Retarding ignition at high rpm
06-20-2012, 05:49 AM
#1
Senior Member
MASTER BUILDER
Thread Starter
Join Date: Aug 2007
Location: Iowa - USA
Posts: 218
Retarding ignition at high rpm
MSD Digital 6 has a retard function that can be activated by putting 12 volts on the pink wire. Is there a way to figure out how much retard to dial in. Max is 10 degrees. This is suspossed to add a little high rpm hp.
06-21-2012, 07:57 AM
#3
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RACING JUNKIE
Join Date: Dec 2008
Location: Sugar Hill, GA
Posts: 1,365
We ran dual point distributors in the old days and had a swtich to cut out the leading set of points in high gear. By then the engine is hotter and has lost some of its mechanical advantage and reducing timing would increase the performance.
07-11-2012, 07:00 AM
#6
Senior Member
RACING JUNKIE
Join Date: Jan 2012
Posts: 628
Taking out timing at (or about) the 1000' brick is a hot tip if you're running a high compression engine.
One of the gains in running a lot of lead is increased static compression. It assists your HP curve in the low and midrange areas but once momentum is gained, compression will kill your top end MPH . . Of course, that's dependent upon a lot of things, starting with air density.
Up here where we race (5000'+) corrected air on any given day could be around 7500-8500 feet so a lot of compression is needed . . Until you get into the top of your HP curve . . Up until the latest group of Ignition smart boxes came out, what worked on one end didn't help at all on the other . . Now, all of us can adjust your timing as the HP curve demands. Take a little out from the starting line to about the 60' brick, add it back in incrementally to the shift point and then cut some out for the last 320' or so . .
I just wish I'd had this back years ago when I was racing seriously. I can't count the blocks and cranks we spent learning where the happy medium was!
One of the gains in running a lot of lead is increased static compression. It assists your HP curve in the low and midrange areas but once momentum is gained, compression will kill your top end MPH . . Of course, that's dependent upon a lot of things, starting with air density.
Up here where we race (5000'+) corrected air on any given day could be around 7500-8500 feet so a lot of compression is needed . . Until you get into the top of your HP curve . . Up until the latest group of Ignition smart boxes came out, what worked on one end didn't help at all on the other . . Now, all of us can adjust your timing as the HP curve demands. Take a little out from the starting line to about the 60' brick, add it back in incrementally to the shift point and then cut some out for the last 320' or so . .
I just wish I'd had this back years ago when I was racing seriously. I can't count the blocks and cranks we spent learning where the happy medium was!
