Hi, I have a 95 integra that I'm preparing to experiment HHO on.
I have modified the ECU to let me have full control over it. I'm using crome to edit the roms.
I installed a Wideband O2 and EGT probe. I have the wideband outputting to the ECU and the EGT probe is installed about 1.5" from the head on the 3rd cylinder.
Before I experiment with the HHO, I want to see how much I can improve FE with tuning.
I have changed the fuel and ignition timing on the cells I cruise at (60mph). I'm experiencing low EGT's with advanced timing and trying to understand the data. I'm also not hearing any pinging/knock.
This is what I have noticed so far from the datalogs.
A/F set to 18.5:1, Ignition timing at 50deg, EGT ~1000F.
A/F set to 18.5:1, Ign. timing at 45deg, EGT ~1080F.
A/F set to 18.5:1 Ign. timing at 35deg, EGT ~1100F.
From the researching I've done, this is what I understand.
1. If you lean out the mixture, it takes longer for the fuel to burn.
Timing should be advanced to start combustion sooner, so it can burn the leaner mixture completely.
2. Advancing the timing should lower the EGT assuming it's not overly advanced.
3. Retarding the timing should raise the EGT to a certain point because fuel is still burning as it leaves the head.
4. I've also read that advancing the timing with a leaner mixture will increase temperatures.
Since I am working with a significantly leaner mixture and not stoich, Am I correct in saying that the EGT will also be significantly lower, since there is less fuel to burn?
When I had the timing set to 50deg and noticed the low EGT's, I thought I may have advanced it too far, even though drivability was fine.
My thought was, increasing the EGT may increase the engine efficiency with the leaner mixture. I read sdsefi's
EGT article and they say "It is safe to say that peak power will occur at an EGT somewhat colder than peak EGT."
I started retarding it in 5 degree increments to see what happens. I noticed the EGT did rise a little. In terms of drivability, I can't say I noticed much of a difference from 35deg. to 50deg. But the MAP and throttle position did rise.
At 50deg, the map would hover around 400-500mbar and throttle position was around 10-12%.
At 35deg, the map would hover around 570-650, and throttle position around 14-15%.
So with the lower timing, the hit points are at a higher MAP.
This is what I have observed so far and trying to see which approach I should take.
Should I continue retarding it until EGT starts falling off?
Should I continue advancing it until I hear pinging?
Sorry for the long post. I just wanted to get my thoughts out and see what others have to say.
Thanks for reading