High compression VG33?

[MY1PATH]

Yeah I wouldn't mind some experimentation. I would like to see your results. How are you going to adjust the ECU to get the timing back on track?

The cam timing can be left alone, Like I said 1.17 Degrees will not be noticeable. Ignition timing (because the dizy runs off the cam) will be corrected simply by rotating the dizy. When you start getting closer to 1.5 deg I'd reccomend adjustable cam gears and if you keep going towards 2 deg you are certainly going to feel it but it may or may not be right where you want it.

 

Typically when you increase Compression ratio you decrease timing (3deg per 1CR point is a starting point, fine tune from there) because the mixtre expands more rapidly but stock VG tune has conservative timings to begin (many people advance a stock engine 3-6 degrees) with so setting the ignition timing to stock should be just fine.

[Tungsten]

The distributor does run off the cam but the ECU has the ability to slightly delay the signal to get it as close to 15 as possible. For this reason you only need to set the distributor to about 15 and it does not have to be exactly 15. That's how the 90+ ECUs work. At least this is what they have been doing from my experience.

 

BTW where did you find the 0.928 deg for every 1mm formula?

[MY1PATH]

The distributor does run off the cam but the ECU has the ability to slightly delay the signal to get it as close to 15 as possible. For this reason you only need to set the distributor to about 15 and it does not have to be exactly 15. That's how the 90+ ECUs work. At least this is what they have been doing from my experience.

 

BTW where did you find the 0.928 deg for every 1mm formula?

 

SCHOOL!

lol they taught me that 360 divided by the circumfrence (belt centerline arround the gear) gives you distance traveled per degree.

[Tungsten]

Right then, that would be a radian. Did you calculate this yourself? Is that how you got the for every 1mm figure too? Not questioning your methods, just curious.

[MY1PATH]

Right then, that would be a radian. Did you calculate this yourself? Is that how you got the for every 1mm figure too? Not questioning your methods, just curious.

That's exacly how I did it. the measurement is to the center of the belt (not to the edge of the gear) because the belt centerline is how far out the radius goes. I measured the gears in metric but .050" is 1.27mm.

1.27x0.928= 1.17856 degrees

 

(ouside of belt stretches inside of belt shrinks, center says consistant lenght relative to a bend.) I wil have pictures and details on my thread once I start one.

 

I hope to have before and after Dyno's so folks know what a 3.3 is worth compared to a stock 3.0.

Edited January 17, 2013 by MY1PATH