Barefoot88

should you buy the chip or the injectors and do you need to upgrade your fuel lines and pump

HOHN

IMO, injectors offer more bang/buck.

Even the hottest box adds maybe 130hp. They run about $650. They are harder on the pump, but not unreasonably so, imo.

With your SO pump, you can get injectors that are 200+hp for $1100 or less. Try some used Mach 6s

Boxes have the advantage of adjustability, which is nice; injectors are "always on". That said, injectors are smoother in power delivery, and imo are easier to control.

Your truck will not "need" an upgraded pump until your over 700hp.

Upgraded fuel lines are a good idea. -06An lines will flow more than enough fuel to drown your pump. I have -08AN

RustyJC

Something not often factored into the equation is that, with larger injectors, you'll need (at a minimum) a boost elbow (or turnbuckle for the HY35) and boost fooler to provide the additional air required to burn the additional fuel the injectors provide. You need to add this cost into the injector equation.

Most boxes include the boost fooler function and ship with a boost elbow.

Rusty

CTD NUT

With big injectors, like a Mach 6, you will not have to bother with a boost elbow - you will need a whole new turbo that will flow much more air to support that fueling level. IMO, a box AND moderate injectors are best.....you will have your adjustability and boost fooling capabilities and make huge power without having to run a really large injector.

RowJ

If it's to be either Chip...or Injectors, I would go with the Chip/Box...for reasons already mentioned;
-It's adjustable....so you can find a level that won't over tax your tranny
-Built in boost fooler....to give more air to match extra fuel
-designed to work with factory injectors/fuel lines. Your fuel pressure gauge will tell you when you need to upgrade fuel lines/supply.
-Less expensive than injectors.

Would probably recommend an Egde Comp Box....or similar (with timing). If funds are tight, there is a used one for a 2000 in the classifieds!

Agree best option for moderate power gain is box and mild injectors. It's really time to decide, as honestly as possible, where you want to end you...HP wise, being aware you will probably under guess!
RJ

HOHN

True-- injectors alone are not the whole story.

I don't really separate the two, as I think that a box needs injectors and injectors need a box.

But I was under the impression that he was looking at it differently, as an either/or situation.

Any adjustable box AND injectors is the way to go, imo. Size the injectors based on the largest you (and your truck) can handle for box-off usage. Then crank up the box to have fun.

jlh

CTD NUT

Yup, I agree.....that is exactly how I would do it......they really work best together.

azcrawler

Keep this in mind also... Given any HP gain you're looking for; a box with stock injectors will run cooler than that same HP injector alone. Easy principle... Same fuel pressure/timing exiting a larger nozzle=less atomization=higher EGTs... Extended timing and or higher pressure coming out of the smaller stock nozzle=better or equal atomization=less increasing EGTs. Also keep this in mind... Your fuel curve will be the same as stock with just the injectors... It WILL still lug on the bottom end, boost will come on hard and fast, then almost as quick as it came, you'll be sitting there dumping boost out of the wastegate. However with a box, you WILL get considerably better bottom end power and given you get a box with built in fooler and elbow, you WILL get the extra pull and lowered EGTs up top from the additional air/boost.

Barefoot88

thanks guys that is just what i was look for i think the box is the way to go
kiley

HOHN

Well, one would THINK this to be true, but it doesn't always turn out that way in reality.

First, larger injectors don't always atomize poorly. For example, Don M's 1.6 injectors are almost 50hp over an RV275, yet the MPG is often EVEN BETTER than the 275s!

Guys are even reporting better mpg with don's 150hp injectors!

So, what's at work here? Well, you have to keep in mind that a larger injector passes the same amount of fuel in a much smaller amount of time. This means that the cylinder pressure rises faster than it would with a smaller injector.

This sharp rise in cylinder pressure creates an effect similar to advancing the timing, or raising the compression ratio-- BOTH of which are known to help MPG.

All else being equal, a higher-pressure, shorter-duration combustion event is more efficient.

Think about this: when is a gasoline engine most efficient? Answer: when it's right on the ragged edge of detonation. This is because these circumstances create the highest pressure, shortest duration combustion event.

Note that the newer CTDs tend to have lower mpg than the older ones. Because a combustion event like I described (high peak pressure, short duration) tends to produce the highest emissions! When the peak cylinder temp is high, you have a lot more oxides of nitrogen (NOx), which is an emissions element.

Similarly, the newer HPCR trucks have higher static compression ratios (17.2:1) to compensate somewhat for the retarded cam timing, which is driven by EMISSIONS.

Consider the advent of the HO 24V trucks with the VP44. It's well known that the HOs, while being more powerful, actually had smaller injectors. They also had higher static compression ratios (17:1, vs 16.4:1). So why does the HO engine have 1)smaller injectors, 2) higher compression, and 3) retarded ignition timing relative to an SO engine?

EMISSIONS! The HO engines have more drawn-out combustion event, due to the smaller injectors (which have a lower rate-of-discharge, and therefore require more TIME to pass a given amount of fuel), the HIGHER COMPRESSION (to partially offset the effects of retarded timing), and retarded timing, which reduces PEAK cylinder temps, and the formation of NOx.

Note here too, that the HO engines are known for high EGTs right out of the box.

Now, observe that the HPCR trucks are designed to handle 1400° EGTs. Note the trend that as emissions standard get tighter, EGTs go up, and the engines are designed to handle more heat.

WHY? HIGHER EGTs are a necessary byproduct of the current measures taken to reduce emissions. These include retarded ignition timing, retarded cam timing, and higher-pressure injection systems that provide better atomization, yes, but ALSO allow a slower rate-of-discharge which lengthens the burn time in the cylinder for a given amount of fuel. THIS is what causes the higher EGTs of the newer engines, and is the driving force behind design changes (like Inconel Exhaust valves, cobalt valve seats, etc) that allow the engine to handle higher EGTs.

Submitted for your consideration.

Justin

darrenG

Jimmeny Gillekers, Hohn! If you tossed an add @ the bottom for injectors I'd have been reeeaaal tempted.

azcrawler

You are completely right HOHN. GOOD READ TOO ... Worded very articulately. I was making a generalization in relation to the commentary to the larger injector/higher EGT... All of this is of course assuming that correct pop-off's are maintained. I in fact get MUCH better gas mileage with a 120hp Bully Dog than I did with DD2's OR stock SO injectors. Interesting eh? Bully's are generally known for being a smokey injector (less effecient) in comparison with like HP injectors. As anyone should, I take everything I read on the internet with a grain of salt. There's just WAY too many variables out there for one definitive answer. There's a local guy with Mach 3's that smoke more than I'd have ever guessed having read what I have... Oppositely, after I put my injectors in, friends were expecting a 3/4 ton crop duster ... Everyone was suprised. My personal experience was going injectors before a box and in hindsight, I'd have done it the other way around... Of course injectors AND a box are the way to go , but from personal experience I've found a box to to come closest to it's net potential left to own devices over injectors. Where as the stock fuel curve mapping and boost limitations considerably hinder the injectors alone.

Once again... Good read Hohn ... Never had an HO and never thought about how they went about it. Definitely learned something there.

HOHN

Thanks, fellas. I kinda expected a little more response to my novella-- like a bunch of people telling me how I'm all wrong

zulusafari

I don't know nearly enough about the subject to say anyone is right or wrong. I am here to read about it, digest all the information, then contact the experts who can steer me in the right direction.

My truck runs well, gets ~16 mpg with stock setup, rolling on heavier 19.5 wheels/tires. I would love better mileage, but also want more power. Kind of a sickness with us I think! Keep these sort of discussions coming. I learn more each time, and really swing between a box and some of Don M's injectors.....but I think a particular Iowa tranny shop will get my money first. If I only had the money to do it all!

j-fox

The good thing about a diesel is you can increase the power and still have great mileage.
If you go with a set of Don M's injectors and a MAD computer, better clutch or converter/trans, you will be content.