First thoughts after LPG conversion

[sxtacy]

Just though I would post my initial thoughts about getting my car converted to LPG in case anyone else would like to do it.

The mods I have is a 2 1/2 inch mandrel bent exhaust with extractors, high flow cat, resonator and rear straight through muffler; cold air intake with standard air box and a stage 3 chip for regular petrol.

First up fuel is SO CHEAP now! $25 for a 450km round trip to Melbourne. And that was with the car about 500kg heavier. (all the furniture I bought at Ikea).

The exhaust sounds deeper on gas, and there are also non stop crackles when you so down. Cool for the first ten minutes, but gets a bit annoying when you stop and start at all the traffic lights. (plus EVERYONE looks at you) Might change the rear muffler to something a little quieter.

The problem is it lost power, and a fair bit at that. The gas conversion guy said most cars don't lose that much power on gas. It feels like a stock pintara on gas, with not much at the top end.

I have a theory though, The stage 3 chip in the car does stop the hesitation problem on gas, but maybe it is running too rich on gas so not making as much power.

I have to take it back to get it tuned again in 1000kms, but would a new cam help out with the loss of power on gas?

Obviously this isn't going to be a race car, I just want a little driveability back.

[SSS]

What LPG system is on it? Mixer or vapour injection?

Sounds like you have a mixer system; vapour injection typically does not lose that much power.

The good shit coming up quickly is LPi, ie LPG injection. The system carries LPG right up to the injector as a liquid (the other 2 systems do not) and as the LPG passes through the injector and into the cylinder head ports, it changes state from a liquid to a gas, in turn dropping intake temperatures by some 30-40deg C.

I'm waiting for it to be validated in one of the OE applications on working on with it, then I plan on converting my daily driver to it.

[sxtacy]

OK, I just drove the car around the block with no weight in it, and if you drive it hard on gas it is still fast, not as fast as petrol but still it's fast enough unless you are racing someone.

I think it has lost a little bit of responsiveness, which is understandable. You just have to have it a bit higher up in the rev range (or drop it down a gear) to make power

I think I do have the mixer system, the injection one was going to cost 2 grand more, good if you have a turbo but...

That new system sounds awesome, probably be the same as petrol but running cooler so that means BOOOOST.

I was talking to a guy at work who is a car and bike mechanic who was telling me that since LPG has a higher octane rating then petrol, you need LPG spark plugs and hi power leads to make it work properly, I might try that.

Also as the chip would affect the timing, would it be worthwhile to get the full stage 3 chip for premium? Might give it that bit of extra kick?

Anyway, I am very happy with the system, I love the price of gas, and if I need more power, I just press the switch.

[sxtacy]

Well, after a few weeks of issues on gas, I have fixed the problem.

I was playing with the leads when one broke so i replaced it with another I had around. Then I filled up the gas, and around the next corner it started stuttering. I thought it was bad gas so I tried to use it all but it kept getting worse until I couldn't cruise on gas.

At which point I started playing with the tuning of the LPG converter, didn't make any difference. It still ran fine on gas for a few minuted then it would start stuttering.

And here's how I fixed it. I went to supercheap and picked up BOSCH high performance LPG compatible leads and a set of standard NGK plugs for under $50, Runs even better on LPG than it used to on petrol.

I don't think the spark plugs were the correct ones in the engine, and they were filthy; and the original leads were shit too. At least I learned how to tune LPG