Join Date: Oct 2006
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I'm no expert, and I don't have a lot of experience so take my opinion as just that, an opinion.
The more I learn about these trucks the less I believe delivery valves larger than 181's give much power. The definitely deliver more CC's of fuel, theres no doubt about it. But in reading about them I don't think they provide the fuel at the right time. I don't think the EGT's and smoke from them is worth any power gains they provide. They sure are fun though :smoke
DV's remove a predetermined volume of fuel from the line upon closing. This is designed to quickly drop the pressure in the injection line. This cleanly closes the needle in the nozzle and avoids bounce or reopening of the needle after injection is supposed to be finished.
By removing the shoulder and creating laser cuts, when the valve tries to snap shut it won't create a slightly lower pressure in the injection line and fuel may be pushed past the vale and either make a slow end to the injection. Like when you turn the garden hose off with a regular knob valve and the pressure slowly drops until there is none. Compared to using a 1/4 turn valve when you turn the water immediately stops in a instant. The inter-workings of the injectors help to eliminate some of this but I don't think its enough or bosch wouldn't have designed they delivery valves the way they did.
If you used an oversized dv's and holders I could definitely see how they would provide more fuel.
Again I'm still kind of a newby to this stuff and I'm still learning. If some one knows more, feel free to correct me, I'd love to get this figured out