I have owned this truck for almost three years now and have never done anything to upgrade. This is what I have so far. It's a '93 Power Ram 250, 4x4, LE, extended cab, automatic, 102K miles. Upgrades made prior to me buying it were a US Gear exhaust brake, Reese fifth wheel and gooseneck hitches, trailer brake control, 7-pin trailer wiring to rear and inside bed, aluminum american racing rims with 285s and transmission cooler. I love the truck but everyone is upgrading performance and their trucks are a lot faster than mine. The only problems I have ever had was the transmission wouldn't shift right (throttle position sensor-adjusted and works fine) and the limited slip differential seems to bind once it's warmed up.

I figured a good place to start would be the exhaust. I have concerns that the exhaust brake will restrict flow if I upgrade the size of the exhaust being it is a 3" input and output on the brake unit. Should I take the unit off the truck? I've tried using it before and it doesn't seem to do anything with my auto-transmission.

Ideally I would like to increase performance and fuel mileage at the same time. I currently only get about 14mpg in stop and go traffic.

I have no gauges other than those that are stock. Are there any I should add and why?

Advice is appreciated.

 

Welcome Jason! Nice to have you here. Go to your user cp---can be found at the top-ish left of this page---and fill out your signature so we can see what you have everytime you post. Makes it easier for others to give advice.

Moving on to the mods. Exhaust. Yes, the e-brake is almost worthless on an auto-equipped truck. It's really the lack of lock-up torque converter in the 1st gen autos that's hindering the e-brake from doing its job effectively. From what I've read, 3'' pipe will support close to 300 HP, so it won't kill you right away to leave it in place. www.sourceautomotive.biz offers a reasonable 4'' system for us 1st genners. Your goals of power and economy are on par with everyone who's been at the top of the slippery slope looking down......savor the last few moments you're capable of keeping a straight face while driving---the dopey ''lets take the truck for another ride, honey'' grin is ever quickly approaching.

Gauges:You NEED a pyrometer before any fussing with the pump. Why? Because even the itty bitty VE pump can push enough fuel to melt down the mighty Cummins and that repair bill will be more than the truck is worth. Get a pyro.

Since you have an auto, you NEED a temp gauge for tranny fluid. Why? Even a slightly modded Cummins will push tranny temps to critical limits, especially when towing. Once the fluid is too hot, it breaks down...and so do you.

Boost gauge: you don't NEED one, but they're very helpful for tuning and just plain fun to watch!


Take a look in the 'tech facts' section. Read through the 1st gen stuff and pop back in with more questions.

Welcom to DTR!

Greg

 

BHAF and an Exhaust will increase mileage right away. BHAF is a large filter and some sheet metal to hold it (I have a pic of mine in my galler, look at bumpytruck's pictures for plans). For the exhaust I removed the muffler and tailpipe and rerouted it out the side. I'm Cheap!. A 4" would be better. You can do these two mods before the pyro but thats it. Next mod would be Pyrometer.
After that the governer spring. This will cost $15. A governer spring will have your truck pulling hard all the way to the shift. Then start tweaking the pump. Remove the full fuel(power) screw and cut the stop collar off. Give that two turns in for starters. Turn the AFC adjustment screw down 1-2 turns(this helps slow spooling). This will be a major transformation at this point. From there you will have a better idea of what to do next. Enjoy

 

The exhaust brake isn't going to hold you back until you start making serious (300+) HP, but as was mentioned it doesn't work too well on an automatic. I'd suggest selling it to help pay for performance parts.

Put the guages in first and play with the pump if you want power. Exhaust and intake will not make enough power for you to feel. Don't get me wrong, you will need to upgrade them later to lower the EGT's, but if you slap a 4" exhaust and a BHAF on a stock truck you will feel like you just wasted $500.

 

I appreciate the replies. My main interest is economy without loss of power. If I can accomplish this through intake and exhaust, I'll start there. If it won't make a difference without performance upgrades, I'll start with performance. It sounds like I definitely need to get rid of the exhaust brake. I was looking for 4" exhaust but most of what I found started with 3" or 3 1/2" and merged with 4" pipe. I would think that would not be any better than the smallest section of pipe in the run. I was researching and it seems one of the first things I should do is replace the stock tubo housing with the 16cm housing? I'm afraid to mess with the fuel flow adjustment due to the fact it seems to cause me to make other adjustments for smoke and idle. I looked at the VE pump on my truck and it seems to be slightly different from the photo's I've seen. It looks like Dodge may have added some electronic monitoring parts to the top of the injection pump. I see a wire harness and other indicators. I want to turn it up but I'm hesitant without knowing what I'm doing.

By the way, I'll post pics soon.

Thanks,
Jason

 

That mess on top of your pump is the throttle position sensor. Nothing to be scared of, but it's gonna take an auto-equipped member to tell you how it works...I think it's for controling overdrive. As for pump tuning, look in the 1st gen section of tech facts and do some reading there. You'll find some pics and writeups that will help you feel more comfortable around your pump. Remember, as long as you make note of where you started, just about every 'mod' to the VE pump can be undone, usually by turning the screw/wheel/pic etc. back in the other direction---the VE is a tinker-er's paradise!

 

The exhaust question: think of it this way: Would running a piece of 3" pipe straight out the hood be less restrictive than all the way back behind the rear tire? In other words, anything will help. There are several places with 4" all the way, like Here and Here (lists them as diesel headers)

I was hesitant to adjust the pump too, but once you do it you realize how easy it is. If you need an explanation at any time of the TPS or how to adjust the pump, send me (or any number of other helpful DTR members) a PM.

 

The first thing you ought to do if you want better fuel economy is advance the timing. That will help with the mileage more than anything else.

Intake and exhaust are good investments for fuel economy, especially on the highway. The less restriction the engine has to work through, the more effecient it will be. Like gman said, freeing up any area of the exhaust helps some. The classic low budget/free performance exhaust on a 1st gen is to cut the muffler off and take the last 90 degree bend from the tailpipe and run it out in front of the back tire.

Turbine housing selection depends on what you use the truck for. Is this a daily driver/play toy or a tow rig, are you always in local traffic or mostly out on the freeway?

Don't be afraid of messing with the pump. Take your time, read what's available and ask questions until you understand what each adjustment does. Then you will be able to adjust on the pump like an expert the first time, instead of leaning by trial and error.

As long as you pull the TPS and its bracket off as a unit, you will not mess up the TPS adjustment. Just pull out the three hex head screws on the top of the AFC, lift off the TPS/bracket assembly and lay it aside, and your pump will look like the pictures.

 

How do you do this and how does it help with fuel economy? Would cutting my exhaust back in front of the rear wheel make that much of an improvement? I did notice several folks on this site made the same modification instead of replacing the exhaust. I use my truck as my daily driver, to and from work and most of my errands. I have a lot of stop and go and an equal distance on open highway. How much does intake help? I have the stock air intake housing with a steel cage K&N style filter.

Jason

 

A cheap intake would be cutting 2" holes all around the stock airbox. We call this a swiss cheese or shotgunned box. You can also just remove the airbox cover and run an open element. A mufflerless sidepipe can be pretty annoying at times.

 

hey jason...
I'm in pretty much the same boat as you--newish (to me) truck, looking to increase economy (and power, if it won't hurt). Search timing advance in the 1st gen forums, it'll tell you what you need to know. Hardest part, for me anyway, was finding the dern wrenches. had to go to the flea market. After that... it's cake. If you find any killer deals on exhaust systems... let me know.
mike

 

My exhaust consists of stock down tube-4" 3rd gen intermidate pipe and a 4" 2nd gen muffler and tail pipe. I was lucky enough to be given these parts from another group I belong to. They gave me these items becuse they upgraded to stacks.

ask and ye may find,

Michael

 

You loosen up the injection pump and rotate it towards the cylinder head. Most people go 1/8" past the match marks on the pump and gear housing. More timing makes the engine more efficient by giving the fuel more time to burn before the exhaust valve opens.

A lot of trucks have a crushed tailpipe from the axle hitting it. If yours is smashed, the "shorty" exhaust will help a good deal.

If you tow, the 16 cm housing would be a good upgrade. It will help your in-town mileage without being restrictive. If you don't tow, you will see even better mileage in town with a 12 cm wastegated housing off a 2nd gen. The 12 cm will hurt highway mileage when towing, or if you drive at very high speeds most of the time.

Intake helps the same way exhaust does, it reduces pumping losses. The drop-in K&N flows well enough, but a BHAF would get a bit more dirt out of the air.

 

I had a drop in K&N with a "modified" air box and then I switched to a BHAF with a old smokey mount and I actually picked up about 1mpg and that is verified over about 2k miles.

Its funny cause I just filled up for the 2nd time since then to confirm my 17mpg and couldn't remember what I did to pick up the extra 17mpg average untill now.

 

How much of a difference (mpg) did you all get from tweaking the timing? More or less power or same?