tuning d-jet 2.0('75) - A/F ratio, effects on engine temp, Am i running lean on highway?- 14.0 @ 65-70 mph Options

[DRPHIL914]

So i've been able to observe my A/F ratio for the past 2 weeks, driving the car daily to work and some short trips of 30-75 miles.

yesterday evening, with the outside temp being @ 90, i noticed that as i increased my speed from @ 60mph i was running about 190 temp, A/F was @ 12.5-13.2 or so. but as i increased my speed to closer to 70, temp rose to 210 or so, maybe a bit more, and the A/F went up to @14.2 . As i slowed down, and even at idle ,the temp came down to @ 180-190 again.

- so is it because of running more lean? could it be timing/advance effecting this ? or do i need to adjust the MPS?

cold idle it runs at 10.5-11, warms up and driving around town im around 12.5, hard acceleration in leans out some around 13.5, etc .

- its at Bob Woodmans today, getting valves set/checked and timing(lost my timing mark on the impeller) so that will all be sorted out. today and taken out of the equation.

oh, and the thermostat works, fins are in the right position , no blockage etc.
- running brad penn oil.
-

[76-914]

Whether you're running straight gasoline or E10, and using a wideband O2 meter that reads in A:F ratio, you want to see 13.5-12.9 on the gauge while accelerating or climbing, 12.8-12.5 at WOT, and 16-17 while cruising, going downhill or decelerating.

[DRPHIL914]

Whether you're running straight gasoline or E10, and using a wideband O2 meter that reads in A:F ratio, you want to see 13.5-12.9 on the gauge while accelerating or climbing, 12.8-12.5 at WOT, and 16-17 while cruising, going downhill or decelerating.

well i can tell you i am at about 14.5 at the highest when cruising(thats 2800rpm @ 70 mph, that really seems lean , 16-17 for a air cooled motor. after the timing and valves are set today, i will recheck it and see where its at, then may have to make some adjusmtnets to the mps . thats the only way i know of leaning out that cruising mixture. and normally i try to run 89 octane non-ethanol ,but lately its almost $4 a gallon here vs $3.25 for regular stuff.

[worn]

So i've been able to observe my A/F ratio for the past 2 weeks, driving the car daily to work and some short trips of 30-75 miles.

yesterday evening, with the outside temp being @ 90, i noticed that as i increased my speed from @ 60mph i was running about 190 temp, A/F was @ 12.5-13.2 or so. but as i increased my speed to closer to 70, temp rose to 210 or so, maybe a bit more, and the A/F went up to @14.2 . As i slowed down, and even at idle ,the temp came down to @ 180-190 again.

- so is it because of running more lean? could it be timing/advance effecting this ? or do i need to adjust the MPS?

cold idle it runs at 10.5-11, warms up and driving around town im around 12.5, hard acceleration in leans out some around 13.5, etc .

- its at Bob Woodmans today, getting valves set/checked and timing(lost my timing mark on the impeller) so that will all be sorted out. today and taken out of the equation.

oh, and the thermostat works, fins are in the right position , no blockage etc.
- running brad penn oil.
-

Are you running an unmolested stock MPS? It seems similar to what I have seen, and how I find the engine wants to run. It should be richer than 14 when you are heading up a hill though.

[DRPHIL914]

So i've been able to observe my A/F ratio for the past 2 weeks, driving the car daily to work and some short trips of 30-75 miles.

yesterday evening, with the outside temp being @ 90, i noticed that as i increased my speed from @ 60mph i was running about 190 temp, A/F was @ 12.5-13.2 or so. but as i increased my speed to closer to 70, temp rose to 210 or so, maybe a bit more, and the A/F went up to @14.2 . As i slowed down, and even at idle ,the temp came down to @ 180-190 again.

- so is it because of running more lean? could it be timing/advance effecting this ? or do i need to adjust the MPS?

cold idle it runs at 10.5-11, warms up and driving around town im around 12.5, hard acceleration in leans out some around 13.5, etc .

- its at Bob Woodmans today, getting valves set/checked and timing(lost my timing mark on the impeller) so that will all be sorted out. today and taken out of the equation.

oh, and the thermostat works, fins are in the right position , no blockage etc.
- running brad penn oil.
-

Are you running an unmolested stock MPS? It seems similar to what I have seen, and how I find the engine wants to run. It should be richer than 14 when you are heading up a hill though.

I have 2 non leaking MPS's. the one i am runnint was resealed and set to factory specs by Scott in NH(who''s son just bought the 944). he has a wavetech and callibrated it. after installing it, i was having severe hunting, and it was definitely too lean, so ive been gradually tweeking it but before the A/F meter was installed, so it was more by feel and engine response. i increased richness across the board until it quit hunting and would idle decently(consider all thoer things are taken care of- no vac leaks, timing set, etc etc) so it really is running pretty good now, when warm it idles at @ 950 with lights on , maybe 1000 without, very smooth. i was going to take a peak at the plugs too again just to look at color etc.

[Mark Henry]

What you really want to be looking at is head temps. Then you will begin to learn a few things. At 400F your heads only have 1/2 their strength.

16-17 is just way too lean for an aircooled, part of the cooling comes from the fuel charge. I aim for just under 14 at cruise, 12-12.5 at WOT.

[DRPHIL914]

What you really want to be looking at is head temps. Then you will begin to learn a few things. At 400F your heads only have 1/2 their strength.

16-17 is just way too lean for an aircooled, part of the cooling comes from the fuel charge. I aim for just under 14 at cruise, 12-12.5 at WOT.

o.k. based on that i'm not too far off, maybe just a little bit lean at cruising.
, might be good to take a look at head temps, have not assessed that.
really pretty close to the 12-12.5 on WOT,
Phil