Although ive been a regular here on the site, i am a newbie to the 12v and i would like to share what i have learned so far.
Lets start with the Achilles Heel of the 12v motor: the Killer Dowel Pin or KDP. It is used in the assembly process of the timing cover, and is simply pressed in. It will eventually fall out and can wreak havoc on your timing gears. Failing that, it will simply drop down into your oil pan in which case your one lucky person. You can fix this several ways: have your dealer do it, do it yourself with a bolt and a fender washer that's been modified, buy a kit from your Cummins Dealer, or buy a kit from a performance site. perhaps some of our friendly local vendors can get them.
http://www.dodgeownerforums.com/smf/index.php?topic=13711.0 The first thing to go about getting power is getting gauges to monitor your engine. A Pyrometer and Boost gauge are necessary for all rigs, while a tranny temp gauge is advised on automatics. You should never let the Pyro exceed 1250* for very long, or you will melt something. With stock headstuds and gaskets, you should not exceed 45 lbs of boost (if you are running reasonable timing) or you will blow a head. You may also want a fuel pressure gauge. They aren't necessary, but they do help in diagnosing some of the problems that come up concerning the fuel system. To address the head issues, you will want to buy some head studs and possibly O-ring or fire-ring the head as well as a thicker gasket.
If you have an auto, you will want to at least get a new torque converter and valve body, if not buy a fully built trans. Suncoast and Goerend are two good brands for strong auto tranny's. If you have a manual, you will need a clutch like one from Southbend or Valair.
link to follow
Next will be the mods to the pump itself. You will want to grind the fuel plate, or maybe just buy one from a performance shop. Dynomite Diesel Performance
www.dynomitediesel.com Banks
www.bankspower.com and TST
www.tstproducts.comall make aftermarket fuel plates. Here are some installation instructions:
http://www.dodgeownerforums.com/smf/index.php?topic=13754.0If you decide to change the plate, just replace it instead of grinding it with the same process otherwise. Some people prefer to just take the plate out altogether and let the AFC control fueling. (this scares me)
Another good mod is the governor springs. WARNING: IF YOU RUN THE ENGINE AT MORE THAN 3200 RPM YOU RUN THE RISK OF FLOATING VALVES. You can avoid this by purchasing a set of 60 psi valve springs. The stock setting allows the engine to rev to 2750 RPM, but they start to defuel at 2250 RPM or so. You can tighten down the stock springs 3-4 clicks, or shim the springs as described here:
http://www.thedieselgarage.com/forums/showthread.php?t=15634for cheap and get fuel to 3000 with revs to 3300. There are also 3K, 4K, and 5K Governor Spring Kits for sale by performance shops too. A 3K will fuel to 3000 and rev to 3400. A 4K will fuel to 4000 RPM and rev over that. 5K GSK's are for pullers and require extreme modifications to the engine to not be damaged. If you feel like you want the 4K GSK, but don't have the valve springs yet, buy a 4K and leave the smallest spring out. It will run like a 3K. You can use the instructions for shimming the springs to change them.
Another item that could use modification on the pump is the Delivery Valves. Stock DV's on 96-98 autos and 94-95 rigs are 131's. Stock on 96-98 rigs are 181's. There are also 191's, and there has been discussions about using 131/181 hybrids, although the gains are small. Beyond that, there are 022's, 024's, and full cuts aka laser cuts. There are some more, but these are the ones you will usually find on most rigs. Laser cuts don't have shoulder material like the other ones, so they turn off the fuel gradually rather than instantly like most DV's. They smoke more and run hotter, not to mention the loss in economy. DDP and some other performance manufacturers also have their own style of DV's
Staying on the pump, next will be the Air/Fuel Control or AFC. This unit is set up to give you so much fuel per pound of boost. The Starwheel is located under a hex plug on top of the AFC unit. Tightening it increases the amount of boost to get a certain amount of fuel. Loosening it will give you more power sooner, but at the cost of smoke (if you think of that as a cost). The arm that hangs down can be modified by grinding the foot of it flat, as well as the front of the barrel on the AFC arm. You will also need to disassemble the AFC and grind the cupped washer flat to achieve maximum fueling ability. You can also purchase different springs to put in the AFC for adjustments to fueling potential.
After you've modified the Fuel Plate and AFC, you may want to get a 2095 Rack Plug aka Mack Plug. The 2095 plug has a 2mm deeper well than the 2000, allowing the rack to travel further increasing power. You can get one at your Cummins dealer for about $15. They will provide a greater increase in horsepower if you already have more power to begin with. 500hp motors will gain about 20-30hp, while 300hp motors will gain only 10-15hp. Again, this only works if you have an aggresive or no fuel plate and a modified AFC.
One last mod to the pump is timing. Stock timing is 12.5° in 94-95's, 14° in 96-98's. You can adjust it to 16.5° with the stock head gasket. You could go up to 20° for daily driver applications with head modifications, and I've heard as much as 32° in dedicated puller/drag setups. Advancing the timing allows better economy and more power, as well as where in the RPM range you get the most power. More timing moves the powerband higher in the RPM range.
Next we'll talk about injectors. Stock 94-95 autos are 160hp. 94-95 manuals are 175hp. 96-98 autos are 180hp. 96-98 manuals are 215hp. There are also 300, 330, and 370 hp injectors from Bosch. But there are lots of choices. The larger Bosch injectors are designed for marine applications and don't have the correct spray pattern. Running them won't hurt your motor, but they haze at idle, smoke a lot, and run warmer than comparable size injectors of other brands, which is why they are so cheap to pick up. New Era
www.neweradiesel.commakes correct spray 370's as well as 435 hp injectors. DDP stage 3's are like 370's, and DDP 4's are like 435's. To get the full horsepower out of bigger injectors, you will need more air. If you add too much fuel without more air, you drown out the fire.
Once you get the pump going and some bigger injectors, you may find that your fuel system can't keep up with the demands. The stock lift pump will only take you to about 500-550hp. One of the more popular options is to purchase a Fuel/Air Separation System or FASS. FASS pumps have higher gallons per hour rating, and they ensure that no air is sneaking into the system through the fuel. Another option is AirDog lift pumps.
Next on the popular mods are turbos. High Tech Turbo
www.htturbo.com Holset
www.holset.co.uk Banks and many others make turbos. Stock turbos are Hx35's, but some 94's may have the WH1C turbo off of the 89-93 models. For simple adjustments, you can adjust the wastegate for more boost or add a boost elbow or manual boost controller. A boost elbow delays the pressure getting to the wastegate, allowing more boost to build before it opens. A boost controller is a spring loaded valve that can be adjusted to stay shut until a certain psi is made which then lets the pressure go to the wastegate. You may also wish to drill the divider out of the exhaust housing to equalize the drive pressure between the front and rear cylinders. Some people also purchase 14, 16, or 18.5 cm exhaust housings. While you may notice a bit more lag, you will be able to lower your EGT and drive pressures. You can also buy a 60mm compressor upgrade to make your turbo into a HX35/40 hybrid. These are basic mods to a stock turbo.
New turbos are rated by compressor inducer size, exhaust turbine exducer size, and exhaust housing size. The stock HX35 is called a 54/58/12 as in 54mm compressor, 58mm turbine, and 12cm exhaust housing. A common upgrade, the Schwitzer S300g, is a 57/65/14 (a great towing turbo by the way). Some of the bigger daily driver turbos are the Phatshaft 62 (62/65/12) (another good towing turbo) or the Super B Special (64/71/14) and even the mighty Silver Bullet (66/74/14). Some of the popular larger turbos used in a compound set are similar in size to the HT3B (74/80/26). A common 600-650 rwhp setup is the stock HX35 over an HT3B, and it works well for towing, competition, and best of all it's cheap!
To make it breathe, you will want to upgrade your intake and exhaust. You can simply straight pipe it by cutting out the cat and muffler and inserting a piece of pipe. Most people upgrade to a 4" turbo back system. Diamond Eye, Flow-Pro, and Aero-Turbine all make low restriction exhaust systems with flow-though mufflers. If you have to have a cat and muffler, you can take them off, cut a hole in the top and gut the insides to remove the restrictions. Then weld it back in place and put it back in with the weld on top so nobody can tell from just looking at it. It is also possible to run stacks, which you can get from
www.blackclouddiesel.comThere are also lots of other performance parts. For intake, don't waste money on a cold air kit. Buy a Big Honking Air Filter, or BHAF. Wix, Napa, and many many more companies all have them in parts #'s. They flow about 3 times the air of a stock box. You will also want to get an Outerwears prefilter for them
www.outerwears.comFor the big boys, you may want a bigger intercooler but it's not necessary until 550+ horses or if you have issues with high EGT while towing.
I have already begun modifing my 12v and I have an extensive list of things todo. I will chronicle my adventures.
Wish me Luck!
BTW I jacked most of this stuff from other sites! but i am trying to get everything in one place so its easier to find.
Topic: 12v hp modifications (Read 6524 times)