Quote:
Originally Posted by serialk11r
I don't think it's really the enrichment's fault. You have to be giving the engine extremely high load to cause enrichment. If you look at any BSFC chart you'll notice that the efficiency gets really terrible at low rpm (like 1000), even at middle load. I think the reason for this is a combination of:
1. Slow intake air speed, poorer fuel atomization
2. Greater proportion of heat rejection into coolant, oil, pistons, etc.
3. Higher piston skirt friction, possibly bearing friction due to lower proportion of hydrodynamic lubrication
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I agree with what your saying. Today,s cars have to be at almost WOT to go into open loop.
Its nice to see the effect's on running at low rpm, high load with a engine management system that you can control all the parameters. I have the ability to lock in the values and set a knock limit ignition-retard activation. This way I can get down to the wire on my tunes and push the envelope so to speak.
On my engine the payoff for no more great BSFC numbers is around 2100 rpm.
Anything lower the BSFC suffers dramatically (poor fuel atomization). Most of it comes from my intake port size (ports are very large and lose velocity at low rpm) and the other part has to do with running gasoline.