I want to squeeze some mileage and horses out of my '03 Durango. Apparently just by changing the intake will make a world of a difference I have found the Hughes F1 air gap intake and the Mopar M1 air gap intake. Now, I'm keeping fuel injection and really just want to gradually do bolt ons to get a bump in power along with some mpgs.
I don't know much about what can be modified on these engines to bump up some power.
www.thespeedfreaks.net
Mostly GC guys but the engine is the same. Both manifolds are pretty much a waste on an otherwise stock engine. Get a good low restriction exhaust, space the air hat and use a good CAI. Go for an electric fan and underdrive pulleys
Are you talking 360?
M1 intake is good, you'll lose a little bit of lower end (there are some fanatics on the dodge boards who've fabricated "turtles" that sit in the bottom of the plenum and purportedly help with the torque loss).
A lot of folks clean up the throttle bodies, taking away all that extra material around the bores helps them breath easier. Mine's bored out to 53mm. Cold air intake's the easiest quickest bolt-on, but be forewarned that the K&N units always end up cracking around the bolt hole. You're much better off to get yourself a nice piece of 3" chrome and a couple of plumbing connectors (Fermco makes one that fits perfectly - Home Depot $12).
Or a great lookin' Mopar air cleaner to sit on top, like mine
I upgraded my injectors to FMS (Ford Motorsports) - they have a four-hole spray pattern and most of the dodge gurus claim they flow better. Meh, dunno if they do or not, but they bolt right in.
You can also upgrade your PCM (computer) to a Mopar Performance unit... the stock ones have the dreaded "death flash" with crappy, boggy shifts and low rev limiter. Check the forums, (Delphi R/T forum is the best for parts and advice) there's always someone with one for about $200.
I've currently got JBA headers on mine, which have nice thick flanges not prone to warping and leaking. Don't go with any of the ebay cheapies, the forums are rife with guys who bought them and regretted it.
If you decide to open the bugger up, best bang for the buck is a windage tray - cheap and supposedly good for 10-15 hp.
There are all kinds of cams (KRC Performance custom grind quite a few for street and strip, and are really good with advice - they also sell bundled cam & valve train packages). I've got 1.6 roller rockers with teflon guides and hardened pushrods. You can go 1.7s - but you'll need valve covers with baffles in 'em or they get messy.
One easy piece of advice... buy a can of throttle body cleaner. The throttles tend to get carbon build up, which can cause periodic stalling. An easy spray and wipe with a clean cloth will prevent it. 
BoneYard_Racing wrote: www.thespeedfreaks.net Mostly GC guys but the engine is the same. Both manifolds are pretty much a waste on an otherwise stock engine. Get a good low restriction exhaust, space the air hat and use a good CAI. Go for an electric fan and underdrive pulleys
Yeah, a lot of guys just take the stock "beer barrel" and clean up the runners inside. But the really nice thing about the one piece aluminum intake, is that you avoid having to replace the belly pan (made from steel, so it expands & contracts at a different rate from the aluminum manifold and causes blown gaskets and pinging).
I do love a good kegger
Seriously the M1 wasnt good on my GC that said mine is a 318. I now have a slightly ported kegger 53mm TB Dakota RT air horn with. 2.5 exhaust with a cherry bomb. Its great for towing and gets about 17mpg unloaded
Yah, I kinda wish I'd kept mine and got it ported. But the M1 just looks cool 
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Like the others have said, don't bother with M1 for a stock build. I have one on my '96 5.2 Dak. I have a 5-speed so the bottom end loss wasn't as big a deal, but I do notice the difference.
The Hughes intake is based off the Edelbrock RPM Air Gap. Supposedly the MPG benefit is from a better injector position than the stock barrel intake. I think there's still a little bottom end loss, but not as bad as the M1. The Hughes one didn't exist when I put the M1 on. I've been pondering it, but have plenty of other projects to worry about first.
Check your plenum to make sure the gasket isn't blown. If your idle sounds a little tougher than what you thing a Durango should, it's blown and not helping your MPGs. Hughes sells a 1/4" aluminum plate in a kit to replace the stock steel one. We're probably going that route for the 5.9 rebuild I'm specking out for my buddy's truck. Probably going to go with their cam that is one step bigger than the stock Dakota R/T cam too. Anything bigger and it will need a computer re-flash. It's going in a Ram 4x4 so we're looking to build torque. Comp has a couple nice cam choices too.
Freeing up the exhaust can help. I have a Dynomax Ultraflow on the Dak. Had a Flowmaster before. Sounded good, but rotted out. I like the sound of the Ultraflow better. Muffler is under the bed in a Dak so resonance in the cab wasn't bad with the Flowmaster. Something like the Ultraflow would be better under an all passenger area vehicle like the Durango.
Do you have the R/T? That's AWD and will hurt MPGs. Swapping out to a NP231 part time 4WD transfer case would help. But that's getting deeper than simple bolt-ons.
Lesley wrote: Yah, I kinda wish I'd kept mine and got it ported. But the M1 just looks cool
Yea it does look cool. But if you want a stock one to port let me know. I have a couple on the shelf.
Rob_Mopar wrote: Do you have the R/T? That's AWD and will hurt MPGs. Swapping out to a NP231 part time 4WD transfer case would help. But that's getting deeper than simple bolt-ons.
No, I have a regular Durango SLT. It's my wifes truck, but will eventually become mine when it's time for a new car.
Also, The Hughes F1 is supposed to be a stock replacement, but will also help out in any form of engine modification.
I've been following this guy for a while on his Durango build and I like the route he's gone with the engine.
Hah, that's cool... he talks about the "dead spot" being cured by new 24lb injectors... I have a new set waiting to go in. Glad to hear that they'll help!
Thanks Rob, nice idea, but I'd probably never get around to doing it :-)
Vaccuum gauge, more vacuum, less throttle. Less throttle, less fuel. Easy peasy. Ian on Xtreme 4x4 has been doing something like that to his personal truck, and is up to 13mpg with 37's and 4.56 gears. He's been doing it over several episodes, been a pretty cool project.
Your biggest holdup, IMO, is the PCM. It is "junk" from the factory, programming wise, and the AM solutions, including the MP PCM, are marginal at best.
More air OUT will lead to the biggest gains. Normally the Chryslers I have dealt with are fairly decent on the intake side, besides the TB, and abysmal on the exhaust. Camshaft designs are stuck in the smog-era 70's. But changing out the cam leads back to the handicap of using the stock PCM. Cylinder heads are about the same as the cams, but do flow some air. They are handicapped by a detonation/pinging combustion chamber and piston.. So you can't run a lot of timing to make power.
There's a company out of Michigan, B&G that will re-program a PCM to work with whatever modifications you've done. Because the 5.9 wasn't available in Dakotas in 97, I had to get a 5.2 PCM and have it reflashed. Tried several different 5.9 computers - even a MP Ram unit, but none of them would run the gauges. Most of the serious guys just use standalones now. I've got a 3" exhaust from y-pipe to tips, with a Borla muffler. Sounds pretty good.
Thanks for all the advise guys. I hope to in due time start some of these mods to my Durango.
I've gone over the Hughes Engines site and I am surprised how many things they have available for my engine.
Yea, Hughes does have a pretty good selection. The were one of the first Mopar places to really jump in when the Magnum motors came out.
If you do get their Air Gap setup please post a thread on it. I would love to know the results. I've run the Ed carb version of that manifold on a couple motors and really like it. I do think the Hughes kit, even though it's expensive, is a better deal than the MP kit.
Oh, and Hughes have PCM flashes available. Might want to give them a call and run by what you are planning.
Stupid question, but were the 03's still Magnums? I thought they left in 01? I don't know - I'm a Jeep guy so I don't speak Dodge other than the years we can use parts from. (I'm a moderator on the Jeep site listed above - thespeedfreaks.net)
Anyway - all good info from Lesley, Rob_Mopar and others, and agreed the PCM is a limiting factor but I'd go a different way than flashing. I'd either go used MP PCM for basic builds or go with SCT. MP PCM is a decent option for mild builds and the Dodge ones are probably a lot cheaper with there being so many more of them made and all. Our Jeep 5.9 MP PCMs are pretty rare so even used they aren't cheap.
Flashing is kinda old school. it's expensive, requires downtime while you send the PCM out (and/or the expense of buying another PCM to use in the meantime) and a lot of the same expenses/inconveniences all over again of you decide to build it up a bit more further down the road.
Since about 08' when SCT got into the Mopar tuning game they're hard to beat for pricing and offerings. Handheld tuner (like the blue oval and bow tie guys had for so long!) that comes with three "canned" tunes good for most common engine drivetrain mods - or for a bit more you can get hemifever's "unlimited tuning" option where, based on AFR and other feedback the tune is tweaked and emailed to you for DLing into the handheld. FYI that unlimited option is overkill for most people unless your running stroked and supercharged, going for 1/4 mile times etc or are going to be building it up a lot but in several steps.
Contact Sean Powell, aka hemifever@aol.com - a vendor on our site and on dakota-durango.com - where you'll find some of the more hardcore Dodge builds. I believe SCT is also available from Hughes and probably even your neighborhood speed shop - but not sure how many people besides Sean off the unlimited tuning option.
FYI: SCT also does "econo tunes" - but I don't know anyone that's had experience with that! LOL :)
Z
In reply to Z88Z:
5.9Ls were still around in '03, but it was the last year do to the '04 redesign. You could get the 4.7L optional and I do believe the 3.7L V6 was still a base engine.
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