ECT mod pot value
03-13-2004, 09:19 PM
#21
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Because I'm bored and have no money I've been thinking about this one for a while. But where is the best local place to buy POT. Would Crap Shack have these or Fry's electronics? Found a lot of 4 on Ebay for $16
03-14-2004, 07:08 AM
#22
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Originally Posted by Dr. Zhivago
Jamie,
Actually, for best POWER, the AFR should be between 12-1 and 13.3-1. 14.7-1 is what gives you the most complete combustion for fuel economy and for the most efficient catalytic converter operation. The ECT mod bumps timing advance a little and slightly richens the AFR, which gains you some oomph down low and into the midrange until you reach the maximum advance built into the ECU.
It really does work. Granted, it's not an earth-shattering difference, but I have had plenty of people email or PM me who have done this and they all say the same thing. It makes a noticeable difference where it really counts: In the RPM range you use most.
Peace.
G
Actually, for best POWER, the AFR should be between 12-1 and 13.3-1. 14.7-1 is what gives you the most complete combustion for fuel economy and for the most efficient catalytic converter operation. The ECT mod bumps timing advance a little and slightly richens the AFR, which gains you some oomph down low and into the midrange until you reach the maximum advance built into the ECU.
It really does work. Granted, it's not an earth-shattering difference, but I have had plenty of people email or PM me who have done this and they all say the same thing. It makes a noticeable difference where it really counts: In the RPM range you use most.
Peace.
G
You are right.....I guess I was thinking more of going to the lean side which does loose power for sure but it also becomes more efficient. The hotter the burn the more effiient it gets. On the other end, for making torque, which most people notice first, then you are bang on with richening the fuel mixture (like a race car), but I wonder how economy suffers? I can't say much about the mod because I have not tried it, so I don't speak from experience. If you say it works I certianly can agrue it doesn't. Empirical evidence always rules!
The stoichiometric ratio (14.7:1) just means all the gas molecules are completely consumed according to the chemical combustion of gas and air. IF you deviate too much either way on the ratio, the converter becomes ineffective at controlling emissions.
It was the advent of the 3-way converter which really pushed for EFI.
Are you still running the mod?
Last edited by MTL_4runner; 03-14-2004 at 07:10 AM.
03-14-2004, 07:22 AM
#23
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Jamie,
I still have it hooked up, because I never bothered to change it. However, it is "zeroed out". I use my SMT-5 for performance modifications concerning AFR and Timing. I let the ECU decide what works best for the AFR (for the most part) when in Closed Loop. I do use the SMT-5 to bring LTFT to Zero, which helps throttle response and fuel economy. I had to add fuel to bring it to Zero, as it was running about +9-12% most of the time. So, the AFR in Closed Loop remains at 14.7-1.
I have modified my Open Loop maps a bit to lean them out since they are so rich in stock form on a NA engine. I keep them around 12.5-1 to 13.3-1.
I have Advanced Timing EVERYWHERE by at least 3 Degrees and as much as 10 in some areas. I run mid grade gas (89 Octane). All of these little changes really make a big difference in the driveability of the truck both on and off the trail.
G
I still have it hooked up, because I never bothered to change it. However, it is "zeroed out". I use my SMT-5 for performance modifications concerning AFR and Timing. I let the ECU decide what works best for the AFR (for the most part) when in Closed Loop. I do use the SMT-5 to bring LTFT to Zero, which helps throttle response and fuel economy. I had to add fuel to bring it to Zero, as it was running about +9-12% most of the time. So, the AFR in Closed Loop remains at 14.7-1.
I have modified my Open Loop maps a bit to lean them out since they are so rich in stock form on a NA engine. I keep them around 12.5-1 to 13.3-1.
I have Advanced Timing EVERYWHERE by at least 3 Degrees and as much as 10 in some areas. I run mid grade gas (89 Octane). All of these little changes really make a big difference in the driveability of the truck both on and off the trail.
G
03-14-2004, 07:27 AM
#24
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Originally Posted by Mossback74
Because I'm bored and have no money I've been thinking about this one for a while. But where is the best local place to buy POT. Would Crap Shack have these or Fry's electronics? Found a lot of 4 on Ebay for $16
Peace.
G
Last edited by Dr. Zhivago; 03-16-2004 at 04:43 AM.
03-14-2004, 07:44 AM
#25
Contributing Member
Originally Posted by Dr. Zhivago
Jamie,
I still have it hooked up, because I never bothered to change it. However, it is "zeroed out". I use my SMT-5 for performance modifications concerning AFR and Timing. I let the ECU decide what works best for the AFR (for the most part) when in Closed Loop. I do use the SMT-5 to bring LTFT to Zero, which helps throttle response and fuel economy. I had to add fuel to bring it to Zero, as it was running about +9-12% most of the time. So, the AFR in Closed Loop remains at 14.7-1.
I have modified my Open Loop maps a bit to lean them out since they are so rich in stock form on a NA engine. I keep them around 12.5-1 to 13.3-1.
I have Advanced Timing EVERYWHERE by at least 3 Degrees and as much as 10 in some areas. I run mid grade gas (89 Octane). All of these little changes really make a big difference in the driveability of the truck both on and off the trail.
G
I still have it hooked up, because I never bothered to change it. However, it is "zeroed out". I use my SMT-5 for performance modifications concerning AFR and Timing. I let the ECU decide what works best for the AFR (for the most part) when in Closed Loop. I do use the SMT-5 to bring LTFT to Zero, which helps throttle response and fuel economy. I had to add fuel to bring it to Zero, as it was running about +9-12% most of the time. So, the AFR in Closed Loop remains at 14.7-1.
I have modified my Open Loop maps a bit to lean them out since they are so rich in stock form on a NA engine. I keep them around 12.5-1 to 13.3-1.
I have Advanced Timing EVERYWHERE by at least 3 Degrees and as much as 10 in some areas. I run mid grade gas (89 Octane). All of these little changes really make a big difference in the driveability of the truck both on and off the trail.
G
Would you choose to run the mod if you were only normally aspirated?
Are you running a wideband sensor to see your A/F ratio?
The SMT's ability to vary the input to the ECU at all RPM bands really makes it in a whole other league (both price and performance). Seems like the mod would be completely pointless if you have control over fuel and timing maps all at once. I was just thinking that forcing the car into constant 12-13 AFR (with the mod) would result in pretty poor gas mileage. So you get a constant trade off of MPG or max power. The SMT gives you the best of both worlds and you are not stuck in one AFR over the full RPM range.
03-14-2004, 05:52 PM
#26
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I am only normally aspirated and yeah, I would still run it without the SMT-5 with the rest of the mods I have on my truck. I wouldn't recommend it unless someone installed both a free-flowing intake and exhaust.
I am using the SMT-5's display to see the output from the stock O2 sensor. It can extraplote the AFR from the O2 sensor voltage, or I can monitor the actual voltage istelf or it can display Lambda. It is also capable of logging this and many other data inputs.
The ECT mod doesn't force the truck to run TOO rich since you're in Closed Loop most of the time. The main benefit is the timing advance it provides, plus a little bump in fuel trim. And yes, the SMT-5 is a far better choice, but it's $250 vs. $5.00 for a decent potentiometer.
Peace.
G
I am using the SMT-5's display to see the output from the stock O2 sensor. It can extraplote the AFR from the O2 sensor voltage, or I can monitor the actual voltage istelf or it can display Lambda. It is also capable of logging this and many other data inputs.
The ECT mod doesn't force the truck to run TOO rich since you're in Closed Loop most of the time. The main benefit is the timing advance it provides, plus a little bump in fuel trim. And yes, the SMT-5 is a far better choice, but it's $250 vs. $5.00 for a decent potentiometer.
Peace.
G
03-16-2004, 04:29 AM
#27
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Originally Posted by Duffdog
question...
couldnt you just use a 741 operational amplifier wired to the output wire to adjust the voltage to whatever value you wanted-- since 741's have high input impedance, they shouldnt adversely load the computer and could be altered without all the super-precise tweaking with pots. It seems that with an amplifier--even set to negative gain, you could tell the computer that the temperature is slightly different at any temperature, not just a fixed temp. does this make sense to anyone else?
T
couldnt you just use a 741 operational amplifier wired to the output wire to adjust the voltage to whatever value you wanted-- since 741's have high input impedance, they shouldnt adversely load the computer and could be altered without all the super-precise tweaking with pots. It seems that with an amplifier--even set to negative gain, you could tell the computer that the temperature is slightly different at any temperature, not just a fixed temp. does this make sense to anyone else?
T
So, simply adding resistance to the circuit via a variable resistor allows you to lower the "apparent" temperature that the ECU is seeing. It also allows a fair amount of control over the temperature change. You don't need to use an Op Amp and get all complicated-like.
Hope this helps.
G
Edited because I hit submit before I meant to...
Last edited by Dr. Zhivago; 03-16-2004 at 04:33 AM.
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