Quote:
Originally Posted by m6-lt1
The 6.7 is an entire new generation of GM small block. It’s a Gen VI engine, not a Gen V. Some differences include (aside from the displacement)
Dual port and direct injection
Fully forged bottom end
Different intake
13:1 compression
Probably different cam, heads and valve sizes.
Probably a different size throttle body (too lazy to google this and the one above).
It is going to be a neat engine and I am excited about it. I just hope the piston ring end gaps aren’t as tight as the gen V stuff but it most likely will be unfortunately.
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So the way emissions works is, emissions is a byproduct of burning fuel.
If you increase the amount of air (adding displacement) you have to add fuel. Otherwise you will have an incorrect air to fuel ratio. So more air = more fuel = more emissions.
You can do fun things like turn off half your cylinders to reduce your displacement to reduce emissions. And it might work correctly somtimes.
If you want an LT2 to get better emissions the it can be done. Sacrifice displacement by running an even more aggressive DoD system, and change the tune. It's not rocket science.
If you wanted to turn a LT2 into a 6.7 then just shorter rods and longer throw crank and you do it. Compression ratio will follow it, its just engine math. Peak power rpm will follow cam and intake design. Stroker engines usually make their power sooner in the rpm vs the square counterpart.
If they were trying to meet emissions standards they would have made the engine smaller. not bigger. Now if you said they are trying to stay competitive and one up the last engine in power but needed a new fueling option to achieve the goals. Then i would believe that.