How does methanol affect wideband readings?

[Steve]

I am getting ready to start tuning my car for methanol injection and I am curious to how the methanol will effect my wideband readings. Will the a/f target remain the same on and off meth or will the meth affect the readings that I will need to comensate for? What kind of a/f ratio do you guys tune for with meth? Thanks

Steve

 

[Razor]

Depends how much fuel your displacing. The more fuel you displace... the lower your target.

Like on a 10-15 replacement, typically about 1 point lower. So if you tune 12.0 on gasoline, you displace 15% fueling target 11.0 and work from there.

 

[Steve]

Razor, thanks for the help. I am under the impression that it would take 25%+ to be able to run a car in the 10's on 93 and methanol so the target would be pretty low in that situation. That will be the tough part is trying to figure out how much I will actually be using so that I can decide which a/f target to use.

 

[Razor]

Who's to say 25%.. it may have enough with 15%.

Start the tuning.. and complicate yourself as needed.

 

[Alky V6]

Tune the A/F ratio as if you were running 100% gas. The sensor reads stray oxygen molecules only. It doesn't care what the fuel is. You could be running nitro and if the sensor and controller are calibrated to readout for gasoline, you would read the A/F numbers as if you were runnning gasoline. I'm running 100% methanol and I tune as if I'm running gas as far as the A/F numbers are concerned.

 

[spork]

If you have a wideband, use the lamda figure, not air/f as that number WILL change depending what type of fuel you're using...lamda stays consistant. A/f is just a mathimatical formula using lamda...

 

[vacuum 6]

Tune the A/F ratio as if you were running 100% gas. The sensor reads stray oxygen molecules only. It doesn't care what the fuel is. You could be running nitro and if the sensor and controller are calibrated to readout for gasoline, you would read the A/F numbers as if you were runnning gasoline. I'm running 100% methanol and I tune as if I'm running gas as far as the A/F numbers are concerned.

How are your running 100% meth?

 

[Razor]

If you have a wideband, use the lamda figure, not air/f as that number WILL change depending what type of fuel you're using...lamda stays consistant. A/f is just a mathimatical formula using lamda...

Correct

Vacuum 6.. his entire fuel system is methanol, not gasoline

I just tune for what makes the most power on my own engine. Then use the numbers as a reference to where i'm at or where i've been :redface:

 

[Alky V6]

If you have a wideband, use the lamda figure, not air/f as that number WILL change depending what type of fuel you're using...lamda stays consistant. A/f is just a mathimatical formula using lamda...

I'm really only familiar with the system I use and it allows me to set an A/F number per target lamda, represented by the O2 sensor's voltage output. The manufacturer of the wide band sensor system supplies me with a lamda voltage curve and gives suggested A/F numbers for various points on that curve. The A/F numbers supplied usually pertain to burning gasoline. I'm sure you may find that some O2 manufacturers can give you alcohol A/F numbers, but since there are already very well established and published A/F ratio performance ranges for gasoline, I just stick with the gasoline A/F reference numbers. I then program that curve into my EMS using the manufacturers suggested A/F numbers or changing them to my own reference numbers. My system takes the O2 voltages and directly translates them to the A/F numbers I have chosen for each O2 voltage step. I don't understand how using a different fuel can change the relationship between O2 voltage and the A/F number assigned to the various points I have picked in the O2 voltage curve.

I completely agree with Razor. Tune to best performance and use the resulting A/F number as a reference only. The A/F number to lamda voltage relationship can vary from system to system.

Don't get me wrong here. I'm not trying to be argumentative. I am a firm believer that there is always something to learn and I'm very interested in finding out if I've been missing something here. Did I just answer my own question in the previous paragraph? If I did, still, how can changing to a different fuel mix change the A/F reference number output?

 

[evil666]

If you have a wideband, use the lamda figure, not air/f as that number WILL change depending what type of fuel you're using...lamda stays consistant. A/f is just a mathimatical formula using lamda...

I just installed a zeitronix wideband on my car and would like to know how to read lamda numbers so I could tune the car right? When are the numbers rich and when are the numbers lean?

Thanks for your help.
Marco.

86 Grand National t-top (59900km)
stock long block,stock suspension, red stripe convertor, te44, smc alk injection, 24lbs boost, 94 octane, hooker cat back with dyno max ultra flow muffers, tomco 30lbs injectors, dynotech stage 4 street chip, thdp, mease 24 row IC, Ron Custom max boost brake module, MT drag radials (275/50/15) 3800lbs race weight with driver. (Torque convertor not locked)
.New set up: 42 ½ 009 injectors, turbotweak alky chip, rjc power plate, rjc boost controller, and will lock the torque convertor, zeitronix wideband, HR motor mounts, comp cam 980 valve springs, the rest is the same, will be going to the track this fall with new set up.
BEST E/T
60FT=1.52
1/8= 7.38
I/4= 11.74
MPH=113
BEST MPH= 114

 

[Alky V6]

I just installed a zeitronix wideband on my car and would like to know how to read lamda numbers so I could tune the car right? When are the numbers rich and when are the numbers lean?

Lambda = target excess air factor = Stoich = 1

Wide band lambda sensors can generate a steady signal within a wide lambda range of 0.7 < lambda (stoich) < 4.

Using lambda numbers directly to tune with can be a very confusing thing. First off lambda = 1 = stoich. This corresponds to an output voltage signal of 450 mV.
Best engine torque is achieved at lambda = .9
Maximum fuel economy is achieved at lambda = 1.1

Lambda is a theoretical number that must be translated to a voltage signal to be useful to the end user.

We already know that lambda = 1 = 450 mv for the vast majority if not all lambda sensors. I have not been able to find any documentation that will give me voltage signals as it relates to off lambda (1) values. Which leads me to believe that the voltage relationships to off lambda ranges is dependant on the type of lambda sensor along with several operating parameters that include absolute temperature, oxygen partial pressure of the reference load, oxygen partial pressure in the exhaust gas, Faraday constant (lookup Faraday's law), and general gas content. Ever wonder why modern lambda sensors must be individually calibrated and be attached to dedicated controllers? There are variances from one sensor to the next. Even within same model batches. The best thing you can do is go with the lambda sensor manufacturers suggest reference table supplied with your lambda sensor. If one didn't come with your sensor, call them up and get one.

 

[Steve]

So if I already have my car tuned for race gas and I know what the Lambda reading is for the best performance on race gas could I use the same lambda target for 93 octane and methanol? Thanks

Steve

 

[Alky V6]

So if I already have my car tuned for race gas and I know what the Lambda reading is for the best performance on race gas could I use the same lambda target for 93 octane and methanol? Thanks

Steve

Start at a safe A/F ratio and work from there. Read it as if your using gasoline only. Anytime you make a major tuneup change, you should re-visit your total tuneup. Changing fuel in the way your planning is a major tuneup change.

 

[howracer]

Vout Lambda Petrol LPG Methanol Diesel

1.40 0.686 10.08 10.63 4.39 9.94
1.45 0.696 10.23 10.79 4.45 10.09
1.50 0.706 10.38 10.94 4.52 10.24
1.55 0.716 10.53 11.10 4.58 10.39
1.60 0.727 10.69 11.27 4.65 10.54
1.65 0.739 10.86 11.45 4.73 10.71
1.70 0.750 11.03 11.63 4.80 10.88
1.75 0.762 11.20 11.81 4.88 11.05
1.80 0.774 11.38 12.00 4.95 11.23
1.85 0.787 11.57 12.20 5.04 11.41
1.90 0.800 11.76 12.40 5.12 11.60
1.95 0.814 11.96 12.61 5.21 11.80
2.00 0.828 12.17 12.83 5.30 12.00
2.05 0.842 12.38 13.05 5.39 12.21
2.10 0.857 12.60 13.29 5.49 12.43
2.15 0.873 12.83 13.53 5.59 12.66
2.20 0.889 13.07 13.78 5.69 12.89
2.25 0.905 13.31 14.03 5.79 13.13
2.30 0.923 13.57 14.31 5.91 13.39
2.35 0.941 13.84 14.59 6.03 13.65
2.40 0.960 14.11 14.88 6.14 13.92
2.45 0.980 14.40 15.18 6.27 14.20
2.50 1.000 14.70 15.50 6.40 14.50
2.55 1.037 15.25 16.08 6.64 15.04
2.60 1.078 15.84 16.70 6.90 15.62
2.65 1.121 16.48 17.38 7.17 16.26
2.70 1.169 17.18 18.11 7.48 16.95
2.75 1.220 17.93 18.91 7.81 17.69
2.80 1.276 18.76 19.78 8.17 18.50
2.85 1.337 19.66 20.73 8.56 19.39
2.90 1.405 20.66 21.78 8.99 20.38
. . .
4.00 free-air (can be used for calibration)

 

[Alky V6]

Thanks howracer! This is like finding gold on the internet. I hope a lot of people copy this table down. You don't come across this type of info everyday.

 

[SPEEDSTAR]

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

 

[SPEEDSTAR]

Sorry my reply was in context to Don running 100% methanol, not to alchy injection.

 

[Steve]

I appreciate all of the replies and help. I looked over the chart above for the different type of fuels and thier effect on lambda and A/F ratios and to make sure I am on the right track how does these numbers sound to you guys. If you ran a 12.17 ratio with 100% gas and wanted an equivilant ratio with 80% gas and 20% methanol you would need a target of 10.796. Sound correct? I understand the numbers are theoretical, but I am just looking for a good logical starting point to begin my tuning. Thanks

 

[Razor]

I appreciate all of the replies and help. I looked over the chart above for the different type of fuels and thier effect on lambda and A/F ratios and to make sure I am on the right track how does these numbers sound to you guys. If you ran a 12.17 ratio with 100% gas and wanted an equivilant ratio with 80% gas and 20% methanol you would need a target of 10.796. Sound correct? I understand the numbers are theoretical, but I am just looking for a good logical starting point to begin my tuning. Thanks

Yes that would be a good starting point. Most of us end up typically between 15% and 20%. That is why the 11.0 target is used so much.

 

[Race Jace]

My experience with alky injection supports Julio's statements.

On cars using alky injection and pump gas and to maintain the same EGT numbers while injecting the alky we have to shoot for 1 number richer on the wideband o2 sensors. (we have the fast shoot for one number richer on the fast A/F table)