Thrival -Vapor Carb

[BEMET]

[Bob Boyce]

[thrival]

[thrival]

[kww]

[pertyfly]

[kevinsatterfield]

[eco]

[kww]

[quote="pertyfly"]
I don't, however, believe that timing should be changed at all when running a booster unless it's almost large enough to be the sole fuel (with gasoline as a helper fuel). When running on hydroxy alone, even though I believe it should be retarded I don't believe it should be anywhere near 45 degrees, really. When you're talking about high rpm running hydroxy terribly retarded, you will notice either almost no power, or a huge decrease, as the higher rpm, the spark will start to become seemingly more retarded in relation to the engine (as the engine is turning so quick).

We seem in basic agreement in all you say, but I'd like to mention that around 45 degrees is the timing that fast burn engines use, it's not a theory. Going from liquid gasline to hydroxy is a radical change which greatly effects the timing, time, etc. of the explosion/burn and this is very important because of the changing mechanical advantage of the piston/rotor on the crank/eccentric shaft through rotation. A full combustion(theoretically speaking) at top dead center would give no power, but near 45 degrees you'd get maximum power and rpms. Btw, it's the base timing you change, the computer, etc. advances the timing as rpm's increase, all(I'll assume) modern engines advance timing automatically.

[johnh]

[quote="kww]
SNIP
but I'd like to mention that around 45 degrees is the timing that fast burn engines use, it's not a theory. SNIP.
[/quote]
You have to be fairly careful when quoting timing and mention how the measurement is made.
The following quote from the Sallee Chev site


GMPP Fast Burn 385
Ignition Timing 10° BTDC @ 800 RPM; Max. 32° Total @ 4,000 RPM with vacuum advance disconnected.

It seems that the timing is actually set at 10° Advanced but with the ignition lag and full retard on the vacuum and mechanical advance means it runs at 32° retarded.

Regards
JohnH

[johnh]

I am still looking at other fast burn sites but everything else I am turning up suggests that the timing is running at 30° to 45° degrees advanced ie. BTDC. not retarded. So I may have been wrong about the above assumption. The Timing in all these engines seems to be BTDC.
Is there anyone here with actual experience at setting a fast burn engine up?
quotes from another site
Impulse engines High Octane 25° BTC 22° BTC
The vacuum advance at the crank should not be more than 45° with open chamber heads and 40° with close chamber heads.

Regards
JohnH[/quote]

[kww]

[Bob Boyce]

[Bob Boyce]

[pertyfly]