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Cummins Engine - Indiana and India

One of my sons has a Dodge pickup with the Cummins engine. I watched the dyno when he got it smog tested in Denver: it managed to deliver 220 h.p. to the wheels. If even for a few minutes, I thought that was remarkable.

I don't pretend to know how much h.p. it takes to move a rig down the freeway, but I'm fairly certain most high power rigs are only delivering a fraction of what the average owner imagines.


Diesel engines are incredibly "over built" engineering wise.They will put out three or four times the horsepower the factory rates them at. It usually will take three stage turbocharging for them to reach maximum potential closely followed by catastrophic failure. Hot rodders will always find a way to build unbelieveable horsepower and break expensive parts. If you want to see the three stage turbo diesels, check out a hot rod tractor pull, they're pioneers and experts in the field of staging turbochargers.
Forgive me, my age is showing.

I never thought that the dowty old Diesel engine would pique the interest of the hot rodders.

When I was messing around with sports cars in the sixties, the engine from the Honda Civic was something beyond our wildest dreams.

Now gasoline engines from Honda, Toyota, BMW and some others that I can't think of now would put fighter plane engines to shame if they were a bit larger.

These are everyday engines, not something that Enzo Ferrari or Ferdinand Porsche thought up.

The first time I ave ever gone 115 miles and hour in a car was when my daughter took us out in her Accord with a V6 on Rt. 70.

Perfectly quiet, under full control, normal conversation level.

It never ocurred to me that anyone would even think of messng with a six cylinder in line Diesel.

I went to the two links posted above. Scroll down to the botton of Cumminsracing.com.

Yup, live fast die young.

I do have a bit more respect for the Cummins BT 6 now. Keep it at it's commercial rating and it is one tough sucker.

In the course of reading, I did some rough figuring. The BT 6 has about 350 cu. in displacement. It will take half of that on each revolution. 175 cu.in is 1.215 cu.ft.

At 3,000 RPM, the engine is passing 3,646 cu. ft. swept volume per minute.

Now the turbo's are compressing air so that the manifold pressure is 80 PS!. at that rate of volume.

As a conservative figure, let's say that it takes 19.5 HP to compress 100 cu ft of air per min. to 80 PSI from atmospheric. This is an Ideal figure from the compressed air handbook. Single stage compression.

That turns out to be a theoretical value of 710.9 HP.

The turbochargers are making way more power than the engine.

That stands to reason, most of the heat of combustion is rejected through the engine's exhaust.

This reminds me of the "Free Piston Engine" The engine didn't do aything but burn fuel in it's cylinders. The exhaust drove a gas turbine for power output.

Maybe the wheels of the dragster should be hooked to the turbos.
Jim, my B 5.9 came from the factory rated at 175 hp. What is kinda hard to understand is this engine is a monster for a pickup truck, but maybe a thing that Lee Iococa came up with. This engine is used all over the word in dump trucks, garbage trucks, city busses and everything else that reqiures a medium duty industrial engine. The engine is rated in the 35,000 lb class. Now when Dodge put this engine in a pickup it had to be terribly derated to keep people from tearing things up. When I reached about 250 hp my clutch wouldn't hold it so had to get a bigger one. The rear axle is a Dana 80 which is a monster rear end. The driveshaft and ujoints are the same as a 2 ton truck. I put in bigger injectors, delivery valves, worked on the pump some and bigger exhaust housing on the turbo. It is a five speed and when I go through the gears at wide open throttle, the pyrometer {That monitors the exhaust temp.} is sitting at 1500*. Pistons are melting at less than that! The boost pressure is 40 psi. The power increase was done with adding air and fuel only, they come as a stroker with high compression {18 to 1 } from the factory. Nice thing about that is the engine thinks it is stock until the petal is put on the floor. All of this was easily done and I could easily have gone another 100 hp but I thought enough is enough. Now before everybody gets after me for doing this to my pickup, let me say I am an old man and drive that way. I simply did it to see if I could. I would never want to go back to stock.
Michael==The old geezer that looks for Mustangs and Cameros
I have never seen an exhasut pyrometer go much over 900 degrees and even then I was reaching for the shut down.

I am way too set in industrial practice for this to sink in.

Do the Cummins Bt's have oil cooling jets for the bottom of the pistons and oil coolers?

I am not accustomed to those on engines of that small size.

At 1,500 degrees, the exhaust manifold is blazing red hot. At that turbine inlet temperature, it is no wonder that the turbo develops more power than the Diesel.

GE makes a sweet little helicpoter engine. Maybe we should just say "screw it" and go get one of those.

!500HP, no outside cooling system and much lighter to boot.

No tansmission needed either.

One hell of an exhaust pipe, though.

This has turned out to be a neat thread. And to think all Jimmy started out with is one of his stories about the ugly engines he loves.
I have never seen mine at over 950 deg. post turbo with 45-50 psi boost. At 5,000 lbs (about 2,000 lbs lighter than most Dodges ) I'm going so scarry fast that I have to take my foot out of it anyway. The one time I saw 950 deg. I was going about 85+ mph up one of the longest steepest grades I could find in the Sierra mountains on a hot day.
I have never seen an exhasut pyrometer go much over 900 degrees and even then I was reaching for the shut down.
Please understand I said, "When I go throught the gears". That only takes a matter of 10 - 11 seconds and the truck is doing 90 mph. I'm ready to back off because of the speed {I'm not a speed freek} and the pyro temp. This is driving as though it were a Porshe and not a truck. Hot cars are built for short spurts of power and then your out of it. That is why a turbo'ed car should never be used for towing. They don't have pyro's in them. If I were pulling a long hill grossing 16,000 lbs and lugging the engine, it would melt down within a minute. This is why they now build engines a driver can't hurt unless he is really trying. My experience has been, with the rps at 2,100 I can pull any hill out there with a max load and the pyro won't go over 800*. Cummins says the B will run 24 - 7 at 1200* with no problems, but I wouldn't do it. Believe it or not, I really baby my truck. The last big truck I bought, a 99 Freightliner Classic with the N-14 525 hp, the pyro would only go to about 900*. Yes they have the piston cooling nozzles.
You ask about the rpm at 400 hp and of course I can't find the dyno print out now, must be out in the shop. I did change out the govenor springs and it pulls hard to 3200 rpm. I would give anything to take you for a ride in it. Chevy43, that is what mine weighs is 7,000 Lbs.
Sorry about the delay. The Scout with the 4BT is getting an average of 25mpg. It has got as high as 35mpg on the highway. Our last trip, which was approximately 25% 4-wheeling averaged 24.3mpg.

The Scout isn't aftercooled yet. If it was, the fuel mileage would improve a little bit.

The 4BT weighs about 900# dressed out. In comparison, the 6BT is close to 1200# with all the trimmings.
Actually the 6BT only weighs 905 lbs with all electrics and flywheel and housings - this straight from my Cummins 6BT brochure. That is without the 3 gallons of oil in it. I weighed in at a cummins sled pull at just a bit over 5,000 lbs with my tools and fuel and me in the truck.
This is what happens when your exhaust temps are around 1700*F:


That's a honda F4i engine, sitting on a loading dynamometer.

Justin, is that F4i engine destined for a formula SAE car? That intake restriction looks about right. I was captain of the mini-baja team when I was in school. Fun times. We didnt have the $$ to build and campaign a formula car, but it was a salivating temptation.

I am suprised about the mileage. I had a 97 F250 Superduty (4x4 reg cab) with the powerstroke and an automatic, it was lucky to get 17 empty. I cant see a scout being all THAT much lighter... What kind of mileage do the Dodge trucks with Cummins and manual tranny get?
I really liked my powerstroke, but what killed me was the $20 oil filters and 4 gallons worth of Rotella every couple thousand miles. An oil change (me doing it) was getting upwards of $50. I just couldnt justify keeping it as I didnt use it as a "truck" very often. I sold it before the price of diesel jumped. Now I am somewhat intrigued by the home brew biodiesel from used vegetable oil. Apparently you can make it for about $0.70 per gallon assuming you get the veggie oil for free. All you need is some filters, a mix tank, some lye and 1 gallon methanol per 10 gallons veggie oil. And no taxes. ;)
I am suprised about the mileage. I had a 97 F250 Superduty (4x4 reg cab) with the powerstroke and an automatic, it was lucky to get 17 empty. I cant see a scout being all THAT much lighter... What kind of mileage do the Dodge trucks with Cummins and manual tranny get?
The Scout with the 4BT weighs about 4300#. That's less than it weighed with the Nissan 3.3L TD that it came with.

My 94 Dodge, 2nd gen 4x4 (w/auto transmission), gets 20mpg city or highway. It stays pretty constant. That's even when hauling a small trailer.

My husband's Dodge 92, 1st gen 4x4 (w/manual), gets 15 mpg, but it is also undergeared with 4.10 gears and 35" tires so the engine is running a bit fast. It's more like a brick on wheels. He said it got 19mpg in town when it was box stock.

I expect the Willys to get at least 25mpg in town. The body and chassis should weigh about 700# (best guess) less than the Scout when the project is done.
The 1st gen 6BTs use 3 gallons of oil
The 2nd gen 6BTs use 2.75 gallons (a quart less)
The 4BTs use 2.75 gallons

They all can use the same oil filter, which costs around $10 -- direct from Cummins. We buy them the case since we have 4 diesels to maintain.
Slim, it sure is. I'm not sure how the guys did up in detroit, as I didn't go. But the car was running pretty well and they were getting lots of practice time in, last I saw it.

What kind of mileage do the Dodge trucks with Cummins and manual tranny get?
I really liked my powerstroke, but what killed me was the $20 oil filters and 4 gallons worth of Rotella every couple thousand miles.
My 94 is a five speed and when it was stock it averaged 19-20 everyday driving and on the interstate could get 26 mpg. Weight is 7,000 lbs.
Linda is right, no need to pay $20 for an oil filter. I usualy go to one of the larger truck {semi} supply stores for filters. Walmart has Rotella for $7.00 gal. Do not believe those commercials and the little stickers that the quick change oil places put on your windshield. If your changing oil every few thousand miles your wasting money. Even your owners manual will say 6,000 miles. Fifteen years ago I called Valvoline and talked to a technition about changing the oil in my semi's using semi-synthetic oil. After the parameters were figured in he said safely 25,000 miles. That was three trucks ago and I put 800,000 on each one with no engine trouble.
These engines as well as other pieces of machinery are sold to outside sources, sometiimes the plans but also sometimes the dies and tooling.
The thrid world produces these for domestic use.
In the 70's south america was building 65 ford fairlanes and marketing them as a 70's model.
This also serves the purpose in many cases of allow the orignal OEM to have a access to spare parts without having to maintian the production
What is the consensus on using synthetic in diesels then? I was changing the Rotella oil in my powerstroke around every 5000 IIRC. But it was BLACK, which wasnt too reassuring to a gas engine guy. I have my daily drivers (gas) on synthetic Mobil 1, and I have slowly extended out the changes from 3000 to 7500. It still looks decent at 6-7000, but definitely not looking new.
What kind of mileage do the Dodge trucks with Cummins and manual tranny get?
I don't know about mileage with a manual transmission. I have an '01 Dodge diesel with an automatic and pull a 8000# travel trailer with it. I consistently get 13-15 MPG pulling the trailer (even in the mountains) and closer to 18 on the interstate while not towing.