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Power Upgrades for Ram 24 Valve (ISB) Engines
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Dodge is offering a computer upgrade for 1998+ 24 Valve engines that raises the engine to 235 hp, 505 ft-lb. This is a $900 replacement ECM module, not a TSB or computer reflash.
Some details are available from the Cummins website.

Q: Do I need an Exhaust Gas Temperature (EGT) gauge?

   If you have a stock engine, you probably do not need an EGT gauge, but there have been spotty reports of high EGT levels. If you tow a heavy trailer, it would be a good idea to install the gauge.
    Anyone who is tinkering with fuel rates, boost levels, or power enhancements should install a gauge and watch it for a while before they make any modifications. You are really "flying blind" without a gauge.

Q: If I bomb my engine, do I need to install larger fuel lines?

   Larger lines are not necessary to handle the fuel flow. There are 4 banjo fittings that will need attention. The inlet on the lift pump, the outlet on the lift pump, the inlet on the filter head and the outlet on the filter head. The banjo fitting at the inlet on the injection pump is already 3/16 or a little larger, which is adequate.

The banjos on the line between the stock lift pump and the stock filter housing need help because, while the barb is 5/16 on the outside, the hole thru it is LESS than 3/16.  A 3/16" or 9/32" drill bit chucked in a drill press will ream the holes to a more reasonable size. The main thing is to make sure the holes are de-burred after they are drilled. Compressed air is also necessary to blow out the fittings. With your intended modifications, this should be more than sufficient to supply your injection pump.

Torque spec for the Banjo bolts is 18 ft-lb.

These TDR threads address the fuel line issue:

See also Brandon Fenley's fuel line install page.

Q: Does Increasing the boost cause an increase in EGT?

   Generally, for a given fueling rate: increased boost = lower EGT.
   Remember that at a given engine output, 1/3 of the heat generating by combustion is converted to useable engine power, 1/3 is lost to the cooling system, and 1/3 goes out the exhaust pipe. 1/3 of the energy leaving through the exhaust is used by the turbocharger to compress the intake charge. The exhaust gas temperature increases as the fueling rate is increased to make more power. More fuel = more power = more heat going out of the exhaust pipe. The boost should be tailored to the fueling rate - not enough boost causes the engine to run rich, increasing the EGT; too much boost only adds additional stress to the engine and turbocharger while producing no additional power.

Q: How much boost is required for a given engine output?

Generally, 1 pound of boost at the intake manifold for every 10 horsepower is adequate. (i.e. 20 pounds at the intake manifold is adequate for a 200hp engine.)

Q: Can you turn up the boost for more power?

   First: Boost does not make power- fuel does. To make more power you must increase the fuel delivery rate. Re-read the preceding Q&A until you this concept.
   Second: The ECM is programmed to detect boost pressure above 21psi, and reduce fueling when overboost is detected. Increasing the boost pressure WILL NOT increase power unless the signal from the manifold pressure sensor is modified to conceal the additional boost. Some DIY folks install a simple pressure regulator between the manifold and the sensor. There are companies that modify the electronic boost signal. The best modules allow normal boost signals to pass to the ECM, then cap the signal at 20.5 psi.

Q: How can one increase the boost?

The wastegate is plumbed into the turbo outlet through an elbow fitting. Some engine versions have a fitting on the turbo outlet with a hose to the wastegate, others use a steel line directly to the wastegate.

Boost Module - This is a device that plugs into your map sensor and basically it "tricks" your ECM into letting you run higher then stock boost. If you don't have this device in place when you increase the boost you will set off a check engine light "overboost code", and the ECM will cut back the fuel rate to the engine.

Boost Elbow - A boost elbow is a brass fitting that that replaces the original wastegate elbow and allows "adjustment" of the wastegate for a "higher" boost level.

The "module" takes care of the electrical signal to the ECM, and the "elbow" bleeds off some of the original boost signal and fools the wastegate into opening later than OEM spec.

See this TDR posting and this TDR posting for elbow and module sources.

Q: In what order should I upgrade the 24Valve engine?

This was posted to the TDR forum by Ted Jannety, who runs the respected Jannetty Racing Enterprises, Inc. Numerous others responded to this thread, see the Forum thread for all responses.

  1. Guages, boost Pyrometer, optional transmission temp.
  2. K&N air filter in the stock air box or a scotty air system.
  3. 4" exhaust turbo to tail pipe, preferably mandrel bent aluminized.
  4. Then some sort of fuel enhancements, i.e. Van AAken CPC or larger injectors, but not both at the same time until upgrades to the torque converter and valve body on Auto's, or a clutch on a manual
  5. High quality low stall converter, preferably 1600 rpm, and a valve body modifications to recalibrate to handle the extra power. I prefer the Centerforce dual friction clutch on the manuals.
  6. Depending on what you choose on #4 finish the job with injectors or Box.
  7. 1/2 inch fuel system to feed that hungry powerhouse, and keep that injection pump cool and lubricated.
  8. US Gear 20% Overdrive auxiliary transmission so you can use all that new found power. How's 1800 rpms at 75 mph sound?
  9. A BD turbo mount exhaust brake to slow her down.

This information is based on my 19 years experience modifying vehicles to fit the needs of individuals, buying parts that don't fit and making them work better than they where designed too, finding ways to put 850 hp to the ground with a 10 inch tire, soon to be 1100 hp 360 cubic inch small block chevy. Leaving the starting line with the front wheels three feet in the air for the first 70 feet is a rush like you wouldn't believe. I love what I do! only second to my wife and kids. I hope this helps Ted Jannetty

Q: Is there a TST kit for the 24 Valve ISB?

TST Products had released a computer upgrade for the Ram ISB. A $500 computer reprogram raised the engine power by about 35 hp, and received accolades from those who had the procedure performed. Unfortunately, Cummins filed suit to stop the reprogramming on the basis that TST was using Cummins proprietary software to store the upgrade in the OEM computer. TST briefly withdrew from the ISB upgrade market to redesign a power enhancement.

Mark Chapple went back to work and released an add-on control box that accomplishes the same performance improvement without altering the original computer code. The add-on has been well received, and customers are happy with the new upgrade.  Contact TST for the latest information.

Q: Are upgrades available from other vendors?

Yes, see the performance specialists on the diesel links page. The market is constantly changing, vendors are feverishly working to produce the maximum safe power upgrade, and I can't keep up with it all.

CAUTION:    Be aware that one performance specialist still reprograms the computer for power gains. Daimler-Chrysler and Cummins have sued to stop the procedure. Also be aware that Chrysler constantly develops computer revisions to improve drivability, transmission shifting, gauge display, and cruise control operation. Any time a vehicle is taken to the dealer for service, the service department will probably reflash the computer to provide the most recent version of the factory software, and the power upgrade will be gone.

Q: What about Larger Injectors?

ETC: Larger injectors add about 40 hp / 60 lb-ft of torque, and usually improve fuel efficiency. This kit requires about two hours install time and is something most do it yourself enthusiasts can do. Part numbers and installation instructions are posted.

ETH: Joe Donnely reports a 42hp gain, measured at the rear wheels, when 275 RV injectors are installed.

Q: What is propane injection, and what does it do?

Propane is introduced into the engine via intake manifold nozzles when the engine is running with at least 3psi of boost. A regulator, tied to a boost sensor and an airflow sensor, meters the correct amount of propane vapor for the engine load. Inside the combustion chamber, ignition of the diesel fuel causes a secondary ignition of the propane. The burning propane then adds BTU fuel to the cylinder, and the propane/diesel mix burns for a slightly longer time than diesel alone would burn. This produces a power increase and a cleaner combustion because the propane burns most part of the remaining diesel fuel, which otherwise would have been wasted in the exhaust. For more, see the propane thread in the TDR forum.


TST Products

Date: Tue, 24 Aug 1999 17:40:16 -0700
From: arlan arneberg

I installed TST's PowerMax1 computer box this afternoon and it is AWESOME. I don't know how much power was gained in numbers but it was allot. I've been driving city and freeway with my camper (4000LBS) on, and what I've been wanting ever since I got the truck is now there. The boost jumps instantly to about 30 LB. (doesn't set off any codes) and it pulls the hills easily that it worked to do before. I only put about 30 miles on but I can tell the power is defiantly there.

The hardest part of the entire installation was clamping the scotchlock connector on the wire from the fuel pump. I found that by removing the air intake, (easy, 5 minutes off and on) I was able to get to it and stop cussing. Hope it goes as well for everyone as it did for me. Great instructions, piece off cake! Thank you Mark "Your the Man." And my thanks to you also Gina, you've been great every time we've spoke.

Arlan 1998 D3500 4x4 3.54 automatic, Cummins ISB, RV injectors

Date: Wed, 25 Aug 1999 13:41:32 -0700
From: arlan arneberg

Hey all; I just went out for another test drive. I found myself driving down the freeway talking to myself and grinning like some kind of idiot. It seems I have a whole new truck here, one that I'm in love with all over again. Before the TST's "PowerMax1" computer was installed I had a pretty nice truck, now it's a killer beast. I went to one grade that I am accustomed to and here's what I found. With my camper on and my toy trailer hooked up my total combined weight is 13,800 lb. I realize that's not allot but I can tell it will comfortable with more. Before, I would approach this hill in OD at 70 mph and slow to about 62 at the half way point and need to shift down to third. I could then accelerate to 70 again. Of coarse I could maintain 70 my down shifting before slowing but the RPM jump wasn't all that comfortable of a feeling. Today I started into the hill at 70 and at the half way point I accelerated to 75 with lots of pedal left. The truck never even considered downshifting. Before my EGT's were running about 1350 degrees max. Today they stayed below 1000 degrees. On a previous email to Scott I mentioned high EGT's, 1450 degrees. True I can get them that high but that's by holding it to the floor and leaving it there. There was absolutely no need to mash down like that today. EGT's are running way cooler. I love this box and my "NEW TRUCK".

Arlan "Can't Stop Grinning in San Diego" Arneberg

Date: Wed, 25 Aug 1999 10:15:21 -0700
From: "Richardson, Joe"

I just installed mine on 99 5spd 2500 4x4. Last week I installed the injectors also. Let me tell you, this thing screams. With just the injectors, I was getting about 20lbs -max boost, seat of pants pretty good, and low end power very strong. MPG improved about 1.5. Well, last night after installing the TST box, I actually slipped the tires in 4th gear. Very much power indeed. The boost max gets to about 31lbs now, and it is really evident from 3rd-4th gear. I'm even afraid to really punch the pedal all the way cause the engine screams and I'm afraid my differential would be bouncing behind me. I agree the scotch lock connector for the fuel pump was a bitch. I used a different scotch lock connector and cut the connector off and wired the two together. a little more secure. Well worth the money. I just wonder, they say for manuals 275hp 670torque, but I actually wonder what the figures are with a 5spd with this box and the injectors. feels scary..


Date: Fri, 09 Jul 1999 08:39:09 -0700

I just installed Dyno Sources Power Button, what a breeze. Only three wires. It's supposed to double the torque to something around 800. Flip the switch on while accelerating and it's like an afterburner kicking in. Love it.

Date:    Mon, 10 May 1999 22:09:49 EDT
RE:      Dr. Performance polished injectors

> specially polished injectors for both diesel and gas engines. Real performance gains or snake oil?

Bosch spends a lot of money optimizing the holes in their injectors. Polishing them might make them flow more fuel, but at the 17,000+psi under which fuel is delivered, I would not expect the fuel to be delivered more efficiently or atomized any better. Bosch already puts a pretty good finish on the injector holes. This aftermarket company advertises a lot of stuff and says they don't add fueling, but several customers reported to me that the fueling is increased substantially. A well respected Cummins engineer reported to me that he tried 2,4, 6, and 8 hole injectors and found little difference in their performance.

From Scotty's Ram page:

Before TST:
     5th gear: 45 mph to 80 mph 32-34 seconds
Dyno: HP 203 at 3,000 RPM for aproximately 3 milliseconds Talk about a spike!
4th Gear (direct drive) I couldn't generate over 100 HP in the 1600-1800 RPM range Torque was awful too. This was a spike at 2750 RPM... 302 torque. There was nothing even close to a flat curve like what is posted on the Daimler-Chrysler site or the Cummins.

After TST:
     5th gear: 45-80 in 17 seconds
The HP was over 220 at the wheels at 1600 RPM 2350 RPM - 274 HP 2800 RPM - 286 HP Horsepower dropped off after 2800 RPM. It was not a sharp drop. Torque is now 602 at 1750 RPM! 2350 RPM - 644 and that's to the ground! Mileage has improved by at least 1.5 mpg.

275 HP Injectors Installed
    Mileage has increased 3.2 mpg from stock. Very quick throttle response and spool up of the turbo. This truck does not strain to get moving. I bought the diesel to pull things, not to race. I feel that the truck is running excellent now. Power is over 350 HP and right around 800 torque now. A proper dyno will be performed when possible and results will be posted. I have found a good source for the injectors at a good price. Email me if interested.

Blue Chip Diesel Performance

Date: Thu, 13 May 1999 10:49:22 -0700
From: William Rosenberry

I just called Blue Chip. they sell a box "about the size of a pack of cigarettes" that will enhance the power on your ISB by adding more fuel.

Dyno numbers they gave me:

@2000 rpm    Stock       With Box
   HP               142               237
   TQ               375               612

Now this device only works above 1/2 throttle. There is a little LED that tells you its in "fuel enrichment mode" To install it you need to cut a wire and splice in this box. She said all you need is a pair of pliers and know how to use wire connectors. There will be more information on there web site after this weekend      Co$t: $ 795.00

Date: Thu, 13 May 1999 16:39:50 -0700

As a matter of fact, because I live close by, I drove up to see Chip of Blue Chip last night. I got a first hand look at his electronic marvel, as well as a ride in his new '99 dually. In a word, it's awesome.

With one push of a button, his truck absolutely came alive. It's amazing what he's been able to do with electronics and wires, that used to take all kinds of parts (torque plate, turbo housings, exhaust systems ) to do on the old 12 valve engines.

There were a few other folks there to see it, and every one who drove the truck said things like, "This is a totally different truck! This box makes it fun to drive"!

Hp/torque is around 250/660.

Other nice features are that the box has a little indicator on it - and if you drive mild, it stays off, so it doesn't affect your mileage. And if you don't believe its doing something, just turn it off, mash the pedal, and then turn it on while you're accelerating - it's like getting smacked in the butt.

Installation looks simple too - just hook a few wires on to the wiring harness and it's done. This thing will absolutely make the 12 valve folks jealous, finally. -Jim Smith

Dr. Performance

Date: Sun, 11 Jul 1999 21:45:40 -0700

I met with the people from Dr. Performance and rode in their trucks and was sold on their program. I had the Phase 2 upgrade and injectors performed on my 98 4x4 and it has all the power that my auto can handle and it smokes less and gets about 1/2 to 1 MPG better mileage plus I haven't voided My warrantee. I have over 44,000 miles on the truck and it has never run better.

98 4x4 auto

Garry Brooks

TDR Forum threads on 24 Valve Upgrades:

Note: the old links quit working when the TDR site was upgraded. Links to threads do not work because the thread number changes when someone adds a post to the thread. To find these, you will have to use the search engine.


Last Update: June 21, 2001