Ignition advance feedback

linzerl · Post by **linzerl** » Thu Jul 23, 2009 6:50 am

Given I am using this advance table for my 5.0L Rover engine with no pinking and all round good performance, can I get some feeback whether the advance is coming in too slowly.. or infact any other comments?

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Cobratone · Post by **Cobratone** » Thu Jul 23, 2009 7:41 pm

That table is quite different to mine, I must get a photobucket account soon so I can post pictures up, but if it works for you then go for it!

Cobratone · Post by **Cobratone** » Thu Jul 23, 2009 7:56 pm

sorted it

bobtail84 · Post by **bobtail84** » Thu Jul 23, 2009 7:59 pm

This is mine in a mainly standard 3.9. Your map look's like it has too much advance at tickover, that's just my opinion and as I have not worked on your engine probably wrong...

jeff

ppyvabw · Post by **ppyvabw** » Fri Jul 24, 2009 11:25 pm

At Cobratone,.....

Forgive me as I have no experience with computer mapped ignition, but your table seems somewhat erratic compared to bobtail84's and linzerl's.

They have bands of colour representing the advance whereas yours isn't in bands. Why is this? Is yours set up properly or am I just showing my ignorance?

Cobratone · Post by **Cobratone** » Sat Jul 25, 2009 12:15 am

ppyvabw wrote:At Cobratone,.....

Forgive me as I have no experience with computer mapped ignition, but your table seems somewhat erratic compared to bobtail84's and linzerl's.

They have bands of colour representing the advance whereas yours isn't in bands. Why is this? Is yours set up properly or am I just showing my ignorance?

In my OPINION Linzerl's table is what would be used as a "startup" table, ie one to get the engine running which would then need tweaking. Bobtails is much better but still different to mine. On the Megasquirt table there are several area's that aren't used in normal daily driving so those parts of my map haven't been touched from the startup map. on that map I idled approx 50-55kpa and 850rpm so the first row of figures were a "boost" in case my revs dropped then the increase in advance would kick the revs back up, then from 900-3000rpm and below 55kpa woukld be my cruising part which is where i spent most of the fiddling and the upper right hand side being WOT is approx as it should be according to John Eales. lots of engines will be different as cam/exhaust/induction etc will change things slightly. This map worked for me. Unfortunately I've recently fitted ITB's and had to go TPS based megasquirt rather than MAP based and the whole spark table looks different, still playing with it though

Post by **Coops** » Sat Jul 25, 2009 9:04 am

im watching this topic,
as in the next few weeks im going to be at this stage of starting up and need to sort the ignition table out

sidecar · Post by **sidecar** » Sat Jul 25, 2009 9:36 am

Cobratone wrote:
ppyvabw wrote:At Cobratone,.....

Forgive me as I have no experience with computer mapped ignition, but your table seems somewhat erratic compared to bobtail84's and linzerl's.

They have bands of colour representing the advance whereas yours isn't in bands. Why is this? Is yours set up properly or am I just showing my ignorance?
In my OPINION Linzerl's table is what would be used as a "startup" table, ie one to get the engine running which would then need tweaking. Bobtails is much better but still different to mine. On the Megasquirt table there are several area's that aren't used in normal daily driving so those parts of my map haven't been touched from the startup map. on that map I idled approx 50-55kpa and 850rpm so the first row of figures where a "boost" in case my revs dropped then the increase in advance would kick the revs back up, then from 900-300rpm and below 55kpa woukld be my cruising part which is where i spent most of the fiddling and the upper right hand side being WOT is approx as it should be according to John Eales. lots of engines will be different as cam/exhaust/induction etc will change things slightly. This map worked for me. Unfortunately I've recently fitted ITB's and had to go TPS based megasquirt rather than MAP based and the whole spark table looks different, still playing with it though

Hi Tony, if you ever want to get rid of all this junk and fit a nice carb and dizzy just let me know, I can help you set them up!

(Before anyone kicks off, Tony and I know each other, its a JOKE!)

Post by **Coops** » Sat Jul 25, 2009 7:00 pm

gets confussing with all these Tony's about

bobtail84 · Post by **bobtail84** » Sat Jul 25, 2009 7:31 pm

thev8kid wrote:im watching this topic,
as in the next few weeks im going to be at this stage of starting up and need to sort the ignition table out

You could use any spark map on here but the fuel map is a bugger to get right. Have you got all the other setting as in the engine constants, cranking, after start enrichment ect, ect..

jeff

Post by **Coops** » Sat Jul 25, 2009 7:58 pm

yes mate the fuel map was spot on for the old engine,
but until the new engine runs not sure how far out its going to be.

so its a waiting game until she fires.

Cobratone · Post by **Cobratone** » Sun Jul 26, 2009 2:50 am

sidecar wrote:
Hi Tony, if you ever want to get rid of all this junk and fit a nice carb and dizzy just let me know, I can help you set them up!

(Before anyone kicks off, Tony and I know each other, its a JOKE!)

Well Pete, in September I'm going to the Goodwood Revival so might fit a carb then to match the old fashioned 50's feel

RoverP6B · Post by **RoverP6B** » Sun Jul 26, 2009 7:39 am

I am probably going to make myself appear rather dimm, but how do you read those charts,..?

When there are a range of advance figures for the same engine rpm, and what do the different colours represent, and are even continuous bands of colour desirable?

Many thanks,
Ron.

sidecar · Post by **sidecar** » Sun Jul 26, 2009 8:29 am

Cobratone wrote:
sidecar wrote:
Hi Tony, if you ever want to get rid of all this junk and fit a nice carb and dizzy just let me know, I can help you set them up!

(Before anyone kicks off, Tony and I know each other, its a JOKE!)
Well Pete, in September I'm going to the Goodwood Revival so might fit a carb then to match the old fashioned 50's feel

Oh that hurt!

Cobratone · Post by **Cobratone** » Sun Jul 26, 2009 8:48 am

RoverP6B wrote:I am probably going to make myself appear rather dimm, but how do you read those charts,..?

When there are a range of advance figures for the same engine rpm, and what do the different colours represent, and are even continuous bands of colour desirable?

Many thanks,
Ron.

This is probably easier than how I'll explain it Ron, as I sometimes don't put into the written word what's inside my head

As you've noticed along the bottom axis are the engine revolutions, on the vertical axis is the engine Manifold Air Pressure in kiloPascals (MAP). When the throttle is closed there is quite a vacuum shown in the manifold (approx 55kpa in my case) so for idle advance, follow the rpm and kpa scales at 800 and 55 to see that I idle with an advance of 13 degrees. now when the throttle is opened, not only do the revs rise but the vacuum gets less so the advance sort of moves over the table in a diagonal line from the bottom left to the top right. If the throttle is opened quickly then the angle of that line will increase so that you may see no vacuum at all (approx 99kpa) at lower revs. Now if you are cruising at 3500rpm and take your foot off the throttle then the throttle plate closes and creates a lot of vacuum in the manifold so the advance will be right along the bottom part of the chart as the engine slows down (quite high figures in my case so I can run quite lean at those points). Because of this there are certain parts of the chart that are seldom "seen", the top left and the bottom right, this is because in normal driving the manifold hardly ever "sees" low revs and no vacuum or high revs and lots of vacuum.

This is all perfectly clear to me but as I said at the start, I may not put it down very well