The Garage - Hughes FI
The Hughes Intake Manifold for more power under the hood!

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Last Updated: 12/3/2013
Hughes FI Airgap Manifold

Hughes Engines, Inc.
Address: 23334 Wiegand Lane,
Washington, Il 61571
Phone: (309) 745-9558
Hours: Mo thru Fri
8AM - 5PM (CST)
Click here to visit their website.

Summit Racing Equipment
Address: P.O. Box 909
Akron, OH 44398-6177
Phone: 800-230-3030
Fax: 330-630-5333
The Order Line is open 24 hours
a day, 7 days a week.
Click here to visit their website.

Edelbrock Corp. Headquarters
Address: 2700 California Street,
Torrance, CA 90503
Phone: 310-781-2222
Fax: 310-320-1187
Tech Line Only: 800-416-8628
Hours: Monday-Friday 8:00 am-12:30, 1:30-5:00 pm PST, weekdays
Click here to visit their website.

The fabrication, modifications and designs you see on this web site are completed by myself. If you duplicate these modifications you do so at your own risk. I do not endorse or make any claims to their safety, performance, On-road or off-road worthiness. Any "Product Reviews" are my sole and personal opinion. These reviews are on items purchased from or provided by reputable aftermarket suppliers. All registered trademarks belong to their respective owners.

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Hughes Engines Inc. was formed in 1969 as Hughes Engineering, to build stock and super /stock cylinder heads for AHRA and NHRA class racing. Since then we have grown into a complete custom engine building facility. We were one of the first ASE certified engine machine shops in the nation. Dave Hughes has a long history of drag racing as well as writing tech colums and doing Q&A for several national magazines.

Edelbrock, LLC is a specialty performance automotive and motorcycle aftermarket parts manufacturer , focusing on increased performance.Based in Torrance, California, Vic Edelbrock founded the corporation in 1938.
After much research on the web, I have decided to exchange my already runner modified barrel or keg style OEM intake on the Durango for a considerable better unit, thus I purchased the Hughes Engines FI Airgap Intake Manifold kit.. This will also eliminate any possibility of problems resulting from a failing plenum cover gasket in the future.

The increase in horsepower is what sold me on the intake, though. Many enthusiasts before me who have purchased this kit have noticed increased performance and claiming to have gained an additional 15-20 hp on a stock engine after the install.

My truck is an all-time AWD with a highly modified engine, thus I don't expect getting better milage from this intake as most people on the web have reported using the manifold with the stock engine.

Hughes Engines
FI Airgap Manifold Kit

Everything needed for the install comes along including a full gasket set, a throttle body adapter, and a bag with an assortment of bolts & brackets. Also included are all fittings and a bunch ofn pvc caps for those unused fittings.
I usually prefer to purchase Mopar Performance parts for the engine, but sometimes the aftermarket just does a lot better. The Hughes Intake is one of them.

The mopar option would have been the M1 Mopar Intake (which I also in detail researched) but it just doesn't quite provide the results in upper RPM range without loosing on the low end.

This intake has been designed by Hughes Engines specifically for the Dodge Magnum engine and is manufactured by Edelbrock for them. I really like this kit as it contains everything needed for the swap.

The UPS guy brought me a box just one day before Christmas! The intake manifold from Hughes Engines arrived well packed and without any damage. It looks great!

Getting Started
The basic procedure of this project is to remove the old barrel type intake manifold from my vehicles Magnum engine and replace it with this new high performance manifold. Hughes Engines has provided a helpful set of colored instructions to assist me in the process.

Let's get started!
There is nothing quite as exiting as starting a new project. In the garage I am setting up my propane heater, getting my air compressor charged, tools cleaned, and yes, you bet, I am about as ready as I'll ever be to tackle this project which has a lengthy to-do list

1. I start out by cleaning the engine bay at my local DIY car wash center. Then I towel the engine off to get rid of any water left. I then blast the engine with my compressed air to get rid of any particles which I may have overlooked at the wash center. It is not only important to get rid of the dirt for this install but in general it's a lot nicer to work on a clean engine then on a grimy one.Now, I am removing the Mopar Performance aluminum cast air cleaner.

2. Disconnecting the negative battery cable is good insurance that nothing shorts out while working under the hood. Yes, it's a hassle to reset the radio clock, but for this install it's more then that. If you disconnect the battery for a lengthy amount of time, the powertrain control module's (PCM) capacitors empty out and the learned peformance curve get's reset. This is what you want before a performance upgrade.
The PCM in the Dodge Durango is located on the passenger side of the engine compartment. It's the box with the metal lid and the big multi-wire connector on the bottom. It is the computer which receives information from the engine, transmission, drivetrain and other areas and controls them.

3. Time to drain liquids starting with the coolant from the radiator by opening the drain valve located on the bottom of the radiator at the driver side. I also need to drain the windshield wiper tank which in my case is an integral part of the radiator reservoir tank. I use a simple siphon hose to do that. I then disconnect the connectors from the pumps and the empty indicator sensor and remove gently the windshield washer lines from the washer pumps.

4. Next loosening the fan belt is an easy job if you have the right tool. There are tools available from the parts store but none of them lasted me very long being of low quality. I am sure I could find a good one but hesitate to spend 100 bucks on a tool I use one a year. Thus, I made my own from and old socket and a long piece of steel for about 5 bucks total. In fact I made a whole set for all my trucks and they work just fine for over a decade by now.

5. Removing the throttle linkage is a pretty simple task but being careful not to break any of the plastic retainers which keep the cable from popping out of their location. I really don't like to use any type tools or pliers on the cables themselfes.

6. After disconnecting all vacuum lines and wiring to the injectors, sensors, and throttle body. I proceed with unbolting the throttle body. Instead of disconnecting everything, I just move the entire assembly it out of harms way to the left side of the engine bay (passenger side). I am paying especially close attention to the Cruise Control lines and wiring as I don't want to damage this system, it's an expensive part! It helps to secure the out-of-the-way-parts with some cable ties. It's easy to get distracted when parts want to return to their original location at the wrong moment.

7. I now can remove the A/C compressor and the bracket that attach them to the intake, cylinder head, and engine block. I do not remove the A/C lines since this will allow the A/C charge to escape into the atmosphere and that wouldn't be good. It would also require a trip to the shop to get it refilled and extra cost. I then move the A/C compressor off to the side with all A/C lines still attached and intact.

8. Removing the idler pulley, the alternator and the entire accessory bracket from the block is followed by removing the the heater hose, and loosening the bypass hose.

9. I take off the fuel rails with all injectors still attached. (I do not remove the injectors from the fuel rail or disconnect the fuel lines since they could still be under pressure). I am very careful when doing that not lose any o-rings from the injectors as they could get stuck in the old intake manifold.

I moved the whole assembly out of the way so that I can remove the intake manifold while leaving the lines still attached. Now I am replacing any damaged or worn o-rings and put a film of engine oil onto them which will make the later reinstall easier and I wont forget to do this later.

10. Before unbolting the manifold I re-check for any debris which could enter the valley. All OK, I now remove and set the old barrel intake manifold aside with the bypass hose still attached. I remove the thermostat clean it and set it aside. Although the bypass hose looks still good I will be replaceing it. The barb on the Hughes intake is of different shape and I try to avoid any problems with sealing against it by simply using a new hose.

11. I plug all holes in the cylinder heads and then cover the entire valley with a boat load of shop towels to prevent any debree to enter any openings in the cylinder heads while I am cleaning all of the mating surfaces. To remove old gasket material and all grease and oil using a standard gasket scraper. These are available pretty much for cheap at any local Auto Parts store and make this job not only easy but prevent any scratches to the surface which is very important for proper sealing. Once the majority of material is removed I clean the rest with shop towels soaked with a bit Goof Off Heavy Duty Spot Remover & Degreaser. This stuff works really well.but a bit of acetone would be OK for the job as well.

The cleaning and the prep work for the new gaskets was defenetly the most time consuming task this afternoon (I spent close to 3 hours) and without the vacuum cleaner and the compressed air pistol, this job would have been impossible to do. I am glad this is done!
I am now quite exhausted which is likely a result of having not yet fully recovered from my last chemo treatment. I am also a bit cold as it is in my garage only 20 degrees fahrenheit despite the propane fed little Mr. Heater I had running.

Thus, that's enough for me for today and I am looking foward to a hot cup of coffee and some fresh baked chocolate cake my wife has made. I will continue tomorrow with the assembly and install of the new Hughes FI Airgap Intake Manifold.

1. I have transferred the following components over from the old intake manifold to the new one (by-pass nipple, heater hose nipple, and the coolant temperature sensor). I have used LocTite thread sealant in the tube on any threads of the fittings and on the sensor.

2. Installing the new intake onto the engine is as simple as the removal, it just bolts in place. In my case I could not use the gaskets that where supplied for the front or rear valley seal because it would have made the intake sit to high, so insead I applied a nice thick bead of Black High Temp Silicone.

3. I use on all bolts anti-seize to prevent them from seizing up in the engine block. This is really important when mating steel with aluminum! I purchased this at my local auto parts store quite some time ago and still have plenty left.This stuff is a must have!

4. I then installed the throttle body adapter (which I have painted black last night) with a new gasket and the brackets for both of the fuel rails which all came with the kit.

5. I then installed the plug for a secondary temperature sensor. Next was the 180 thermostat and the thermostat housing with a new gasket. The housing received a new coat of black paint the day before. I went to the local parts store with my old bypass heater hose and picked a new one up and installed it.
It was a real pain to get the bypass radiator hose back on. I had to shorten it almost a 1/2" until it finally did fit.

6. I installed the fuel rails with the injectors still attached using the supplied bolts, washers, and nuts from the kit. The included rear bracket mount on the right side did not align perfect and had to be modified. That's something one has to expect on any kind of upgrades. I then pluged the connectors for the injectors back in.

7. I am spending an hour to clean the accessory bracket while I have this great access to it before re-installing it, the A/C pump and the Goodyear Gator belt followed.

8. All connections to the alternator have been re-established. The upper radiator hose and heater hose have been reconnected and the trottle body mounted to the intake adapter

9. I re-connected the throttle linkage, checked for smooth operation, and made sure it does not bind or interfere with any wiring or vacuum lines.

You may have noticed that I didn't mention the Intake Air Temperature sensor (IAT). This is because the new intake does not provide a location for it. This is actually great for me because it will make for some free power! Here is the story about that.

Finishing up!
Installing my Mopar Performance air cleaner, the battery cable, and refilling the cooling system with anti-freeze finishes the installation.
All what's left do do is starting the Durango back up, checking for any leaks and if everything checks out, then this project has been successful completed and I am hitting the road for a test drive.

Installing the Hughes Airgap Intake was overall an easy task, however I wouldn't recommend it for the beginner.
I waited to write up the verdict for this project to allow some time for testing this performance intake from Hughes Engines.
So what's the story on it? Two words: Holy Cow!!!

This kit has made a significant change in the performance department after installing the Hughes Airgap Intake Manifold. I certainly can feel a strong power gain from 2500 RPM's all the way up to my sealing @ 6000RPM. The truck feels a lot more responsive, meaning it seems to react to the pedal without any lag and pulls strong throughout the entire powerband. It revs now well too and produces a more beastly tone which makes my Durango sound a lot better, I like it!

I am extremely happy with the outcome and I would do it again as it is now one of my most favorable mods I have done to this day, just awesome!

...oh, about mpg's... Did I gain any fuel milage? Probably, but it's hard to tell because I have a hard time keeping my foot out of it, it is just so much fun putting das pedal to das metal :-)

This project was completed on 01-04-2010

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