high egt ethanol

[gus]

Running ethanol, we're getting super high egt's at pretty low rpm/load. As in 1200F at 6000rpm and 30% throttle. The o2 sensor is putting out a 12-14:1 signal, which I believe means the air fuel is correct, regardless of ethanol or gasoline being used. When i richened up portions of the map a bunch (reading of 10:1), the engine runs horribly and won't rev unless it uses cells that are still at leaner levels. At all times, the plugs look perfect.

I guess I have 2 questions: when using e-85, should the o2 sensor still be indicating 12-14:1, or the ideal 9:1 ethanol range.

AND why is the engine either running horribly or hot?

-Gus
www.cyclone-racing.com (http://www.cyclone-racing.com)

[gus]

Running ethanol, we're getting super high egt's at pretty low rpm/load. As in 1200F at 6000rpm and 30% throttle. The o2 sensor is putting out a 12-14:1 signal, which I believe means the air fuel is correct, regardless of ethanol or gasoline being used. When i richened up portions of the map a bunch (reading of 10:1), the engine runs horribly and won't rev unless it uses cells that are still at leaner levels. At all times, the plugs look perfect.

I guess I have 2 questions: when using e-85, should the o2 sensor still be indicating 12-14:1, or the ideal 9:1 ethanol range.

AND why is the engine either running horribly or hot?

-Gus
www.cyclone-racing.com (http://www.cyclone-racing.com)

[Dan Deussen @ Weber Motor]

Gus-

I am not very familiar with E85, but I think you are right assuming that your Oxygen sensor should read in the 12-14 range for gas or E85 regardless. Oxygen sensors are typically lambda sensor and lambda is defined as actual A/F divided by stoich A/F.

High EGT's typically occur when you don't run enough spark advance. I am not sure what numbers are good for E85, but with gasoline 1400-1500F are about normal under high load at high rpm.

[sixholer]

An alcohol engine will run hot when it is lean. Richen it up, and the engine temp should drop considerably. The evaporative cooling of the alcohol on the back of the valves is the cause for the temperature drop. You should be able to tune the engine just with the temperature gauge. If it's climbing-it's too lean, and if it's cold-too rich. Hope this helps

[gus]

Thanks for the help, a few days later, i'm tuning with a big grin. Here's some info on my progress for anyone who may have similar problems:

tossed up the advance, it's at 12 at 1k and goes up to 45 degrees by 5k rpm

on a wideband, the air/fuel reads 10-12

egt's are going from 500C at 5k to 750-800C at 10k, i'm still climbing the charts, but it looks like i won't be going over 800C by much.

plugs look beautiful, almost textbook perfect clean. i'm having some issues with hot restarts, but think i fixed it by cutting lots of fuel at low rpm and adding a bit more advance.

just wondering, what are other e-85 teams seeing? i love this low temp stuff, if i raise the egt's it runs horribly, so i'm thinking you want to stay rich, and the kicker is our cooling system is working less than a union folk. e-85 pals, how do i compare to your numbers?

[jack]

we should be tuning our e-85 F3 within the next week or so, I'll let you know how it goes. are you runing nat/asp gus? we are using garret's G12.

[gus]

we're blowing about 1.001 atm of boost with our radiator fan sometimes...better said, we're NA on a '98 kawi zx-6r. I'm guessing your advance will be less agressive than ours, but as your blowing it, our egt's are gonna be different. good luck!