671 dual exhaust - which manifold & where would it be best to place a EGT probe?

[gg04]

Pinging,prefire knocking... detonation from pressure..rdw

[chessie4905]

You may need larger feed lines. How about water injection while you are at it to provide combustion cooling? It keeps exhaust temps under control on my 6.5 pickup with power chip. Mine is variable with boost and flow control.

[luvrbus]

I love Banks Power take on propane injection "save the propane for the cook stove"

[Scott Crosby]

I love my little extra hp I get from my propane.  It keeps both my buses from loosing momentum on grades and hills.  I've seen bent rods and holes in Pistons on 71 engines not using propane.  I use propane and have yet to bend a rod or put a hole in a piston so it must be better than diesel.   just using the logic   

Seriously the amount I use and the way it's used it's not a big deal as a few people try to make it out to be.  A 10-15hp boost is nice and worth it to me.   If used in higher heat situations and with a lot more gas yep I would agree it would be harmful but fogging in small amounts does not effect the timing, does not increase the engine temp, and yet gives a little more power.  It's not a $ diesel fuel saving effort.  My buses could not even go up a simple overpass without loosing 5 mph or more and with the propane I keep up my speed.  I can cross a long grade at 50-60 instead of 20-25.  I can accelerate up steep hills with it when without it I loose speed.  i would even lean towards the idea that the benefits out way the negative side effects.  I love my results.  Only warning is don't use too much, and don't operate your engine like its not a 71 series, all the 71 limitations still apply as far as lugging, temp range, etc.    Used in a small limited capacity and in my 3 years of real world using propane, on two different buses it works.  Yes Clifford just saw an engine that was destroyed possibly and probably from propane.  But that is not apples to apples as that system used more than 10x the amount of propane and added even more with higher boost.  It's not the same at all. 

I had a compromised cooling system this past summer and I could run 10mph faster at 5 deg cooler than I could without the propane on.  I don't remember the exact numbers but it's documented on my website and it was dramatically different like that.   For example I was 190 at 50mph without propane but if I turned the propane on my temp would drop and I could go 60mph and maintain 185.  If it turned the propane off the temps went up and I had to slow down.   If and or when I blow up or destroy an engine I will be sure to post about it.  Until then I'll be safer in the right hand lane going much closer to the speed limit instead of under 1/2 or 2/3 of what is the posted speed on grades and hills.  Anyone that says a bus is better going 22mph up a grade is dumb.  It's Better for the bus but not better for your safety because of the semi's behind you are closing at you 40-50 mph faster and not paying attention.  Same thing with "I can see and enjoy the scenery when I'm going slow". Good, go slow on a side street or frontage road, not the Interstate and keep your eyes on the road and traffic not the scenery anyways.  Using propane has benefits along with the risks... That's all I'm saying.  Around a $150 investment is what my system costs and it works!

[luvrbus]

The propane debate has last 50 years it comes and goes it will destroy a engine I have seen it more than once.Electronic engines have a more control for the time of injection the old manual 2 stroke engines don't you flip a switch it's there.
Sooner or later it will take a toll, first you get 1 weak cylinder pumping a little oil then it's down hill from there.
Scott's little system is nothing new it's been around long when people would draw the system on a big chief tablet and pass it around to others long before the internet and YouTube.
The engines will usually blow at full throttle when it's low on oxygen and you flip the switch.
I don't understand why propane you can achieve the same affect with air and have full time power but people like to get outside the box and I am ok with it just not for me     

[buswarrior]

I recall some stuff from long ago discussions...

No matter the fuel, you need oxygen to get it to burn.

Is there any "spare" oxygen present in the cylinder before the propane is added?

If there's a bit of smoke, indicating unburned fuel, is all the oxygen being used up?

The propane has a cooling influence on the burn. Cooling the burn has advantages all the way back to the end of WW2, with the first water injection used to good effect to get the heavy bomb loads off the runway.

Are we being fooled? Is it the cooling, not the burning, that is giving the modest improvement?
Would water injection accomplish similar effects to the propane in our 2 strokes?

I miss the engineers that used to haunt the bus boards and the chat rooms, back when the internet was shiny and new...

happy coaching!
buswarrior

[Scott Crosby]

It is replacing fuel.  When you are on the governor and turn the propane on, the fuel racks dial back maintaining rpm.  It is the propane giving you more power and in smoke situations my exhaust smoke dissapears and or lessons greatly when the propane is turned on.  I firmly believe it gives a more complete burn of the fuels too.  I think it adds to better performance for a few reasons not just adding a fuel.  Cooling, increasing o2 via density, the propane is more evenly mixed already with the air in the cylinder Allowing the diesel to burn better and cleaner when it ignites.   It works for me.   I've experienced it first hand make my bus Getty up and go!  I was about to roll backwards down a steep hill with my automatic screaming full throttle and when flipping on the propane I went right up it and the mosquito fogging disappeared.

[luvrbus]

It is replacing fuel. 

I rest my case that is what put Bully Dog out of the propane injection business Propane is like CNG it has no upper cylinder lubrication diesel engines are required to have.Just be with careful it,I have a 92 series here that is complete junk due to propane use that went astray with a factory installed kit       

[Scott Crosby]

It's less than 10% and I only run it on grades and hills.  If it was on full time and at a larger amount the lubrication would be effected but not as much as the low sulphur fuel is effecting it.  Any fuel additive for lubrication will be a benefit above and beyond any small reduction from the propane.

[Scott & Heather]

I never jump into the fray, but I'm feeling risky today so I'll just say this, I know nothing about propane injection on diesels, but I've done a ton of research on propane as a fuel for my twin Honda EU3000is generators. They have a propane kit for them. A recent thread by a guy who bought one of these generators new and ran it on propane was very interesting. Basically, he tore the motor down after the genset died (6000 hours) and realized that the propane fuel system caused it to run too hot and ended up killing the motor. He pulled the system and is running gas only now after installing a fresh honda motor. Probably completely unrelated, but generator owners are reporting shorter lifespans running propane.

[buswarrior]

off topic, the delicate balance between fuel economy and lean burn is the devil with compressed gas fuels.

At Big Transit with the CNG Cummins engines long ago and far away, run them rich, get poor fuel mileage, run them lean to get better mileage, burn the exhaust valves and snap them off.

I'll bet the generator propane things will be related.

happy coaching!
buswarrior

[Scott Crosby]

That's all fine but I don't think it really applies or matters much when the propane is only a 10% mix used for one min here and three min there.  Total usage is probably averages to two min per hour of running. 

[luvrbus]

It all adds up anyway you slice the pie,propane is a dry fuel I recall the old 549 IH V8's and the 534 Ford V8 you had to retard the timing a lot to keep one from flying apart every 40,000 miles when using dry fuel back then it butane

[Scott Crosby]

My bus's will continue to work because I use 40wt cf2 oil... That's the answer to everything working right from what I've read. 

If I break it I won't even complain about it.  It's been that good to me and such a benefit to have the power with the flip of a switch that I don't care at this point.  I wonder How many years I need it to continue to work before people will believe it works? 

[Scott & Heather]

You're a living science experiment Scott and if anyone is gonna feel comfy breaking down the motor and building it again, it would be you. Keep reporting back your results. Sorry OP for how much this thread drifted


Sent from my iPhone using Tapatalk