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Author Topic: Timing/fueling - quickie??  (Read 987 times)

Offline rowlers

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Timing/fueling - quickie??
« on: 10 August 2007, 13:25 »
1990 Valver... but prob applies to all cars??
If you advance the timing does ths lean out the fuel mixture?? Do you then have to increase the CO to suit the advance on the timing? Or is this boll0cks? And what does happen?


Cheers
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Offline herbster

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Re: Timing/fueling - quickie??
« Reply #1 on: 10 August 2007, 15:03 »
 :smiley:
Are you on about the ignition or valve timing ? If you advance the ignition then less fuel has got in so you will get a longer leaner burn as the fuel is still being delivered whilst burning(less response more umphh), if the valves are advanced the opposite will happen, almost like a high lobe cam effect, the co2 will only need altering with severe advancement/retardment this is best left unless you got a tester or know someone who has. Theres more of a chance of burning the inlet valves with prolonged use in this respect, the co2 just tries to keep a balance to avoid this as its a cooling property in the chamber. As its a digi you should never need to adjust it to suit, a good tune up will get it to where it should be. Hope this helps.
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Offline rowlers

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Re: Timing/fueling - quickie??
« Reply #2 on: 10 August 2007, 17:40 »
cheers for reply, Valvers are K-Jet though!!! :smiley:

So my valver is currently timed (ignition) at factory 6BTDC. I've got a P&P head with 270 Pipers. Just had MOT done and CO was read at 0.8%!! I had this set at 2% a few months back so it must have drifted out.

It is running great, but I know it has a lot more potential to GO! Really it needs a RR i know!

If I was to advance to say 7BTDC would I need to increase the CO as well?
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Offline herbster

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Re: Timing/fueling - quickie??
« Reply #3 on: 10 August 2007, 18:03 »
 :smiley:
I don't think 1 degree would make that great deal of difference in either areas, might just be worth geting the co2 back up thats where your poke has gone. Maybe check your plugs etc, give your air filter a blast through, sounds like you got a nice set up there.  :smug:
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Offline rowlers

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Re: Timing/fueling - quickie??
« Reply #4 on: 10 August 2007, 19:06 »
thats good then - I'll get it to my mates garage 2moro and get the CO tweaked.

It used to pull well then fly after 4-5k, at the moment there isn't the extra surge higher up the revs!

Cheers for info! :wink:
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Offline fused

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Re: Timing/fueling - quickie??
« Reply #5 on: 12 August 2007, 14:51 »
My 8V was running very lean and had very little top end omph, the CO2 adjustment sorted it out for me! :grin:
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