Help!! C15 twin turbo MPG...

if its ur own truck u shouldnt have the driver incentives on anyway, and if its not ur truck watch when u mess with the incentives unless u got someone other then a dealer to do it. As for the trim files the e models and early c15s did gain by switching the trim to 5232, 5234, and 5236. 5232 only for on the road trucks the other two will cause longevity problems. The trim is merely a way to increase or decrease injector output to match each other when leaving the factory. No injector is made the same, some put out more and some less, thus the trim file brings down strong injectors and pulls up weak injectors to make it equal. 5232 was a number that was on the higher side of fuel output thus one on each injector made it run pretty sweet. However on the acert and newer engines the trim file cant just be typed in it has to be programmed and then a passoword to lock it in place. Once one of these is programmed it wont let u do it again like fall call said. (unless ur a computer hacker or something even then ud have to find the hot number). Best bet for acerts running strong is to do the fuel temp reistor and add a fuel cooler, much like a tranny cooler to keep the fuel temp down so u can keep ur power increase. Also a lot of acerts only run 90 psi fuel psi. Easy way to jack it up is pull the plus on the side of the fuel transfer pump and stretch the spring by hand, doesnt take much, they like to see 100 to 110 psi. One last thing is the primary fuel filter was built with to small of passages, cat had and not sure if they still do a program if u buy a primary filter u would get the base and labor free. Easy way to tell if u have it or not is the fittings on the filter base, old style were pipe and the new style are jic o ring, or pull the filter off and there should be a longer nipple hanging from the threads. properly adjusted ivas are also a difference maker on these things, a tight 20 thousandths adj, tighter then a normal mechanic would adjust will show a better running engine under load. hope this helps bud.

 

What makes you think that?

 

Because my 20 thousandths feeler looks like the dog chewed on it from setting them so hard, I tried them normal and tight it makes a difference

 

, old style were pipe and the new style are jic o ring

updated primary filter head ( 120 gph ) is offered in multiple NPT sizes . not just jic or boss o ring

 

Sorry, what I meant was, explain how setting them tighter makes the engine run better since the purpose of an IVA is to bleed off compression when the engine has high boost pressure (and therfore high cylinder pressure), if you bleed off compression you lose effiecency and power, I would think setting them tight would make the IVAs work better and bleed off more compression?

 

the purpose of iva is to push more air when piston goes upstroke,thats way they need 2 turbos and high boost, to overcome the pressure of air that is been already in the cylinders

 

The Iva can only hold the valve open after it's been pushed down by the rocker for a brief moment to allow the chamber to be filled with more air thus the 52 PDA of boost that is applied

 

So what's the answer here guys?

Do we run clearance tight or loose?

We all need to make the most HP possible.

By the way please speak s-l-o-w-l-y using small words for the Dummies.

Tony

 

Unless someone can show me something published by Cat explaining how the IVAs are used we'll have to agree to disagree, I believe they are used to lower compression (when boost pressure is high) by holding the intake valve open as the piston begins to travel back up the bore from BDC on the compresion stroke, this allows some of the air in the cylinder to return into the intake manifold, this is refered to as the millar cycle I think. As such setting the IVAs loose would lesses the compression dropping effect of the IVAs, and thats how I set them and I have never had any complaints.

Tony, Sorry to hear you had some bad luck at Targa.

 

I'm sorry but the only person with IVA tech info will be an engineer himself, cat doesnt want anyone to know the true purpose of the iva. Lets think logically, and what i mean by that is what i came up with when trying to fix the very same device cat refused to explain to me.

the difference between an acert c15 and a normal c15 lets take an mxs and a 6nz for instance.

twin turbos making 52 pounds of boost vs. one turbo making 30 pounds ( i know u can put more to it but that is another argument lol)

addition of intake valve actuators vs. none

now if 2 engines are both set to 550 horsepower, and one is makin around 20 more pounds of boost, then where is it going? if im making the same horsepower and im shooting that much more air into the cylinder is that extra boost even being used for combustion?

to me it doesnt make sense to use an iva to releif compression under high boost loads, thats what a wastegate is for, if ya got to much boost set ur wastegate, not spend thousands of dollars developing a compression releif on the top of the engine.(feel free to argue any of this im simply putting this into bare engine operation.)

Ill admit the Iva will never be fully understood unless u talked to an honest cat engineer. But im simply sharing with the rest of you my endless nights of waiting for work in the shop trying to solve this very same puzzle. I am not smarter then anyone here but i have spent a lot of time on this subject. Together if we continue to pick each of our theories apart with logical explanation i believe we can cut the possibilities down no hard feelings i hope, ill be delighted to explain my opinions and take any critisism.