How does methanol affect wideband readings?

[Alky V6]

Isnt the ratio of methanol to air roughly 6 to one , this I see in his meth values. This is lambda .941.....This is right on Don's best engine torque lambda of .9. So target lambda .941 and watch egt's for 1200 to 1350....JEFF

Actually the stoich or lambda 1 for methanol is 6.45 to one.
As the chart shows, stoich for any fuel will always be lambda value '1' period. Richer or leaner from stoich is a percentage value of lambda one. I have some ratios that pertain to methanol such as rich best torque, lean best torque etc. I'll dig those numbers up and share them. It will be interesting to see how those numbers compare to gasoline rich best torque (12.8) and lean best torque (13.3) on howracer's chart. From this day forward to be known as 'THE CHART'.

 

[Razor]

That Howard is one smart cookie

I like "The Chart" :biggrin:

 

[howracer]

i am really happy to be able to give something back to this site as i consider it the most valuable source of auxiliary injection info on the net. i have benefitted greatly from reading the entire site.

the chart came from Techedge's website. Techedge made my AFR setup. thanks Techedge and thanks to all that have previously contributed to this site.

howard coleman

 

[Alky V6]

Actually the stoich or lambda 1 for methanol is 6.45 to one.
As the chart shows, stoich for any fuel will always be lambda value '1' period. Richer or leaner from stoich is a percentage value of lambda one. I have some ratios that pertain to methanol such as rich best torque, lean best torque etc. I'll dig those numbers up and share them. It will be interesting to see how those numbers compare to gasoline rich best torque (12.8) and lean best torque (13.3) on howracer's chart. From this day forward to be known as 'THE CHART'.

Correction! Rich best torque should be approximately 11.5 to one. (ducking the wrenches being thrown by the tuners)

 

[Alky V6]

Comparison Chart of AFRs. Gasoline to Methanol

Gasoline / Methanol

6.0 / 4.1 - Rich Burn Limit (engine fully warmed)
9.0 / NA - Black Smoke / Low Power
11.5 / 4.5 - Approximate Rich Best Torque @ WOT
12.2 / 5.5 - Safe Best Power @ WOT
13.3 / NA - Approximate Lean Best Torque
14.6 / 6.45 - Stoichiometric AFR (chemically ideal)
15.5 / NA - Lean Cruise
16.5 / NA - Usual Beast Economy
18.0 / NA - Carburetted Lean Burn Limit
22+ / NA - EEC / EFI Lean Burn Limit

It is interesting to note that while burning 100% methanol and using a lambda sensor calibrated to read out for gasoline, my best performance has been at an AFR of 11.4-11.5. Any richer and the engine would get lazy. Compare this to 'The Chart'. Lambda .9 is lean best torque and 1.1 is best economy.

One other interesting thing to note. Look at how small the window is between 'approximate rich best torque @ WOT' and the 'rich burn limit' for methanol. I guess that's why they say you need a mini arc welder to fire very rich mixtures of methanol.

 

[cpac]

WIDEBAND READINGS lamda

HI..MR.SPOCK what should lamda readings be??????

 

[Alky V6]

HI..MR.SPOCK what should lamda readings be??????

Scotty! I'm surprised. After all, your the one that watches over the warp drive. Make a copy of 'The Chart' and stick it on the wall next to the plasma injection unit for quick reference. Oh, by the way, you can beam me up now. Spock out.

 

[norbs]

Interesting stuff, but there is a formula to figure out the equivanent gas a/f ratio, but you need to know the exact % of methanol. WIthout that number its a tough guess on what a/f to use, as the more meth in the eqaution the a/f numbers drop large........ I posted the equation a while back from the innovate motorsports forum,

As expected, when Schnapps is mixed with cars, things get a little complicated.

If ethanol (stoich AFR of 9) is mixed with gasoline (stoich AFR of 14.7) the resulting gas has a lower stoich AFR than 'pure' gasoline. As the fuel injection is tuned to mix a certain amount of fuel for a given amount of air, the resulting mixture would be leaner when using a fuel with lower stoich AFR.
This can be calculated:

sAFR = (%ofAdditive * sAFRadditive + (90-%ofAdditive) * sAFRgas) /100

where:
sAFR is resulting stoich AFR
%ofAdditive is amount in % of mass of additive (ethanol) mixed in
sAFRadditive is stoich AFR of additive (9 for ethanol)
sAFRgas is stoich AFR of base gasoline (14.7)

For a 10% mixture of ethanol to gasoline by mass the resulting stoich AFR is 14.13

So, for an engine that's tuned to certain AFR at a certain load and RPM on straight gas, the resulting (gasoline equivalent) AFR when running the mixture can be calculated as:

new AFR = tuned gas AFR * (gasoline stoich ratio) / blend stoich ratio

An engine tuned to 12.5 gas AFR will run at the equivalend of 13 gas AFR with a 10% ethanol blend. This is what these people were seeing.

 

[norbs]

I put some numbers in those equations and the results are ugly.


20% meth , 80% gas= 14.7 a.f would be the same as your wideband reading 10.77 a.f if it was calibrated for gasoline.

1 x m10 haggo nozzle @150 psi flows= about 12.5 gal hr x 6.5 lbs per gal=81lbs/hr fuel.

I was running 83's iinjectors at 50% duty cycle max = 250 lbs/hr fuel.


81/250= 32% meth with a single nozzle?


Am i out to lunch here or what?

 

[cpac]

Wideband Readings Norbs

I would like your comments on these figures wot . 100mph. 25 psi boost.. LM1..SHOWING lamda .77 and af 11.3..i am useing 93 octane and razors kit scanmaster shows .700 but there is no knock

 

[Alky V6]

Norbs. The formula your using is good for calculating the new A/F ratio the engine will need to run properly. It gives you an actual, physical 'X' lbs of fuel to one lb of air requirement. This will also help you calculate the engine's brake specific fuel consumption and from this you can calculate a new injector pulse width that will be needed to supply that lbs/hr figure, but do not use the O2 reading from your oxygen sensor as the measurement to varify your new calculated A/F ratio. What you calculate on paper will not be what you see on your lambda sensor reading. Unless someone has re-structured the readout to reflect your new fuel combination.

For any given stoich mixture for any given type of fuel or mix of fuels, there will be a certain amount of residual oxygen after a perfect burn.

Methanol with a stoich of 6.45 to one will have 'X' amount of oxygen in the exhaust after it is burned.
Nitro with a stoich of 1.7 to one will have 'X' amount of oxygen in the exhaust after it is burned.
Simple gasoline with a stoich of 14.6 to one will have 'X' amount of oxygen in the exhaust after it is burned.
The 'X' amount for all three previous examples will be very close to the same. This is the thing that the lambda sensor is monitoring. Not the actual A/F ratio of the fuel mixture being used. It is measuring residual oxygen molecules after the fuel is burned to judge how efficient the burn was. Perfect (stoich), rich, or lean. It is looking for that 'X' amount. The A/F numbers you see on your O2 reading are simply numbers that relate to the fuel mix that the sensor is setup for. Most, if not all, sensors are setup to read out A/F numbers as it relates to burning gasoline. The programmer of the unit has just assigned a certain A/F number to each lambda reading. See 'The Chart'.

If you still don't understand, let me know and I'll try to explain it a different way.

 

[norbs]

Thanks for clarifying that, but ill just tune to around 11.0 a/f with razors kit and fudge the a/f until it goes faster or blows up

 

[Razor]

Thanks for clarifying that, but ill just tune to around 11.0 a/f with razors kit and fudge the a/f until it goes faster or blows up

In the 9's yet.. JC just went 10.35 at 134.6 on a 109, DR's, & pump gas..

You need to step it up

 

[BDC]

Let me test my math out here:

Assuming 80% of gasoline running 11.57:1 and 20% of methanol at 5.04:1 (figuring the same, comparable AFR of gasoline):

11.57 * 8 = 92.56
5.04 * 2 = 10.80

92.56 + 10.80 = 102.64 / 10 = 10.264:1 AFR

What do you guys think?

B

 

[norbs]

Thats not a bad calculation, but where did the 5.04 come from? Razor i know i need to step it up, but i;m too busy trying to get the epoxy out the PAC controller to see how it ticks... :wink:

 

[Alky V6]

Thats not a bad calculation, but where did the 5.04 come from? Razor i know i need to step it up, but i;m too busy trying to get the epoxy out the PAC controller to see how it ticks... :wink:

Norb. Refer to 'The Chart'.
A gasoline A/F ratio of 11.57 is the same as .787 lambda.
.787 lambda is the same as a methanol A/F ratio of 5.04.
lambda / gas / methanol
.787 = 11.57 = 5.04

 

[BDC]

Norb. Refer to 'The Chart'.
A gasoline A/F ratio of 11.57 is the same as .787 lambda.
.787 lambda is the same as a methanol A/F ratio of 5.04.
lambda / gas / methanol
.787 = 11.57 = 5.04

So Don, was my calculation reasonable?

B

 

[Alky V6]

So Don, was my calculation reasonable?

B

Heck if I know. I'm not familiar with blending formulas. I've been playing with Norbs formula and I can't get it to work.

 

[Alky V6]

Norb. You must have written that first formula wrong. It's junk.

 

[norbs]

I will talk to Klaus about it, could be a typo, its a copy and paste from his site.