Underdrive Horsepower Gains

I was wondering about underdrives. I know that there is a lot of debate over the UD's but I also noticed that nobody that I could find can tell me if they have seen any real gains. I know that ASP says that they put out like 10HP but is that at the motor or at the wheels? Can anyone here tell me what they have seen when putting UD's on their car as far as revs, HP and 1/4 mile times, if any? Have any other issues with the UD's that are note worthy?

SCaddict said:

I was wondering about underdrives. I know that there is a lot of debate over the UD's but I also noticed that nobody that I could find can tell me if they have seen any real gains. I know that ASP says that they put out like 10HP but is that at the motor or at the wheels? Can anyone here tell me what they have seen when putting UD's on their car as far as revs, HP and 1/4 mile times, if any?

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I didnt feel it but it revved faster and knocked .20 seconds off the 0-60 and 1/4 mile, when at idle you might see your headlights dim a little at red lights, never had a battery or starting problem yet, even when I had 13 speakers hooked up.