Exhaust tuning proved helpful...
Exhaust tuning proved helpful on BBK's GT500 test car, with the key piece right here in lead technician Mike Briggs' hands. The stainless steel long-tube headers are tough to install but definitely add efficiency to the big engine's airflow. Adding a freer-flowing induction apparently doesn't hurt either.
So much attention is paid to enhanced supercharging on GT500s that it's easy to overlook less expensive but still effective power boosts. BBK is one parts house that's supported this thinking by offering long-tube headers, throttle bodies, and cold-air induction for the big Snakes. In this article, we follow along as BBK installed these three aftermarket parts on a customer GT500, gaining an amazing 100 hp over two cars and a few months, so there were more than the usual variables involved.
Of the three parts, we found the headers the most interesting. Moving from manifolds to long-tube headers is a guaranteed power maker once the engine is moderately hotted-up and what's not hotted-up about a stock GT500? Furthermore, blown engines are supposed to benefit from better exhaust, although our experience with Cobras hasn't always followed that hot-rodding law.
BBK's GT500 long-tubes fit the '07-'08 GT500s, are stainless steel and mate to BBK's 3-inch X-shape crossover. These new headers were prototypes when we started this article, and went through a revision to make them easier (read "possible") to install during the article. That's why this examination was stretched out over a few months.
Premium rides such as the...
Premium rides such as the GT500 deserve well-built hot rod parts, so BBK's long-tubes are built from mandrel-bent 304 stainless steel. The primaries are suitably large at 1 3/4-inch and mate to 3-inch collectors.
On the intake side the larger BBK throttle body was a shoe-in to pony up a few more horsepower, while the cold air intake and mass air meter were likely to corral a few more as well. BBK figures the stock GT500 air meter is large enough, and provides its oval housing to mate the conical air filter to the stock oval inlet. This leads to the unique situation of a cold air intake with no electronic tuning because none is needed to support an enlarged mass air meter. So, for once this test encompasses strictly hardware changes; there was no electronic tuning.
It's great to see meaningful power increases with the headers and an intake on the GT500. For the majority of owners mainly content with the GT500's already strong performance and not wanting to spend another $5,000 on more blower boost, the BBK bolt-ons are worth investigating. Emission compliance is definitely an issue here, so that strong consideration will weigh in the decision, but the power is there. At approximately $1,800 plus tax and installation for all three BBK parts-headers, throttle body and cold air inlet-this isn't low-buck tuning, but compared the price of a huff-happy blower the BBK option delivers more than half the extra zoom for about half the price.
On The Dyno
How did this combination of inhale and exhale hot-rodding do? The short answer is great-the dyno showed staggering extra horsepower over stock. But the real answer is toned down from that three-figure optimism. Sometimes the real world just gets in the way of dyno science, and this is one of those times thanks to necessarily extended schedules and prototype work in the middle of this bolt-on examination. Most importantly, a baseline (*) wasn't taken with this car, but grabbed from another stock GT500 BBK ran on its dyno two years earlier. We're comfy with dyno repeatability and Ford's ability to build reasonably similar cars and all that, but here there are a few degrees more separation than optimal.
Along the same lines, some of the testing was done in summer heat while the final test just happened to fall on a gorgeously mild autumn day with cooler temperatures and just 5 percent humidity (it can get dry in So Cal!). That, and the engine was revved to max effort after just a minute of warm-up. This meant the air inlet tubing was still cold to the touch after the power runs, so clearly a real-world underhood environment was not duplicated here.
The final 520 hp configuration shown here was tested under ideal conditions: at 7:45 a.m. in dry, cool air, with an engine cold-soaked overnight, and given minimal warm up before being smacked three times in a row.
No matter what the exact numbers are in the hot real world with the hood down, the BBK gear definitely lifted the power curve. Power and especially torque were notably increased across the entire rpm range. For sure the headered and intaked GT500 approaches the practical limit of its supercharger, pump gasoline, and rear tires, so they make a sensible, affordable addition.
All testing was done on BBK's in-house Dynojet dyno using premium pump gasoline, no electronic tuning, and SAE correction.
|Baseline*||Exhaust & TB||CAI||Baseline VS. CAI|
Just The Facts
|Headers||16495||$799.99||Full-length, stainless steel|
|X-shape||16985||$349.99||Off-road, no cats, 304 ss|
|X-shape||16995||$499.99||W/high-flow cats, 304 ss|
|Throttle body||1764 ||$349.99||Twin 65mm bores|
|Cold air||1757 ||$329.99||Air filter, adapter, and dam|
Supercharged engines build...
Supercharged engines build big heat when strutting their stuff, leading to strong thermal stresses on the exhaust system. BBK counters this with 16-gauge tubing and healthy 3/8-inch-thick, plasma-cut, stainless-steel flanges at the cylinder head. The driver-side flange is notched between cylinders Two and Three for dipstick clearance. Stock GT500 manifolds use a two-piece flange here, likely for increased clearance at the assembly plant, but BBK forgoes the notch.
Deep-breathing 3-inch collectors...
Deep-breathing 3-inch collectors and ball-type flanges attend to the GT500's large airflow needs. BBK is clearly supporting a 3-inch exhaust system from collector to tailpipe here.
Our test occurred early in...
Our test occurred early in BBK's development cycle for GT500 exhaust parts, so the only X-pipe available was this 3-inch off-road style in 304 stainless. After our visit, a high-flow catalytic converter equipped version was released as well.
BBK's over-riding goal for...
BBK's over-riding goal for its late-model Mustang throttle bodies is to precisely replicate the factory throttle body except with larger bores for increased airflow at WOT. Therefore this twin 65mm BBK Mustang throttle body features injection-molded gears, with the throttle shaft molded right into the gear. The plastic gears are just like Fords and are superior for long-term wear. BBK says that because its throttle bodies are functionally identical to Fords, save for larger throttle blades, that no electronic tuning is required.
Here's a simple cold air intake....
Here's a simple cold air intake. Designed to be "less expensive with no tuning," the BBK GT500 cold-air kit is also super easy to install. Its sole purpose is to replace the stock airbox with the freer-flowing conical air filter. The cast-aluminum mass-air housing is the same size as the corresponding section in the airbox-think of it as an air filter adapter-so no electronic tuning is required.
Supporting pieces for the...
Supporting pieces for the major BBK hardware are the header gaskets, bolts, and oxygen sensor wiring extensions. The gaskets are BBK's own and designed to take one re-torquing after the first heat cycling and then maybe annual torque checks thereafter. BBK also supplies the header bolts with its long-tubes; they are Grade 8 metric with an 8mm shank and compact 10mm head for clearance. The O2 sensor extensions are from Caspers Electronics (PN 109015) and sold by BBK. Like all BBK hardware, the parts are available from BBK dealers or its parts outlet, Brother's Performance.