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Old 04-25-2012, 11:52 PM   #111 (permalink)
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Originally Posted by tjts1 View Post
You don't need to be insulting just because you think you're right. And yes, you are advocating for it.

You need to clearly specify:
There is NO evidence that there is any FE benefit here
This DOESN'T work on EFI engines which makes up 99% of the vehicles on the road today
It HAS NOT been tested on emissions controlled vehicles.
There are UNKNOWN long term consequences of putting diesel fuel into a gasoline engine in any proportion.
EFI engines actually probably handle SLIGHT mixtures even better due to the fact they can sense knock, rich/lean mixtures in exhaust, and can adjust fuel input, as well as ignition timing and in newer cars even intake/exhaust valve timing.

NOW, I know you guys dont know me but I'm going to put your mind at ease before I go into some detail. I have a degree in automotive machining. My knowledge, what little I have, seems to fill a hole in the wealth of information you guys have. Your all actually right.

Diesel actually, if you wanted to compare apples to apples, has MORE detonation resistance, which in gas, is rated by Octane level. So yes, it would in theory RAISE your octane level. If diesel had a "low octane" rating, per say, they would not be able to run 14:1 or higher compression. YES, Diesel engines are compression ignition engines. But the fuel allows for it, producing more torque when its all said and done... What do you do when you build a race engine with 12:1 compression? You need a fuel that will NOT burst into flames too soon at that pressure, so you go HIGHER burn resistance, be it race gas (110 octane?) or Methane, or...Ethanol based fuel. E85 actually is about 110 Octane... but only a car designed to be able to adjust valve timing, and advance ignition timing far enough, can actually run it (flex fuel cars) which brings me to your diesel theory...

I'm staying out of the Carb'd discussion because with the right tuning equipment, you can manually adjust a carb'd engine to run on anything that makes fumes. You adjust everything from the ignition to the air/fuel ratio and idle, all that. But in an EFI.... lets break it down...

You run 10% diesel in your gas mix. OK here is what happens.
The mix is sprayed in, the gas ignites, igniting the d as well. The D burns slower, much like 110 octane gasoline. The engine will sense the extra unburned fuel in the exhaust. Your ECU will adjust several ways. It will either spray less fuel because it thinks its running to rich a mixture, and you will save fuel but lose a little power due to less actual fuel (energy potential) being in the cylinders. That is ONE way.
Another way your ECU may adjust is to keep spraying the same amount of fuel and just increase the ignition timing. If you have a TBI setup you may have a distributor and I'd suggest running your 10% mix a couple miles then advance your timing a little. You'll not save fuel if you or your ECU does this, but you may gain a little hp. It will be like running higher octane fuel and advancing your timing a little to adjust, in an old school car, except your ECU can do this for you. NOW... Here is my suggestion...

The 10% or whatever mix would work BEST for you in one of two situations.

Either you have a Flex Fuel car that can run on anything from 87 to 110 octane (e85) and your car can SERIOUSLY make good use of that extra ignition resistance (octane, per say) just as it would on E85. But without the alcohol hehe. Plus, nobody around here even sells E85 so yeah. You could have your own sortof mix.

The other scenario to BEST get a benefit is if you have EFI and you put your mixture in, drove it somewhere to get it good and in your fuel system, and get someone to redo your ECU tune WITH THAT FUEL IN IT. It would actually recalibrate your entire ECU setup to run that type fuel if its within engines adjustment ranges, and your car can make the best power/economy from it.

Now at low percentage mixtures I'm pretty certain even a regular EFI car would have some sort of way to adjust for the mix. I just put the above two as the BEST CASES. What would be really awesome is a Flex Fuel car with a custom tune, simply due to the fact they have Variable Valve Timing, as well as the ignition timing and all the other junk, plus direct injection.

You might COULD run a 50/50 mix in one then. Not sure.

ANYWAYS I am just adding to what you guys have already stated. Your all pretty awesome. And any google search telling you Diesel is more prone to detonation is an idiot. Pour gas on something, and throw a match. Do the same with diesel. See the difference. LOL I could get into the actual specifics of how diesel actually has a higher burn resistance "octane", but thats not as fun as burning stuff.

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