Actually it does not increase the amount of air bieng sucked in rather it blocks air flow causing a decrease in preformance. Here are some dynos I pulled from the bay area probe club.Spiral Intake a.k.a. The Tornado (Back to Index)
Here's what I found on the dyno. The data is uncorrected and smoothed (to avoid getting too many unbalancing peaks) to S=3 on dynojet's software. I made six passes on the dyno. Two with the Tornado unit installed followed by a 20 minute cooldown (with the engine idling) and two runs without the Tornado installed. Following yet another 20 minute cooldown with the engine idling I proceeded to make two more runs with the Tornado unit installed.
Run #1 w/Tornado: 145.1 HP, 147.3 lb-ft Run #2 w/Tornado: 145.3 HP, 146.7 lb-ft
Run #3 noTornado: 148.0 HP, 149.8 lb-ft Run #4 noTornado: 146.8 HP, 149.3 lb-ft
Run #5 w/Tornado: 145.6 HP, 148.8 lb-ft Run #6 w/Tornado: 146.3 HP, 148.4 lb-ft
As you can see from the above numbers, coming in "hot" from the street produced the lowest numbers. I did allow for about a 10-15 minute cooldown before hitting the dyno the first Time. So perhaps the second run wasn't surprising, with the car probably being a bit cooler. The third set of runs is what put the nail in the coffin when it comes to the Tornado. Although the third set was a bit improved over the first set, it was still visibly lower than the second of runs. (thanks to JTT)
Yet another snake oil automotive product