Toluene and running lean
11-17-2002, 01:03 PM
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Toluene and running lean
Ok. I got hooked on toluene & race gas. But is it safe? I wanted to see if it could run rich or lean for peace of mind. So I did a little calculation. Turns out its OK.<ul><li><a href="http://mywebpages.comcast.net/s4what/Combustion.htm">Combustion</a></li></ul>
11-17-2002, 01:11 PM
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If that is so, and under WOT, yes it does not matter
But I thought the O2's are read only at part throttle and under light load/cruising. Could be wrong. I just ordered the Bosch EFI manual
11-17-2002, 02:34 PM
#4
I understand what you did; and your stoichiometry seems correct; but I think that there is more to
the combustion process than simply the number of carbon bonds broken. The double bonds are more difficult to break vs. single bonds, but they produce more energy. The toluene has higher density vs pump gas, but it takes more energy to vaporise it and it should burn slower so the flame front will be altered. I'm no internal combustion expert, but I'm thinking that you'll be OK with the higher octane and shouldn't run lean with the high toluene mix. I would think that at WOT, all engines and especially ours would be programmed to run slightly rich to avoid such problems. The program has to be able to handle ALL available U.S. pump gas (even CA craptane - sorry guys and gals out there).
My guess is that unless you go pretty far out of the range of pump gas characteristics, you should be fine. I'd be interested to see what the Fuel Injection manual has to say, though - so please post when you find out!
My guess is that unless you go pretty far out of the range of pump gas characteristics, you should be fine. I'd be interested to see what the Fuel Injection manual has to say, though - so please post when you find out!
11-17-2002, 03:40 PM
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EGT sensors widen the injector pulse width at 1045 degrees celcius...
TO cool down the temps. Running a mix that's roughly 2% lean most likely won't hurt anything if you calculations are correct. I can't tell, you got a better grade in chemistry than I did, but what you're saying sounds plausible....
11-17-2002, 03:49 PM
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EGTs are also monitored at WOT (so it can't go too lean). Also, long term fuel adaption
will shift the WOT fuel tables, I believe, to compensate for a slight lean or rich condition. Pump fuels in many areas are up to 10% oxygenated, which has a similar leaning effect on air/fuel ratios, but it's all good I think.
11-17-2002, 04:02 PM
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The O2 sensor senses oxygen in the exhaust stream it does not calculate anything...
The catalyst in the sensor generates a voltage that is picked up by the ECU.
Anything over 80% throttle position is considered WOT (full enrichment) to the computer then EGT sensor comes into play.
The O2 sensor is strictly a feedback device only.
Every thing that you see from the sensor has already happened. They are critical to the ECU for short term fuel correction.
Anything over 80% throttle position is considered WOT (full enrichment) to the computer then EGT sensor comes into play.
The O2 sensor is strictly a feedback device only.
Every thing that you see from the sensor has already happened. They are critical to the ECU for short term fuel correction.
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11-17-2002, 09:09 PM
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Point is the ecu adjusts the fuel based on O2 readings...
at and off boost in the S4.
And yes I know about the EGT sensors and I know how an ecu uses fuel maps based on maf readings. But the discussion here was on running leaner gas, nothing more.
And yes I know about the EGT sensors and I know how an ecu uses fuel maps based on maf readings. But the discussion here was on running leaner gas, nothing more.
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