1989 GMC S-15 Syclone Land Speed Truck

The Banks history is laden with trophies and awards for its accomplishments in gasoline performance. One example was the naturally aspirated GMC S-15 Syclone.

That’s not to say that the original idea wasn’t to turbocharge the engine in the Syclone. On the contrary, Banks originally proposed things that would have made this vehicle a completely different animal as what was intended was for it to be based on a full-sized Sierra truck using the all-wheel drive for better traction and more evenly distributed power on the salt, and that it would be powered by a twin turboed big-block 502. Those plans were dashed during a meeting about the endeavor with staff from the Chevy group saying if there was going to be a full-sized performance truck, it was going to be under their banner. GMC reps said that they didn’t make all-wheel-drive trucks and that none of the trucks they sold were turbocharged. The GM top brass made clear that they all had an idea of the truck’s image to be represented as a hopped-up stock truck that went to the salt. Banks was left the S-15 mini-truck powered by a naturally aspirated V-6.

The largest engine displacement available in an S-15 was a 4.3-liter. Since GM had ideas for power other than Gale’s twin-turbo V8 monster they decided to boar and stroke the stock V6 engine to a 5.0-liter size, but they still needed extra power. Banks came up with a rather ingenious way to “supercharge” the air into the intake… naturally, and with no forced induction. The outside air was rammed in from two locations in the front of the truck and then passed through heat exchangers running circulated ice water from a tank in the bed of the truck and then into a specialized intake manifold. The density of the intake’s air dramatically by 40 degrees and increased the power throughout the entire run.

In the Summer of 1989, the Syclone truck went on to take five-speed records, including an FIA International World Speed Record of 194 MPH.