Engine/Transmission (1994 - 1998) Pump Questions

[PARTSMANAL]

I'll try a different question since I didn't get a lot of answers on my first post.

If internal calibration modifications can raise power, increase boost, and increase RPM's, why would we buy aftermarket parts to do the same thing?

I took a TST#8 plate, AFC spring kit and 3GSK spring kit to Cummins. They took the pump off and recalibrated it on the bench and say they get the same results. They didn't install any of my parts. Does this sound right?Should I go ahead and install my plate and boost elbow?I am getting about 25lbs of boost now on hard acceleration.



98 3500 12V quad cab 2wd dtt trans 3. 54

 

[Bob4x4]

If you are happy with that amount of power you are good to go,if not keep on going



Bob

 

[RonA]

If you are only getting 25 lbs of boost and your plate is full forward, I don't think you got much for the effort of taking your pump in. A 3k kit and a plate should have given you a bit more than that. Quite a bit more I would think.

 

[Bob4x4]

If you are only getting 25 lbs of boost and your plate is full forward, I don't think you got much for the effort of taking your pump in. A 3k kit and a plate should have given you a bit more than that. Quite a bit more I would think.

I think what he was saying is they didn't play with the plate but set it up for a more powerful cpl.



Bob

 

[Jim Fulmer]

I wish you were closer I would show you the difference. Might I recommend a trip up to Garmon's Performance and let him play with it, I think he knows just a thing or two about a 12V.



Jim

 

[RonA]

I think what he was saying is they didn't play with the plate but set it up for a more powerful cpl.



Bob

I think he will see a bigger difference from the plate and 3k kit than he saw from the "tune up" from Cummins.

 

[PARTSMANAL]

A follow up to my post. When the pump guy at Cummins installed my 3KGSK springs, he said it would run past 3800 on the bench and not stop. So he would not leave them in, took them backout and said he could change the pump internally to give me 3000 rpm. I have not tested it to that RPM yet.

 

[JoshPeters]

That's on the Bench. Sure the thing is going to flow to whatever speed the flow bench spins to.



At 3500, you have to have a certian ammount of fuel, Under Load, to get to that RPM.



Fullmers advise is spot on. Take a weekend trip to see Jeff Garmon in GA.



I think the Cummins mechanic did a few things with the pump, but did not go anywhere NEAR what a fuel plate and a 3kGSK will do.



The other thing to remember is... Guys are putting in 4k valve springs (I'm one of them) and the engine is fine running to that level. My truck pulls hard to 3300rpm with a 3k gsk. Auto's generally shift before that, Manual, well you know how to shift before 3k.



I'd take it to a shop that knows more about Modifying these trucks. Cummins probably reset the pump timing to stock too.



Josh