Quote:
Originally Posted by serialk11r
I don't know if 60% is the right conclusion to be drawing, since no load operation is affected by incomplete combustion. It's certainly a horrific number.
How's your IAT? Have you experienced any knock? You could try a more aggressive warm air intake (maybe with a manually controlled air door in case it gets too hot). The engine speed is in a pretty good spot IMO, but you're pulling too much vacuum. If you can successfully get the IAT higher than the engine can tolerate, you should be able to change the cam timing to reduce internal EGR but delay valve closure which will reduce your pumping losses further.
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I've thought about changing out the head for one that closes one of the intake valves at low RPM, as I figure it would help combustion quality in the regions I operate in, but I'm sure there's some low hanging fruit in ignition timing, air fuel ratio and cam advance.
Intake temps vary; I have some minor issues with heat soak. With my grille block fully removed and outside temps around 80F, I'll see my intake temps hover around 100F while driving. Last summer I recall seeing them get over 140F when in traffic.
The thermostat starts to open around 170F and is fully open around 190F. My radiator fan is set to come on at 195F. I had to pull all of my grille blocks off when it got above ~70F outside as I was seeing the fan cycle under normal highway driving. When outside air is even a bit cooler however its hard to get the engine up to temperature. My radiator is pretty small and is also fairly beat up. What I believe I need is a better radiator and to restrict airflow over the block when outside air is colder.
When coolant temps reach ~200F I start to get knock at WOT between maybe 1500rpm and 3000rpm. Intake temps seem secondary to that. Currently waiting to see if a Facebook contact can come through with a custom radiator that fits in the space of the stock one.
I'm hoping to play with cam advance this weekend, and build separate timing tables for different amounts of intake advance. I expect you're right in that delaying valve closure could help.