Chaz
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| posted on 20/8/06 at 07:38 PM |
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Safe Maximum advance? (Megajolt)
Hi, i'm on to the basic tuning stuff, now i have my car on the road.
I have a Zetec Silvertop Std Cams (at the moment) and R1 Carbs.
My questions are what is my safe maximum advance, can you work it out (formula)?
What is my idling advance?
Whats the best method to work out the inbetween?
What rpm do you reckon i can take it before it starts redlining?
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mark chandler
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| posted on 20/8/06 at 09:46 PM |
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Just before it pinks !
Not a lot of use that so.... engines with decent heads should max out at about 38 degrees btdc.
Idling is probally between 4 - 8 degrees btdc.
Inbetween is find a steep long hill and experiment in third gear, if it pinks at certain engine speeds back it off a couple of degrees at these
points.
You then repeat with after playing around with the fueling and if really keen time yourself.
Regards Mark
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paulf
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| posted on 20/8/06 at 09:46 PM |
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Hi Chaz.
Good to hear your on the road with your car.
I mapped an 1800 zetec on R1 carbs a couple of weeks ago for Bernie who posted on here about a missfire.
He had about 22 degrees of advance at 4500 revs and had a missfire at full load I advanced the top couple of lines up a bit and then went well . I
cant remember the exact amount we ended up with and didnt keep a copy of the map as it was on his laptop but the map I started with has 25 degrees
advance at full throttle above 4000revs. if you look on the Cd there is a map entitled zetec 1800 twin webers and also one Zetec 2 cfg, try these and
adjust to suit .I have seen 32 degrees quoted as a safe figure for max advance at full load they rev to 7000 plus so set rev limit at 7000 to stat
with.
Paul.
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martyn_16v
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| posted on 20/8/06 at 09:48 PM |
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I've used the method described here a couple of times now to generate a starting ignition
table. It works quite well actually, certainly gets you in the ballpark and with a table you can quite happily run with.
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martyn_16v
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| posted on 20/8/06 at 09:55 PM |
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quote:
Originally posted by mark chandler
Just before it pinks !
No no no. Doing that you will be losing economy, probably some power, and have an engine totally intolerant to a poor batch of fuel. Under certain
operating conditions most normally aspirated engines will be starting to lose power well before pinking occurs. The only way to properly tune ignition
timing is on an engine dyno or load holding rolling road, where you want to aim for the minimum advance for best torque (MBT) everywhere.
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Chaz
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| posted on 21/8/06 at 01:02 PM |
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What about redline? Keep it standard at 6500rpm for a zetec silvertop?
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