Fox Body H Pipe
One of the most popular Fox Body upgrades is an H-pipe. An “H” pipe equalizes the pressures between both banks of the engine giving a broader and flatter torque curve throughout the rpm range. It also eliminates “back-rap” common on deceleration, and creates a deeper mellower tone both inside and outside of the vehicle.
Benefits
Horsepower gains from installing an H-pipe are in the 5 to 10 horsepower range. It really depends on what other mods your car has. Add a good flowing set of shorty headers and free flowing mufflers and you can pick up even more horsepower. The best part is that your Fox will sound like a symphony of horsepower. You may also see an in increase in gas mileage and better throttle response.
Options
There’s several options when it comes to choosing an H pipe for a Fox Body. My Fox is a Sunday driver. I was looking to improve performance and improve the sound while not breaking the bank. Going full on race mode wasn’t the goal.
I decided to go with the SMR Premium H-pipe. It is a true bolt on installation for 1986 to 1993 Mustangs. This 2.5″ diameter H-pipe fits factory or aftermarket shorty headers. The aluminized steel tubing is bent with CNC equipment ensuring an exact fit. Buying directly from the manufacturer can save a good deal of cash. You can pick up these H-pipes on ebay. These are made in the USA!
H pipe laid out in my driveway
Design
The SMR H-pipe has a different design when compared to other H-pipes. Other H-pipes clamp together at the H- connection. The H section on the SMR premium is welded solid. The two down tubes attach to the H-section with ball and socket connections. This allows for quite a bit of adjustment during installation.
H section detail
Features
SMR welds the oxygen sensor ports instead of pressing them in like other manufacturers. There is no chance of these ports working loose from heat and ruining expensive sensors.
welded sensor ports
SMR also welds in the smog pump tube. You can custom order pipes without oxygen sensor ports and without smog pump tubes for various applications. Be sure to check your local laws.
smog pump tube
Hardware
SRM supplies all necessary hardware making installation easier. You will receive 12 high quality bolts and locking nuts to complete your installation.
included hardware
Flow Tubes
To complete your installation you can also pick up SMR’s flow tubes. These slick pieces allow you to easily connect your H-pipe to your mufflers after cutting to the proper length. The flow tubes are made using the same CNC bent 2.5″ aluminized tubing.
flow tubes
Installation
I found the installation process was fairly straightforward. Everything fit well and went together pretty easily. My stock O2 sensor wires easily reached the O2 ports. Since I don’t run a smog pump, I simply plugged the smog pump port. The flow tubes allowed me to connect my mufflers to the H-pipe without any hassles or welding.
It’s been almost 4 years since I installed the H-pipe. I’m still pleased with the SMR H-Pipe. My Fox also still sounds great.
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