Really dumb question regarding displacement:

[Guest Anonymous]

Hotter spark plugs have a little more room between the ground/plug body and the electrode. I have been told numerous times that you do not get any more bhp from different plug setups, but isn't this adding some more displacement to the combustion chamber? Doesn't this affect the combustion?

[Guest Anonymous]

(nt)

[Guest Anonymous]

h...is so small that the change in horsepower would be negligible.....Besides, there are too many other variables that could account for horsepower differences of that magnitude......like running your car in a shaded area, as opposed to a parking lot in the sun....differences in air temperature of 2 degrees will affect your power, etc......

[Guest Anonymous]

Displacement is measured as the difference between the volume at bottom dead center and the volume at top dead center (BDC minus TDC). Since you are subtracting a very small volume from both, the difference remains exactly the same. Coompression ratio, on the other hand, is BDC divided by TDC. If both see an equal decrease, the C.R. will see a small increase.

ThePumpkin

'70 Colorado

[Guest Anonymous]

Sorry, I just reread the original posting. I had the situation reversed--I thought it was a "bigger" spark plug(more volume of metal), not smaller. In the smaller case, C.R. and power will go down a tiny amount.