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Not really an electrical problem,but....
Posted: Tue Aug 14, 2007 8:00 am
by bogfrog
Does anyone know what the likely effect of removing the orange vacuum delay unit on the ignition advance will be on my carbed v8 landy
I'm struggling to see what the point of this unit is
Andy
Re: Not really an electrical problem,but....
Posted: Tue Aug 14, 2007 12:24 pm
by Paul B
bogfrog wrote:Does anyone know what the likely effect of removing the orange vacuum delay unit on the ignition advance will be on my carbed v8 landy
I'm struggling to see what the point of this unit is
Andy
Er, un-delayed vacuum advance?
Posted: Tue Aug 14, 2007 3:05 pm
by The Original Tom
An increase in fuel consumption, reportedly about 20%.
If you do remove it, can I have it? Mine's shagged.
Posted: Tue Aug 14, 2007 8:41 pm
by jrv8
The Original Tom wrote:An increase in fuel consumption, reportedly about 20%.
That's very interesting..........how does that work ?
Jim
Posted: Wed Aug 15, 2007 4:47 pm
by sidecar
[quote="The Original Tom"]An increase in fuel consumption, reportedly about 20%.
quote]
JMHO but I don't think that removing the delay will cause an increase in fuel consumption, removing the vac advance completely will, and reduce the mid range power, and will increase the exhaust valve and exhaust temperature.
What it actually does to the igintion timing depends on what sort of delay the unit provides.
If the delay is how quickly high vac advances the ignition then when you take your foot off the throttle the ignition won't advance immediatley...I haven't got a clue why you would want to do this!
If the delay is how quickly low vac reduces the ignition advance then when you floor the throttle the ignition would remain fairly advanced for sometime before the ignition timing reduced....again, I don't know why you would want to do this.
It could be a combination of both of the above!
Regards,
Pete
Posted: Wed Aug 15, 2007 5:22 pm
by badger
It only gives a delay on the "advance" side, there is no delay in retarding. it's function is to prevent pinking under load if you lift off momentarily then floor it quickly again. It prevents the advance from being applied in a situation where you could apply the load quicker than it can retard again, allegedly. I run one on my 4.7 thor/hotwire hybrid - it pinks going onto full throttle from the over-run otherwise.
Posted: Wed Aug 15, 2007 8:13 pm
by katanaman
is this about vac advance or is it about an additional unit to it? I read it as an addition but some others don't seem to be.
Posted: Wed Aug 15, 2007 8:57 pm
by Alley Kat
Oh ar, spot on...
Posted: Fri Aug 17, 2007 2:19 pm
by The Original Tom
sidecar wrote: The Original Tom wrote:An increase in fuel consumption, reportedly about 20%.
JMHO but I don't think that removing the delay will cause an increase in fuel consumption, removing the vac advance completely will, and reduce the mid range power, and will increase the exhaust valve and exhaust temperature.
What it actually does to the igintion timing depends on what sort of delay the unit provides.
If the delay is how quickly high vac advances the ignition then when you take your foot off the throttle the ignition won't advance immediatley...I haven't got a clue why you would want to do this!
If the delay is how quickly low vac reduces the ignition advance then when you floor the throttle the ignition would remain fairly advanced for sometime before the ignition timing reduced....again, I don't know why you would want to do this.
It could be a combination of both of the above!
Regards,
Pete
I was confused about the vacuum advance delay, I was just talking about the vacuum advance unit in general, never know about any delay.