What I meant by the "preheating of the piston and head” is that the piston and head are needlessly subjected to higher heat levels, (during non-power generating periods), for a longer period of time, instead of being able to cool with lower temperatures. The power losses are from having to compress the extra air in the cylinder that could not get into the Prechamber.


The Prechamber design was employed by MB for reasons that they had. They work fine in low boost and low fueling quantities.

My intention is not to make a Prechamber, rather I want to end up with an external constant volume combustion chamber that is connected to the work cylinder by a tube. Very much like an Air Cell Chamber as apposed to a Pre, or a Swirl Chamber.

Some of the reasons I give why the Prechamber was used was to address the poor injection quality, long duration of the delivery at higher delivery quantities, and ignition noise.

The small holes of the Prechamber maintain a high pressure inside the Prechamber, (post ignition), after the pressure curve drops, (on the downward slope of the curve), to that equal to the start of injection, (ignition), pressure on the upward slope of the curve.

This increased pressure duration is intended to support the continued combustion of remaining fuel after TDC, and help reduce emissions (NOX), reduce smoke, and increase operational speed.

IMO, given the above theory of operation, storing pressure in the Prechamber for the purposes of combustion, would only be necessary after the end of delivery accurse to late in the pressure curve, so that not all the fuel can be burnt in a pressure environment, grater than or equal to, the Prachamber pressure at the start of delivery.

If all the fuel is burnt by TDC, there is no reason to restrict/maintain pressure in the Prechamber that could be used for work.

Should, at full power delivery quantities, the end of delivery accrue at a point where the pressure will drop below start of delivery pressures, before combustion of the all the injected fuel is completed, then, and only then, should the Prechamber be designed to maintain pressure to complete combustion.

The Prechamber always will have a grater volume of gasses trying to get out of it than get into it. As such, the restriction point of the holes, (hole size), should be selected to flow freely, just up to the additional volume of gasses generated by the fuel quantity which is delivered at the point where the end of delivery accurse too late for complete combustion with in the useful pressure curve.

In my case, I am going to shorten the Pulse Width, (length of time the injection takes place), with Modified 10mm Elements, so that even at increased delivery quantities at full power, delivery can be completed as early as 10 degrees BTDC.

Additionally, the increased quantity of fuel delivered, along with increased intake air from higher boost, will result in the pressures during combustion being increased, which will take longer to decay after TDC, allowing additional time with in the useful pressure curve for fuel to burn as completely as possible.

This theory, I think, is evident by the reports from Tomnik regarding his 7.5mm M pump elements. He is injecting more fuel than stock, and doing so with no, or no additional smoke as the result of the shorter delivery time, (pulse width).

With the delivery duration reduced, the only limiting factors to operational speed is the oxygen content of the air, the quality of the injection (atomization), and the burn rate of the fuel it self.

My Chambers will flow over twice what the stock Prechamber will, plus additionally intercooler boost pressure will be raised. For injection quality, I will be using custom modified nozzles, and running a pop pressure in the 200 bar neighborhood to attempt to get the most burnable injection straight out of the nozzle.

The burn rate of the fuel is what it is.

I see trying to make power with a Prechamber like others see using a stock T3 turbo making 25 pounds of boost on a 300D. It can be done, but at the cost of efficiency.

Coments?