I finally got my vtec-e up and running. This was an hmotors jap engine so I had to round up the oil cooler and throttle body to make it a real, complete d15z1. No doubt this is a neat little engine.
This is a low mileage engine, but the O2 sensor has about 130k so it may be slightly out of calibration, but it is the original L1H1.
I've found so much false information about the leanburn operating parameters on this site and many others that I'm going to post my own recorded data in this thread.
Here's a little data I've observed from my previously-turbo car setup (hence all the gauges) :
- EGT's are roughly 250 degrees F cooler in leanburn mode
- Air fuel is 22-23.5 while in leanburn mode (measured with a new Innovate XD16 and LC1)
- Engine will stay in leanburn up to approx 4 in.Hg (which is nearly ambient manifold pressure) in all gears but 1st
- leanburn engages only between idle speed and 2650 rpm. When in any gear (including neutral) other than 1st, a manifold pressure of approx 4 in.Hg can be a achieved in leanburn until 2500 rpm, over that rpm manifold pressure must be ramped down as RPM increases to 2650.
- car must be moving a certain speed for leanburn to activate, it will activate in neutral if over idle speed and vehicle speed over 5 mph???
- Closed loop remains active under all conditions except for on a cold startup, it is possible to fully load the engine at stoichiometric fuel ratios up to 3000 rpm. Under 3000 rpm fueling richens in stages, not gradually, this is based on load and it appears to be based on throttle position at its richest and final stage. So fueling ratios go from 14.7 then steps to 13-13.5 then steps to 12.3-12.5/full rich at WOT. After 3000 rpm air/fuel continues to run 12.3-12.5 up to rev limit (regardless of throttle position) when coolant temp under approx 197* F. if temp is over 197* air/fuel richens to 11.5. Needless to say, stay under 3000 and don't let the radiator fan come of if you have to hammer down on it.
- oil temp seems to be very well regulated with this engine due to the oil heater/cooler. Even coming up the mountain and full throttle for 5 minutes I have yet to see oil temps over 210 degrees at 85* ambient temps.
Here are the parameters, very close to what the ecu requires for leanburn:
- NO Leanburn in 1st gear
- 2nd-5th gear:
rpm: 800-2400 manifold pressure ~4 in.Hg max. / 2400 rpm 5in.Hg tapering off to 8 in.Hg @ 2650. Over 2650 - no leanburn
(Seems best to shift at 2500 max with VX gearing)
- Coolant temp: Unsure of exact temps, but leanburn will activate in 5th gear or neutral before full operating temps, probably about 140*F. All other gears require full temps before engaging leanburn.
- After engine restart, even at normal operating temps, leanburn will not reactivate until after 10 seconds or so
VTEC parameters -
Low load engage - 3000 rpm
High load engage - 2250 rpm
High load disengage - 2000 rpm
Note: No leanburn while vtec active.
The leanburn difference? I drive a lot of miles per week with my D15Z1 and have done a bit of testing. The difference between ignoring leanburn/normal burn and trying to stay in leanburn whenever possible seems to be only about 3 mpg. What I have found to make the most difference is keeping the rpm under 2800.
Hope this clears some of the mis-info up, may be back to add or edit.
Link to maximizing lean burn thread (leanburn at idle and ambient manifold pressure)
http://ecomodder.com/forum/showthrea...nda-23288.html