Changing ignition advance on a 3.2 qv

Russ, for what it's worth, Here is my ignition map (at 0 psi), but I didn't really get to optimize it yet.
RPM-degrees
0 - 8
500-10
1000-16
1500-20
2000-25
2500-28
3000-30
3500-30
4000-31
4500-32
5000-32
.
.
.
7700-32

 

Russ
Awaiting your results with interest.

One "data point" to think about (and all engines are different). On the 4-valve/cyl, 9.5:1 CR Mazda Miata engine, we found it easy to load in too much advance, to the detriment of power. Indeed, the "advance until it pings and then back off 2 - 3 degrees" adage did not work for NA cars.

BTW, max power was at about 26 - 27 degrees BTDC.

You might think about a testing regime where you base line, go up a couple of degrees with the curve, go down a couple to understand sensitivity to, and direction of, change.

Philip

 

Russ, there are those like us who are taking notes on evey bit of info we can get!
I certainly agree, the 4V do not seem to benefit from as much advance as the 2V do.
As is often the cas, Phillip is right on the money in his input.
Some food for thought...
The newer cars all have detonation sensors. I wonder how hard it would be to adapt just that part of their system to older cars? All it would really need to do is set off a dash light.
Any input? I'd sure like to have one, if for no other reason than Dyno tuning, but in daily use, wouldn't it be handy?
Kermit

 

yes, QV.

To Phillips point, my buddy found on his H-D drag bike the correct timing was 22 degrees. +2 he lost 5%, -2 was 10%. My 0 psi timing is my best interpetation of the stock maps, but smoothed a bit to remove stuff that was clearly EPA driven. I kept the stock timing as the baseline figuring ferrari must have dynoed these things and should have gotten it about right. I will probably adjust my maps based on what you learn though.

Mark

 

One device that does this well is a J&S Knock Sensor. [BTDT with the Mazda 7 or 8 years ago]. Has a plug that bolts to the engine block (we used an engine mounting point, but anywhere where the sensor can "hear" the frequency well works. Gets wired into the ignition trigger (with the Mazda, we just intercepted the cam angle sensor). Has two modes: retard all cylinders or just the one experiencing the "ping". Pulls up to 6 degrees. Has a sensitivity control to govern how "loud" the input needs to be before it pulls timing.

 

Russ,

Are you saying best HP was achieved at 35 BTDC? What did the fall off look like at +/- 2 degrees from 35 BTDC?

How about a 2V, carb car? Anybody have a best HP vs toatal advance for these animals based upon dyno runs?

 

Russ
If I remember 4v curves right, this is a lot more advance than the "0" vacuuum (WOT) curve, isn't it?
Philip