Lean cruise option ?
09-20-2017, 07:35 AM
#1
Lean cruise option ?
Have crap fuel consumption, so, does lean cruise is now permit with the "swap segment" on HPT ?
(don't want destroy my PCM for test if i'm not 100% sure as i have a race in 3 weeks)
Any other solution (no only one time but "flex" solution as i often make change on my tune about timing/afr/tire/rpm limit/airflow/fuel stoichio... each time the situation change)
(don't want destroy my PCM for test if i'm not 100% sure as i have a race in 3 weeks)
Any other solution (no only one time but "flex" solution as i often make change on my tune about timing/afr/tire/rpm limit/airflow/fuel stoichio... each time the situation change)
09-21-2017, 01:56 AM
#2
Le Mans Master
Member Since: Aug 2005
Location: CA.
Posts: 5,255
Likes: 0
Received 281 Likes
on
258 Posts
St. Jude Donor '13-'14-'15
Lean cruise was a "dream by GM" to install an unused program in your ECM in case the technology ever progressed to where they could later activate this program to get you better fuel mileage during cruising speeds----It never happened---
However there are other ways to get better mileage on a C5---On an auto car this is mostly gained with trans shift point and TCC lock up tuning--On a manual car it's very difficult to get a MPG gains as driving habits have too much to do with better MPG's
On an auto car the 4th gear TCC lock up is at a horrible 38 MPH-making your car lug and putter in 4th gear lock up---When an engine lugs-- the ECM ADDS fuel and removes timing to prevent detonation--all bad for gas MPG's Raising the TCC lockup to freeway speeds like 53 MPH will prevent lugging and dumping of extra wasted fuel---- Ideally raising all the shift points on even a manual trans to be in the sweet spot like 2200 - 2500 RPM's will prevent lugging and added richness of fuel----
When a stock C5 auto trans locks the converter at 38 MPH the RPM's are way to low like 1300 RPM's The ECM will compensate by subtracting 1/2 of the timing and adding 20 -30% more fuel to prevent detonation
PS On the newer Corvettes with VVT GM solved this problem of low RPM pinging with variable valve timing---
However there are other ways to get better mileage on a C5---On an auto car this is mostly gained with trans shift point and TCC lock up tuning--On a manual car it's very difficult to get a MPG gains as driving habits have too much to do with better MPG's
On an auto car the 4th gear TCC lock up is at a horrible 38 MPH-making your car lug and putter in 4th gear lock up---When an engine lugs-- the ECM ADDS fuel and removes timing to prevent detonation--all bad for gas MPG's Raising the TCC lockup to freeway speeds like 53 MPH will prevent lugging and dumping of extra wasted fuel---- Ideally raising all the shift points on even a manual trans to be in the sweet spot like 2200 - 2500 RPM's will prevent lugging and added richness of fuel----
When a stock C5 auto trans locks the converter at 38 MPH the RPM's are way to low like 1300 RPM's The ECM will compensate by subtracting 1/2 of the timing and adding 20 -30% more fuel to prevent detonation
PS On the newer Corvettes with VVT GM solved this problem of low RPM pinging with variable valve timing---
09-21-2017, 06:39 AM
#3
Lean cruise happened, but not permit in US
(i.e. it's on monaro if i remember, in australia, some video with afr show it work, even on C5 with a special tune for bypass the "Y type = no LC permit")
I'm manual :-(
Be sure that for best mileage test my right foot have... like a baby muscle lol
(i.e. it's on monaro if i remember, in australia, some video with afr show it work, even on C5 with a special tune for bypass the "Y type = no LC permit")
I'm manual :-(
Be sure that for best mileage test my right foot have... like a baby muscle lol