E85 ?

[dumpster]

Does anyone got any tips and tricks to tune in E85 good it runs good but think it can run better .... thanks

[oakleafresin]

It likes to run a little richer. Shoot for 11.5:1 AFR on your wideband and you can raise the timing a little bit probably. At idle it might like to be slightly richer, maybe 14.4:1 rather than 14.7:1.

[BlackGS]

Since you have a wideband hooked up all the time, you can run open loop and it will help to smooth out the tune and work with increased timing better. When I first raised cruise timing on e85, I would see blips of KR, but it was unpredictable and frustrating to tune around. What I realized is that closed loop fueling oscillates back and forth and creates random lean times where the higher timing is going to knock. By running a fixed open loop commanded AFR, I no longer see any of the cruise KR, and I can safely run maximum timing which has helped tremendously with MPG. Open loop will also help to keep idle from surging, and eliminates any problems with transition fueling into PE because of trims not locking at zero.

Just be warned, when you switch to open loop you will need to keep on top of your tune much more. You won't have the trims to adjust fuel when weather changes, or mixes of ethanol are different from station to station.

Also, you will have to be running the beta version (2.23) or wait for the next release of HPT as the open loop tables are currently not available in 2.22.

BTW, I run 1.05 lambda AFR (15.5 AFR gas equivalent) at idle and cruise, and try to keep it around .80 lambda at WOT (~11.8). When the weather gets colder, I'll drop the idle AFR back to .98-1.0 (14.5-14.7).

[Google]

It likes to run a little richer. Shoot for 11.5:1 AFR on your wideband and you can raise the timing a little bit probably. At idle it might like to be slightly richer, maybe 14.4:1 rather than 14.7:1.

read this before you melt someone's engine down.

http://en.wikipedia.org/wiki/E85_in_...tio_comparison

[murphinator]

Dumpster , the afr's mentioned in the posts above are referring to widebands set to read afr on a gasoline scale - dont want you to get confused....

gasoline afr =14.7 to 1

e10 pump gas afr = 14.13 to 1

e85 afr = 9.87 to 1

above are for stoich which will only apply to idle , cruise ,etc - low load circumstances

in other words if your wideband is still reading in a gasoline scale but you are running e85 your wideband will show 14.7 as stoich when its actually running at 9.87

the wideband doesnt know what fuel you are running , only if there is excess unburned fuel passing by it (rich) or not enough unburned fuel passing by it (lean)

under load ,at wot , etc.. the numbers will /should decline in any case and as black gs said you want to be in the 11's at wot if reading on a gasoline scale regardless of the fuel you are burning

[dumpster]

ok thanks guys my WD now is showing 10.4 so im thinking that is to lean now so ill have to do some tuning lol to richen her out a bit

[dumpster]

as of right now im getting 21* of timing and 0 kr and 10.4 wb

[E85GP]

Is that 10.4 value at WOT / PE Mode? Or closed loop?

If it's closed loop, something is wrong with the reading. The PCM will keep the mixture exactly at stoich.

If it's open loop, then it's gotta be reading the values for gas. In which case you are very rich.

[dumpster]

10.4 with pe mode on, with closed loop on, wot

[BlackGS]

If you are going to run e85, or mixes of e85, you should change your wideband readings to show lambda AFR. Do you have a gauge with the PLX, or are you just scanning with HPT?

If you are scanning with HPT, you can create a user defined EIO input and change the formula to show the lambda range of 0.68 to 1.36 instead of the default 10-20 gas AFR that is used with the PLX AUX input. The output from the PLX is linear from 0-5v, so 0v = 0.68 lambda, and 5v = 1.36 lambda.

When you start reading lambda, then stoich AFR will always be 1.00, no matter what fuel or mixes of fuel you are running. At idle and cruise, you want to keep AFR right around 1.00, probably a little to the leaner side for best mpg. When you go WOT, your lambda AFR should be .80 for e85. If you think in terms of gas AFR, you can always multiply the lambda by 14.7 to get the gas value (14.7 x .80 = 11.76). However, once you start thinking in terms of lambda, you will have a much easier time tuning around e85.

If you see 10.4 AFR at WOT, I am going to assume you are still reading gas AFR by the default PLX AUX input. If you convert that to lambda (10.4 / 14.7 = .707), you realize that you are running too rich, and again, you want .80 lambda at WOT.

[dumpster]

oh i see blackgs im to rich. i do have the plx wb how do i go about it to change it to lambda

[BlackGS]

oh i see blackgs im to rich. i do have the plx wb how do i go about it to change it to lambda

Open HPT VCM Scanner.
Open the Table Display window.
Right-click on the EIO Input cell that you currently have the PLX WB hooked into, and select Insert Input.
Click on the + sign next to User Defined in the AUX list.
Double-click on Configure User Defined.
Select one of the <undefined> items in the list.
Enter a Name and Abbrv (Something like PLX Lambda). Leave Sensor empty, and select afr under Units.
Click the radio button for Linear.
The formula is Volts / 7.35 + .68. Enter 7.35 under volts and .68 in the other box.
Close the window and commit the changes.

Now when you scan, your PLX WB will record in lambda. If you use the EIO input in other displays, like the Chart, you may have to change those displays to recognize the new EIO. If you are using AFR Error % anywhere, you will have to create a new AFR Error % PID using the new EIO input. Modify the original AFR Error % formula in the default Air Fuel Ratio Error PID by replacing SENS.120 with your new EIO USER.XXXX PID, and change SENS.121 to be SENS.121 / 14.7.

[dumpster]

I got it to read in lambda, I already leaned her out when i scaned the lambda was at .79 so just a hair rich. I will be doing the main tuning tomorrow. thanks for info blackgs. and thanks to everyone who helped me out

[oakleafresin]

read this before you melt someone's engine down.

http://en.wikipedia.org/wiki/E85_in_...tio_comparison

Should have mentioned I was referring to a gasoline calibrated wideband reading.

[dumpster]

I got one more ? what is the best plug and gap to run for E85

[dumpster]

ok so now i have a problem with the car i got it all tuned in good the other day and now my ltft r on working at all and it is running rich .70 lambda any thoughts guys im lost