Finally we can get a properly calibrated Butt Dyno and the price ain't too bad either. Follow the ling for a good pic of the unit
http://kalecoauto.com/index.php?main_page=product_info&cPath=6&products_id=8
"Just installed a great mod like a cold air intake? Electric supercharger? Big Muffler? Magnetic fuel line ionizer? Awesome wing? Are you getting no respect from your friends for your newly found power? As we all know, these are high end and sophisticated modifications. Some may be TOO sophisticated to actually show up on a traditional dyno. So here we have: The Butt Dyno. Simply place it in the seat, and drive fast, weaving in and out of traffic. (On a race course, of course.) Now you can tell your friends with confidence "That oil-saturated air filter gave me 20 horses!"
6 Units in Stock"
Old but funny. Be sure to zoom up the product picture, there's a detail you might not see otherwise 
GameboyRMH wrote:
Old but funny. Be sure to zoom up the product picture, there's a detail you might not see otherwise
And what's that? I didn't see anything really unusual other than what appear to be some air vents in the seat.
They look more like rollers to me instead of vents. Otherwise I don't see anything unusual.
yamaha
HalfDork
8/7/12 11:32 a.m.
My butt dyno told me I was enjoying the car's secondaries too much last night.
http://www.dynolicious.com/
Same thing, but $12.99. Great iPhone app. Think they have it for android as well now.
Argo1
Reader
8/7/12 9:25 p.m.
Yes, but no...ah...rollers. 
mr2peak wrote:
http://www.dynolicious.com/
Same thing, but $12.99. Great iPhone app. Think they have it for android as well now.
Not the same at all, since that one actually works.
The same MEMS accelerometer that senses if your phone is pointing up or down can sense G loads, and (given the weight of your car) calculate the HP using rather simple physics.
Similar apps for iPhone and such have been available for some time now: http://itunes.apple.com/us/app/bosch-light-em-up-dyno/id361276412?mt=8#
