Engine/Transmission (1994 - 1998) Injecting Logic

[DMcClenaghan]

As a GAS guy trying to get my head into diesel mode, I'm hung up on one thing so far: Companies claim an HP gain from changing injectors! What's with that? AFAIK, the injectors are just delivering the fuel that was measured and sent to them by the pump, right? Where does the gain come from?

Thanks in advance!

 

[truckstom]

Bigger nozzles=more fuel=more power...



and welcome to the site... .

 

[Rattlin_Ram]

The way I understand it, someone will correct me if I'm wrong, but the injection pump returns a lot of fuel back to the tank. Bigger injectors let more fuel through, therefore use more of the fuel supplied by the injection pump, and less goes through the return line back to the tank. The fuel is already there, just not used (with smaller injectors).

 

[Joe G.]

The larger injectors change the injection period. The bigger the injectors the quicker the fuel is delivered. That means more of it is burned at the most effective crank angle. More fuel can be delivered during the injection period. The amount of fuel potentially delivered is determined by rack position in the pump and the size of the plungers. The unused fuel is returned from the injectors via a small pipe that attaches to each injector and goes to the input side of the fuel filter. It is called the fuel drain manifold. The overflow valve on the pump is used to control fuel pressure in the fuel supply to the injection plungers. Basically, with big injectors you get a big quick squirt instead of a small slow one.

 

[LHallmark]

As a GAS guy trying to get my head into diesel mode, I'm hung up on one thing so far: Companies claim an HP gain from changing injectors! What's with that? AFAIK, the injectors are just delivering the fuel that was measured and sent to them by the pump, right? Where does the gain come from?

Thanks in advance!

Think of it this way... ... Your house is on fire and you have the choice of a garden hose or a 2" fire hose..... both hooked to the same supply manifold. Which would you choose to fight the fire with?? Bigger diameter hole means more volumn... . considering the same pressure source.

The "diesel mode" can be fun !!!!!

 

[Jdimig]

three numbers - 370. youll love them on a 12v

 

[DMcClenaghan]

Thanks to all who responded, seems like the lights are coming on gradually! I think I'm getting my ducks in order on this project:

1. Gauges

2. KDP surgery

3. transmission fortification

4. MORE POWER!

 

[Shrimpy]

Hey D, This is what the ole Master used to write when this type of question was asked back in the day (1999-2000). The Master I speak of is Joe Donnelly. The ALMOST (not picking on anyone) undisputed King of the 12 valve. His formula was more fuel, more air,-------- more fuel, more air---------more fuel, more air. As the fuel increases, the air also be increased to keep up with the added fuel. Not enough air, sky high EGT's, mucho smoke.



Once the EGT's are in check it's time for??????????????? More Fuel, which will then require?????????????? More air to keep the EGT's in check.



D, do you notice a pattern? It's like an addiction. A very good friend of mine JUST wanted a 10 plate (97, 4x4, CC, 5spd) and an HX-40. He now has a set of Prince Performance Twins (with ALL the accompaning parts) and has finally got all the parts in his 5spd to hopefully hold up. He puts 600+ hp to the ground.



Good luck in your quest... ... ...



Jim

 

[Joe G.]

Remember, when you go to larger injectors you can't inject more fuel than the pump puts out. You have to balance the pump and injectors. If you increase fuel at the pump and try to cram that thru small injectors a lot of fuel will just go back to the fuel filter. If you use large injectors with a stock pump it won't do nearly as well as you expect.

 

[Howard Durand]

Joe,



An almost uncontrollable urge for "mo power" is creeping in here.



Do you have the 160 pump in your 95? If so, what have you done to it to be able to use the 370's?

 

[Joe G.]

I put a #5 plate in my 160 pump. It's about 1/3 forward. I was going to get the 215 injectors until I found that Pier's 370s where quite a bit cheaper. I was worried about a stumble with them or rough idle but that didn't happen. I talked to a guy on another forum about it. He says that I took care of that problem by turning my stock governor springs in a couple of clicks and by turning in my fast idle screw. That guy also said that Piers 370s preform better than OEM marine injectors in this situation. Your GSK would do the same thing. So far, so good with the 370s. From what I can tell I just stumbled into a very good combination. I need to get an exhaust housing for my turbo to help with EGT, but that will have to wait.