Recently had mine dyno'd. 30 odd kw difference between petrol & LPG!

I have about 218 - 220 RWHP in a N/A I6

Impco system and built motor and auto

i would say something is wrong with lpg system....thats a massive difference

were all very keen im sure to see what mods you have mate.... spill it!

Hey guys my baby has been fitted with the poliauto lpgi system also and its finally running quite well, Im hoping to get it put up on the dyno next time i do a run to geelong. Toranaguy, POLIAUTO told parnell to f**k off basically, not sure why and no luck with the cable and software... they dont sell em.. sorry. but i may be able to organise a day where you may be able to use it well im there... sorry mate, best i can do.

After reading the question and answers, I notice a few errors and assumptions that should be cleared up here!
Firstly, it must be remembered that petrol cars were designed to run on just that...petrol. ULP has a lower compression ratio then engines built for super but ULP engines have superior ignition systems which don't require upgrading. In fact, for LPG, ULP ignition systems are great! EF, like AU's use a coil pack with many of you would know, but understand that the output of a coil pack is as high output as you'll ever require.
Saying that, LPG require only one thing that Falcon engine were not produced with, High compression ratio..!!
LPG really starts working at an optimum level from 11:1 Comp ratio onward if you have the hardware to handle it and survive everyday driving and expect your engine to last!
If you’re running a duel fuel Falcon, the figure shouldn't go much above 9.5:1 compression because ULP doesn't like it and will experience detonation which will really ruin your day! This is the dilemma of duel fuel ULP engines with has been a bit of an issue since 1985, a year before Falcons were ULP only. Pre ULP engines on the other hand don't have the same problem to that extent because they were designed at around 9.5:1. But Super is dead (the real lead super) and about the only real worthy option is PULP (premium). If you use PULP and boost the compression ratio to 9.5:1 or even slightly more (your call) you will have the best of both worlds for a duel fueler and get the added power you’re after!!
An LPG car that has a noticeable difference in power from a standard engine is a dodgy LGP system that doesn't suit your application properly!
A Falcon isn’t tunable!! Only by fitting an after market management system can you tune one. It's the LPG that needs looking at in that event, not usually the car if all else is good with it! Straight gas rocks!! I have built a few and one was 380 RWKW and was a stoking hot son of a B.....!! I loved every minute of it!!
My advice is buying a dedicated LPG AU and pump it out to 11.5"1 and through in as big a cam and exhaust as will fit as these baby's don't have anywhere near the limitations that a petrol car has! Have fun.....x-dub