I went back to working on Open Loop Cruising now that I have been running for E85 for a bit now.

I logged 23 mins of driving on the Hwy the other night. Some pretty interesting data.

So far I have it up 46-47* timing advance, although you can see from the log it's a bit sporadic.

Looking at the TPS over time is also interesting as well. I think I need to cut down on my coffee consumption.

AFR is currently at 15.8-16.5:1

Keep in mind 2byte load is x10 on the plot so 5 = 50, RPM is x100

I'm going to push the timing and AFR a little bit more and try and smooth out the TPS by loosening the cable a little.

 

Cruise control would be nice right about now pretty much impossible for me to keep steady throttle. Is this for MPG?

 

ahha. Yea this is pretty much for MPG. Trying to see if I can get it much better on E85.

 

Good luck, let me know how it goes, I was only getting about 12-14mpg on e85. Switching back to pump gas gained at least 10mpg, but lost 40hp or so

 

'

You lost 10mpg going to E85? I lost about 3-4mpg going from 91 to E85 and that was when I was still running Closed Loop.

I'm trying to match 91. However I pretty much drive my car like I stole it whenever it's out of the garage.

 

Sure did. But then again, my car was so much more enjoyable on e85 at sea level than it is now on 91 pisstane and 6000ft altitude that I don't find myself pushing it nearly as much. That probably has more impact on my mpg, thus not really making it a true comparison. And oh, by the way, if you know of any tricks or tips for making the most of bad gas at high altitudes, I'm all ears.

 

6000ft? Where are you now?

 

Yeah I run about that timing on 93 at 15.7AFR at sea level. (not open loop, modified signal-closed loop) You shoulda never given up that ECU+. It gets better daily, my friend.

 

Four Corners area, New Mexico.

 

I accept the fact that even with the increased burining efficiency of e85 the extra 30% fuel volume (approx.) we add by scaling trumps the claimed 5-8% greater combustion efficiency or burn of e85 and the fact you can run more timing etc.

What makes it harder yet as you stated is the fact the car runs so much stronger on e85 it is more difficult to do apples to apples comparison when it comes to mpg.

The closest I have come is about 15% less mpg with e85 although I have not messed with tuning to your extent.

Good luck and as always.....

thanks for Sharing

 

Great to hear. I'm on stock suspension and I know my TPS is all over the place on the "smooth" Chicago highways. I can feel that I must be moving it at least 10% over rapid bumps on some parts of the road around here.

Finally got all of the parts to do closed loop wideband. Hopefully I'll have it in within the next week and be able to report back!

My MPG was ~18-18.5 my first 5 or so tanks, but has recently dropped to more like ~17.5. That's down from a very consistant ~22.5 when the car was new and more recent ~20-21mpg for no apparent reason. When I retuned my new 780cc injectors and timing it went back to ~21.5-22.5. I'm hoping for 21+mpg when I get the wideband up and running, but I had to pull my timing back a ton from MRFred's E85 timing map. I suspected this was because of the richer AFR I was running compared to his.

My driving to and from work is mostly highway (~10%city/90% hwy) and pretty consistent, so changes usually yield usually predictable results.

 

With my closed loop patch set to give 15.7:1 in the main cruise cells (30-60 load, 2000-3500 rpm), I'm getting about 16.5 mpg on E85. I need to try something like 16.3:1 to see what that does.

 

Alcohol has a higher egr dilution limit than gasoline. ethanol can be a more efficient fuel and be as efficient as diesel too but it would require direct injection and much higher compression.

Looks like you got it as efficient as possible with what you have though, gas would have lean missfired long before 15.8 afr

 

Really? I was getting 17mpg with normal Closed Loop.

 

For whatever reason, I can't seem to get as good of mileage as other people. With 14.7:1 closed loop, I was getting about 15.8 mpg. I'm working on a patch that will be very helpful in tuning both fuel economy and have a few other perks.