Quote:
Originally Posted by Clarke
Anyway, help me understand the differnce between putting larger jets in a 2bbl versus installing a 4bbl. I'm assuming the 4bbl allows more air to cycle through; therefore, you can mix more gas?
I don't have any desire to
Thanks,
Clarke
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To understand, lets discuss the basics first.
An engine is an air pump. More air, more fuel, (mixed in the PROPER proportion) more power. The advantage of a 4 barrel carburetor over a two barrel is that the 4 barrel allows the engine to inhale more air at WOT than the two barrel, thus horsepower is increased.
Installing "larger" jets has nothing to do with what type of carburetor this is performed on. In my last paragraph, I mentioned "proper" proportion of air and fuel. This is commonly refered to as the air/fuel ratio.
This is a very technical subject, but instead, I will keep is simple to help you understand. If the air/fuel mixture is to "rich" (more fuel than is needed for proper combustion), fuel ecomony and power suffer, as well as more carbon deposits, oil contamination and spark plug fouling.
If the air fuel ratio is to "lean" (not enough fuel for proper combustion) power and driveability suffer, and the EGT (exhaust gas temperature) can become excessive.
Apparently, the dyno operator found the fuel/air mixture on your engine to be to lean. They may have measured it with an oxygen sensor or EGT probe in the exhaust, or just suspected it was lean by the way the engine behaved on the dyno. After the jet change, the figures probably showed "richening" the air/fuel ratio was improving the numbers (air fuel ratio, EGT, horsepower)the dyno operator was looking at.