From stock exhaust to Gills
#12
Charter Member #394
Charter Member
27, it's a 22' Avanti (built in New Jersey for the Atlantic ocean) that needs lots of help holding the bow in the air, great in the rough for a little boat though. A Bravo One prop could be 3 to 4 slower if your boat does not like the stern lift. A Mirage will be faster than the Rev. 4 on a boat that likes bow lift. Most boats need stern lift so the four blade large diameter high pitch props work well. Mine needed bow lift so I changed gears (1.36) to run a smaller diameter lower pitch prop for a net gain of 5.5 mph over a stock Bravo One 26" with 1.5 gears. I have a 23" unmodified Mach Sterndriver on the boat now, just haven't gone out to test it yet, should be even faster than the Rev. 4 (I hope -please-please)
#14
Registered
27 Fountain, ANYTIME you add a better breathing exhaust system to an engine it's going to help(some more than others)....and the more the engine is modified the more the engine is going to breath better with the better breathing exhausts. That's what helps make the power. Because you're running a blower application, the engine builders you were refering to probably meant more like you "don't really NEED the Gils" vs. "Gil's won't help". If you have increased your speed by 2MPH, I would say that is equal to approximately a 40HP gain just by adding the the Gils. And "yes" they were right, with a blower application you probably didn't really need the Gils, but it certainly helped---and you can't argue with that!