Modifications makes turbo boost too fast

[J_Da_Fox]

Hey guys. On my 2005 3500 ctd, I put in a wix drop-in filter, removed the silencer ring, removed the baffles in the hose going from the airbox to the turbo, and my cat went bye bye with the muffler. Now my boost builds extremely quickly. The computer isn't fueling enough to use the boosted air at the lower rpm. I can get 21 mpg if I keep my rpms below 1500 rpm and keep the boost to a minimum, but running 70 at 2200 rpm just kills the fuel mileage when the boost builds at about 20 psi. Any suggestions??

 

[RRees]

Myself being a new Diesel owner would suggest:



1. Different injectors (more fuel)

2. Or something (box, tuner) that would keep the duration of the injector open a little longer.



Or replace some of the air restriction pieces you removed. But I bet that's now what you were wanting to hear.



Personally, I'd wait until somebody who knows more about this than me.

 

[Bob4x4]

The stock turbo is on the small side for a stock truck,when you add a box it is worse.



Bob

 

[crawler]

Too much boost isn't your problem.



The fact that you are cruising over 2000-2100 RPM is your issue.



The fuel mileage difference between a 1800 cruise and 2100 cruise is astounding.



~Wes~

 

[J_Da_Fox]

I disagree with you saying that my cruising is the problem. I said my mileage drops when my boost is running 20 psi. Even at 55 mph at 1800 rpm if i build boost my mileage drops to alsmost 9. At any rpm when my boost builds I lose mileage.



And as far as the stock turbo, I happen to think it does a fine job for a stock truck. Right now I think its working too well.

 

[Forrest Nearing]

you're not going by your instant overhead computer are you? it's very inaccurate...



and there's no such thing as a turbo spooling too fast

 

[J_Da_Fox]

No, I'm not going by the overhead. My turbo seems like it is spooling too soon. Now, whats next?

 

[BSwope]

Do u have the Nv5600 or the G-Uint?

 

[robertyoke]

it takes fuel to spool! and to make boost. if you are cruising along and it takes 20psi then you must be bucking a headwind , pulling something or you forgot to release the e-brake :-laf !

-robert

 

[MCharlebois]

no need to yell,boost equals fuel milage ,cruzing at 20 pob will kill milage... i just put a bigger turbo on mine and boost dropped 3to 4 pounds across the board=milage is up at least 1 to 2 mpg

marcel

 

[UP N MTNS]

No, I'm not going by the overhead. AND LET ME REPHRASE MY PREVIOUS STATEMENT BECAUSE PEOPLE HAVE ISSUES: MY TURBO BEGINS SPOOLING TOO SOON... IS THAT BETTER??? I'M SURE I CAN DRAG OUT THE FRIGGIN WEBSTER DICTIONARY AND FIND THE PROPER TERMINOLOGY FOR WHAT MY CONDITION IS. Now, whats next?

J DA Fox first off I see you are pretty new here by your post count,so welcome and next try to relax a bit this place is very calm and so are the members...



My milage sucks big time going from a easy 65/70 MPH(1800-1900 RPM's) to doing 80 MPH (2200-2350 RPM's) regardless of boost. .



And I'll agree that a turbo can not spool too soon or to fast... IMHO

 

[16919]

Take it easy, J DA Fox. I don't think he was trying to offend you or anything. Im guessin you have too much air and not enough fuel for that level of boost. The stock computer doesn't fuel a lot @ high rpm. Maybe think about a smarty I hear they rock on a 3rd gen.

 

[robertyoke]

No, I'm not going by the overhead. AND LET ME REPHRASE MY PREVIOUS STATEMENT BECAUSE PEOPLE HAVE ISSUES: MY TURBO BEGINS SPOOLING TOO SOON... IS THAT BETTER??? I'M SURE I CAN DRAG OUT THE FRIGGIN WEBSTER DICTIONARY AND FIND THE PROPER TERMINOLOGY FOR WHAT MY CONDITION IS. Now, whats next?

I wish my twins spooled too soon! holly tire smoke! :-laf

everybody on this board tries to take the turbo lag away and you want it back??

-robert

 

[J_Da_Fox]

If I put the throttle down from fully closed down one inch, by boost will build to twenty or so. At WOT, I peg 35 psi, then my wastegate will open, drop to 25, then hit 30, then drop to 25, the hit 30 again and so on and so forth. Does this happen to anyone else? And I haven't crawled under the truck to see which transmission I have... I know its a 6 speed with revese to the right and up

 

[BSwope]

Yeah calm down alittle bit hoss, the only thing we are tryin to do is help.

That little stocker is gonna spool fast no matter what!

 

[J_Da_Fox]

Im guessin you have too much air and not enough fuel for that level of boost. The stock computer doesn't fuel a lot @ high rpm. Maybe think about a smarty I hear they rock on a 3rd gen.

I am thinking something along theses lines. At higher rpms (anything above idle) i get more of a sucking sound from the turbo than a whistle, and the exhaust sounds like it is passing air thru. And my apologies to everyone.

 

[BSwope]

Ok u have the NV i was gonna say that the G-unit has little bit lower ratios and cause the rpms to be a bit higher than that of the NV, that will cause ur fuel milage to be abit lower!

 

[2broke2smoke]

Too much boost isn't your problem.



The fact that you are cruising over 2000-2100 RPM is your issue.



The fuel mileage difference between a 1800 cruise and 2100 cruise is astounding.



~Wes~

after racking up 400k miles on cummins motors in dodge trucks since 1991 i can assure you the above statement is EXACTLY correct ...

 

[cerberusiam]

I disagree with you saying that my cruising is the problem. I said my mileage drops when my boost is running 20 psi. Even at 55 mph at 1800 rpm if i build boost my mileage drops to alsmost 9. At any rpm when my boost builds I lose mileage.



And as far as the stock turbo, I happen to think it does a fine job for a stock truck. Right now I think its working too well.

The difference IS yur cruising speed not boost. Once you hit 70 mph any semblance of fuel mileage is gone. Its the after effect of shoving a 7000 lb brick thru the air, the rpm's with the 6 speed, and the new fuel.



If you are building over 6 lbs of boost at 55 and 1800 rpm's you loaded, fighting a big headwind, or have a major problem with the truck. Track your boost and EGT's across the range of speed an aimfor 6-8 lbs of boost and 600-700 on the pyro . What ever your speed is where your best mpg will be.

 

[robertyoke]

If your boost drops then rises like you say then I would guess you have a fuel delivery problem. It may be lift pump, cp3, or rail problem. does the truck surge when at steady throttle? have you ever had any dtc's? like high rail pressure? when the boost comes up does the truck make smoke then go away?

-robert