Cruise Mixtures

[Busky2k]

14.7 is what the factory ECU would target for anything but high load. Sometimes leaner is OK provided the EGTs are under control. However 14.7 is perfectly safe, and also will give you very good economy. There shouldnt be any reason why you should go richer under vacuum conditions.

[3R1K]

I think some of us may have to do a research or test on how exhaust or filter change the factory a/f ratio, as Most of us do change exhaust and filter once you get the car into your possesion.

[JaFF]

My yellow light normally lights up quite early about 40l used then I just fill it up on the E , I will fill around 45-47l max haha.

I thought I was doing bad with those 350km (I'm a student so not much highway driving) , since BP Ult petrol price went up to 126 cents per litre!!! ridiculous (In Perth)

<{POST_SNAPBACK}>

haha did you read my post, I'm paying 132 cents per litre for normal premo 95RON. I'd give anything to be able to get 98RON for 126cents pl

[mad34]

well i feel better now atleast i know i am not alone. If i fill my tank to the point of overflow. Even if i drive like a granny the best i can get out of the tank is 350. before i put exhaust airfilter fmic i used to get 450. ah well the price we pay for owning PHAT cars hehehehe

[ed]

I get 400km from a tank.

Stock ECU

turbo back exhaust

FMIC.

I get on boost nearly every gear except when cruising.

Maybe try giving your AFM a clean with a spray of contact cleaner?

[3R1K]

a tank = how many litres?

[ed]

on the specs it's 65L.

if you're asking me, it's around 50L (when the light comes on)

[Cubes]

I've had mine checked out.

The std pfc map & light load up until around load point 12-13, it was reading spot on 14.7:1.

I had a vs v8 common whore, it had a mild cam that you could only ever so slightly hear lope over. It was remapped.

I remember the bloke saying light load was tuned to 16-17:1.

It still had sh*t economy around the city.

Driving nicely the most it would get around the city was 430-450km's per tank, but on the open road whoahhh.. an easy 650. lol

Its tank was big, I remember with cheap petrol back then (0.72-0.79c) it was costing $55-$60 to fill.

When tuning for a leaner mixture you not only have to change the afr, you also have to change the ignition timing.

A leaner mixture will require more ignition timing as it burns slower, you need peak combustion pressure to occure ~10degrees ATD.

Advancing the ignition timing also lowers the EGT, so I would think if its done correctly the egt would be very similiar to the richer mixture will less ign. timing.

Edited August 24, 2005 by Cubes

[BOOSTD]

Is Julian Edgar quoting 16:1 for a nissan?  Is that cruise or lean cruise?  Most cheap (non sequential) aftermarket computers wont cope with those kind of numbers.  We continue to run lean cruise in most holden v8's with durations up to about 220deg at 50 thou as a rule of thumb.  But this is only with sequential ECU's.

<{POST_SNAPBACK}>

"Light-load cruise conditions permit the use of lean AFR's. Ratio's of 15-16:1 can be used in engines with standard cams, while engines with hot cams will require a richer 14:1 AFR. If a specific lean cruise function is available, air fuel ratio's of 17:1 or 17.5:1 can be used, normally at standard light-load advance. The cruise air/fuel ratio can be leaned out until exhaust gas temperature becomes excessive for these conditions eg. 600+ degrees C" =)

[Cubes]

So basically.. A little can be gained. But it must be done properly and not half arsed. EGT's must be monitored.