MAC Performance - Cat-Back Exhaust & Cold Air Intake
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Are you looking for information on exhaust and cold air intakes for your Mustang? Maybe we can help. We were able to install and review the MAC Performance cat-back exhaust system and their chrome cold air intake (CAI) for the late model Mustang GT's. This article is meant to help anyone with installation of these parts, or just to decide if either of these items are good for installing on your Mustang. We've included SoundClips of the exhaust as well as dyno results of before and after the installation to show actual horsepower gains.
We chose to go with Mac parts on our red 2000 GT Convertible (a.k.a. Project Firestorm) simply because we had heard lots of good comments about the MAC exhaust and intake and wanted to get proven results to see if the claims were true or not. We also noticed a new design for the chrome intake kit with a larger diameter tubing between the MAF and throttle body. We happen to have an older version of the same kit on our 99 GT and the tubing appears to be 3" whereas the new tubing is 3.5". We assume this will help greatly with airflow restrictions.
The quick and dirty results:
Click HERE for VIDEO(3.5Mb) of dyno run with sound at Precision Dyno in Belmont NC.
(Dyno Graph of all 3 pulls)
Dyno BEFORE (Bone Stock): 232HP / 280TQ
Dyno AFTER exhaust & CAI: 236HP / 284TQ (Running rich)
Dyno AFTER correcting rich fuel mixture: 244HP / 290TQ
The long version:
All Dyno results are posted as "SAE Corrected" format which simply means it corrects for any changes in weather or temperature to ensure the comparison was accurate and not affected by humidity, or temperature. Tom Lesperance at Precision Dyno in Belmont, NC just outside of Charlotte, was very knowledgeable and helped us with the accurate testing on each occasion. Dyno runs were done on a Dynojet Model 248C Dynomometer within 2 days of each other.
Horsepower Gains: As the above numbers show, there was an approx. 4 HP and 4 lb/ft of torque increase by simply adding a cold air intake and exhaust after the catalytic converters (catback). By adding a cold air intake, it sometimes causes the air/fuel ratio to become more rich than it should be thus preventing the real gains that are available. This turned out to be the case on our car. By leaning out the mixture at the mass air meter (MAF), the car pulled drastically harder and reached a peak of 12HP and 10 lb/ft of torque gain! So we recommend purchasing an aftermarket component that will modify the air/fuel ratio manually (such as the MAFterburner) or the Pro-M Optimizer in addition to the cold air kit. This helps get the full potential out of the intake/exhaust combo.
Exhaust Sound: As for the new exhaust note, it improved 100%! Firestorm now rumbles to life with a turn of the key, and during acceleration screams all the way to the 6000rpm redline. The tone is very deep but not overbearingly loud. It is deeper than the sound of the Flowmasters we currently have on our '99 GT Coupe We love the deep tone it now has and definitely creates some intimidation on the street. (MAC Soundclip & Video (3.5mb))
MAC Cat-back Exhaust:
I was able to install the entire exhaust/intake combo by myself but having a helper always makes it easier. To show the ease of installation, we chose to do the exhaust install in our garage on a set of wooden ramps instead of a professional lift. It took about 2 hours to install the exhaust cat-back system and that was stopping to take pictures and notes.
Drop out the old exhaust
First step is to get the old piping off the car. Because the stock stainless steel pipes and mufflers are welded into one long piece, it is impossible to get the entire piece out unless you are on a lift to twist the whole unit over the rear axle. Since we decided to do this on ramps, and don't expect to re-use the stock piping, we used a hacksaw to cut the pipe in two near the big elbow over the rear axle. You'll have to unbolt the connection to the Hpipe (15mm deep socket) and remove the rubber grommets from their hangers. Once the pipe was cut, we were able to remove each side in two pieces.
Installing new exhaust catback
The MAC catback comes in 2 pieces for each side so there was no problem getting it together with the car on ramps. The first component to install was the main muffler assembly. Before installing, remove the factory exhaust hanger and place it on the new piping. This will make it easier to get on under the car, as the rubber grommet can be difficult to push on from under there. After working the "hook" of the pipe over the rear axle we loosely bolted the flange to the Hpipe using the stock hardware to hold it in place. Install the two screws in the hanger to hold the rear section in place. The muffler bottom should be level with the ground so once you hold that in place, tighten down the nuts just enough to hold it there without it moving out of position.
Next, grab the chromed tailpipe extension and set the exhaust hanger at the tip. Once that's in, you can work on loosely bolting together the flanges that hold the 2 pieces together. You just want it to set there until you get the muffler assembly fully tightened.
Going back to the first piece, you can tighten down the Hpipe connection once you make sure everything else looks lined up and the bottom of the muffler is flat, not twisted to one side. Tighten down the exhaust hanger bolts if not already done. Also check the U-shaped elbow over the axle to ensure it's not rubbing anywhere. You can adjust this by moving the rubber grommet on the hanger left or right. You certainly don't want any strange rubbing noises going down the road from this!
Once that is set in place, you can adjust the tailpipe section to be centered in the bumper cutouts. Hold the unit where it should go and simply tighten down the flange bolts holding the 2 pieces together. Repeat for the other side and you're done!
Cold Air Intake Installation
The cold air intake (CAI) was much easier to install than the exhaust of course. The difference in the unsmooth restrictive surface of the stock air tube and the slick MAC surfaces is amazing. The factory airbox and tubing are very restrictive for airflow into the engine and the MAC kit opens this up to allow more oxygen in as well as bring cooler, denser air from the fender as opposed to the hot engine bay air. We had this install finished in less than 1 hour easily.
Removal of Stock Airbox and Tube
To begin, you'll need to pull all the old parts off the car. We started by pulling off the MAF sensor plug, IAT sensor (right behind the MAF), and the 2 plastic tubes inserted on the main assembly. Remove the airbox itself by taking out the 8mm bolt holding it in place. The remaining tubing and MAF can be removed from the car by loosening the hose clamps at the throttle body. Once off the car, the mass-air assembly needs to be disconnected from the main assembly as this goes back onto the car later. It's a smart idea to stuff a lint free rag into the opening of the throttle body while you're working to prevent debris from entering the engine.
Installing new Cold Air Intake
There are instructions included with this kit that you can follow so we won't go into detail here. The first part to go into the engine bay is the 90 degree fender tube and chrome bracket that mounts to it. MAC includes all the necessary hardware to do this with a professional appeal. You'll need to connect the MAF assembly to this flange using the gasket and bolts they provide. It's a good idea to keep all connections loose until everything is in, so you can make the final adjustments before tightening.
And just as the instruction sheet suggests, next you would need to set the main tube into the car with the blue rubber connectors in place. Lightly tighten the hose clamps until everything is aligned where it should be. We tried to rotate the hose clamp as far down as possibly so only the silver band was visible for a cleaner appearance. Once all components are aligned, you can begin tightening the pieces together starting at the throttle body. Use the rubber hoses provided to reconnect the 2 air tubes to the main assembly.
Next is the air filter to be installed from the bottom of the car into the fender well. This works best if you jack up the passenger side of the car for better clearance. Once under the car, there is a black fender well cover you'll need to reach around to get the filter in. It is easier to remove the fastener that holds this black plastic in place, to give you room to maneuver your arm into the hole. With the hose clamp on the filter, you'll need to reach it up into the fender, and slide it over the chrome pipe pushing thru the hole from the engine bay. Make sure the clamp fastener is visible and then using a flat screwdriver, tighten this filter down making sure it is firmly in place. If you need more pipe to fasten to, go back under the hood and push more into the fender area to work with.
All that is left is reconnecting the plugs and double checking to see that all connections are tight. Wipe off the fingerprints and you're done!!
What can we say? We created more horsepower. We enhanced the engine and tailpipes with chrome. We made the car sound like a true muscle car. And we now find ourselves wanting to drive this Mustang all the time just to listen to it!
Changing the exhaust tone is one of the first modifications we recommend to your Mustang if you're getting the "mod bug". Just before you turn the key to start her up, you actually anticipate the adrenaline rush that's about to come when she roars to life. The MAC exhaust is one of the best we've heard, and we've heard just about every exhaust combo out there. Not only do you get the great looking exhaust tips, but the extra horsepower increase is great to have around as well. Typically adding a cat-back exhaust system and cold air intake do not create a lot of additional horsepower. We've since fixed the richness that the car was experiencing and are now taking full advantage of the 12HP and 10 lb/ft torque increase. I'd also like to add that there was a noteable weight drop on the car going from stock piping to the new equipment. (estimated 12lbs) The dragstrips are closed this time of year but we would expect a small gain in the 1/4 mile in the upper RPM from this new combo.
Feel free to visit the all-new Mac website at macperformance.com for further details about their products and information on purchasing it.
July03 UPDATE: 7 months after the install of our MAC products, we still enjoy the awesome sound of our new catback system. The only negative observation we've noticed is that the inside of the tailpipes has began to rust. The exterior chrome finish of the pipes however is still in great condition. It does not pose any issues with us other than the rusting appearance when viewed directly from the rear. If rust in the inside of the pipe is a concern to you, you can spend about twice as much and get a stainless steel catback. But we still can't beat the sound and price of this catback system we chose.
Written by: Steve Shrader, YMR