I was talking to a guy today, and somehow the subject of trucks came up. He ended up telling me was a Cummins mech for 25 years. He has a 2000 dodge diesel and I have 2004.5 diesel. He said (not to tell anyone) but the easiest way to get some extra horsepower (45), was to cap the fuel return line at the end of the injectors. Is this true, safe, or has anyone else tried this?

 

That's an old trucker trick. Another variation was to drill a really small hole in a dime, and then put the dime in crossways in the return line. I suppose it worked once upon a time, as for the modern stuff I can't say.

 

So...

We overpressure the output side of the pump and do the same to the injectors in the name of cheap horsepower. Interesting!

Why not just reroute the return fuel into the air intake? I hear that makes for an interesting few minutes on the cheap side... Until the "BOOM". Then the cheap mods get expensive.

For the mechanical Bosch units there's a throttle plate. For the electronic units we have appropriate modifications. For Gen III's with common rail injection there already exists a huge number of safe mods.

But we're going to save money and plug a return on a $40k truck? I don't think so!

 

Truckers years ago would take the return line at the tank and pinch it partially closed with vice grips , but the DOT cought on so then they would take the line off and put somthing in there to restrict the return fuel. More fuel at the eng means more hp, but I don't think I would try it own these new engs. The old diesel engs didn't have ecm boxes and computers on them. Just my .02.

 

I don't think these new computers and such would be happy at all with out a return line. My guess is that injectors or pump will blow.
The days of mechanical injection are over. Sometimes I miss "turning up" the motor with basic hand tools, not a $400+ module!!

 

This post is repeated again in the high performance forum. I am shutting this one down as we do not need duplicate posts here.