Supercharging is on my list of mods but with petrol prices climbing i would like to retain the lpg system. Has anyone had any experience/problems with supercharging lpg.

what lpg system do you have now?

Parnel fitted at dealership before i bought the car

The Gas tank will be OK but you might wanna discuss the rest in more detail with these guys

http://www.gasresearch.com.au/

Your car is a 6cyl I am guessing, If so GRA is probably easiest to package.

Nah hes got an 8

Hence NFURI8 and pacemaker p4000's

hence the ""NFURI8" Fairlane ghia nf2 v8. " in his sig

Not necessarily the GRA being the best system. The pro's on GRA is own throttle body and easy to tune (costly though). The cons, parts arent covered by warranty much ive been told, tuning is very expensive as it has to be 'rejetted' everytime for different power outputs. Also pro is that it can handle ANY amount of power through it, turbo or blower.

Impco or Factory Gas can be setup to use on a blow-through system or even a suck through on a negative feed setup to, your best bet could be a) get someone who REALLY knows there gas to discuss your options (try joe from CMS (02)9600-6229) and see what u can do, b) get a throttle body from a dedicated LPG ute/sedan from au onwards as the gas goes directly in and is perfect for a lpg/turbo/blower setup.

GRA is very costly, you would be lookin at $1400+ for underbonnet setup only! Yep, ONLY the underbonnet bits!

yes definately an 8.

I would preffer to keep the original setup using CAPA blower. Blow through i guess. i would assume this would work with a converter / mixer upgrade possibly.

will do some enquiries soon.

GRA isn't good for whatever you want from it, it must be sized accordingly, there are 5 different sized mixers and the larger few will require multiple converters to supply enough gas to equal there rating.I think they go 350, 400, 440, 480, 510.

Impco has a 425, and some smaller ones, 225, theres probably more.

The benefit of Impco is most tuners can handle it, GRA requires different and sometimes custom fuel metering rods, and jets also. So

GRA is more sensitive to barometric pressure, and the tune will change with altitude, in theory it should also effect impco but I guess theres just more people running fast GRA cars so more people notice it.

GRA requires special springs inside the converter, the converter must be mounted horizontal. Impco parts are cheaper and it is generally accepted that there converters can be mounted however you want, although horizontal would be safest.

Impco has/can use a model E converter, they are bigger than the typical B2, B2 is rated at a maximum 296HP of gas delivery. I don't know what the model E would deliver but its bigger, maybe another 30-50HP???

You can use multiple lockoffs to improve flow, and I think a VFF30 flows a fair bit and is a refferenced reg, the others are not refferenced. I don't know if that helps flow or whatever. running one lockoff per converter would be ideal.

One small tank will not supply much gas for extended periods, the pressure drops inside the tank and then the flow also drops and you go lean, the only remedy to that is big tanks and more of them. The excess flow valve can also trip if the pressure drops causing lean out.

Both systems will need balance lines to each converter. Using a metal lid is safest option.

If you go to the strip you will find most fast cars that run LPG use GRA products, thats not to say Impco or others doesn't work but generally speaking GRA is performance oriented. There are many 10 second 6 bangers using a single GRA 510, with two B2's.

Since you have a V8, packaging the system will probably determine what you go with, the GRA stuff is basically like a throttle body on its own, it is easily adapted onto existing manifolds in place of the original t/b. The impco stuff would require a seperate t/b and is a little more bulky.

One nice feature of the GRA is the partial throttle jets that help deliver fuel in the same manner as an accelerator pump, it helps reduce the common lean backfire you sometimes get with LPG, if you floor it suddenly. Having said that I personally found GRA used more fuel, but made more power, A single 425 Impco on a 5.8lt engine will run out of puff up top, usually around 45-4800rpm. My GRA twin setup pulled 6000+rpm easily. Running two 425's would be good but you would have poor low RPM mixture control. The same goes for GRA if the mixers are too big the vacuum signal that pulls the gas from the converters will be weak at low rpm.


Gra mixers are about 440$ each, The GRA B2's(they are just std B2's but with a spring kit) are about 176$ each, metal lids are 30$ each.

There is more info here just search for it.

cheers

Very very informative LTD351, cheers mate.