12 valve cummins upgrade ?

khwrx

Active Member
Joined
Dec 10, 2006
Location
lincolnton nc
hey guys, i got this 94 dodge cummins. im wanting to so some upgrades. im wanting to know what you cummins guys have done and who works on them around the hickory/ lincolnton area.
this truck is a manuel trans too , its completly stock except for some stacks installed by previous owner.
 
Turn the fuel up :Rockon:
 
Fuel plate (ground stock one, or purchased)
3k governor spring kit
adjustable boost elbow
adjusted AFC
intake/filter
injectors
gauges(pyro and boost)

I think this is what Hurley had on his '95 to dyno 332 wheel hp. Pretty much the max most people would go for on the stock turbo. The sky is the limit once you get into bigger turbos.
 
If you do any mods at all to the motor, start saving immediately for a replacement transmission.
 
does he have to worry with the nv4500 (i think it is) My friend had one with alot done to it on a stock tranny. Upgraded clutch flywheel and input after a while but the tranny itself was fine.
 
The NV4500 will survive until you start getting up to like 500+ HP. The clutch will need upgrading.

If you like turning wrenches to get power the 12 valve can be a mechanics dream. You can do a few things cheap and easily get 100 hp extra. If you do anything at all to it GET GAUGES.
 
thanks guys, i have be reading up on the cummins. i think im gonna do a fuel plate and 3k gov springs to start with and some gauges. are there some cheap tricks to get some power?
 
You can do a homebrew 3k kit by installing certain sized washers in between your gov springs and their seats(not 100% ideal, but works just fine). Grinding the fuel plate, and cranking the AFC a few clicks are all of the essentially free things I can think of off the top of my head. Boost elbow is really cheap as well.
 
- 35psi max on the stock turbo. dont let anyone else tell you otherwise - anything higher makes no appreciable gains.

- something that is free is pulling the turbo, removing the exhaust housing and drilling out the wastegate opening through BOTH volutes with a 15/16" bit. this will even the drive pressure between the front and rear (3) cylinders and bump up the 'gated flow some.

- A hand fabricated intake "horn" to replace the cast unit is also an upgrade. 3" mandrel bent exhaust tubing, duplicate the bolt pattern on a 1/4" plate and weld that shit up.

- keep the stock delivery valves if you stay with the stock turbo. grind the fuel plate flat (to a "0" profile), set it full forward and then adjust starwheel tension to get the best boost response. A good setup on a 160 horse engine should result in a pretty good haze... if it's belching solid black smoke with the stock turbo, you're doing it wrong.
 
whatever you do, do not block off the wastegate. Apparently the guy before me did that to the turbo in my truck and now i am having to buy a new turbo.

I thnk the most noticeable change will be the fuel plate. i have a #5 in mine and just to see the difference i took it out and put a stock one in and man it was a dog.

If you upgrade the intake make sure to do the same to the exhaust.
 
highrollintj said:
whatever you do, do not block off the wastegate. Apparently the guy before me did that to the turbo in my truck and now i am having to buy a new turbo.
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What happened, what exactly failed? Why are you blaming only the wastegate block off for this?

Just curious, because I've never read anything really negative about this mod. As long as you're keeping the turbo within its spec'ed operating range, there shouldn't be any failure that wouldnt happen otherwise.
 
Once you do the fuel plate, governer springs, turn the afc, and adjust the wastegate you should look into changing the timing. It makes a huge difference on a 12 valve. You can buy the tools from snap on and do it yourself or have a cummins mechanic do it for you. Be careful of who you get to do this though because it can do some damage as easy as it can help. Give Scheid diesel a call and see what they recommend the timing be set at for the mods you have.
 
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