1989 Cummins Modification

Mopower

Well-known Member
The old Dodge I've been talking about here on YT will get a little waking up before it's said and done, but I've read of some limits on these older 12V. Limited boost? Head mods? I'm sure it'll need an intercooled turbo, but what about existing pump, injectors, etc?
 
I had a 91 non intercooled someone had turned up at some point. That thing was a horse. Would out pull my 01 24 valve and laugh doing it. It did have a nv4500 tranny in it though, so i'm guessing the getrag didn't handle the extra hp. It would really beller smoke too. Didn't have an exauast temp gauge. Probably would have scared me. I would suggest buying the 3 gauge set(exaust, boost, fuel pressure) and go from there. I think you can turn those pumps up a good 50hp without touching internals. Doesn't sound like much, but it makes a difference.
 
Your biggest issue with the 89 having the injector pump turned up is your Exhaust Gas Temp climbing.
The main issue I've heard about with your truck in particular is that it can get high EGT's(hot) quickly. Thats why they came out with the intercooled models and have stuck with that ever since. The best mod you can start off with is an intercooler. BEFORE you do any mods, get gages. EGT, boost at the least.
IF you dont do that, you'll likely fry some pistons with the pump turned up, and your stock clutch won't hold up.
You want the boost gage because with more added fuel you NEED more boost pressure to help keep those EGT's in check. But, your stock turbo is limited. I dont know about your turbo for sure, but on my 97 the stock turbo is not designed to go over 35psi. I will never replace it with anything but stock because I wont be pushing over 350 horsepower(800 something ft-lbs torque).


Lastly, and I hate to sound like a pessimist here, is the older 3/4 ton trucks were equipped with an inadequete rear end. If your rig is a 1 ton dually, you may not fall into that catagory but I'm not sure. They used to put Dana spicer 60's in the gen 1 ram's with the cummins and they learned quickly that it wouldnt hold up.

My rig : 97 Ram 2500, 12v Cummins, P7100 injector pump with #10 plate full forward. Boost elbow cranked up to 35psi. Big air filter, 4" exhaust. Beefed up 47re auto. Boost, EGT and tranny pressure gages.
Approx. 250hp 525ftlbs
 
Thanks for the info. I believe my rear end is a Dana 80. No worries there. It's looking like I can coax a nice 50-75 horses out of what it is now, but gauges are a must and an intercooler is a good possibility.
 
Yea gages are a must especially EGT. You may find your EGT's tough to keep under control when using that power without an intercooler. You can get a boost elbow for the waste gate but dont push the stock turbo over 35psi. That boost is a must for increased fueling.
 
This is a learning process. I like the mechanical simplicity. I'm currently running a 1995 F250 5spd 4X2 7.3 Powerstroke at about 325hp with no intercooler. It's simply just better injectors, full 3" exhaust from turbo back, and a mild program that will soon be bumped up to several settings with some gauges. It does a great job even though it's a beater. It's not the simplest thing to work on. I can see driveway on both sides of the old Cummins when I lift the hood.
 
I'll second pretend. One thing I will add is the intake elbow is very restrictive. Buy the 4" exhaust from the turbo back your going to needed it anyway. WHEN you get your EGT gauge put it in the manifold before the turbo.
 
All this can be found if you look around the DTR forums.

1)make sure you are getting full throttle travel at the pump. The throttle cable and bell crank can get loose/stretch and not give you full travel at the pump lever. The bell crank isn't needed on a manual but they put it on for commonality between the manuals and automatics.
2)366 governor spring. Stock RPM is limited to about 2700 where it defuels rapidly. The 366 will take you to 3200. Guys say they get better fuel mileage even with the higher RPM capability.
3)M&H timing spacer. Goes on under the KSB on the side of the pump. It gives you more timing at the top end for more power on the same fuel, without giving up anything on the bottom as you would by bumping the pump timing.
4)powerstroke intercooler. I'm not sure for which years but there is one that fits fairly well behind the bumper.
5)BHAF (big honkin air filter)
6)fuel pressure guage and use parts for a second-gen (94-98) piston lift pump to mod the first-gen piston lift pump for more flow at the lower pressure required by the VE.

These engines usually were a little hotter than their ratings. Diesel Power Magazine's "project rust bucket" was put on the dyno for a baseline and was putting 170 HP to the wheels with 20% convertor slippage.

Non-intercooled trucks had larger injectors and higher-compression pistons than the intercooled trucks.

Non-intrcooled automatics came with the 727 3-speed and Dana 70U (70 Utility) AKA Dana71 rear-end housing with 3.07 gears. Manuals and intercooled automatic trucks came with the 518 overdrive and Dana 70 rear-end. Front 4X4 axles were all Dana 60 with front GAWR of 4,000#. Dana 70U with the 3.07's were available in the intercooled manual trucks.

Hamilton and Colt make cams that lower the RPM at peak torque as well.

Get your lights off the headlight switch and on relays. They have been known to burn trucks up, especially pulling a trailer with a lot of lights on it.


Go look around you can find all this and more
here
 
(quoted from post at 12:59:29 12/03/13) Yea gages are a must especially EGT. You may find your EGT's tough to keep under control when using that power without an intercooler. You can get a boost elbow for the waste gate but dont push the stock turbo over 35psi. That boost is a must for increased fueling.

This could be something that is now updated but I thought that Exhaust getting too hot as in a heavy truck application was in a low RPM setting under a heavy load, where the air flow was inadequate to keep temps down as opposed to lack of cooling of the intake air. It has been my understanding that the reason for the use of intercoolers is to stuff more air into the motor by increasing its density by cooling, as opposed to it being an additional cooling attachment.
 
(quoted from post at 14:47:38 12/23/13)
(quoted from post at 12:59:29 12/03/13) Yea gages are a must especially EGT. You may find your EGT's tough to keep under control when using that power without an intercooler. You can get a boost elbow for the waste gate but dont push the stock turbo over 35psi. That boost is a must for increased fueling.

This could be something that is now updated but I thought that Exhaust getting too hot as in a heavy truck application was in a low RPM setting under a heavy load, where the air flow was inadequate to keep temps down as opposed to lack of cooling of the intake air. It has been my understanding that the reason for the use of intercoolers is to stuff more air into the motor by increasing its density by cooling, as opposed to it being an additional cooling attachment.

I would say your spot on.
The intercooler...well.... cools the air. The end result is the engine running at cooler temps.
Also, turning up fueling without increasing boost will give high EGT's. The biggest function of the turbo is to get more air in there helping to keep it cool.
 
(quoted from post at 20:03:26 12/22/13) There was no waste gate on the Cummins in a Dodge application til the 24-valve.
Not true.
Every turbo powered Cummins has a waste gate. They are set at different levels depending on the rig. How do you explain a stock 97 auto cummins being set at 19psi? Where did you hear that they had no waste gate. Doesn't even make sense. Without a waste gate, I could either blow the turbo or not get any boost at all.
 
I have a 90. Please, come show me where to find the wastegate. We'll have a look at the boss' 96 as well. All the wastegate does is let exhaust by-pass the turbine so you don't over-speed the turbo. The 12-valves were governed to 2500 RPM, unlike the 24-valve at 3200, so it wasn't as much of a concern.
 
(quoted from post at 17:08:59 01/04/14) I have a 90. Please, come show me where to find the wastegate. We'll have a look at the boss' 96 as well. All the wastegate does is let exhaust by-pass the turbine so you don't over-speed the turbo. The 12-valves were governed to 2500 RPM, unlike the 24-valve at 3200, so it wasn't as much of a concern.

I'll be happy to take a picture and post the one from my 97 12 valve.
The best upgrade is an upgraded waste gate. But most people like me put in a restrictive adjustable boost elbow to get our boost numbers higher.
The stock waste gate on 2nd gen 12 valves is set to 19psi on automatic rigs and 21 psi on stick shift rigs.
It is very easy to overspeed a turbo on 12 valves if you block off the waste gate completely.
 
I had the turbo off my 90 last summer. NO WASTEGATE! Stock H1C Garrett.

If you're necking down your intercooler tubes to show more manifold pressure you're going backwards.
 

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