Prechamber Mod "Flame" Front

SuperDieselVan

294

01-29-2011, 12:33 PM #105

(01-29-2011, 09:39 AM)yankneck696 <<Could a heavily modded engine benefit from chamfered AND enlarged PC holes, common sense would say yes to me. In a carbeuretor, when you increase air volume, you need to change jets (as an example).>>

That was the whole statement. Now, as injected fuel volume is increased & more air introduced, would not the chamfered & enlarged PC holes allow for better HP numbers? Wouldn't the larger orifices do a more efficient job being calibrated to the volumes changes? Kind of like changing the jets to allow more fuel in a carbeuretor with more airflow?

Why would you introduce more air to the PC? You already have enough for the pre ignition and the atomization of the fuel. The main combustion happens in the combustion chamber and you want more air there.

(01-29-2011, 09:39 AM)yankneck696 <<A bell-mouth form will improve flow efficiency into any tube, its simply not cost-effective for a manufacturer to do that on a large scale production. Increasing flow efficiency is a good thing, increasing flow volume isn't (in this case).>>

OK, I think we are all in agreement of the chamfering, then. Cool. That means that air is going in & fuel-air/possible combustion is comming out is more efficient. Now, again, with more volume of air & fuel, would not the smaller holes be a restriction? Would not the larger diameter in this instance lead to better clearing of the prechamber? Would it also bring the velocities & atomization back to comperable to factory, but more volume & get the same effects with more efficient HP gains without the lag in fuel ejection from the prechamber that might raise the EGTs (biggest enemy of diesels as far as I understand?

The small holes would be a restriction but you don't need more air in the PC so they are not.
The small(original) holes will not raise the EGT. Raised EGT is a result of increased fueling and insufficient amount of air in the combustion chamber(among other factors)

(01-29-2011, 09:39 AM)yankneck696 Let's take a garden hose with a an old time brass twist nozzle as an example. at a certain pressure & volume of water, you get the spray pattern that you want & when you turn off the valve, the water stops immediately (theoretical circumstances, I know) . Now, turn up the volume to that nozzle & it increases the pressure comming out. Fuel may be more atomized, but when you turn off the valve, there would be a certain ammount drizzling out of the nozzle. Put to diesel applications, that drizzle would lead to higher EGT' & unburned fuel (black smoke which is undesireable due to HP out the tailpipe?

Not arguing, but trying to understand better.

Ed

The last example makes no sense to me. maybe someone else can explain

erling66