My gauge set:





My plan:

1. AE for reasons already stated.
2. Muffler delete alone to compare data, performance, and sound.
3. 4" as needed, with the configuration I decide, based on my experience with the stock pipe and muffler delete.

I just need to learn more about how to protect my turbo from my ignorance.. so as not to repeat my costly transmission disaster. With 250K miles, I'm betting my injectors will blip on my radar screen very soon. I need to make sure I don't squander the simoleons - thereby sapping my savings to solve subsequent snags.

My lisp just sent copious quantities of spray on my keyboard while proof-reading.

 

As they say down under, "No worries, mate." I typically have 10-12 hours days... working 45 miles from home will do that.

Sometimes people ask if that drive wears me down. The drive is in the Columbia River gorge and it never gets old.



So... waddya think of my test track for diesel performance?

 

I guess that we can never be on friendly terms. I'm cool with that. You don't have to like me.

Nevertheless, the reason I may come off as a "total tool" is because I have a real problem with misinformation. I know that you've seen it as well in your areas of expertise (whatever it is you do for a living and hopefully make good money at doing). I don't purposely go out searching for poor souls to make fun of or to try to insult. I go out with the intention of trying to explain exactly what's going on without beating around the bush or over-complicating things. I try really hard not to be derogatory or demeaning. I think that EVERYONE has the right to know exactly how something works without being belittled.

If you don't like the way I come across, that's too bad. I don't know you from Adam so it really doesn't bother me that much. I have never claimed to float on Bill's attitude. If you think that it hurts his company's sales, I'd beg to differ as I am never short on custom tuning work. I am who I am and I do what I do. I don't view it as a fault, just a personality trait.

I didn't say tuning changes nothing. I said that timing changes very little and "doesn't make that big of a difference" in regards to the 7.3L. To elaborate, the stock tuning on a 99-03 7.3L varies the commanded start of injection (SOI) from 0 to about 28 degrees before TDC (at full operating temperature) depending on speed, oil temperature (the commanded SOI is MUCH higher with more viscous/cold oil), and load. Do aftermarket tuning companies alter that? Of course, most do. However, adding more than just a few degrees in some of the operational areas has a profound effect on cylinder pressure and as we all know, the bottom ends of the 7.3L (especially the ones with brittle powdered metal connecting rods) aren't as robust as the bottom ends of the aforementioned mechanically-injected Cummins. In addition, starting with a statically-timed mechanical system like the VE or P7100 5.9L where the factory specs are listed as something like 16 or 18 degrees (I can't say for sure because I don't work with them on a daily basis), it stands to reason that it would help immensely to go an additional 10. This does wreak havoc with engine noise though, especially at idle and during cruise conditions.

 

Pretty. That makes a guy from my area pretty dang jealous.

I hear you on the driving part. I could do it for a living (as long as I'm not in a GM or Dodge seat because they're a little hard on the lower back).

Yep, you have stepper motor gauges as well.
As I said earlier, it's not really something that I would consider "good" for your turbo, but as long as you don't make a common practice out of it, you should be fine. A forum would be the place to hear about turbocharger failure (more specifically shafts that are snapping) if it were a huge issue.

 

It figures... I pull the red line to get more boost, now I have to drive in a way to protect the turbo from the red line being pulled. If driving a turbodiesel without harming it was simple, a lot of mechanics would have different careers.

 

Pay to play!

I must retort on one of my statements earlier:

After a little bit of searching through diagnostic information, it turns out that stock VE/P7100 mechanical Cummins engines' static timing can be set from the factory in the vicinity of 12 degrees + or - 2 (not 16-18 degrees as stated).

Adding even a few degrees of static injection advance WILL net some power/fuel economy increase in that case!



I went back a ways in this thread and came up with some more information that I didn't address initially.

jkidd_39 DID have a valid point about advancing SOI without increasing fuel to help with fuel economy/power, etc. Yes, it works with static timing as I finally got to explaining later but it's not really something that helps with the 7.3L for reasons below........

The technical reason for even dealing at all with when the fuel is injected is that in an ideal world, the peak combustion pressure will occur at 10-15 degrees after top dead center. This is what is accepted by many to be the ideal "time" for peak combustion to occur. With a static-timed engine (like the mechanical Cummins), the peak combustion "time" is going to occur later and later as the RPM increases. For all intents and purposes, let's assume that the flame speed is constant in a given scenario. 1200 RPM will be the engine speed with very little load (very little fuel being injected). 3700 PSI is the injection pressure of our injection pump (that's when the injectors "pop off"). Let the fuel be injected at 10 degrees BTDC. Once the fuel starts burning (delay), the peak cylinder pressure occurs at, say, 3 degrees ATDC. This is fine, the cylinder pressure is ok, there isn't any unburned fuel, etc. Now, we increase the engine RPM to 2200. The rate of fuel burn is exactly the same. However, since once the piston passes TDC, it is moving away from TDC faster than it was at 1200 RPM. Now the actual peak pressure is occurring with the crankshaft at a farther position. To put some actual values to it:

If the engine speed is 1200 RPM and the injection event lasts 1mS (one millisecond), the crankshaft has traveled 7.2 degrees. When the engine is turning at 2200 RPM, the crankshaft now travels 13.2 degrees in that same 1mS. By advancing the timing on one of these mechanical engines, the fuel spray is started earlier before TDC so that peak combustion pressure occurs earlier after TDC. Just a little information, you NEVER, EVER want peak cylinder pressure to occur near 0 degrees TDC or any time before TDC. That makes a big mess!!


The programming of the 7.3L already takes into account dynamic changes in when the fuel should be injected. Also, the injection pressure is constantly changing as well as the time that the injector is commanded to spray fuel. The SOI that is calculated is already more optimized to "hit" that combustion pressure sweet spot under all operating conditions.

That portion of my explanation revolves around instantaneous peak pressure with stock equipment. It doesn't take into account higher AVERAGE pressure (longer injection duration) or larger nozzle orifices (more fuel with time and pressure being equal).

Maybe that makes sense. There's an awful lot of stuff there.

 

Oh, and sorry for derailing the thread!

Back to your regularly-scheduled discussion!

 

I understand everything you're saying. If my time wasn't already in high demand, I might have attempted to program my own truck. I know I wouldn't do as well as those who gut diesel engines all day every day.