Diesel Progress North American

to adjust operational parameters to reduce turbo lag under low flow conditions without compromising top end performance. When compared with a conventional VGT, Blaylock said the Switchblade turbo offers similar performance with significantly fewer moving components.

“Turbo lag has been a major problem affecting both performance and emissions,” Blaylock said. “Smaller turbo housings would help to eliminate lag, however, performance of the overall system was limited. Turbo manufacturers attempted to address this issue with VGTs, which helped to reduce turbo lag, but significantly increased cost and failure rates due to the number of additional parts.

“The Switchblade design incorpo-
rates a blade in the throat of the
turbo, which is controlled by an elec-
tric actuator. During idle or low flow
conditions the controller actuates the
blade, closing off a portion of the
turbo housing and forcing the exhaust
stream directly onto the turbine tips at
an increased velocity by increasing
drive pressure.”
According to Blaylock, testing on
the Switchblade has demonstrated
that by closing the blade, the tur-
bine wheel spools more quickly,
producing the first psi of boost in
0.3 seconds. As the pressure con-
tinues to increase, the blade opens
up, allowing the entire housing to
be utilized and cross over (high-
er boost pressure than backpres-
sure) and more complete fuel com-
bustion to be achieved. He also
said the Switchblade’s perform-
ance has been mapped by several
large turbo manufacturers and test-
ing has indicated that the system is
capable of adjusting A/R ratios with
a single moving component.

Blaylock said the company has conducted initial testing on the turbos used on a 2002 Dodge 3500 and a 2006 Dodge 2500 pickup, each powered by a 5. 9 L Cummins engine, as well as on a 1997 Ford F series truck with a 7. 3 L PowerStroke diesel engine. According to its findings,

According to Blaylock, the Switchblade’s 18 cm housing (left) — designed for an 8. 3 L engine — is capable of generating boost as quickly as a stock 9 cm housing.

showed fuel savings up to 3 mpg, as well as reduced visible smoke, Blaylock said.

Blaylock has been working to develop the Switchblade initially for the performance aftermarket sector, but believes it will also provide a benefit to those applications where VGT performance is required, but cost and durability are concerns. The company’s goal is to develop relationships with fleets looking to increase fuel efficiency while at the same time reduce particulate emissions, as well as establish a relationship with an engine manufacturer looking for an alternative to current VGT technology. dp

Blaylock said the Switchblade’s 18 cm housing — designed for an 8. 3 L engine — is capable of generating boost as quickly as the stock 9 cm housing. Other than lowering drive pressure, the testing