I used one in my stock eliminator car, but only at points meets and events...was worth .03-.05 sec depending on the temperature. The hotter it got (90-100*), the more it helped but like some have stated above, not in bracket racing. Class racing is a different situation and worth it. At certain events even using a towel packed with dry ice on the intake (prior to a run) is helpful, especially if it's heads-up. The Moroso unit in the next post is THE one to use, if you're going to run one as they are real nice and will probably yield more than my old school one in the picture.