Well i finally got my LPG tune done, basically spark was tuned for LPG for loads 70% and higher, so car is no longer drivable on petrol at WOT, but looking at those results you really would not want to drive it on petrol. Result is amazing, due to high octane of LPG timing was advanced 3-5 degrees further than 98 octane petrol, and can be advanced at least another 3 degrees further but tuner did not want to do so that without knock sensor (my next project to use one from Diamante) as risks with forced induction are much greater. Blue is 98 Octane Petrol, Red LPG. This was not done on a dyno, this was done using EVOSCAN so actual HP shown seems a bit low (ive been on few dynos and all showed higher power), what im trying to demonstrate is the difference between two fuels. Its important to mention that petrol tune (blue line) was done for 98 octane.

http://i1012.photobucket.com/albums/af244/e363ma78/AndreJERVETSKI_3rdgear9-Sept-2012.jpg

Wow great result. Is it a mixer type or injected ?

It's a vapour injected system

While LPG has higher octane than 98, you need to remember that it burns hotter. So while you can technically advance timing more, your cylinder temps are going to be a lot hotter and more conducive to pre-ignition/detonation.

It's a bit of a catch 22.

How are you going to manage the extra heat of LPG? Have you changed plugs & oil to cope with the extra heat? Is your cooling system in mint condition?

Great numbers :)

We have addressed this issue by using water/meth injection, it goes on at about 4 psi boost, cooling the intake temperature & most importantly combustion temps. In regard to oil i always used top shelf products, in this instance im running royal purple. Plugs are platinum all around, but i should decrease the gap though, although we only missed on one occasion during tuning when AFRs were about 10.3, it was leaned out to about 12.5 no misfire occurred since, this AFR proved to produce the most power.

how much did the direct injection lpg setup cost? where did you have it done?
also where do you get you tunig done and how much does it cost? any idea on where to get it dyno tuned and cost involved?
looking at saving for an lpg setup and seeing this makes me really wanna get it done. probs cant get the money for atleast 12 months but need to know what i'm looking at

Its not a cheap exercise, you are looking at around $4k for a good vapour injection system (maybe cheaper now). Once it fitted and tuned you need to have another tune done for spark advance, LPG computer will not do that, so you will need to re flash your factory ECU, lucky for you guy in Sydney knows how do it (and very cheap). You will not however get that much gain vs petrol what i did. If you are planning to keep your car NA your LPG power will probably just match the one of 98 octane. Why? Magna already has quite low compression (for NA) of 9.0. Which means heat generated during compression will not cause 98 octane to knock so easy even with aggressive tune which means LPG advance will be very similar (perhaps slightly more aggressive) so you get maximum push at desired PTDC angle. This all changes when you deal with forced induction, intake temps are hotter (especially in my case), you get a lot more air in the combustion chamber, once you compress it temperatures rise well above NA compression temps, this is where 98 starts to struggle, high temperatures cause it to knock much easier, this is where LPG comes in, with octane of 110 (can vary, depending where you fill up) it can take much more aggressive spark advance & not knock, this is where that extra power comes from.

$4k or so you are going to spend on lpg conversion will take a long time to pay for itself. I would just suggest to have your car tuned for 98 octane (pm me if you are interested, ill give you contact info). Dont go for cheaper mixer systems as they will reduce your performance (if this is what important to you) as they choke you intake with mixer ring, so you loose power on both Petrol & LPG.

pretty much answered all the questions i had that i hadnt even asked yet. i was looking at a normal lpg set up for the cost side of things knowing that is relatively cheap and would hopefully pay for itself quite quickly after the $1000 from the government. however was unhappy with the perfomance loss. also i would love to go down the road of superchard 3.8 however cant see myself doing that anytime soon and i know that lpg would burn better than petrol in those conditions. was otherwise going to do the 98 tune after i get my extractors and exhaust installed soon.

How does economy suffer with the Advance timing ?

Im my case i dont know cause my car is not a daily drive & when i drive it i drive it hard. Anything to do with timing advance will give you better economy due to stronger push from the fuel.

Wow that's very impressive :) and lpg is so much cheaper good stuff

mechanically increasing compression ratio of the engine should be better too! 13.1 or somthing and just run on LPG

Well yea if you can afford to do that, custom order pistons/shaved heads , however with such high cr might not be a smooth drive.

Should drive ok, i would just think changing the engine that much wouldn't give a huge boost to power, you are already supercharged even with forgies i think it would put alot of stress on parts.