wondering if anyone has ahd experience with propane on a stock 400 or equivilant engine. And how was the difference in mileage, power and drivabilty. Where is a good source to get a kit for daily useage?

 

Propane as the primary fuel will yeild less power and reduced MPG than gasoline, regardless of the engine.

 

If you increase the compression in your engine you get the same or better.Propane is 104 octane so it needs higher compression .

 

generally power and mileage will be reduced by 20%.

 

just because its propane fuel,does not mean you will have less power. propane fueled engines are fine for power if they are higher compression. mine is better for power now on propane, than it was on pump fuel.propane is a higher octane than pump gas,so if you have an engine like mine(428 SCJ ,12:1 compression) it runs better on lpg than pump gas. i was mixing 94 octane and av gas just to get good power and no preignition before converting to propane.lower compression engines or worn engines are not as "happy" on propane,so you won't get as good results with them as you will with a higher compression engine.as for mileage,mine was always bad,4-5 mpg.thats not the normal mpg,but my truck is not my daily driver so it doesn't bother me.my engine has big horsepower/torque that was my need more than good mileage (so it doesn't matter to me)this has bin my experience anyway.

 

Were you looking for a mono or dual fuel kit for your truck?

 

The basic problem with "conversions" or "flex-fuel", "bi-fuel", etc. is that the engine itself, compression, timing curves, etc are still setup for 87 octane unleaded gasoline. You will always lose power and mileage this way.

Jim

 

You're right, you will lose some power and mileage on propane. But what's more important: mpg or $/mile?

Typically, conversions with the Impco propane systems get somewhere between 75% to 80% of the vehicle's gasoline economy. If you get 20 mpg on gasoline, you'll get around 15 - 16 mpg on propane.

The overall savings comes from the difference in fuel price and the price of propane depends a lot upon where you live but Flying J truckstops usually have cheap LPG. If you can buy propane for $2.00/gallon and gasoline is selling for $3.00/gallon, your truck running on propane will COST you as if it were getting 22.5 - 24 mpg on gasoline. That is:

15 x 3/2 = 22.5 and 16 x 3/2 = 24

Obviously, if you need high octane gasoline for your vehicle, propane makes even more sense. Remember, propane has an octane rating of 104.

Newer commercially available injection systems get closer to 80-90% of a vehicle's gasoline economy but these systems only work with an existing gasoline EFI system.

Whatever you do, do NOT use portable DOT lift truck tanks on an on-road vehicle. They are illegal and dangerous for this purpose.

 

propane is a good choice for the enviromentally concious person, its cleaner burning and non toxic if spilled. Being cleaner burning it is also better for the engine internals (less carbon build up and oil contamination) longer plug life as well as longer oil change intervals saving you even more money.

 

If you're stuck in traffic, propane can also save you time because some highways allow alternative-fuelled vehicles to travel in the high occupany vehicle (HOV) lane.

 

It can also cost you time and money if you have to drive miles around because you are not allowed in certain tunnels.

HOV stickers are given for CNG in CA, but not LPG.

Jim

 

In AZ, i believe the HOV sticker is given for JPG as well.

 

i have a 95 f250 with a 7.5L and i run it on propane all the time because i get way better mileage compared to running it on gas.