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| myblacktruck |
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Anyone know where I can find a 25mm power valve for the vapour line. I'm feeding a 425 on a 351C, a little thursty.
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| HELLPG |
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did you, or are u wanting to fit and auxillary power valve to it?
425 mixers have the power valve in the mixer itself, its the one in the middle fyi. idle mixture is adjusted from the screw on the sideplate. set it them both around 1.5% CO on gas analyiser. idle mixture at idle and power mixture at around 2-2500 rpm in neutral. |
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| myblacktruck |
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Auxilury or extra power valve, I was going to fit one in the vapour line to reduce the gas flow. lucky to get 200KM from 95LT
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
You don't think you are going about this all wrong?
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| myblacktruck |
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Not sure what you mean, just trying to address excessive gas consumption.
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| twase |
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Have you thought about adding a O2 sensor and a fuel processor to tame that consumption?
If not might pay to visit an LPG installer and enquire.
_________________ BF Fairmont Ghia Series II update. |
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| myblacktruck |
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Live in the middle of NT, very hard to find specialist advice, especially gas tuning.
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| bry40l |
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How come it says newcastle,nsw for your location
_________________ BF XR6 |
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| myblacktruck |
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Need to update
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
myblacktruck wrote: Not sure what you mean, just trying to address excessive gas consumption. Limiting peak gas flow into the engine isn't going to help. All that will do is cause a lean condition at high throttle openings. Poor consumption on is going to be from over rich mixtures at cruise and light to medium acceleration (if mixture strength is even to blame) The 425 mixer has an adjustment for peak gas flow already and is more then capable of the job. First things to do is basic tune up items, Good plugs and leads, valve clearances, air filter, making sure there are no vacuum leaks. Make sure the vacuum advance hose from the dizzy IS NOT connected directly to a manifold vacuum source It is meant to be to a ported vacuum source ABOVE the throttle plates. Have the right ignition advance. make sure you have good strong spark. Make sure you don't have excessive exhaust back pressure. Then check your A/F ratios across the engines entire operating range. |
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| myblacktruck |
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Ok,
Tune is fine, running an Ice ignition extended spark duration, point to add is there is no Vac advance on this distributor, Timing = 12deg static-----all in 26deg AFR idle - 13.1 cruise - 14.5 WOT - 13.5 Are we maybe looking at spring length or varing spring pressures |
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
It's too rich across the board. Your not tuning petrol. Stoich for Auto LPG is about 15.7:1 Depending on the ratio of propane to butane, but it doesn't change more then 0.2 from straight propane to straight butane.
If you can use an A/F meter that can display LPG on the lambda scale, then tune for lambda 1 at idle and cruise and lambda .93 - .90 for WOT, once you that you can fine tune WOT AFs on a dyno. 12 initial is not enough, it should be up around 16 or so to start with. 26 total is ok. but if you have to go to 30 total to get enough initial that would be ok. |
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| myblacktruck |
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Thanks for the pointers, but not sure how to adjust AFR for cruise, isn't this controlled via the contour of the gas valve.
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
there is more then one gas valve available.
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| myblacktruck |
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Ah, I see, currently running a 19 gas valve, can the different gas valves be bought seperate, maybe to lean out a little.
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