popwars123

iTrader: (1)

Hey yall, I was curious about the actual readings between our regular wideband afr numbers and what it should be on e85, and came across this. nice to not have to do the math.

DISCLAIMER: I got this off of Yellowbullet from user "Drag Chevette". I cannot guarantee accuracy, but seems right as far as calculations go.


stay out of the RED.

Lambda E85 AFR Gas AFR
0.500 4.880 7.350
0.510 4.978 7.497
0.520 5.075 7.644
0.530 5.173 7.791
0.540 5.270 7.938
0.550 5.368 8.085
0.560 5.466 8.232
0.570 5.563 8.379
0.580 5.661 8.526
0.590 5.758 8.673
0.600 5.856 8.820
0.610 5.954 8.967
0.620 6.051 9.114
0.630 6.149 9.261
0.640 6.246 9.408
0.650 6.344 9.555
0.660 6.442 9.702
0.670 6.539 9.849
0.680 6.637 9.996
0.690 6.734 10.143
0.700 6.832 10.290
0.710 6.930 10.437
0.720 7.027 10.584
0.730 7.125 10.731 @ Max Power Multi Turbo
0.740 7.222 10.878
0.750 7.320 11.025 @ Supercharged/Turbo
0.760 7.418 11.172
0.770 7.515 11.319 @ Max Power NA
0.780 7.613 11.466
0.790 7.710 11.613
0.800 7.808 11.760 @ Consistant Race
0.810 7.906 11.907
0.820 8.003 12.054
0.830 8.101 12.201
0.840 8.198 12.348 @ Part throttle RACE
0.850 8.296 12.495
0.860 8.394 12.642
0.870 8.491 12.789 @ Idle
0.880 8.589 12.936
0.890 8.686 13.083
0.900 8.784 13.230
0.910 8.882 13.377 @ Part throttle STREET (economy)
0.920 8.979 13.524
0.930 9.077 13.671
0.940 9.174 13.818
0.950 9.272 13.965
0.960 9.370 14.112
0.970 9.467 14.259
0.980 9.565 14.406
0.990 9.662 14.553
1.000 9.760 14.700
1.010 9.858 14.847
1.020 9.955 14.994
1.030 10.053 15.141
1.040 10.150 15.288
1.050 10.248 15.435
1.060 10.346 15.582
1.070 10.443 15.729
1.080 10.541 15.876
1.090 10.638 16.023
1.100 10.736 16.170
1.110 10.834 16.317
1.120 10.931 16.464
1.130 11.029 16.611
1.140 11.126 16.758
1.150 11.224 16.905
1.160 11.322 17.052
1.170 11.419 17.199
1.180 11.517 17.346
1.190 11.614 17.493
1.200 11.712 17.640



HOPE THIS HELPS SOME PEOPLE OUT!

portenio78

iTrader: (1)

This is a good read. Everyone I know still uses the same AFR for gas and E85. So if your runnin in the 12's WOT....its really in the 17's? I dont think my motor would still be together if this was the case?

popwars123

iTrader: (1)

not neccesarily, stoich, no matter what fuel on is 1.0 lambda, which is 9.7xx on e85 and 14.7 on gasoline. just different conversions based on burn rate and other factors. with that being said, you have a reference as to what you are at on e85, while reading it on your wideband that reads out gasoline afr's without doing the math.

dschenke

here is a chart i got long time ago
gas
vs
PURE Ethanol
vs.
Nitro Methane

By dschenke at 2012-01-05

joppe

For first post, everything is too rich, i tune e85 on gas afr:s so i run 11.5-12:1 and cruisin 16:1. With na i tune them @ wot to 13:1 both fuels, again with gas afr:s. Here is another conversionchart. I havent seen much cars or dyno results with .73 lambda, also .9 lambda for cruising is wasting fuel.

92frostwhtdb2

my tuner told me theres no need to try to convert the readings..the sensor originally reads in lambda then converts to a gas afr on the wideband..lambda never changes

joppe

Yes, Lambda is independent of fuel type. I allways use normal gas values in gauge.

suckerpunch

Can anyone confirm this? I have an old school plx M-300 and I am curious if mine works in this manner.

Would I tune for roughly the same afr readout for e85 as I would for 93 with the m300?

DDTECH

Its hard to explain to people who dont understand tuning.

However most AFR gauges you can purchase to display a numerical value of the AFR, are showing you values for gasoline. This is where it can get tricky, and it's important to understand how this ratio works on both gasoline and ethanol-based fuel.

All AFR's regardless of fuel type work off of a common number called Lambda. A value of 1.0 in Lambda represents the stoich for any fuel. Gasoline is Lambda 1.0 at stoich. E85 is Lambda 1.0 at stoich

Gas vs e85
14.7 vs 9.7

rich7777

^^^^ yeah thats right . The good thing about Lambda sensors is that they read in Lambda and not ARF. So stoich will always be 1.0.

Muckman

iTrader: (2)

This is correct. No need to over think this guys. Lambda is universal and AFR is a simple multiplication from that. So we can use gasoline AFR readings that we all know and love for any fuel.

suckerpunch

I can't speak for everyone else, but I do understand lambda and how it doesn't matter for whatever fuel one would use.

My question was if my specific plx device (older m-300) uses lambda and then converts it to an afr on the gauge? Thats what I am curious about. I would think it is, but I don't want to be wrong as it would be costly. I would rather be safe and ask then be sorry and lose a motor.

thanks

V-SPEC 1

As long as it is wideband sensor,I am sure it is using lambda and converts it to afr.

SovXietday

Yes it does, I have an M300 on my race car.

suckerpunch

Thank you so much!

Boost4Breakfast

11.9-12.1 (gas) afrs are what I've found to make the most power on e85 in boost. I'm referring to summer blend e85 as winter blend "e85" is around only 65-75% ethanol to cope with hard starts

rich7777

Your user name rules lol.