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L67 super6 on LPG Injection?

Discussion in 'V6 Development And Modification' started by jip123, Aug 16, 2012.

  1. AirStrike

    AirStrike Administrator Staff Member

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    Dark the car has actually gone 8.98 and unless proved otherwise is the fastest LPG car in the world. Keep in mind it is a dedicated gas setup, would never in a million years get close to that on a dual fuel setup.

    ***EDIT***
    Found a vid for you.
    [video=youtube_share;DBvQmJ34mRQ]http://youtu.be/DBvQmJ34mRQ[/video]
     
  2. DAKSTER

    DAKSTER Beam me up Scotty!

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    Cool mate I hadnt seen that one. That is an awesome machine.

    I know its dedicated gas, I wont be going the dual fuel road personally. As I keep saying, tuning a dual fuel system will always be a compromise, both with the computer and the components.

    I'll be keeping the boot tank and replacing the original fuel tank with another gas tank, for those rare occasions where gas isnt available. Thats only ever happened to me once though, I was going from Charleville to Quilpie and returning, 190K each way, and gas is not available in Quilpie or anywhere inbetween. I had no problems but it occurred to me at the time that more tank might be advisable in the future lol

    In that case incidentally, I think fuel was at about $1.20 at the time in Charleville, but gas was 95c which stunned me. If you lived out there, it would take a long time to recoup your initial costs. Gas is still only half the price of petrol on the coast though.
     
  3. pjdm1980

    pjdm1980 Shut up Jr I'm thinkin!

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    The JTG has a dedicated computer for the tuning which means you can get the best tune for both, I'm pretty sure the vapour injection is the same set up.
     
  4. Loaded Dice

    Loaded Dice .... Lets roll.

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    My vapour injection starts on petrol, so no way around dual fuel. Not a bad thing though if you are low on gas and late for work, good excuse to run the petrol out and replace with fresh stuff. Its only on petrol till the engine warms up then switches its self over, so is still tuned to run at optimum performance on gas.
     
  5. Trikky

    Trikky New Member

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    completely agree with the vapour and liquid injection systems it is not a compromise as with the vapour system all the LPG ecu does is alter the injector pulse so they match the amount of fuel that you would get on petrol. The car's ECU still controls when the fuel is injected etc. so if you change the tune for petrol it also does the same thing when running on LPG. From what I have been told about the liquid injection it does the same thing except you can get more power from this type of system compared to vapour and then the old mixer systems that are crap, the other thing about liquid injection is the tank runs a pump in it to lift the pressure to 3 or 4 bar and it is a constant flow system like a normal petrol tank in that it is circulating the LPG so you always have liquid at the injectors

    As others have said you cannot compare the injected LPG systems with the old mixer stuff, fuel economy and performance is far far better

    BTW I have the BRC system have had it for just over 12mths and could not be happier
     
  6. AirStrike

    AirStrike Administrator Staff Member

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    Why run dual fuel at all, even if only till it's warm?
     
  7. 383 hatch

    383 hatch Well-Known Member

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    As much as i hate LPG with a passion, respect to guys like that who can pull big power with it.
     
  8. DAKSTER

    DAKSTER Beam me up Scotty!

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    OK now thats interesting. Most of the people who turn their noses at LPG know nothing, the standard pack response of the know-all kids we see in here. You however I respect as someone who knows their stuff.

    I'd be genuinely interested to hear why you hate it so much?
     
  9. 383 hatch

    383 hatch Well-Known Member

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    Honestly, i've just seen and repaired too many engines with damage caused directly by LPG. I've lost count of how many heads i've seen with valve seat recession (even with that bullshit valve seat saver crap), especially Commodore V6's. The ONLY engine i'd even contemplate running on LPG is incidently a Ford straight 6, for the simple fact that they seam to give little to no trouble on it (apart from the usual plugs and leads).

    The other thing is LPG isn't what it used to be. It used to be a fantastic alternative for high comp engines, as it was higher octane than petrol, but these days it's rubbish. I wouldn't even think about using it in a performance application myself (like i said though, well done to the guys who have used it successfully), i'd rather fork out the money for petrol. Let's also be honest here, the gap between the price of LPG and petrol is nowhere near as big as it was years ago.
     
  10. Cheap6

    Cheap6 New Member

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    How much of the damage to valves/valve seats is inherent in the fuel and how much is due to badly tuned LPG systems? If you run an engine badly tuned on petrol it's going to hurt stuff too.

    A mixer system can be made to work well. They're easier to set up than the equivalent petrol fuel systems (carburetors). The problem is they're usually not set up very well. Often you're fighting poor engineering - up until a few years ago every LPG system could be engineered for each individual installation - as well as poor implementation.

    On a NA engine on LPG with a bad tune, if it backfires through the intake, you break the airbox and not usually anything worse. If it happens on a S/C engine the S/C may be pushed backwards. Not so good.

    On a purely monetary basis, assuming nothing is being damaged as ^, vapour injection doesn't make as much sense as a cheaper mixer system (there's an epic thread in VT-VX on why). Liquid phase injection is worse. On a performance basis there's probably a better case to make for them.

    If you are running a NA V6 (not what the OP was asking I know) using LPG injection means losing the possibility of using the "off the shelf" ignition timing map for LPG. Of course, you can have a custom map done.

    Dual fuel has some advantages in that you have a greater range, should you need it, and there's a cost penalty in removing the petrol system, without much benefit other than losing some weight.

    If you are prepared to make internal engine mods or maybe boost on a stock compression ratio, I think dual fuel E85-LPG would be interesting as many of the modifications you would make over an engine optimised for operating on petrol are the same.
     
  11. Trikky

    Trikky New Member

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    with either vapour injection and the liquid injection there is no reason why you cannot have a an off the shelf tune, all of the tuning done to my maps etc. have been done on petrol and it has responded very well on LPG as the LPG ECU mimics the flow requirements of the petrol injectors.
    The only issue I had in the early stage was the AE & PE were a little bit too aggressive and caused a stutter on LPG but once they were reduced slightly it has been great, I am around 1 second slower on a 0-100 run when on LPG
     
  12. SimonL67

    SimonL67 New Member

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    Hi guys I am running a Vy Calais Super 6 on JTG LPG injection. We have just had the heads setup for gas. The heads are now 10% bigger in port size for both inlet and exhaust and has had brass K-lines and stellite valve seats fitted. The car from factory had double row timing chains and a stage 1 cam with stage 1 roller rockers and a 69mm throttle body. We have replaced the exhaust manifolds with hurricane ceramic coated headers and hi flow hurricane cats and there full 2.5 inch twin pipe system. I have also replace the factory ECU with a Wolf V550 system so I can run a dedicated Petrol and seperate LPG tune.
    I have been running JTP LPG on the car well before these latest modifications and found it to be well worth the investment for cost savings and performance gains. On the highway the car gets well over 650Km on 68 litre of LPG before latest modifications (68 Litre usable tank size). Once we do the full power tunes I am hoping to run 16psi of boost which will be controllable by the wolf and the boost solenoid via the power switch.
     
  13. vytonner

    vytonner New Member

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    was that measured at the bowser or just what the trip computer says?
     
  14. EYY

    EYY Well-Known Member

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    Liquid injection's nice, but not worth the expense. Sure, you get a few more rwkw and can support higher hp levels and work well with forced induction (where the in tank pressure needs to overcome the positive manifold pressure for it to work properly).

    Liquid systems are incredibly expensive to set up and maintain. Lpg is a waxy/oily/dirty fuel, and if filters aren't changed often you end up going through injectors very quickly. When those injectors die, you're looking at $250-300 each for decent quality keihin replacements.

    Basically:
    -Liquid injection for high power applications, but incredibly high cost.
    -Vapour injection for applications that require less than 30fwkw/cylinder in N/A applications (usually slightly higher power capability in FI applications) and where cost is a major concern.

    Fuel economy may be 1L/100km higher with vapour injection but that's dependent on how well the system is tuned. Most are equal with petrol consumption figures.
     

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