HOHN

The “proper” order for upgrading your 24V CTD (2008)
(jmo)

Someone recently posted Ted Jannetty’s excellent reference, “the proper order for upgrading your ISB.” With all due respect to Ted, the diesel business has changed quickly with products available and we’ve learned a lot of things since it was first written.

In Ted’s article, he recommends the following order for upgrading your CTD:
1) Guages
2) Exhaust
3) Intake
4) Fuel system upgrades
5) Injectors
6) Transmission or clutch upgrade
7) Electronic fuel or timing enhancements
8) Turbocharger
9) Revisit electronic fuel or timing enhancements

While this is still a good baseline in many cases, it can lead someone to make wrong choices. For example, your choice in transmission upgrade (especially converter)should match the power level, which will change with the addition of the “electronics” that come later. So perhaps we can expand and refine the idea of the “proper order” for upgrades to a VP44-equipped Cummins Diesel.

With huge thanks to Ted Jannetty, I present my opinion on what the “proper order” should be, knowing what we now know (Feb 2008):

1) GAUGES: In order of importance, you’ll need 1) Fuel Pressure and Pyrometer (EGT) gauges, 2) Transmission Temperature (for auto transmission only) and 3) Boost pressure. Even completely stock trucks need at least fuel pressure and pyrometer gauges. Boost gauges can be useful tuning tools, but a pyrometer is far more important.

2) FUEL SYSTEM UPGRADES: Your gauges will be your guide here, but you’ll want to upgrade the plumbing as a minimum, even if the stock pump is still performing. You’ll also want to consider another pump option, because the factory pumps are infamously unreliable. There are many on the market.

3) INTAKE/FILTRATION UPGRADES: Even if you don’t add much or any power, the factory intake is prone to perimeter leakage and cold-weather cracking. A “dry” filter will generally catch more dirt, but sacrifice ultimate airflow to do so. An “oiled” filter will flow the most if you are shooting for big power.

4) SELECT A POWER GOAL: How much power do you want to end up with when “done”. Be realistic. Be cautious, knowing that the amount of power that can be added in a cost-effective manner changes a lot with how you use the truck. The cheapest horsepower to add is the first, and each horse after that gets progressively more expensive, sometimes exponentially so.

5) AUTOMATIC TRANSMISSION UPGRADES: Even mildly upgraded and stock trucks will benefit from upgrades, and cost depends on how much hp you decide it needs to hold. It’s far cheaper to upgrade the transmission before you’ve added a bunch more power (no trans damage), and you might find that the improved power deliver of the upgraded transmission eliminates the need for more power. Because automatic transmissions more commonly fail catastrophically, they should be upgraded before power is added.

6) LARGER INJECTORS: Consider the versatility of your electronic modifications when choosing. Do you have to start the truck in -40F temps? Then you might need to stay under the 100hp size. How heavy do your tow? How much weight? Ease of smoke control should be important especially if you tow or live in a “smog state”, and just because something CAN be driven smokelessly doesn’t mean that you’ll enjoy the effort it takes to do so. You want injectors that allow easy control of the appearance of smoke. Modern injectors are sophisticated enough now that there’s little reason other than budget to consider anything under 80hp rating. I prefer slightly larger injectors over cranking an electronic box up to “kill”—I think it’s easier on the pump and slightly cooler for EGT. Large injectors can be run even with stock software and turbocharger equipment—it will just require the driver to accept that his injectors are won’t be “uncorked” until supporting modifications are made.

7) ELECTRONIC POWER UPGRADE: The market for these is enormous and can be overwhelming. Upgrades fall into three general categories: programmers, “timing” boxes, and “fueling” boxes. A programmer modifies the software inside the ECM to increase power. A “timing” box manipulates the data between the ECM and the fuel pump and achieves most of the power increase through changes in timing (and slightly broadening the fuel curve). A “fueling” box connects directly to the injection pump and governs it directly for maximum power—though at the price of increased workload on the injection pump. Power gains range for claims of 40hp -60hp for programmers and “timing” boxes, all the way up to 180hp for aggressive “fueling” boxes.

8) CLUTCH UPGRADES: You’ll have to address this when the time comes. The best time to upgrade is when the old clutch is worn out, not burned out. Match the choice to your usage of the truck, HP level, and budget. There is no consistent level of what a stock clutch will hold, so if you add ANY power, expect to replace/upgrade the clutch.

9) TURBOCHARGER UPGRADES: This topic can get pretty heated, and not just from warm EGTs. At certain power ranges, a single turbocharger can be very effective and deliver sufficient response to allow for towing and smoke control. But beyond that area, you can rapidly narrow the usability of the truck with certain ill-advised choices. Here are some generalities to consider when in the market for a turbocharger:

1. USE THE STOCK TURBO AS LONG AS POSSIBLE. It’s cheap (free!) and spools well. If you absolutely HAVE to have more power than the stock turbo can support, then you’ll need to ponder upgrades very carefully.
2. COMPRESSOR SIZE ISN’T A CURE FOR HOT EGT: simply adding a larger compressor often will disappoint you. Many times high EGT is a result of the engine having to work too hard to make boost, or it’s making more boost than required. The TURBINE is the heart of a turbocharger, and it should be the focus of your turbocharger selection, along with an appropriate housing choice (if available).
3. LIMIT BOOST TO 45PSI WITH AN UPGRADE, 35PSI FOR STOCK: At most elevations and weather conditions, this is the ragged edge of turbocharger efficiency for even the best models. Small centrifugal compressors (like a turbocharger) simply cannot compress to high ratios efficiently, and a pressure ratio of 3.5 is about as far as any single turbocharger can efficiently go, regardless of size. Beyond this, a compound turbo setup or nitrous oxide should be considered.
4. THERE IS NO ONE PERFECT TURBO FOR EVERYONE: Getting turbo advice is risky because of how differently people use their trucks. Make sure that you compare apples to apples (similar mods, similar conditions, similar loads, similar options) when accepting advice.

10) EXHAUST UPGRADES: What? Way back at number 10? But everyone is telling me to upgrade my exhaust! Your factory 3.5” exhaust is far from optimal, especially at elevated power levels. But you really cannot unlock the full benefit of a larger exhaust until you install a turbocharger with a larger turbine that flows more. While modest increases in performance may be perceived with larger exhaust, the factory 3.5” pipe pales in significance compared to the restriction of the very small factory turbocharger. You don’t want or need 5” unless you are doing compound turbos. Stacks are trendy, but damage the re-sale value of the truck and in some locales aren’t legal. A single 4” pipe will suffice to well over 500hp.

11) CHEMISTRY: For big power levels, supplemental injection can be worth considering. Nitrous Oxide is by far the most potent and effective—but requires special preparation for use. Consult a performance shop with experience in this area. Water injection is effective without methanol. The addition of methanol makes more power, lowers EGT a little farther and drastically increases the stress on the headgasket. Propane should not be used. Nitromethane should not be used. Hydrazine should not be used. C-4 should not be used, nor should Semtex or Comp B. Stick with water for the typical user, or nitrous for the more adventurous.

JH

Mike D

Very good, Justin!

haloman

Great Post, should be included in the tech fasts or a sticky.

gies

I wouldn't mind seeing mention of the exhaust manifold and aftermarket cams. Maybe both could be added to the turbo portion?
jason

HOHN

Could be-- but this is intended to be a entry-level approach where 500hp would be considered a lot. Cams and manifolds are not entry level mods, and a manifold can be looked at from a "repair" standpoint since the stockers tend to crack and shrink.

Maybe I need to add a "more advanced" section at the end?

jh

gies

I would say with Nitrous mentioned that you have pushed the 'entry-level' moniker a bit. But, just trying to help.
You do make a good point about the manifold often being a fix-it item rather than a upgrade.
I think it would be fun to have a more advanced section just so that when we look back at this in another year we can see how much things change.
JG

xtoyz17

I already broke the proper upgrading order rules. Use me as an example of what NOT to do.

Ph4tty

I do like the fact you did turbo then exhaust. Might be easier to do both at the same time anyhow. I think the intake, exhaust,... is the gasser mentality

Adam3291

Nice right up. Only thing I wonder about is exhaust. I dug back into the forums for our two most recent dyno days in NCDTR #18. Pete 2141 made 509/1094 Feb 17, 2007. On Nov 10, 2007 he made 540/????, we were having issues with a couple things related to the dyno that day so alot of people didn't get torque readings. Both of these runs were done at Carolina Auto Masters in Durham. The only difference is Pete was running a 4" the first go around and a 5" the second time. Nothing else had changed. I'm defanitly not trying to bash anyone but I think the 5" is a nice upgrade for the 500hp and up crowd.

Tate

That could be the exhaust, could also be the local conditions that day, and some days trucks just run better than others. Are those uncorrected numbers?

Adam3291

I believe they are uncorrected, could be wrong though. I know in Feb it didn't get above 35F all day and I think Nov was between 40F and 45F.