Performance 6.5 Injectors

[More Power]

There are a multitude of reworked injectors for the Duramax, Powerstroke & Cummins diesels. The hi-flow nozzles are usually the result of extrude-honing to increase fuel-rate (fuel passages are increased in size). The developers can show the flow rates for stock and their performance injectors. The current Duramax, Power Stroke & Cummins all use some form of high pressure common rail fuel injection systems. Common rail systems can push huge volumes of fuel through modified injectors.

The electronic 6.5's Stanadyne DS4 rotary fuel injection pump is limited in the amount of fuel it can deliver because of a finite volume in each of its four pumping plungers. Opening the nozzles beyond a certain point won't deliver more fuel because of this finite limit.

Hi-pop 6.5 injectors use higher-rate internal springs or additional shims to increase spring rate. This increases the "pop" pressure, which is the fuel pressure at which the nozzle begins an injection cycle. Higher pop pressure may improve atomization and combustion efficiency. Hi-pops may work fine when used with a healthy fuel injection pump, but they could also contribute to poorer starts or no starts, especially on a warm/hot engine if the injection pump is too worn. This is because an aging fuel injection pump might not be able to generate the fuel pressure it must to "pop" the injector at a typical 180-200 rpm cranking speed.

Many stock 6.5TD's dyno at about 160 rear wheel horsepower. I've been present at dozens of dyno events where, through the years, hundreds of 6.5L diesel powered trucks and Suburbans were dyno'ed. I absolutely know what they are capable of. Here is a series of questions that you should ask any vendor who wants to sell you a set of non-stock "performance" injectors for your 6.5L diesel.

1- What exactly is a 40 hp 6.5 injector?
2- Would they produce a 25% gain in horsepower from just a simple injector swap?
3- How are they different from a stock injector?
4- What is the flow rate for a stock injector, and what is the flow rate for a "performance" injector?
5- Does modifying the 6.5 injectors for additional fuel flow affect fuel economy or cold/hot startability?
6- Are there any dyno graphs - anywhere, that show a performance gain when comparing new stock injectors to new performance injectors?

Let me know if anyone knows the answers to these questions.

Maybe we need to do a product review. I now have access to a local Mustang chassis dyno...

Jim