Quote:
Originally Posted by ConnClark
This information I got from a mechanic a couple years ago. However I did find an article on motor scooters which don't have to meet the strict emissions levels cars do and don't have catalytic converters. A 1968 2 stroke scooter emits 0.49% unburned hydrocarbons. A more modern 2 stroke scooter emits 0.11% unburned hydrocarbons. A modern 4 stroke emits 0.0168% unburned hydrocarbons. To get the percentage of unburned fuel I think we need to multiply these values by the stoichiometric fuel ratio of 14.7 for gasoline engines. So that results in 7.2% , 1.6%, and 0.25% of the fuel left unburned respectively. Granted these are motor scooters and not car engines however the budget for developing car engines is much greater than the budget for developing motor scooters. Also the technology employed to burn fuel efficiently and completely is far more advanced in a car engine than it is in a motor scooter. From this data I think it is safe to say cars burn 98% of their fuel.
Willamette Week | “Polluter Scooters” | August 9th, 2006
Note: I think the author has CO2 confused with CO emissions
An engine that has its timing retarded produces less power per unit of fuel and thus runs less efficiently.
I thought I might spend a moment debunking the source of this myth. If you look at the different versions by the originator of this myth you will see that he claims to have 50 years of data on this.
Internet Archive Wayback Machine
However despite having 50 years of data his acetone ratios change wildly in the first 6 months and he claims that the ratios must be precise. He claims that he isn't in this for profit and he is giving these findings to the world for free. This was a half truth, at the time he was selling scan gauges for people to try and verify this myth. He is essentially pulling off the classic scam of giving away a fake treasure map and selling you a shovel. |
So by measuring the HC in the exhaust gasses, how are you measuring the ammount of fuel lost to blowby during the compression stroke? It ends up in the oil. Perhaps you should track down those scooters with their 1 or 2 cylinder engines that have probably proportional blowby for thier size and measure the gasoline content of the oil.
Timing is a bit more complex than that , more timing only means more efficient if the engine is retarded to begin with. You add timing if the flame front hits the piston late, you take timing if the flame front hits the piston early. When it hits it at the "right" time which is about 15 degrees past TDC then you are at ideal timing.
Maybe, just maybe, his acetone ratio changed so much in the first 6 months for experimental purposes, maybe he just didnt have the ratio correct. I have seen a couple mpg improvement so far and im not being precise really. Also, is he saying he will give you the treasure map with the purchase of a shovel, no, he gives you the treasure map and if you feel it looks like a probable location for treasure he just happens to also sell shovels. The device he is selling is useful with or without the acetone.