Diesel engine upgrade

The cat is in the muffler,or it is on the Cat engined Freightliner chassis. Change the muffler. That will help a good bit, I heard someone say, not me.
No DEF it should be fine.
However go online to the Cummins engine forums. Lots of people have Cummins engines.
Ask questions of others running tuners.
Be comfortable whith whatever you do.
A tuner will raise power and increase mileage. I would still install a pryometer, in the exhaust next to turbo or wherever a Cat Rep or Mechanic would recommend it.
It will give you the temps, of the the exhaust near turbo and let you know if you should have to back off.
Remember, to always idle, for five minutes, tuner or no, to cool turbo bearings when you stop. imo.
I don't think there is enough oil cooling going on in my mh,and when the opportunity arrives and extra oil cooler is going on it. Checking the oil can burn you.

But, being that year, chances are that it has a DPF and EGR. The Cab and Chassis pickups didn't use an EGR and relied on DEF. Adding any more fuel to this without a programmer to remove the exhaust, would only make the problem worse. That is if it does have a DPF....

...pictures of the exhaust and even of the turbo side of the engine if you could?

Banks is way overpriced. Pump, injectors & intake will wake it up.

Thanks for the replies I've received. I haven't followed up on them yet, but I'm collecting them to follow up. The engine is a Cummins ISB 340 6 cylinder variable speed turbocharged diesel that doesn't use DEF. The transmission is an Allison MH-2500 6 speed automatic. Due to a fall I had in November, I haven't been able to get under the unit yet to determine what the muffler and exhaust look like.

c-webster wrote:
Power is of more interest than mileage, since I doubt we could ever recover the cost based on fuel savings. We drive to CA every year to visit our daughter and her family, and more power on the steep grades isn't needed, but would be nice to have. (Monarch pass drops us down around 40-45 mph.)

I bet that it has a 6.7 Cummins, right?

If so, there isn't anything that can be done.

I am interested though if it does take DEF, but the HP rating would say no to me.

I haven't tried it with our Mh but our 02 F350 tow vehicle I used a tuner sodl by the Dealer, and connected through the port under the dash. It had three stages. I only used the tow setting not either of the higher settings.The mileage increased very noticeably. Performance, without the Fifth Wheel was like a sports car.
Diesels now are turned down a lot. upping fuel and timing improves mpg and power.
too much fuel and timing can cause burnt or melted pistons but you're not going to run into that generally with a tuner. I can't think of the name right now but you can find thee or four, on the net. I would install a pryo monitor on the turbo also, just for info and in case a long pull uphill fully loaded, might raise temps bit too warm.
Cummins are stoutly constructed engines. Tuners aren't going to endanger their pocketbooks, generally, by selling too much tune.
I can't quote power increase or mileage increase expectations but I think twenty to thirty percent is reasonable in power.
Banks sells the Tuners too or did. The pipes and bigger coolers, and all that are too sell. Look on the Cummins forums on the net and make the decision yourself. I'm just saying what is available. I think the Tuenr was about four hundred dollars or less. They reset the tunen for me when the check engine lite came on when accelerating hard up a ramp towing.The torque converter clutch was unlocking( the weak link) behind the excellent 7.4 international Diesel and was nothing to worry about. In tat particular set up again I would adapt the later 6 speed trans and stouter torque converter behind the 7.4 diesel.
The larger intercoolers, radiators, and trans coolers, may not be required with a mild tune. Depends on how small your engine is now etc. The exhaust with cat and or the pig the pig p--- injectors( sorry can't think of the name) may be little different. See what the forums say unless someone come here with info where they have done it.

I put a Banks GitKit on my 2000 7.3. It was expensive, but I managed to save a ton on labor by installing much of it myself. I started with a turbo saver and that was a great convenience item. Next was a tranny controller and air brake. That was a definate upgrade that was well worth the money. Next I built the air flow part. Intake and exhaust upgrades, then the engine tuner. Next was the high performance turbo wheel, waste gate actuator and gauges for boost, egt's and trams temp. There were marked differences in every step.
The engine performed well before I started but these definitely "woke it up". The low end performance was way better. The engine was much, much more responsive to the throttle. Long hard grades like the gauntlet and Loveland passes was much easier with seemingly less effort from the engine. My TT weighed in @ 9000# and was 11' high.
I did have to replace the transmission at 110,000 miles but was told by almost anyone that that was about the lifespan of it anyway, so I don't think the kit had anything to do with it.
All in all, I think it was worth the cost. I gained some fuel economy although not nearly enough to cover the price of the parts, but that wasn't the goal to begin with. I did have huge performance gains, which was the goal.
Guess it just depends on what kind of results you are looking for and what you're starting with.

You really should research your particular engine/system and find out where the choke points are. You can save money by only changing what really needs to be changed. I did one change at a time so I knew for sure what helped. The first thing I did to my 03 was go to 4" muffler. That was a no-brainer for that truck because the eom muffler hissed like it got smashed in. The turbo on my year 5.9 was a terrible bottleneck and going to a larger towing turbo (not a racing turbo) made a huge improvement. Then adding fuel was icing on the cake. Craig

1999 7.3... re-chipped the computer--- not much change... change to a diff air intake and Banks monster exhaust--- like night and day... no point dumping more fuel in there if it can't get out... think about the engine as being a big air pump.

We had motorhomes for 17 years both gas and diesel. The biggest bang for the buck was increasing the air intake from 4" to 5" and adding a performance muffler.

Getting a lot of air into and out of those engines improved our fuel economy by .25, cooled the engine on climbs, and made it a tad bit quicker on starts.

A side benefit was climbing grades....our mph increased from 45 to about 55mph.

I looked at K&N filters, but was concerned about the dirt passing. But there are high flow filters that clean as well as stock filters. The biggest gain was the muffler.

First off, it weights 1/4 of the stock muffler and it's straight through design was very apparent in performance. It increases the noise slightly, but the wife wasn't bothered by it. And that's always been my rule of thumb. :)

I put an MBRP muffler on our last ISC, but there are also Magnaflow and Aero to name others. We also used a high flow filter, but I don't remember the name. It was one of those that were on the filtration test report a few years back. Be careful with K&N and AFE.

Just my .02 worth.