine got some pretty major upgrades.

2 things that I don't like about the upgrades in 2019 are hydraulic lifters. I think those are weaker and more prone to failure then solid lifters. and the introduction of the cp4 fuel pump. now in 2021 Cummins and RAM removed the cp4 fuel pump because of failures and I'm just shocked why they went with that in the first place.

So all of those upgrades are shared across both the Standard Output and the High Output.

the major differences between the two engines are compression ratios. so the high out engine has a lower compression ratio at 16.2 :1 then the SO at 19:1. This allows the HO to utilize the turbo much better and be able to handle more boost giving this engine more power. sounds counter intuitive but its true.

the pistons on the HO are most likely different to give it a different compression ratio. I would also imagine there is some sort of fueling difference weather the injectors are tuned differently or the fuel pump is I'm not sure.

lastly and probably most importantly is the ECM tune. this is where all the major happens for these engines. A more advanced tune for the HO engines most likely gives it the biggest difference when compared the the SO engine.

Anyways I hope you liked the video!