Post pics of your fuel-consumptions
04-18-2018, 02:57 PM
#16
Why would you expect disabling PSM to improve your mileage? I thought it just cuts engine output when you're doing smokey burnouts and works the brakes in an emergency to prevent you from landing upside-down like a turtle. Is there some other aspect to it?
cheers,
c
cheers,
c
04-18-2018, 03:15 PM
#17
PSM also changes the shift points, doesn't allow first gear starts without kickdown (large throttle openings).
Lotus (sorry I've been a Lotus guy for 20+ years) did a study comparing different shift points and their effect on mpg. IIRC they found a somewhat faster launch using all the lower gears and higher rpms (in general) getting up to speed and then shifting to the tallest gear (without lugging the engine) was better for mpg. This was compared to shifting up as early as possible and slowly accelerating (lugging the engine). Porsche actually says not to lug the engine in the manual... but then they program the tiptronic to always start in 2nd gear. There are some theories that the higher engine load and larger throttle opening in a taller gear (because the driver will tend to push the throttle farther to get going), can tend to spray too much fuel, possibly washing the cylinders and potentially leading to the cylinder scoring issue... also hurting mpg.
So I did a test with PSM off, starting in 1st gear, faster starts, manual shifting without lugging, and I got ~4mpg better...
Lotus (sorry I've been a Lotus guy for 20+ years) did a study comparing different shift points and their effect on mpg. IIRC they found a somewhat faster launch using all the lower gears and higher rpms (in general) getting up to speed and then shifting to the tallest gear (without lugging the engine) was better for mpg. This was compared to shifting up as early as possible and slowly accelerating (lugging the engine). Porsche actually says not to lug the engine in the manual... but then they program the tiptronic to always start in 2nd gear. There are some theories that the higher engine load and larger throttle opening in a taller gear (because the driver will tend to push the throttle farther to get going), can tend to spray too much fuel, possibly washing the cylinders and potentially leading to the cylinder scoring issue... also hurting mpg.
So I did a test with PSM off, starting in 1st gear, faster starts, manual shifting without lugging, and I got ~4mpg better...
04-18-2018, 03:37 PM
#18
PSM also changes the shift points, doesn't allow first gear starts without kickdown (large throttle openings).
Lotus (sorry I've been a Lotus guy for 20+ years) did a study comparing different shift points and their effect on mpg. IIRC they found a somewhat faster launch using all the lower gears and higher rpms (in general) getting up to speed and then shifting to the tallest gear (without lugging the engine) was better for mpg. This was compared to shifting up as early as possible and slowly accelerating (lugging the engine). Porsche actually says not to lug the engine in the manual... but then they program the tiptronic to always start in 2nd gear. There are some theories that the higher engine load and larger throttle opening in a taller gear (because the driver will tend to push the throttle farther to get going), can tend to spray too much fuel, possibly washing the cylinders and potentially leading to the cylinder scoring issue... also hurting mpg.
So I did a test with PSM off, starting in 1st gear, faster starts, manual shifting without lugging, and I got ~4mpg better...
Lotus (sorry I've been a Lotus guy for 20+ years) did a study comparing different shift points and their effect on mpg. IIRC they found a somewhat faster launch using all the lower gears and higher rpms (in general) getting up to speed and then shifting to the tallest gear (without lugging the engine) was better for mpg. This was compared to shifting up as early as possible and slowly accelerating (lugging the engine). Porsche actually says not to lug the engine in the manual... but then they program the tiptronic to always start in 2nd gear. There are some theories that the higher engine load and larger throttle opening in a taller gear (because the driver will tend to push the throttle farther to get going), can tend to spray too much fuel, possibly washing the cylinders and potentially leading to the cylinder scoring issue... also hurting mpg.
So I did a test with PSM off, starting in 1st gear, faster starts, manual shifting without lugging, and I got ~4mpg better...
cheers,
c