rb25 head on rb30 - N/A performance with LPG

[warpz0r]

maybe a weird combination

but a nice setup with petrol will get you around 130-140RWKW

since gas has a higher octane rating, what possible figures could be achieved by running a dedicated LPG system with a compression of approx 10.5 to 11:1?

would the final output figure gain much? 160rwkw?

[meggala]

careful lpg isnt high an octane as it was previously and look at 11.5 to one compression and head work and cams for that sort of gain

meggala

[warpz0r]

i rang up a gas conversionist, and he said since its harder to get higher octane gas, the best compression used should be between 10.5 and 11.1 for a N/A engine....

a power increase should be noticed but i would like to know by how much...

[warpz0r]

even though the worst lpg in sydney is still better than the best premium unleaded which is 98 octane? lpg is about 106 octane i think...

[Brackez]

LPG as sold at the pump is high-octane enough to run better compression than 98 unleaded, but it's not as good as it could be. Pure propane is better again, and I believe it is what was originally sold as LPG, but this is no longer the case. Not sure why, perhaps someone out their with a little more wisdom could clarify the differences between pure propane and pump LPG?

[Richard Everett]

Hi guys,

- We are looking at installing LPG into my son's R31 RB30e Aussie Skyline sedan, with a 50+% operating cost saving the main attraction as compared to 98 RON PULP. As he is a student & so money is tight then a monthly saving for him of $100 - $150 cannot be easily ignored.

- As LPG in Sydney is about 102 - 106 (depends on the mix of propane & butane) then he can dial up a lot more ignition advance than on petrol, so enabling his RB30e to run more efficiently.

- We were going to instal a serviced head anyway, so will take the opportunity to shave the head quite a bit to up the static compression (from the stock 9.0 :1).

- So, if all goes to plan, then he should have a bit more performance as well as save some $1500 / year in his operating costs.

- Will let you all know how it all works out, including pre & post dyno readings.

Cheers,

Richard Everett

[warpz0r]

where are you getting your gas setup from?

any price ideas?

is it just the standard taxi gas setup or a performace gas setup?

thanks

[Richard Everett]

We will post up all details on the conversion the SA forum when its all completed, incl. dyno reads.

Cheers,

Richard

[Cubes]

I remember back in the old TE 250ci Cortina days that there were gas spec cams available. I bought the car with a gas cam installed. It appeard to have a lot more mid range and bottom end torque vs other TE 250ci Cortina's.

Top end still felt like it was over reving at 4000rpm. lol.. 4000rpm. Its quite funny when you get used to the Nissan RB's where 4000rpm feels like its only just reving.

What differs with the gas spec duration, lift and timing specs vs the normal fuel spec cams?