Thread: 318 truck mods??

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Greetings all:
I have a 98 short box 4X4 with 318 & less than 100K on it. I would like to get some more power out of it without doing any major engine mods or breaking the bank. My thoughts for best bang for the buck are:
1) cold air intake
2) keep a single exhaust, but increase the diameter after the cat & add free flow muffler

I had also considered the following but was given some negative vibes by friends
1) add a throttle body spacer and or bored out throttle body - was told this would give better air flow but wouldn't do anything for adding more fuel & thus probably wouldn't give much HP gain
2) add headers - relatively expensive add on for not a great deal of added power when dealing with fuel injection & computer
3) modify the computer by using either **pertech or *et modules = was basically told they work well for diesels but aren't worth much for gas engines (& way overpriced)

Sounds like there isn't much I can accomplish with the FI 318. Is this true?? Any thoughts on how to get more out of this setup & a guesstimate of cost and power gain would be appreciated

Thanks

'without doing any major engine mods or breaking the bank"

Not possible.

My eldest son has the 5.2L in his shortbox, and has had the same desire to get a bit more power.

He added a cat-back system - seat of the pants says more noise, same power. I suggested that he pass on anything to do with the intake system since it's the same parts group as used on the 5.9L (throttle body, injectors, manifold, etc.). My guess was that there would be no improvement with most replacement parts. With the 5.9L being 13% larger there should be an adequate amount of reserve in place.

He's saving his money for one of the upgrade EPROMs for the computer, hopefully it will make use of the surplus in the intake system.

Regards, Mark

Well, you can't go wrong with the CAI...not too expensive, gives you a little more power.

With the magnums, you've got a couple of obstacles to making more power though.

1. The beer barrel intake: That thing is done making power by 4200rpm on a 318. Best bet is to plan on doing a new intake gasket (common failure for magnums...look for oil down the throttle body to see if it's failed) and either going with a modified beer barrel (preferred for your goals imo) or going with a mopar m1 single plane intake (not a bad choice).

2. Throttle body: It's a little small for making best power. Don't worry about going bigger as TB's ARE NOT CARBS! They don't meter fuel, so going too big won't effect throttle response nor fuel mileage negatively. With a TB you can only go too small really...it would take a monsterous TB to be "too big". What it DOES do is remove restrictions in intake air flow during higher engine speeds....this "frees up" the engine to make HP at higher rpm's.

BTW, spacers will do little if NOTHING for your truck.

3. The down pipes to the Y-pipes are a big hinderance to making power as well. Will they aren't great on Rams, they are really bad on dakota's. You can get away with having new pipes and high flow cats run to a new hi-flo y-pipe,...but your best bet is to just get some long tube headers and new Y-pipe or duals with new hi-flo catyletic converters. BTW, don't go with "shorty" headers...NOT WORTH IT, only long tubes will do!

These three mods combined with ECU mods will do wonders for your magnum powered ram. This is the basic recipe I outlined for a friend of mine with his dakota RT. He went from a 15.0 in the 1/4, to a 13.7...and got better mileage to boot. (Of course, now he's done several other chasis mods and is lower 13's...on the stock CAM!)

The mods above would probably get that 318 from a stock 230hp to about 270 or so. This might SEEM high, but remeber...we are markedly increasing the engines ability to breath and REV. The HP gains come from it's ability to make power beyond 4200rpm and up to around 5000+...torque would only increase marginally.

All the above would probably run less than 2G's...probably more than you were looking to spend.

If it was my money and I didn't want to spend a whole lot, I'd just do the CAI and retune the ECU...maybe include a TB as well. That should give you a few more HP without breaking the bank.

There IS alot you can do to get HP out of the magnum engines...just very little of it is really cheap

Thanks Uglyvaliant - that's the kind of input I was looking for.

It appears you believe that one of the aftermarket programmers are of value (Jet or Hypertech - which one?) or is there a mopar option?

If the engine approaches 270hp wil there be any problem with the stock injectors not being able to supply enough fuel leading to a lean condition? Any idea what hp the stock injectors will support?

Thanks again

I' personally lean to the Jet's. The Hypertechs aren't bad and I like the ease of going from stock to mod, and back to stock and the overall flexibility of the hypertech based on the mods you've got...I just think the JET gives you a better more complete package when all is said and done.