Closed loop Lean cruise and idle and cruise timing
Closed loop Lean cruise and idle and cruise timing
So my daily driver l67 ute on 11p does a lot of cold start short trips. My drive to work also is only 7-8km each way.
Winter time now 180deg thermostat and i noticed my fuel economy has gotten a bit worse. Like 300km to a tank all city driving short trips.
Car is 91 fuel only
standard boost pulley
Not driven hard etc. Bit of a work tow horse
Couple of questions i have been doing some googling on some usa pages and they say because of the low compression ratio of the l67 you can add a fair bit of timing in the cruise area some guys running up to 40deg of cruise timing and saying it has improvements of 1-2l per hundred km fuel economy ?
Also i am guessing these are the main closed loop and lean cruise tables below how do they all look on my tune ?
Any reason why on the A/f ratio - Idle A/F ratio vs Coolant temp, Once the car is warmed up at 92 deg c coolant temp it asks for 14.5 idle af ratio?
Air fuel ratios are good in open loop i spent a lot of time to get them pretty spot on.
Have wideband also my cold starts from stone cold and they are decent
Fuel filter not that old same as spark plugs and air filter
Closed loop set to come on at 40deg c also in the tune
and at 44deg c for idle
leads are good condition etc etc.
Car runs pretty good all round.
Just trying to get a bit better fuel econ out of it
Winter time now 180deg thermostat and i noticed my fuel economy has gotten a bit worse. Like 300km to a tank all city driving short trips.
Car is 91 fuel only
standard boost pulley
Not driven hard etc. Bit of a work tow horse
Couple of questions i have been doing some googling on some usa pages and they say because of the low compression ratio of the l67 you can add a fair bit of timing in the cruise area some guys running up to 40deg of cruise timing and saying it has improvements of 1-2l per hundred km fuel economy ?
Also i am guessing these are the main closed loop and lean cruise tables below how do they all look on my tune ?
Any reason why on the A/f ratio - Idle A/F ratio vs Coolant temp, Once the car is warmed up at 92 deg c coolant temp it asks for 14.5 idle af ratio?
Air fuel ratios are good in open loop i spent a lot of time to get them pretty spot on.
Have wideband also my cold starts from stone cold and they are decent
Fuel filter not that old same as spark plugs and air filter
Closed loop set to come on at 40deg c also in the tune
and at 44deg c for idle
leads are good condition etc etc.
Car runs pretty good all round.
Just trying to get a bit better fuel econ out of it
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- Cruise lean may 2021.jpg (361.42 KiB) Viewed 3943 times
Re: Closed loop Lean cruise and idle and cruise timing
The idle table setting is set to that figure.vp304 wrote:...Any reason why on the A/f ratio - Idle A/F ratio vs Coolant temp, Once the car is warmed up at 92 deg c coolant temp it asks for 14.5 idle af ratio?...
Can you post your timing table.
When you said you were fussy you weren't kiddin'
Re: Closed loop Lean cruise and idle and cruise timing
Hey quipt4it
This thing has to go like a sports car
But be as fuel efficient as a toyota prius lol
This thing has to go like a sports car
But be as fuel efficient as a toyota prius lol
Last edited by vp304 on Sun Jun 06, 2021 1:17 am, edited 1 time in total.
Re: Closed loop Lean cruise and idle and cruise timing
lolvp304 wrote:...This thing has to go like a sports car
But be as fuel efficient as a toyota prius lol ...
The general rule is that added timing helps part throttle feel and economy.
Add some in, maybe 0.5 degs. at a time (from 70 KPA), but keep an eye on the spark plugs for signs of detonation.
Those cruise figures look high enough. Extra timing may not help much. Won't hurt to try, as you say, off boost would have low cylinder pressure.
Re: Closed loop Lean cruise and idle and cruise timing
The 85 onwards map
400rpm to 3200 rpm area has low timing as on 91 fuel and even sometimes on e10 (i tried) down low i would get knock just as coming onto boost up to around 1-3 psi when the Intake air temps were up high exp after being stuck in traffic. I noticed it in 2nd gear. Thats why that is that way.
But that should not affect cruise much.
I have done 4000 plus km on the street now with this timing map and run on a friends dyno around 3500km ago. I also check the plugs here and there at the start before and after the dyno.
Could i add a little in at cruise areas timing wise. Watch knock sensor while driving and also check plugs after some road time.
400rpm to 3200 rpm area has low timing as on 91 fuel and even sometimes on e10 (i tried) down low i would get knock just as coming onto boost up to around 1-3 psi when the Intake air temps were up high exp after being stuck in traffic. I noticed it in 2nd gear. Thats why that is that way.
But that should not affect cruise much.
I have done 4000 plus km on the street now with this timing map and run on a friends dyno around 3500km ago. I also check the plugs here and there at the start before and after the dyno.
Could i add a little in at cruise areas timing wise. Watch knock sensor while driving and also check plugs after some road time.
Re: Closed loop Lean cruise and idle and cruise timing
If it were mine I would try it.vp304 wrote:Could i add a little in at cruise areas timing wise. Watch knock sensor while driving and also check plugs after some road time.
Gee, a 7-8 km trip is barely warming it up (in Winter).That's where you're fuel is going. Extra richness in the Cold A/F R tables. See if you can sneak a lil' of those numbers.
I know we spent a lot of time on those, but maybe juggle AE with that Cold A/F R table if you're that concerned about getting 50 mpg lol.
Re: Closed loop Lean cruise and idle and cruise timing
Yeah i know those dam short trips are killing me, and by what i read on google search cold starts can use up to 20% more fuel i think thats were its all going.
I trimmed those cold start settings a fair chunk already also
May have to put a bit of cardboard infront of radiator to block half of it over winter lollll
I trimmed those cold start settings a fair chunk already also
May have to put a bit of cardboard infront of radiator to block half of it over winter lollll
Re: Closed loop Lean cruise and idle and cruise timing
Not to mention what it's doing to the poor engine...vp304 wrote:...Yeah i know those dam short trips are killing me...
Re: Closed loop Lean cruise and idle and cruise timing
Yeah that also
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Re: Closed loop Lean cruise and idle and cruise timing
No use blocking the radiator when your got a thermostat doing it's job.