chev gettin hot!!

[mikesmith]

car was tuned at gas research in dandenong so i am assuming the tune is all good!!.

yeh goin to put the el thermos in it 2moro and see how it runs!!

[PGS 4WD]

Was the distributor curve assesed and recurved? LPG has different timing requirements, more initial less total timing. Are you already using a high flow thermostat? I won't comment on any tune I haven't seen but I do have over 5 years more experience tuning Gasresearch than anyone you will find, having owned that business and worked in R@D for the origional designers of the product back in the mid 90's. They are good guys at Dandenong and I'm sure the mixtures would be fine. There are significant gains to be acheived from the correct distributor curve in performance, economy and engine longevity including running temperature.

Cheers Joel

[mikesmith]

hi joel i think i may bring it to u! cause i am not to happy with the mixtures that have been set on it! wont dissolve information on here!

the dizzy has not been recurved to suit the gas but i am looking at putting a cam in the engine and shaving a lot off the heads to get the comp up so i would wait to do that if i was going to go to the effort of recurving it!

[PGS 4WD]

Thats cool, no pun intended, I can recommend and supply camshafts, we did a lot of R&D years ago and I have been designing and selecting custom application camshafts for a long time. It's important that the cam works with the compression and gearing. If you are looking for more low down torque you might consider doing the regraph first as thats where the improvements are most noticables. Be aware that raising the compression tends to make things run hotter as well, too high is a lot worse than not high enough when it comes to compression. Some people go too far which results in optimum timing not being acheivable due to detonation.

Cheers

Joel

[madrolla68]

So what are the ideal mixtures (measured) for LPG.

I run mine at 15.5 at idle and around 13.5 on cruise,dont they say that it should be 1 point higher than petrol if using stoichometric value.

MAtt

[PGS 4WD]

Not everyone will agree on what the ideal mixtures of any fuel are, remember stoich or 15.5:1 for LPG (14.7:1 ULP) is where the Catalytic converter temp is correct, the mixture is lean at light throttle such that more throttle blade is open causing a reduction in vacuum and therefore pumping loss. Stoich is leaner than optimum power. Peak power comes at peak temperature, that will relate to the quality of the engine, the application and the power of the ignition as a leaner mixture under power will generally make more power provided the ignition can support the spark and the engine is built to cope with the heat. So for example I would run a 4 tonne vehicle richer under load as this will be cooler in a vehicle that can run under sustained load, a small car that has a very high power to weight can be run leaner safely as the load cannot be maintained for any length of time. I would run an old points ignition vehicle richer than a multi coil late model car, particularly at part throttles where a crap igniton will be more likely to missfire.
If you want to be fancy we have set up EFI systems to enrichen via an EGT probe so you can run a heavy vehicle lean at peak power, until the heat comes up to a level that requires enrichment cooling. Power enrichment on current GM engines does a similar thing but it is time based.

Cheers

Joel