LP and H2O injection systems questions

[Elowe65]

Have a few questions on propane use.

1. What is the typical MPG gain with propane use under moderate use?
2. Are most of the current units on the market only activated by a boost switch and what is this switch normally set for?
3. Do the current systems in the market vary the amount of LP injected at all based on RPM, Boost Psi, and TPS?
4. Has there been any problems getting a tank filled when it is an ASME tank versus a DOT tank?

Just asking as I am currently testing a new system, and had a few questions.

As for water injection, just curious if anyone is using a system currently?

Also, off the subject, TPS sensor on the truck is current only reading about 80-83% at full throttle, does anyone know if the TPS is adjustable in some way?

Thanks in advance,

[More Power]

The few propane systems I've seen inject a pre-set amount based on boost pressure.

Water injection does little for an intercooled diesel. The biggest benefit from water usually occurs when non-intercooled. The higher the temperature differential between boosted air and ambient, the more effect water can make. When running an intercooler, it is removing the biggest portion of the heat load from the boosted air.

Either an intercooler or water by themselves can take up to 200 degrees off the temp. An intercooler and water together might only take another 20-30 degrees off that (ballpark figures).

MP

[Elowe65]

Thanks MP

Reason I asked about the water injection is becuase it seems really popular with the turbo buick guys. They run a 50/50 mix of water/methanol and have seen decent power gains even with the intercooler. I believe most of their gain comes from being able to run more boost with the same quality fuel.

As for the propane, the system I currently have starts injecting at .3 psi boost and injects based on throttle position, boost psi, and RPM. Since it injects based on a map, drivability (sp?) and economy seems to be far better then a fixed activation time with a fixed orifice system that most use.
Was just looking to compare this difference.

[Jake99Z71]

Elowe65

A few people here are running water injection on their DMaxs. I know quite a few guys running water on their Dodge/Cummins and a few Fords too. It helps control your Egts. I can stop my Egts from going over 1200*F running just about anything.

[Kennedy]

I hooked up with Powershot 2000, or actually, they hooked up with me. I like the adjustability, PLUS it is so darn simple to install...

[Amianthus]

Under moderate useage, you should be able to expect a 2-4mpg gain. But no matter how you use it, there is no way you will recoup the cost of the system or even the cost of the fuel (LP) with the increase in mileage.
The setpoint pressure for LP is kinda up to the driver. I used to have mine set to go at 7 psi, but have since changed it to 30 psi. 7 is a bit low and the system will still allow LP to be drawn in even off the throttle, so you can get an over-speed condition (as I did). 30 psi seems to work much better for me. For you, I'd recommend 15 to 20 psi for the actuation pressure.
The available systems vary as far as how they work. I think you pretty much know this already. The best system is a system that vaporizes liquid and allows LP to be draw in to the system based on boost (or air flow demand). I like my system (I made it myself) and mine draws LP based on air flow. But there are a couple of quality systems out there. The one I like the most is the Powershot 2000. It's a boost biased system and have heard no ill on it. You want to stay away from the liquid injection systems as you can inject way too much way too fast into your engine and you will wind up with massive engine damage because of it.
As far as the tank goes, being that ASME now has a design code for construction of OTR vessels, you shouldn't have any problems if your tank if built to that standard. But it will always depend on the jurisdiction that you live or travel in. With a DOT tank, it's a little more widely recognized so your useage issues should not be as much a problem. As opposed to using a tank that might be just as legal but not as widely recognized. Does that make sense? Bottom line, either one SHOULD be okay, and both will be safe (for use as intended). It's just a matter of jurisdictional rules.
On the matter of water, I have to disagree with MP and agree with Jake. Water injection works well for aftercooled diesels. Well, those that are running extreme amounts of boost. Some of the benfits of water are cooler EGT's, more power, cleaner exhaust. If you add methanol to the mix, you get an even better kick. My system is made by me with nozzles made by Jake99Z71 (which I still have to pay him for). Don't worry Jake, I haven't forgotten. I will make it up to you. My max EGT's have been in the neighborhood of 1400F. I think with a bit more tuning, I might be able to get it down to 1300F max.

I hope that answers your questions. If not let us know.

[sdaver]

I have the powershot also..

1. no appreciable gains in mpg
2. mine is boost activated and adjustable
3. not sure about others
4 I have a DOT tank

Mine adds a 100 rwhp by itsself............and 40 to 60 rwhp on top of a large stack....as for the water/meth..........I would stay away

[Elowe65]

Thanks for all the replies.

My curiosity is due to the design of the system I am currently testing. The system is the MSD DPI (Digital Propane Injection). This is the same MSD that manufactures ignition units most of which are now pc programmable. It injects propane according to preset maps in the unit by PWM (Pulse Width Modulating) a solenoid. Injection is based on throttle position, RPM, Boost psi, and LP temperature. Liquid is drawn from the tank and vaporized at the regulator.

I have put at least 80 gallons of LP through with no major problems. The only issues and I have had is 1.having to have the ecu file updated for higher boost (originally the unit would start to shut down the propane injection at 26 psi, since has been updated to 32) and 2. Going to a few gas stations, some did not want to fill the ASME tank as they were looking for the DOT tags, this was only 1 time.

The greatest thing about the unit is its internal data recorder. I have saved a ton of