Thread: Gutless wonder

Tune the bloody thing for gas, then try again. Properly set up gas should lose less than 10% over petrol on average, and most of that at high rpm only. Spark plugs should be 1 step colder than petrol, the gap set to 0.7mm, timing advance put forward to about 10 degrees at idle, then adjust the gas flow for full load.

Thanks for that very precise advice. I think I will take it to somewhere who knows Rangies to set it up. Dino tune wanted $400+ I told them I already bought a car!

Gas Tune in Tuggers are pretty good.They set mine up three years ago and it is still running fine - no noticeable difference on gas or petrol - I have 9 degree BTDC set up with standard heat petrol Plugs.

Garry

Originally Posted by garrycol

Gas Tune in Tuggers are pretty good.They set mine up three years ago and it is still running fine - no noticeable difference on gas or petrol - I have 9 degree BTDC set up with standard heat petrol Plugs.

Garry

Thanks Garry, I'll give them a call once I am through the dreaded Dickson minefield. She's in for retest tomorrow.

Cheers

Jez

Why are you having to deal with Dickson - a roadworthy from your local garage and a gas certificate should be all you need.

However if the RR is highly modified then I can understand.

Dickson is not a pleasant place to be rego wise.

Garry

Originally Posted by garrycol

Why are you having to deal with Dickson - a roadworthy from your local garage and a gas certificate should be all you need.

However if the RR is highly modified then I can understand.

Dickson is not a pleasant place to be rego wise.

Garry

Put it in for rego at my usual mechanic and they discovered that it was missing the compliance plate. This meant it had to go to Dickson for a vehicle ID check. Once a vehicle is headed for there nobody wants to issue a RW as Dickson is the Nemesis of the inspection stations. I tried to get the ID check only done at Dickson, but they won't do one without a valid RW! So, going around in circles I just told them to do the bloody test. Of course they found a dozen things wrong and I have been busily and expensively fixing them all. Tomorrow I return for a retest.

Originally Posted by bee utey

Tune the bloody thing for gas, then try again. Properly set up gas should lose less than 10% over petrol on average, and most of that at high rpm only. Spark plugs should be 1 step colder than petrol, the gap set to 0.7mm, timing advance put forward to about 10 degrees at idle, then adjust the gas flow for full load.

Hi Bee Utey, I'm about to get my Rangie tuned for straight gas (I bought it this way) becasue i've also been convinced to give it ago before converting back to petrol. I noticed you mentioned 1 step colder plugs, i'm just curious as to why colder? I didn't think about the plugs earlier, but it has got me thinking now. Doesn't gas run hotter then petrol? The spark plug gap on petrol is 0.8mm (i think) so does this mean you suguest making the gap smaller for gas?

Originally Posted by Jazzman

Hi Bee Utey, I'm about to get my Rangie tuned for straight gas (I bought it this way) becasue i've also been convinced to give it ago before converting back to petrol. I noticed you mentioned 1 step colder plugs, i'm just curious as to why colder? I didn't think about the plugs earlier, but it has got me thinking now. Doesn't gas run hotter then petrol? The spark plug gap on petrol is 0.8mm (i think) so does this mean you suguest making the gap smaller for gas?

Gas burns much more slowly than petrol which is why you need to advance the timing for best burning. Although the peak temperature (hence cylinder pressure) is slightly lower than petrol, the long burn means more actual heat being generated around the plug. Also there is no intake charge cooling as there is with petrol evaporating in the air flow. So a "colder" plug will remain in its designed operating temp range better than a stock plug. Some engines benefit from 2 steps colder, especially if they never see petrol or have raised compression ratios. Note that not tightening a spark plug to its correct torque will make it run hotter than it should because the heat flow path from the insulator to the head has been increased.

As for plug gap, the voltage required to jump the gap is around 25% higher than the exact same engine running on petrol. So a reduction of gap helps the ignition components to cope. 0.7mm is a tested compromise that works well.

Bosh LPG plug brochure:

http://www.bosch.com.au/content/lang...4_Brochure.pdf

Their plug catalogue contains a few errors so the LPG plug I use on all low/medium comp LR V8s is the WR7KI33S version.