horsepower = (rpm/5252) * torque

From this equation you can see that horsepower is nothing more than a contrived unit that is based purely from torque and rpm. You’ll notice the number 5252 in the equation, this represents the point at which every dyno graph must intersect horsepower and torque. Its a mathematical relationship, both strange and interesting since horsepower is a function of torque and rpm. There has been much confusion and rumors across the internet about gaining more horsepower. In essence, gaining more horsepower is gaining torque. If you are after “peak” horsepower, you are interesting in carrying the torque curve as high in the rpm range without falling as possible. You can see from the equation that as the rpm’s increase, and the torque remains the same you get a higher horsepower number. What physically is happening is that the engine is able to produce enough torque to overcome frictional forces through the air, tires, etc. As you are able to keep the torque from falling off on the top end, you are able to maintain a steady torque curve that will “pull” the car through the mph you are trying to reach. So people who are after “peak” horsepower really want to extend their torque curves as far towards redline as possible, without letting the torque fall off. Check out some dyno graphs and see what I mean. Horsepower doesn't describe the true nature of how the engine performs, its the torque curve. From a tuners perspective, I don't tune off of the horsepower curves. The physical relevance towards the engine performance is arbitrary, since the torque is truly what is effected by the fuel, timing, breathing, etc of the engine. The horsepower is merely a concocted unit of measure, showing no true characteristics of the engine power output. A good tuner will only make changes from the torque curves, see what increase/decrease the curves show from the changes. So next time you are thinking horsepower, think “what would I want my torque curve to be”?

Here is the formulas I used

Drag

http://www.thefintels.com/aer/dragcalc.htm

Air Density

http://www.denysschen.com/catalogue/density.aspx

Dodge Ram Specs including Drag Coefficient

http://www.pickuptrucks.com/html/ram_specs.html

So using local information and building a test bed on this.

Vehicle - 2nd Generation Dodge Ram 2500 truck

Test #1 Winter (Column C)

Stats

[*]+10*F Temperature

[*]90% Humidity

[*]2,800 ft Elevation

[*]45 MPH (Road conditions locally)

Test #2 Summer (Column B)

Stats

[*]+100*F Temperature

[*]10% Humidity

[*]2,800 ft Elevation

[*]65 MPH

Test #3 Comparing both using both summer and winter conditions. (Columns E & F)

Which this shows roughly 4.659 MPH difference between winter and summer condition will be nearly equal in drag.

Just for fun compare 55 and 65 MPH...

Here is a very good addon that every should consider doing on the vehicles (Gasoline or Diesel).

The Frantz Filter is a depth type by-pass filter in which oil from the engine flows very slowly through a dense filter media and is thoroughly cleaned. Depth filtration (as opposed to surface filtration) is universally recognized as the most efficient. The design of the Frantz Oil Cleaner provides 4.4" of filter media depth  through which the oil must pass. No other filter design  approaches this media depth and resulting efficiency.

Oil enters the filter through the center fitting, flows upward through the center tube and then downward through the filter media. As the clean oil leaves the filter media, it passes through a fine wire screen assembly to the outlet fitting. A 1/16" restrictor orifice is placed in the inlet fitting to control the flow rate through the filter. Because of the low velocity of the oil passing through the dense tissue, it is easily separated from the contaminant particles which are readily disposed of by changing the filter element. The Frantz Oil filter/cleaner protects every precision part of your engine against wear by removing the smallest harmful particles as well as up to six ounces of water.

Mopar's Notes:

Update! - Mounting Configuration

I found out that it much better to mount the can upside down. This will make filter changes less messy. The thing is when it was mounted can side up then when you pull the can upwards to remove the oil would run out everywhere making a mess. With it hung upside down the can holds all the oil and only the tube will drip just a bit. As you can see in the pictures I made a bracket that mounts the filter on the battery.

Alright here is the writeup on how to do this.

The first thing is to try and get as much oil as possible into the oil pan. An engine that has been running recently (within maybe 3 hours) still has a lot of oil all over the engine interior and you need to let as much of this residual oil drain to the oil pan as possible before draining. You can change it right after it has been ran but the engine will be hot and so will the oil, making it a little hard on your hands when oil gets on them. It also leaves old oil in the engine which isn't necessarily bad but why change the oil if your just going to leave some of the old oil in the engine. If you want to do this, let the oil drain for an hour (or even overnight to get every drop). Sometimes it is better for wintertime when oil barely drains so draining a hot engine would be faster and allowing it to drain overnight ensures it all gets out. Keep in mind the new oil should be in a warm spot to easily flow into the engine.

Next step is the oil filter. For some reason they always tend to tighten over time (or because you used a wrench to get it on last time) so you may need to use a wrench to get it off. It really doesn't matter if you damage it since you are going to throw it away anyways, but a strap wrench usually prevents any damage. If you do have to use something intense like channel locks, make sure to grab the bottom half of the filter because you might crush the filter and if it is on the top half, you may damage the filter head threads. Ideally, you should be able to get it off by hand (which is why you put it on by hand). I can always get mine off by hand but they are always tighter than when I put them on (or maybe I'm getting weaker). Depending on the year of truck, you should be able to wiggle it out without spilling a drop of the oil inside the filter, then you can dump the oil in the pan the engine oil is currently draining into.

What you just unscrewed the filter from should be cleaned with a rag. Dirt gets up in there sometimes and it isn't the best idea to smash the new filter's gasket upon debris. I attached a pic of what I am talking about. Make sure the gasket from the old filter is not up there as well, if you forget to check and put a new filter on on top of another gasket, the 2 gaskets will not seal and the oil pressure will blow out between them. I have never had an oil filter leave that gasket behind but you never know, you will know when you forgot to check though..

Now get your new filter and write the current date and mileage on it with a sharpie BEFORE you do anything else with the filter (I did the next steps first and it made it a pain). Next step is to take the gasket off the new filter and get clean engine oil all over it until the whole thing is wet with oil, then push it back into the groove you took it out of. Now you can fill the filter to about an inch before it overflows, this will give you room to play before the oil spills out when putting it back in the truck. NOTE: If you spilled oil all over the place getting the filter out, you probably will spill a bunch of oil on the way back in, so you will have to judge how much oil to put in based on the degrees of tilt you had to attain to get the old one out.

The previous tip about filling the oil filter is not recommended these days because debris can get into the filter/oil during the installation process and that oil is unfiltered and goes straight to the turbo bearings which is not good. However, I still believe it to be better than having the turbo starve for oil for the time it takes the filter to fill up. Just be aware of this and know that any oil that goes into the filter (the big hole in the center) is the same oil that goes out from the filter and into the turbo..the holes on the outer ring of the filter are the intake holes that send the oil through the filter media).

Spin the oil filter on hand tight. I think the filters say go to where the gaskets gets tight as if you had the filter in a free spin and the gaskets resistance stopped it, then tighten 3/4 turn. I get it as tight as I can by hand and call it good. If you don't have good grip then you may need to resort to a filter wrench. This means dry hands dry filter, an oily filter tightened by hand is not exactly the tightest. Over time the filter tightens, I think because the gasket swells or something. Putting it on only hand tight ensures it can be taken off without channel locks or something drastic (hopefully).

After the oil is drained, tighten the plug back up. My manual says 60 ft/lbs, and I wouldn't go a ft/lb more than that! You shouldn't have to take the plug out to drain the oil since it somehow drains out 4 little things on the sides so you should never have to start the plug into the threads, meaning you will never crossthread it. If you do take it all the way out, just make sure it threads in a couple full turns by hand so you know for sure it isn't crossthreaded. Fixing a screwed up oil plug can be expensive and laborous on these things. You can get lucky and thread it the next size up but it's still a lot of hassle for something so simple to not screw up.

Now your filter should be in and tight, oil pan plug should be in and tight, so fill it up with oil. Every truck seems to be different these days so look up how much it takes. 94' 12V's take 10 quarts while 95'-98' 12V's take 11. Put the oil fill cap back on, start the truck, let it run a minute or 2, then turn it off. Check for leaks around the oil filter just in case you didn't get it tight enough by hand. If at all possible, leave it off for 3+ hours on level ground, then go back and check the oil level on the dipstick. Many people start it then instantly check the oil and wonder why it is not at the perfect mark. The perfectly full mark is an engine that has been sitting for a long time on a level ground. An engine that has been running has oil all over the engine and it takes a long time for it all to accumulate back into the oil pan, giving you a false reading until then. The dipstick has 2 marks; a full mark, and an add mark, with "SAFE" in between. The add mark denotes 2 quarts low.

You have now changed your oil.

This will go over fixing the killer dowel pin and/or fixing the oil leaks that the timing cover is renowned for.

I know I have things still on it in the video and did things backwards and stuff but do it the way I list and it will be a lot easier, I just took everything off that I needed to come off but doing it the way I list will save you from having to deal with a few things I ran into or it will keep you from getting close to messing something up

1. Take the windshield washer fluid and overflow tank off of the radiator shroud and set them aside. They come off by pulling in the middle and pushing up. There are connections on the bottom of the washer fluid tank.
2. Take the Fan and radiator shroud off. Fan nut is 1-7/16” and left hand thread (if you are standing in front of the truck, turn the fan clockwise to loosen). The shroud has four 10mm bolts on the sides. The bottom of the shroud has tabs that go into slots on the radiator, so it has to come straight up to pull it out of the slots. The fan and shroud come off together, it is hard to get the fan off by itself.
3. Loosen the six 10mm fan pulley bolts, but do not remove, just loosen them.
4. Take off the serpentine belt.
5. Now you can take the fan pulley bolts all the way out and set the pulley aside.
6. Take the fan pulley bracket off, four 10mm bolts.
7. Take the RPM sensor off by taking the bolts out. There will be the sensor, a spacer, and a wire retainer thing. The sensor has a magnet in it so it will attract to the damper. Just set the sensor off to the side, no need to disconnect any wires. When reinstalling, get a feeler gauge and just let the RPM sensor lay on top of the thickest feeler. 0.030” is I what I used. Try to keep it level with the damper (yes, the damper goes on before you put the RPM sensor back on).

1. Take the damper off, four 15mm bolts. If you have a manual you can put it in 5th and that will stop the engine. You will have to twist the damper and jiggle it around but try to pull it off as straight as you can. Look at the lines on damper, they should line up, if they are off, you know it is worn out. When reinstalling, use locktite and tighten to 92 ft.lbs.
2. Take the bolt that holds the oil fill tube off, the one that goes into the intake manifold. You should be able to leave everything else on.
3. Take all the timing cover bolts out, there are a million of them and some are long and some are short, all should be 10mm. When reinstalling, put all the long ones in first since there aren’t as many. The long ones also have a smooth hole since they have no threads for the first inch. Tighten the bolts to 18 ft. lbs. Make sure you put the cover back on going straight so you don’t mess up the crank seal.
4. Fix KDP, tab it. Clean off the bolt and put locktite on it. Try to dry the hole that bolt goes in.

Scrape off old gasket/silicone and put new one on. I used this international T442 that supposedly will keep it from ever leaking again, so far so good. If you use it you have to get it on quick (within 5 min) and put the cover back on the truck and tighten all the bolts finger tight (should ooze out a tiny bit, you can just use a deep well socket by itself to help get it finger tight). After another 5 min, torque to spec (18 ft. lbs.).

1. Optional: I tapped all the bolt holes to try and dig the old lock tite out. If you want to do this it is an M8-1.25 tap. Make sure to use oil on the tap and blow the holes out and blow the chips off the tap after each hole.
2. Optional: I also wire brushed every single bolt. That way I don’t have all this old lock tite that won’t do me any good and sure won’t help the new lock tite out.

I'm going to cut to the chase. I'm not going to post the instructions included with the Cummins seal kit because it has a lot of stuff you can skip and save time.

You'll need to pull the intake horn and APPS sensor to gain ample room to work. Now I didn't mess with the power steering pump at all. I unbolted it and pull it back out of the way. I would suggest getting a pan or something under before pulling the power steering pump it will spill some engine oil. As for the 4 nuts on the power steering pump they are 15mm nuts.  The 2 15mm nuts on the drivers side of the pump can be removed from the top, where as the 2 nuts on the passenger side of the pump need to be removed from the bottom.  

You can find the vacuum pump seal kit in our store

There is one stud with double nuts which hold the battery cable away from the steering shaft. Now unhook you vacuum line and the oil supply in the bottom which is 9/16 fitting. Now the 2 bolts holding the vacuum pump to the gear case are 15mm as well. You have the upper bolt with a 10mm nut hold the wiring harness as well. Now the vacuum pump slips right out of the gear case.  The upper colt can be removed from the top of the engine bay, the bottom bolt needs to be removed from under the truck.

Now you'll have two 13mm bolts holding the vacuum pump together.

Now take the power steering pump end. You'll need to find a deep well socket that fits within the hole of the shaft so you can knock the power steering pump seal and collar out. Using a rubber or dead blow hammer knock the collar out with the seal.

This is what should come out.

Now you'll need to find another deep well socket and knock the seal out of the collar. Now be careful there is a raised shoulder inside so be sure you're going to strike the seal and not the collar.

Now all you have left is 2 o-rings to remove. One is on the collar and the other is on the main body of the vacuum pump. At this point, you need to clean all your parts with degreaser or brake clean before assembly. While you're at it grab your Cummins Vacuum Pump Rebuild Kit.

Now basically, you just reverse for assembly. Using the same sockets for driving seals into place. Make sure to replace both o-rings on the body and the collar. During all assembly make sure to lube all seals and o-rings will oil first. 

The order of the parts installed into the pump is,

Part number 3 goes in with the rubber oring closer to the front of hte engine.  you will tap in the collar until the bezel is flush with the vacuum pump housing.  The red arrow shows the direction to insert the collar into the vacuum pump housing.

Now I installed the vacuum pump back to the gear case. Now using a 22mm socket I rolled the engine over using the alternator pulley and positioned the slot of the pump vertically so I could line up the power steering pump. Now carefully slide the power steering shaft into the pump. Now if it's lined up properly it should seat down to the base of the power steering pump. If its doesn't DO NOT force using the nuts you will do damage. It should push all the way into the housing and seat with just hand pressure. If you get the pump lined up run your nuts back on the studs. Don't forget to hang the battery cable back on the bottom stud and using the 5th nut. Now you can hook up your oil feed line because you need the room to work to get the nuts back on the power steering pump. Now it just a matter of reassembling all the other stuff like intake horn, APPS sensor, etc.

Torque Specs

Vacuum Pump Body bolts (2) ...................................... 22 FT/LBS (30 Nm)

Power Steering Pump nuts (4) ..................................... 18 FT/LBS (24 Nm)

Gear Case Bolts (2) .................................................... 57 FT/LBS (77 Nm)