5L V8 on petrol AND gas

[VSCristian]

G'day gents,

Does anyone run their 5Ls on petrol and LPG? And if so, what set-ups do you run, any pros and cons?

My daily driver's a dual fuel EL Futura i6 with a bit of work, and she's been tuned to spike gas into the manifold whilst running on petrol. Apparently this trend started off with diesel fourbies. She was pulled 161rwkw whilst running both fuels and I was wondering if anyone's running, or even heard of this sort set-up on their 5Ls.

(I use the Ford as my daily on gas only because I get a $0.78/km travel allowance and I'm a cheap c###)

I have a VP 5L which I use as my weekend/play car, and am exploring the idea of an LPG-spiked forced induction set-up.

 

[someguy360]

A 5L deserves better than LPG, this is just my opinion though. I have been burned by it too many times to justify the small saving.

I have only ever dealt with the traditional mixer style systems on 5L's before, switching from petrol to LPG felt like switching from a Bugatti Veyron to a moped and the fuel economy wasn't much different between the 2.

I know LPG has come a long way since the mixer system, but for the savings these days I really don't think it's worth if considering the price of LPG has skyrocketed lately.

 

[EYY]

It's definitely worth it imo. It depends on where you live. Here in vic lpg is less than half the price of petrol. Economy is pretty similar on injected lpg and so is power.

If you use mixers, an impco 425 or gas research tb would be the only ones worth considering.

I don't know what you mean by mixing gas and petrol together though?

 

[sleepa]

I haven't heard of this setup before. Is the LPG injected into the manifold, or is it injected into the Intake pipe, or just a mixer?

I can say that Vapour injected LPG is great on a LS1, I would assume it would be good on a 5L as well. Standard mixer setups are not great in my experience, Injected is light years ahead, but installation cost is also a lot more.

I have a VR wagon with LPG and a 6 that I am putting a 5L in and was considering upgrading the system to Injected LPG of some kind.
I would like to know more about your setup though as it seems that power is quite good for even a 4L Ford 6.

 

[EYY]

You're still shooting for the same afr regardless (although stoich is different for lpg). All I can think of is higher octane and therefore higher resistance to pinging - to take full advantage you would need to increase the compression and alter the ignition advance curve though.

With lpg injection you can set it to inject petrol as well as lpg wherever you like throughout the rev range.

 

[Hoska91]

Everything EYY has said in here is spot on.

If you want to take full advantage of LPG you need to build the engine for it.

An engine will only ever compromise on both so neither will have their full potential reached whether it be performance or economy.

 

[wraith]

For the cost of the conversion and the cost of LPG it's no longer really worth it. Would take a lot driving to pay for itself. I bought a VS V6 on gas and I saved what basically amounted to a meal at maccas between LPG and petrol. Petrol would drive great no issues LPG was meh.

 

[VSCristian]

In Western Sydney LPG is around $0.62/L, and some places have it for $0.57 as opposed to $1.32 for regular 91 octane fuel.

Sleepa:

My Ford's setup (as far as I'm aware) is the 4L motor, large snorkel feeding into an enclosed pod CAI, 4499 pacies, unsure which cat, and 2.5" exhaust. She runs a 3.45 LSD from an '07 XR8 ute. Now I haven't opened up the motor, so I can't say what's inside. The gas gets injected into the intake pipe, and she has a some sort of converter. When she was tuned, she was tuned to spew a lot of gas whilst running on gas only, and to spit some gas into the intake pipe whilst running on petrol. So when she's running on petrol, she is in fact running on petrol spiked with gas.

I was there when she was dynoed though, she pulled 152 on gas, and 161 on both. The bloke who was doing the dyno run shoved a sensor in her tailpipe and confirmed that she was running petrol AND gas at the same time.

Like I said before, I don't know what's in the motor. The reason I acquired her is as a daily driver because she costs me around $8.50/100km to run, and I get a $0.78/km travel allowance for work, so I make a killing.

The reason I'm interested in this setup for my VP is because she's already low-comp, and using LPG to spike the fuel might allow for more boost.

 

[VSCristian]

 

[wraith]

You use more LPG then petrol so while the roughly half price seems good you will be filling up more often on LPG.