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Cool. I'd like to know his answer to your question too. It's a good one.

I just sent him an email. That is, if I decoded his email adress properly. :confused:

Yeah, bit of a glitch there! I think it's just: mail (at) fuelsaving (dot) info

I sent one to both addresses. Neither one came back as udeliverable. :confused:

Quote:

Originally Posted by diamondlarry

I have a comment on Tony's article. I agree with him that modern FI cars burn nearly all of the fuel that goes into them. Where I begin to disagree with him is when he says that a fuel warmer won't help mpg much if any at all. While it's true that there is very little unburned fuel coming out of the tailpipe, the problem is that much of the fuel isn't being burned in the combustion chamber. Catalytic converters do a great job of mopping up after what's left over from the engine but fuel that is burned in the cat does absolutely no work in propelling the car down the road. I believe that by heating the fuel that more of the fuel will be consumed in the combustion chamber where you can benefit from it.

Wouldn't this situation be detected to some degree by the O2 sensors?

Yes, and I would think that a cat burning that much gas would be dead in no time not to mention spewing smoke. The way larry makes it sound is that cars are perpetually running extremely rich.

That's a good point. The previous owner of Firefly #1 had burnt out 2 cats due to a bad O2 sensor. But they've got to be able to handle burning some level of HC without frying.

Quote:

Originally Posted by SVOboy

Yes, and I would think that a cat burning that much gas would be dead in no time not to mention spewing smoke. The way larry makes it sound is that cars are perpetually running extremely rich.

I'm not sure I would say that cars are running extremely rich but I think a significant amount of fuel is wasted by keeping the cat hot. I would venture a guess that modern FI cars probably don't need a cat but there is too much money wrapped up in the cat industry for them to go away. It would be interesting to see some side by side emissions tests with and without a cat. My uncle, back in the late sixties/early seventies, took a Rambler straight-6 and milled the head .100"(after doing the measurements to make sure there would be any valve collisions) and put the car on an exhaust gas analyzer and found that the emissions were nearly non-existent. This shows that if cars are PROPERLY tuned that there is no need for a cat; even with 60's/70's era technology.

Quote:

Originally Posted by diamondlarry

I'd like to do a test on an car with no catalytic converter. Checking the HC one foot away from the exhaust valve, then at the tail pipe. By the time the mixture reaches the end of the tail pipe the HC's will probably drop a lot. Fuel burns very slow.

Quote:

Originally Posted by maxc

That does sound like an interesting test. I hadn't thought about fuel burning in the exhaust pipe before it gets to the cat. Below is the response from Tony at fuelsaving.info:

Quote:

Larry:

That's a good question, but the answer is "no". Even before the catalyst the unburnt hydrocarbons only represent 1 - 2% of the input fuel; at the tailpipe, it's a tiny fraction of one percent.

Yours,

Tony
----- Original Message -----
From: Larry Trowbridge
To: mail@fuelsaving.info
Sent: Thursday, December 14, 2006 12:28 AM
Subject: Fuel warmers

I generally agree with you about modern fuel injected engines having only 1-2% of unburned hydrocarbon emissions. You stated that you didn't think that fuel warming would improve mileage much more than that 1-2%. My question is this: Are those hydrocarbon emissions being measured at the tailpipe? If so, I submit that fuel warming may indeed offer a greater than 1-2% improvement in mileage. I say that because, if fuel is being burned by the catalytic converter, it is NOT contributing to propelling the car down the road. If this is the case, warming the fuel would make more of the fuel burn easier in the combustion chamber where you would get benefit from it's burning.

Larry Trowbridge

Hmm, with a response like that, I may have to dust off the ol' open mind.:)