Cruising AFR

[Josh]

Well im now sitting at 15.6 cruising @110kph, with 42 deg timing. Purring like a kitten! Previously tuned at 15.3, 35 deg @110kph and i was able to reduce most MAP values in the VE table by at least 5, some as much as 10! Excited to go on a trip and see what my fuel mileage is! Should be easily >30mph, currently averaging 29mpg highway now.

[Spittybug]

Well im now sitting at 15.6 cruising @110kph, with 42 deg timing. Purring like a kitten! Previously tuned at 15.3, 35 deg @110kph and i was able to reduce most MAP values in the VE table by at least 5, some as much as 10! Excited to go on a trip and see what my fuel mileage is! Should be easily >30mph, currently averaging 29mpg highway now.

Do you mean Kpa not kph? If so, why is it greater than 100 if you are normally aspirated? 15.6 is probably pretty reasonable in the cruise area, but cruise is typically ~2,000 Rpm to 3,000 rpm, with the load at ~ 40 or so Kpa. Timing wise, I would say ~13 for static, ~15 for centrifugal and ~15 for vacuum advance, so your 42 sounds about right.
What am I not understanding?

[Josh]

Do you mean Kpa not kph? If so, why is it greater than 100 if you are normally aspirated? 15.6 is probably pretty reasonable in the cruise area, but cruise is typically ~2,000 Rpm to 3,000 rpm, with the load at ~ 40 or so Kpa. Timing wise, I would say ~13 for static, ~15 for centrifugal and ~15 for vacuum advance, so your 42 sounds about right.
What am I not understanding?

Lol, no i mean kph (kilometers per hour)....

Load sits in the high 40s to low 50s when cruising.

I did notice my vacuum jump from 12 inches to 14 with the timing increase. Ill keep fiddling with the timing and see how high I can get it.


With regards to the delorean dizzy, I was reading Nick's book today. Sounds like they really stretched out the advance curve to squeeze every bit of mpg out of the 2.8. Im running EDIS ignition so I can change up the advance curve to my liking entirely thru tunerstudio. Very cool.

[Spittybug]

Too much advance will really hurt your engine, be careful. BTW, what does speed have to do with anything? It is RPM that matters along with engine load.

[Josh]

Too much advance will really hurt your engine, be careful. BTW, what does speed have to do with anything? It is RPM that matters along with engine load.

Yes I am aware. Keeping out a keen ear for pinging/knock / etc.

For tuning speed has everything to do with it. I want better mpg on the highway, where I set my cruise at 110kph. So I will see where the MAP is sitting at this speed, then tune that spot and work outwards. It is translated to an RPM for sure and thats how the MS sees it, but there is no RPM limit sign on the side of the road haha.

[Bitsyncmaster]

My 2005 Malibu shows MPG in real time. I'm pretty sure it just counts the injector pulses to get the gas consumption and applies that to formula with miles traveled. I would think someone has done this with these EFI systems you add on.

[Josh]

My 2005 Malibu shows MPG in real time. I'm pretty sure it just counts the injector pulses to get the gas consumption and applies that to formula with miles traveled. I would think someone has done this with these EFI systems you add on.

If you tap MS into a speed sensor it can calculate MPG. I had that same feature in my cobalt, it was pretty cool.