Originally Posted by Terry Metro Lawn
Actually propane has about 7% fewer BTUs than gasoline but runs a more robust 104 Octane. Typically usage is close especially given shrinkage.
Fuel pricing differs per region because of transportation costs. It's up to the Districts as far as pricing is concerned. I believe a savings of 15-20% is built in to the calculator. Many do much better than this. After hitting "enter" you can input your current local pricing to get a better idea of savings.
A full 33# alumninum cylinder weighs about 55# and carries roughly 7 gallons. Propane weighs about 4.24# vs gasoline at about 6. Brackets are around 5-7. It depends on the mower whether or not two tanks would be mounted. Sometimes we get a day out of one 43# tank. We try to match the OEM operating time.
MN? You may already be doing business with us. ;-)
I was using 91600 btu's per gallon of propane. Unleaded gasoline has 114100 btu's per gallon. Which is 20% difference.
Octane to my knowledge isn't more robust but lets the fuel burn slower. You can take advantage of the slower burn with a higher compression ratio. If you don't raise the compression ratio the higher octane rating doesn't do much of anything.
Are you increasing orifice size by 7%? If so that flows way more than 7% of fuel.
Not a customer yet. I have a automotive engineering technolgy 4yr degree from Mankato State (MN college). Worked with E85 in cars in the mid 90's, competed in the clean snowmobile comp with direct injection (2stroke), and raced motorcycles with E30.
Ever time I talk to my U of M ME graduate who works for a company doing clean diesel technolgy about running propane on the mowers says it's not the most economical with conversion costs and price points yet. He does say it's a clean burn and the engine valves have less build up.
I'm guessing if a mowing company has a full time mechanic with 5 crews or more you could get over the intial hump of set up costs as he could learn to buy individual pieces for kits instead of the $3K cost with training. Manage your mower purchases so you can transfer kits to the new mower would also help.