Fuel Efficiency differences 870 vs 871

[Rawze]

(06-13-2018 )DLC Wrote:  What causes the 870 to be harder on fuel than a 871?

I've had the intake apart on an 870, the nozzle and Venturi on them appears very restrictive. Once it has been upgraded, what else stands in the way of decent mpg?

Below 550HP and driving the holy piss out of it, the after-market intake manifold will not improve efficiency on the CM870's. For something in the air stream to be "more efficient", you have to be pushing the component above its normal flow rating. -- The CM870 after-market intake manifold does improve power efficiency (does nothing for fuel efficiency though ) slightly, but none of the other components like the exhaust manifold etc. do squat.


The biggest difference is the Air operated turbocharger just does not have the response like newer engines with full VGT's do.