Jesus I paid 3.53 /gal today...where do you live?!

 

near the beach in sothern cali...great place to live, but just damn expensive.

 

It's 4.79 for 87 here in the Central Valley. Cheapest is 4.48 is it just me or do xjs love drinking the expensive gas (shell and chevron)

 

chevron is usualy 1 of the best where i live, usualy either chevron, supersave or petro canada (only in canada) hve the best prices

 

Chevron is just to expensive(4.59) My xj gets horrible mpg on chevron. I get better mileage out of circle k and ampm. Ampm serves bp gasoline. Not sure what circle k sells. Number one seems to be arco(ampm) but its a gallon round trip to get it.

 

depends on where you live supply and demand wise, where the company is getting it from and how the economy alows them to sell it... supply and demand wise there are simply more ppl in the states, i kinda live in the middle of nowhere. on the #1 highway the stations will rob you completly but i know a few stations depending on were im going that are out of the way and dont market like the highway stations...(out of contry now or id hv given you a current price)

 

Hi,

I thought I would give you some information about LPG/Propane and how it works with the 4.0 XJ's as we are very familiar with it in the UK. Here in the UK, LPG is half the price of petrol (gas to you). So the swap is very common on thirsty vehicles like 4x4's.

The principles are as follows:

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KITS: There is three basic types of LPG kit.

The first is a single point system. This uses a mixer, which is a cross between a carb venturi and a cooker hob burner. It sits on the throttle body and lets the engine draw in the propane much the same as a basic carb does. This is a very simple basic system and rarely used now.

The second is the same idea but it adds a valve (stepper motor) in the feed pipe to the mixer on the throttle body. A special LPG ECU reads the Lambda sensor and other variables and adjusts the stepper valve to allow the correct amount of LPG through into the mixer/engine. This system is tuneable, simple but effective. It is my personal choice as it has very limited parts and is therefore easy to problem solve and fix.

The third is a multi-point injection system. It has no mixer but uses individual injectors drilled into the inlet manifold. It injects propane via an ECU in much the same way a petrol EFI does. It reads all sensor inputs and matches the propane quantity appropriately.

All these systems then have emulators which piggy-back the petrol injectors. These cut the signal to the injectors to stop then firing petrol, but fools the vehicles ECU to think its still working fine on Petrol. Therefore no MIL's etc.

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A complete system would therefore include one or more tanks, all with shut off valves for safety, a feed pipe leading to a main engine bay solonoid valve, this then leads to a reducer which drops the high tank pressure down to sensible levels. The propane (now as a gas) feed into whatever delivery system you use (as above), all controlled by whatever ECU you have.

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LPG has less energy than petrol so it takes more LPG to deliver the same amount of power. Therefore if you petrol engine does 20mpg, on LPG (if tuned right) it will drop to 16mpg whilst delivering the same power output.

I notice NO difference in power from Petrol to LPG - some do, but this depends on a lot of factors.

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Benefits:

1/ Half the price (here in the UK)
2/ MUCH lower emissions
3/ Safer if fitted correctly (do some research if you wish)
4/ Cleaner for the engine
5/ Will run in almost any position (no petrol to spill whilst off road etc). If you roll, no fuel spill.
6/ No open tank to fill with water when wading through lakes
7/ Higher Octane (build your engine to suit (higher compression ratio (CR) and reap the rewards)

Disadvantages:

1/ Unless you have a custom high CR engine, you need to atleast start the engine on petrol and then switch
2/ Some systems won't switch until hot - 5 minutes or so (mine doesn't, it will switch within 5 seconds)
3/ Less lubrication for valves - at 90k miles I still haven't noticed any problems.
4/ If the system isn't fitted safely, it can be dangerous!!! BE SAFE GUYS!