Carl Heideman
Carl Heideman
2/5/19 12:35 p.m.

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Story and Photos by Carl Heideman

Remember that salvage yard supercharger build that we chronicled in the February issue? Using pre-owned parts, we boosted a 1992 Mazda Miata from 98 horsepower at the wheels to 153. Total cost for the entire endeavor: less than $200.

The project exceeded our power wishes and met our budget goal, but we’re never ones to leave well enough alone–especially since our constant Craigslist hunts landed us a partial Miata turbo setup for $150. It included a turbocharger, manifold, intercooler and some 2.5-inch tubing.

We set the turbo aside for a future project and decided that the intercooler was the ticket for the next evolution of our reclaimed supercharger. To tie everything together, we coughed up $99 for a brand-new universal intercooler piping kit from Amazon.

Why go to the trouble? While our boosted engine was making great power, it was also seeing pretty high air intake temperatures–around 200 degrees Fahrenheit. When a supercharger compresses the intake charge, a side effect is heat. And heat is not good for power: Not only is hot air less dense, leading to a power loss, it also increases the likelihood of detonation, so we had to dial back our ignition timing a few degrees in order to compensate.

We figured that there was about 10 horsepower on the table if we could lower our intake temperatures. To do so, we put our Craigslist intercooler to use.

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frenchyd UltraDork
2/5/19 3:59 p.m.

Another way to go to cool the charge would be to use alcohol rich fuel like E85.  

It would be wonderful if you could do a pull using the intercooler and then one using E85 without the intercooler. Finally one last pull using the intercooler with E85. 

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