cadebytiger
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| posted on 21/5/07 at 09:54 AM |
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idle advance and progression
on a pinto, webers, fast road cam - what sort of ignition advance do you run at idle? books seem to disaree by quite a bit.
I know it can be a little more complicated thn just setting it as sometimes you need to advance or retard it to get the throttle opening at idle in
the correct place for good progression but as a good starting point - ie to set mixture on?
i have an emerald ecu so don't need to worry about knocking the timming out for the rest of the map.
used to think you just played with it until the reves were as high as possible and then trimed it down on the idle control skrew. This prob led to my
bad progression as the throttle was not close enough to the prgression drillings. any thoughts?
Rupert
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flak monkey
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| posted on 21/5/07 at 10:22 AM |
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Mine's set to 14deg at idle with an FR22 cam (same spec pretty much as the FR32). Seems to go alright! 
Idle advance is just down to the duration of the cam basically. But if you are running a std dizzy then you wont be able to run the max recommended as
you will be over advanced at high revs.
Sera
http://www.motosera.com
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cadebytiger
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| posted on 21/5/07 at 10:38 AM |
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great will try 14 and then work from there.
How much (if any) of the throttle butterfly can you see through your first progression drilling at idle?
i know they are not supposed to be uncovered at all but can you see the leading edge or the top of the butterfly?
Thanks again chap!
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flak monkey
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| posted on 21/5/07 at 10:41 AM |
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To be honest I dont know, never looked as I havent had any problems, but I guess not.
All I know is that the emmissions are well within the 3.5% CO limit (which suggests to me the progression phase isn't in as it would be running
well rich otherwise I think) and that it goes like stink if you plant your foot.
David
Sera
http://www.motosera.com
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cadebytiger
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| posted on 21/5/07 at 01:08 PM |
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do you have idle air bypass valves on your carbs? If so how did you decide how much air to bleed through them?
Thanks
Rupert
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flak monkey
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| posted on 21/5/07 at 04:29 PM |
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No idle bypass circuit on mine, so cant really help you there I am afraid.
Someone will no doubt. Does the book not give you any useful tips? (I dont have mine here).
Sera
http://www.motosera.com
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cadebytiger
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| posted on 21/5/07 at 04:50 PM |
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the book is a little vauge
they seem to be to bleed air in when the throttle is found to be too far open (i.e. over progression holes) at idle.
Also for balancing idle flow between two chokes on the came carb. Which should be the same really!
if anyone out there can put me staight i would be most greatful!
Thanks
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westf27
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| posted on 21/5/07 at 06:32 PM |
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I assume your carbs are 45 version 152 which have the airbleed screws which bleed air past the butterfly.The progression holes,various sizes and
position depending on weber version bleed fuel as you come off the idle stop and progress towards main jets around 2000rpm.On idle stop the idle jet
only fuels the engine,if you have the butterfly set to far open you will start to draw fuel through first progression hole as well.Sometimes the
butterfly set so low doesnt allow enough rpm so you can bleed air through screws and adjust idle mixture screw to achieve desired idle rpm.
On my Webers which are off Holbay Rootes engine the progression hole sizes and positions are in a lousy position for my pinto which needs
45/152's really.I have drilled the butterflys 1 mm to bleed air which makes it better
Dave Andrews site on the links connection is good and also Teglerizer.com
555
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cadebytiger
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| posted on 21/5/07 at 08:13 PM |
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thank you very informative!
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