How To Install a 5.0 Exhaust System
From headers to tailpipes, we install and dyno-test a complete exhaust system on a '95 5.0
From the April, 2005 issue of Mustang Monthly
By Wayne Cook
Photography by Wayne Cook
The installation of a DynoMax...
The installation of a DynoMax after-cat exhaust system was only part of our complete exhaust-system upgrade. The shop techs at X2C Motorsports also installed BBK headers and a BBK X-pipe. The entire package is available straight from California Mustang's warehouse.
BBK's 1 5/8-inch shorty headers...
BBK's 1 5/8-inch shorty headers come complete with new gaskets and header bolts. They're available ceramic-coated, as shown here. The X-pipe includes related hardware and is ready to install. Be sure to specify what year car you have, since there are differences in the pipes for '86-'93 and '94-'95 5.0s.
DynoMax's after-cat exhaust...
DynoMax's after-cat exhaust systems for Mustangs are staples in the exhaust aftermarket. We've had them on numerous cars over the years, including a 347-powered Fox 5.0, and we love the sound. Muffled nicely with the two-cat X-pipe, the DynoMax mufflers have a mild and mellow tone that still has a throaty 5.0-style sound when the gas pedal is tickled. The complete setup includes the tailpipes, mufflers, and mid-pipes that connect the mufflers to the X-pipe. Muffler clamps and hardware are also included.
One of our friends recently traded his '01 Mustang GT Bullitt and supercharged '65 Mustang coupe for a '74 DeTomaso Pantera--the fantastic Ford-powered, mid-engine Italian exotic you rarely see these days. However, once that transaction was complete, he was left without a daily driver to commute back and forth to work as a county sheriff's corrections officer.
Still an avid Mustang lover (even though he now owns that radical Pantera), his dilemma was solved in the form of a creampuff '95 Mustang GT coupe he scored for the screamin' price of $5,200. And since the car was 100 percent stock, it serves as the ideal subject car for a series of sensible but effective upgrades that will make it more fun to drive on the street.
Since our buddy's SN-95 5.0 also represents the final year of pushrod 5.0 production, it's an even more interesting car to work with. We decided to begin with the installation of a complete exhaust system, which in our case included a set of BBK shorty headers, a BBK two-cat X-pipe, and a DynoMax after-cat exhaust that includes mufflers and tailpipes, all of which are available from California Mustang. A solid, well-proven combination that resulted in a mellow but still authoritative tone, we also wanted to test the setup on a dyno to see what power gains might be achieved even though the car was otherwise bone stock (see sidebar).
There were issues with the car that had nothing to do with the parts we installed, so our results weren't what one would expect. But we pressed forward, knowing we could correct the car after the system was installed.
Furthermore, we had the pleasure of working with X2C Motorsports, a competent late-model Mustang performance shop in the Los Angeles area. The techs at X2C made it look easy, having the whole system on the car in well under four hours, even though we stopped them often to photograph the installation.
1 Unlike many cars, including...
1 Unlike many cars, including vintage Mustangs, installing an exhaust system on a late-model Mustang is a made-to-fit procedure. It's mainly a bolt-on affair with no welding required. Of course, having the car on a hoist makes the job much easier. The task can be done on jackstands, but as with any undercar project, having a lift helps. We begin by disconnecting the battery, coating the nuts and bolts with spray lubricant, and unbolting the stock H-pipe from the mufflers. Be sure to remove the oxygen sensors from the H-pipe with a 22mm wrench.
2 Next, unbolt the front...
2 Next, unbolt the front of the H-pipe from the stock manifolds by removing the flange nuts from the collectors with a half-inch-drive ratchet and correct-size socket. Although the X2C techs use an impact gun, a standard half-inch-drive ratchet, extension, and socket will also work. Next, disconnect the thermactor-air tube so the pipe can be removed.
3 Once the stock H-pipe is...
3 Once the stock H-pipe is separated from the manifolds and mufflers and unbolted from the hanger mount, it can be removed from the car. On '94 and newer Mustangs, the bolt-on hanger system makes it considerably easier to R&R the pipe compared to the steel slide-in type used on '86-'93 Fox 5.0s.
4 With the stock H-pipe out...
4 With the stock H-pipe out of the way, removing the stock mufflers and tailpipes takes only a few minutes. Cut the tailpipes away from the mufflers just in front of the rear axle with a hacksaw. A Sawzall, used here, makes the task easier.
5 With the stock mufflers...
5 With the stock mufflers separated from the tailpipes, the system is removed easily by separating it from the four hangers and grommets with a prybar. Coat the rubber grommets with spray lubricant to make it easier to get the exhaust-system hangers separated from the eyelets in the grommets. There's one at the back of each muffler, as shown here, and one at the end of each tailpipe behind the rear tires.
6 Removing the stock exhaust...
6 Removing the stock exhaust manifolds is next. The X2C techs begin by removing this car's OE strut-tower brace.
7 On the driver side, remove...
7 On the driver side, remove the oil dipstick tube and all spark-plug wires. You might have to remove the spark plugs.
8 Although not required for...
8 Although not required for the header installations we've done on Fox Mustangs, disconnecting the steering shaft from the rack on an SN-95 car makes header removal easier on the driver side.
9 Next unbolt the manifold...
9 Next unbolt the manifold from the cylinder head. On an SN-95 5.0, the manifold drops out from underneath the car as shown.
10 To access the manifold,...
10 To access the manifold, disconnect and remove the air-injection hoses on the passenger side of the engine.
11 On an SN-95 5.0, access...
11 On an SN-95 5.0, access to the passenger-side manifold is surprisingly good once the air-injection hoses are removed. As shown here, there's even enough room to fit an air ratchet and socket to several of the bolts, although a standard 3/8-inch-drive ratchet and socket are also perfectly adequate. Also remove the EGR tube from the manifold (unique to '94-'95 5.0s), which has already been done here.
12 Installing the new components...
12 Installing the new components is a reversal of the removal process for the headers, X-pipe, and after-cat system. On the passenger side, the BBK shorty header drops into place from under the hood as shown. Install the supplied new EGR tube on the passenger-side header.
13 Like the removal, installation...
13 Like the removal, installation of the driver-side header on an SN-95 is easiest by slipping it into place from underneath the car. Using the supplied new gaskets and hardware, start all the new header bolts before final-tightening the new headers in place on the engine.
14 With the headers installed,...
14 With the headers installed, fitting the BBK X-pipe is next. Although the air tube is clamped to the stock H-pipe, we decided it would be easier to cut off a section of the air tube and join the tube and new X-pipe with a piece of the correct-size small radiator hose and hose clamps.
15 The X-pipe can now be...
15 The X-pipe can now be installed by hoisting it into place. Installation involves connecting it to the new headers with the supplied hardware and reversing steps 1 through 3.
16 The DynoMax after-cat...
16 The DynoMax after-cat system is a direct replacement for the stock mufflers and tailpipes. The mid-pipes that connect the mufflers and X-pipe are the first to go on. These pieces are joined together with the supplied hardware.
17 The mufflers attach to...
17 The mufflers attach to the mid-pipes and tailpipes with the supplied muffler clamps. It's a simple and effective setup, and the X2C techs called the DynoMax package "a nice kit that fits well." With everything started, the clamps are tightened up with an air ratchet or a standard hand ratchet. The DynoMax system is adjustable, allowing you to move the components around to eliminate rattling or rubbing. Look out for tailpipes rubbing the rear tires and pipes rattling against the car's floorpan. Once these areas are checked, all nuts and bolts can be tightened to finish the installation.
18 This is the complete after-cat...
18 This is the complete after-cat and X-pipe installed on our '95 5.0. We headed off to the dyno, and had mixed results because our subject car wasn't where a stock 5.0 should be.
The original idea behind this how-to was to show what a good-quality exhaust system would do for power improvement on a stock but well-maintained 5.0. Our intentions were honest and the BBK and DynoMax components are certainly worthy of any enthusiast's consideration. The problem was, our test car was a dog and way down on power long before we installed any parts. We didn't have the time to troubleshoot the car before our scheduled baseline dyno-testing on the Los Angeles Performance Division's Dynojet.
This '95 5.0 was detonating on 91-octane pump gas with only 9-10 degrees of initial timing, which was the root of the problem. To keep the engine from detonating into oblivion on the dyno, we had to run the timing at a seriously retarded 8 degrees initial with 91-octane gas.
By the time you read this, the owner will have likely solved this issue. Something was definitely amiss since we were forced to have the timing so retarded that the car made only 172 hp at the rear wheels for a baseline, when we would've had at least 190-200 hp to start with using 10-12 degrees of initial timing. Even though the car was that far off, the exhaust system was still worth 12hp peak improvement at the rear wheels.
We told the folks at BBK what we experienced. They surmised the exhaust system on a healthy car would be worth a solid 20 hp or more at the wheels. We agree, and the exhaust system, combined with other airflow improvements such as an intake manifold and cylinder heads, will make a bigger difference as you climb farther up the horsepower ladder. When this car is fixed, we plan to retest it and report the results to you in a future issue.
BBK Headers, BBK X-Pipe, and DynoMax Exhaust System