Who made the Brospeed headers tested on the Probe GT?

Brospeed is a subsidiary of Bosal USA, Inc.; the testing was run for free at Bosal's R&D facility in Ann Arbor, MI.

What test configurations were run on the dyno?

Four: as-received (Hennessey exhaust, K&N, homemade airbox/scoop), the Brospeed full catback exhaust, Brospeed headers with the Hennessey reinstalled, and an open K&N filter with the homemade airbox removed.

How did the open K&N filter affect power?

Removing the homemade airbox and running with just the open K&N filter lost 3 HP — the author stresses you need to enclose your K&N filters.

How did the Brospeed exhaust compare to the Hennessey?

The Hennessey made more power, but the Brospeed showed a net loss of only 0.2 to 2.2% (1 to 2 lb-ft) while being considerably quieter. The Hennessey measured 105+ decibels near the tip at 6000 RPM WOT.

What kind of dyno was used and how was the data corrected?

A Clayton electric chassis dynamometer that measures wheel torque via a calibrated torque meter (roughly $160,000 vs $20,000 for a DynoJet). All data were corrected to SAE J1349 specs, with radiator fans run continuously, and quoted figures are averages of at least four runs.

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Ford Probe GT Brospeed/Bosal Headers Dyno Test Write-Up (1998) - Page 2

Bosal/Brospeed Probe GT header dyno-test article page 2 with header component photos

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Web-article page (Bosal Headers, p.2 of 6) on Brospeed header dyno testing for a Ford Probe GT, with photos of Bosal header components vs stock manifold; testing done at Bosal R&D, Ann Arbor MI.

AI caption September 2006 · Photo 76 of 90

This document is page 2 of 6 of a printed web page (http://www.mtco.com/~westcj/Brian/bosal.htm, printed 10/27/2001) describing dyno testing of Brospeed headers (a subsidiary of Bosal USA, Inc.) on a Ford Probe GT. Dated October 1998, the author explains that Bosal sponsored before-and-after dyno testing at their R&D facility in Ann Arbor, MI, with thanks to Dan Brown, John Herman, and Greg Nilsson. Photos at the top compare Bosal header ports to stock header ports and components. The document notes additional testing: a stock 1996 PGT was provided to evaluate header/catback fitment for OBD-II 1996/1997 models, and a comparison car with Hotshot Gen. I headers, Hennessey exhaust, no cat, open K&N and a Superchip was also dynoed. Four test configurations are listed, including Hennessey exhaust vs. the Brospeed full catback system, Brospeed headers, and an open K&N filter test (which lost 3 HP when exposed). Testing was done on a Clayton electric chassis dynamometer (measuring torque directly, unlike DynoJet's calculated method), corrected to SAE J1349. A comparison section states the Brospeed exhaust lost only 0.2–2.2% (1–2 lb-ft) versus the Hennessey but was much quieter; the Hennessey measured 105+ dB at 6000 RPM WOT.

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Frequently asked questions

Who made the Brospeed headers tested on the Probe GT?: Brospeed is a subsidiary of Bosal USA, Inc.; the testing was run for free at Bosal's R&D facility in Ann Arbor, MI.
What test configurations were run on the dyno?: Four: as-received (Hennessey exhaust, K&N, homemade airbox/scoop), the Brospeed full catback exhaust, Brospeed headers with the Hennessey reinstalled, and an open K&N filter with the homemade airbox removed.
How did the open K&N filter affect power?: Removing the homemade airbox and running with just the open K&N filter lost 3 HP — the author stresses you need to enclose your K&N filters.
How did the Brospeed exhaust compare to the Hennessey?: The Hennessey made more power, but the Brospeed showed a net loss of only 0.2 to 2.2% (1 to 2 lb-ft) while being considerably quieter. The Hennessey measured 105+ decibels near the tip at 6000 RPM WOT.
What kind of dyno was used and how was the data corrected?: A Clayton electric chassis dynamometer that measures wheel torque via a calibrated torque meter (roughly $160,000 vs $20,000 for a DynoJet). All data were corrected to SAE J1349 specs, with radiator fans run continuously, and quoted figures are averages of at least four runs.