I was wondering what my 1998.5 Dodge Cummin's 2500 Turbo Diesel (2WD, 4speed automatic ) should expect for gas milage? its totally stock.

Also is there a chip/programer that i can get for this? or it being all mechanical i can not?? And im very interested in a gas mileage chip if avalable

If i get a air filter does it make a big difference?(everyone says it will)
I've had someone tell me that if i get a air filter kit that i wont benifit from it since i have stock size exaust pipes. he says that they go hand in hand

Also What matenence should i be doing? i know that i should replace the gas filter every year and Put Fuel Conditioner about every 3rd Tank. Any thing else i should know??

 

First answer is a question. Is your truck a '98, or a '98.5? The former is a 12v, and the latter a 24v. That will affect the answers. Assuming that it has a 12v (being as you posted in the 12v section), then its a no-go on chips (Ford thing), programmers and boxes. You'll be stuck with GSK's, plates, delivery valves, injectors, timing changes, etc. Do a search on those and you'll get lots of info.

Don't expect much (if any) power gains from exhaust or air filter changes, unless they are plugged/collapsed. It will help with EGT's, but not much for power. Need fuel and air for power, and unless your exhaust and intake are that restrictive that you are blowing smoke now, you won't notice it.

Fuel filter change is reccomended about every second oil change. I don't run any conditioners/additives in my fuel, but it depends on what your fuel is like in your area.

 

Sorry its a 12valve. Mine isn't a 1998.5 its a 1998

 

do a search-theres dozens of thread on upgrading a 12valve, & pick what suits you best.

 

im not interested in modding my Cummins.

Still want to know about the gas milage, Air intake and Matenence ???

 

So its a 12 valve then? If so u can't chip them and for fuel mileage I don't nodepend how u drive

 

Because you are from Canada I can help on the fuel mileage question! I deal in litres per 100km. You should be able to get as good as 12L/100km with highway driving, not much load easy on the peddle. and as bad as 20L/100km driving like you stole it. When my 94 was closer to stock I could get 10L/100 straight highway driving with the cruise set at 100km/h. That was basically the ideal fuel economy driving conditions...

 

You do realize that some mods will increase mileage, right?

 

yes i do, and i dont plan on modding the truck.

i hear that a K&N Air filter will increase fuel milage. Its going to be used for Hauling Long distance. so i know that the cummins allready has enough power to pull, but i want to know how to make it better on Diesel.

 

You saying that this is close to stock at the time. What was done? and was it better for diesel or would it use more?

And thanks for the info

And Nice Video!!

 

Eh?

 

First of all, welcome to the DTR. This place has a lot of guys who know their stuff.

Be glad... be VERY glad you have the '98 12-valve engine and not the 98.5 with the 24 valve engine. The 12-valve is much, much more reliable and trouble free.

The absolute BEST thing you can do to get great mileage is relax your right foot. How much you push the go-pedal will determine the kind of mileage you'll get. I get a little over 22 mpg on the Interstate doing about 68 mph. I bet I could get 26 mpg if I kept it at 56-57 mph, but I hardly ever do that for long-distance driving.

You do have the 3.54 rear gears? Correct?

The torque curve of the 12 valve Cummins shows the peak torque at about 1600 rpm. For me that's about 56-57 mph if my speedo is right. That is the RPM at which your truck is the most efficient. So if you really want to get the best mileage, keep it at a little over 1600 rpm's while on the highway.

You won't be sorry you got this truck! You should probably get a Shop Manual for the truck. I got mine at the dealer, but there might be cheaper places.

Besides looking through the Shop Manual, your Dodge Truck Owner's Manual will give you all the recommended maintenance schedules. READ THE OWNER'S MANUAL. Sit down and read it from front to back. It will take you a couple of hours, over a few evenings, but you'll learn a lot.

I change my oil every 5,000 miles instead of the 6,000 the manual suggests. And I grease mine every time.

I know you're in Canada, and I'm sorry I don't speak Metric.

I've run a K&N in the stock box for over 200,000 miles. I've cleaned and re-oiled it three times. If you run a K&N in the stock box, you must bed the O.D. of the filter in grease so the grease forms a barrier with the edge of the bottom box. There are many guys who are opposed to running the K&N in the stock box, but my oil analysis shows no contamination.

 

Robert gives some good info there. I'm not a fan of the K&N air filters though--I think they sacrifice filtration for airflow. I prefer oversized paper element filters. In Robert's case though, it's hard to argue with his oil analysis results.

What you were told about a free-flowing intake not providing much benefit without also improving exhaust flow is correct. If you replace the restrictive stock muffler with either a piece of straight pipe, or some type of straight-through design muffler, you'll see a noticeable EGT improvement. As Tate mentioned though, don't expect any mileage gains.

I'm a little confused when you say that you don't want to mod the engine because in your first post you mention you're interested in a chip. What a typical aftermarket chip or box does is advance the injection timing and change the fuel delivery curve (allowing more fuel earlier). You can get the same thing on your non-electronic engine by having a good diesel shop set your injection pump timing to between 15.5 and 16 degrees advance, and by sliding the plate in your pump.

You want to be careful what things you do though, because some of these will raise your exhaust temps and could be a problem when towing or hauling heavy. I bring this up because it sounds like you're not interested in adding gauges.

Maintenance isn't too much different than a gas-engined vehicle. Like Robert, I tend to change my oil at around 5,000 miles, but sometimes I'm lazy and go a little longer. Keep at least one spare fuel filter in your truck. Never use cheap filters, and especially stay away from Fram. I use Fleetguard filters exclusively.

You might consider replacing all the drivetrain fluids with quality synthetics. The transmission and rear end are relatively easy and cheap to do this too. The engine will particularly appreciate synthetic oil if you see really cold temps in winter and can't plug it in. Regardless, for the engine make sure you use an oil that's rated for diesel engine use. Currently I think that spec is CJ (It'll say on the bottle). If you see something like SJ then you know it's not rated for diesel engines. Most people tend to use Chevron Delo 400 or Rotella T, both in 15W-40 weight. I prefer the Chevron oil because it flows better in cold weather.

Anyhow, good luck with your new truck. I really miss my 1992 12 valve truck--it was the most reliable vehicle I've ever owned.

Mike

 

I wanted a mod that was temporary, becasue i would love to "roll coal" every once and a while, but have the choice to turn it off if the next day if im driving in the city. this trucks going to be used for several things (mostly towing) so i dont want to set it permanitally. also i dont want to fittle with this truck. i have other stuff i fittle like my street/drag car

 

[QUOTE=Robert Rausch;2757042]
You do have the 3.54 rear gears? Correct?



Besides looking through the Shop Manual, your Dodge Truck Owner's Manual will give you all the recommended maintenance schedules. READ THE OWNER'S MANUAL. Sit down and read it from front to back. It will take you a couple of hours, over a few evenings, but you'll learn a lot.



I know you're in Canada, and I'm sorry I don't speak Metric.
QUOTE]

I do have 3.54 gears , Sorry i should have said that

A owners Manual didnt come with the truck. i may have to go and buy one

And Metric is fine, I know how to convert