If you are running a higher ratio of alcohol to gasoline, would your desired O2 readings be different than with a lower ratio of alcohol to gasoline? I ask this because I run more alcohol than most people seem to run. My car seems to run with no detonation at really low O2 numbers. I'm just trying to make sense of it.
Alcohol and O2 numbers?
- Thread starter Brookgn
- Start date
Sounds like you have a bad O2.
The richer the mixture the higher the O2's. So the more alcohol you pump in.. the lower your stoich target. Stoich on gasoline is 14.7, stoich on methanol is like 7.0. Meaning the higher concentration of methanol, the richer you tune your motor.
Also the richer it is, the lower the egt.
Now it is possible your overdoing the amount needed and the alcohol is igniting in the exhuast.. that will make your O2 numbers drop as heat will affect the O2 sensor. But there should be drop in HP when doing this.. unless your Top Fuel
The richer the mixture the higher the O2's. So the more alcohol you pump in.. the lower your stoich target. Stoich on gasoline is 14.7, stoich on methanol is like 7.0. Meaning the higher concentration of methanol, the richer you tune your motor.
Also the richer it is, the lower the egt.
Now it is possible your overdoing the amount needed and the alcohol is igniting in the exhuast.. that will make your O2 numbers drop as heat will affect the O2 sensor. But there should be drop in HP when doing this.. unless your Top Fuel
GNVYUS 1
Well-Known Member
- Joined
- Dec 15, 2002
What do you consider really low 02 #'s??
And you can run really lean and not knock if you're not pushing the cylinder pressure through the roof. I've done it a few times tuning my Talon on 18psi and a mix of 110 leaded, got lean but never showed knock.
And you can run really lean and not knock if you're not pushing the cylinder pressure through the roof. I've done it a few times tuning my Talon on 18psi and a mix of 110 leaded, got lean but never showed knock.
GNVYUS 1
Well-Known Member
- Joined
- Dec 15, 2002
That's low but not super low, I had a chart that had a somewhat comparable graph for millivolt 02 #'s and I believe 780 was around 12:1.
Easy to fix though, fuel pressure or alky knob.
One comment that made sense to me about alky injection was to make it a tad fatter since you are substituting methanol for gas in whatever % you are injecting it in your motor. That would mean you'd want to run a tad fatter on alky but using the Scanmaster for this IMO is not the way to really dial it in. Go for a dyno session and tune it to 11:5 and then save up for tires.
Easy to fix though, fuel pressure or alky knob.
One comment that made sense to me about alky injection was to make it a tad fatter since you are substituting methanol for gas in whatever % you are injecting it in your motor. That would mean you'd want to run a tad fatter on alky but using the Scanmaster for this IMO is not the way to really dial it in. Go for a dyno session and tune it to 11:5 and then save up for tires.
Thats too low. Maybe its sensor, maybe its fuel, maybe its chip... maybe maybe maybe... lots of maybe.. Maybe you need an AFS20 O2 sensor
At least to start.. and turn the boost down.
I forgot to mention I am not on straight pump gas. It's about 50/50 110 and 93. I got a GM O2 today. The pn was afs21. I didn't ask for the 20 because I didn't pay attention to the number till now. The numbers I recorded tonight were as follows.
O2: 33mph and below were >100
42-60mph 801-804
60-75mph 790-780
75-90mph 760-780
90-110mph 760-740
110-128mph 740-720
There was 0 knock and 0 timing retard @23psi The fuel pressure is 43-70ish. I cant really say for sure it stays at 70 in high gear. It's too hard to drive and watch. I have always had really low O2 numbers but the car still picks up over 25mph on the big end.
O2: 33mph and below were >100
42-60mph 801-804
60-75mph 790-780
75-90mph 760-780
90-110mph 760-740
110-128mph 740-720
There was 0 knock and 0 timing retard @23psi The fuel pressure is 43-70ish. I cant really say for sure it stays at 70 in high gear. It's too hard to drive and watch. I have always had really low O2 numbers but the car still picks up over 25mph on the big end.
O2's are crashing. you need more fuel. Chip??? Or fuel system not keeping up.
GNVYUS 1
Well-Known Member
- Joined
- Dec 15, 2002
110 will eat up stock sensors within weeks if driven a lot. I'd get a couple $25 Stainless Denso's ( Rockauto ) and leave one in the glove box ( I do :biggrin: ).
My Talon ate up a stock sensor in 2-3 weeks of daily driven on 110 and 93, Denso lasts me about 8-9 months, nice.
Do you have a Translator?? If so, add fuel up top so you can leave your fuel pressure alone for the lower RPM #'s. Or the Turbo Tweak chips allow you to add pulse width up top.
Bruce posted years ago how his wideband to millivolt readings fluctuated which is why the narrow band IMO should not be trusted at this level of tuning FWIW.
My Talon ate up a stock sensor in 2-3 weeks of daily driven on 110 and 93, Denso lasts me about 8-9 months, nice.
Do you have a Translator?? If so, add fuel up top so you can leave your fuel pressure alone for the lower RPM #'s. Or the Turbo Tweak chips allow you to add pulse width up top.
Bruce posted years ago how his wideband to millivolt readings fluctuated which is why the narrow band IMO should not be trusted at this level of tuning FWIW.
Not sure how this might relate to you guys that are mixing or how precisely you can control this with your stock ECMs, but in a pure alcohol engine, some engines like to be leaned on the top end, past peak torque. If you try this stadegy be very careful. Some engines like it and some don't.
1000NATIONAL
Buick Diecast Nut
- Joined
- Jan 21, 2002
+1 on the Denso's
I buy mine from sparkplugs.com
Denso OE identical O2 sensor PN# 234-1001 $16.16 ea.
Shipping can be a little high so order more than one.....
HTH,
Steve
I buy mine from sparkplugs.com
Denso OE identical O2 sensor PN# 234-1001 $16.16 ea.
Shipping can be a little high so order more than one.....
HTH,
Steve
"O2's are crashing. you need more fuel. Chip??? Or fuel system not keeping up."
That's what I think too. I have an extender chip. It only seems to have provisions to change low gear fuel. I'm fairly sure about the fuel system. I have an Aeromotive pump and new 60#.
"you have a Translator?? If so, add fuel up top so you can leave your fuel pressure alone for the lower RPM #'s."
Yes I have a translator.I hadn't thought of trying that.
"Not sure how this might relate to you guys that are mixing or how precisely you can control this with your stock ECMs, but in a pure alcohol engine, some engines like to be leaned on the top end, past peak torque. If you try this stadegy be very careful. Some engines like it and some don't."
That was what I was thinking because of how much meth I am running and because the car seems to still be making power. I just didn't want to hurt anything based on my assumptions !
Unfortunately it's raining here for the next couple of days,they say. I probably won't be able to test anything till Monday. I really appreciate all the input!
That's what I think too. I have an extender chip. It only seems to have provisions to change low gear fuel. I'm fairly sure about the fuel system. I have an Aeromotive pump and new 60#.
"you have a Translator?? If so, add fuel up top so you can leave your fuel pressure alone for the lower RPM #'s."
Yes I have a translator.I hadn't thought of trying that.
"Not sure how this might relate to you guys that are mixing or how precisely you can control this with your stock ECMs, but in a pure alcohol engine, some engines like to be leaned on the top end, past peak torque. If you try this stadegy be very careful. Some engines like it and some don't."
That was what I was thinking because of how much meth I am running and because the car seems to still be making power. I just didn't want to hurt anything based on my assumptions !
Unfortunately it's raining here for the next couple of days,they say. I probably won't be able to test anything till Monday. I really appreciate all the input!
The limiter was set to ON, per the instructions that came with the chip. I tried it with it off and the car slowed down but I didn't see a significant O2 difference. The WOT knob was a 0. I put it on six. The O2's went up higher but still came down to 740. The car lost 2mph on that pass.
The fastest pass I have recorded, the air was better[30.50in,40f vs 29.90in,82f] but the O2's went as low as 714. I have never had any knock by the DS or audible. The plugs always look clean. I started all this because, when the air got worse I wanted to turn the boost up, but I was nervous. Before I had DS I just tuned by plugs and knock. It seems like the O2's aren't correlating with the MPH, with either the Bosch or Gm sensor.
Once again I appreciate everyones input!
Eric Stage I
TurboTweak Guy
- Joined
- May 25, 2001
If you have an Extender chip, the limiter needs to be OFF in the Translator.
