i'M TRYING TO FIND OUT IF ANYONE HAD THE TROUBLE AND WHAT CAN BE DONE ABOUT WATER SUCKING UP DOWNTURNS FROM VALVE SPRING FAILURE (OR ANY OTHER MAILFUCTIONS FOR THAT MATTER) .
i GOT WATER USING THEM WITH A DRY CMI E-TOP SYSTEM .
THEY REALLY QUIET BOAT AT IDLE AND REDUCED SOME COCKPIT NOISE ON PLANE , i DIDN'T GET ANY POWER LOSSES . BUT SOME MODIFICATION NEEDS TO BE MADE TO PREVENT SUCTION DURING ADVERSE
ENGINE CONDITIONS , OTHERWISE I 'M SCARED TO REPLACE
THEM ( LAW ENFORCEMENT TICKET WAY LESS THEN ENGINE BUILDER TICKET !) CAN ANYONE HELP

THANKS AND BEWARE

drill 2 small holes in them above water level, they are great for high hp engines without power loss

usually a couple of holes on the top of the elbow will release some of the backpressure in the pipes..It is a exspensive trial and error process but it should help>>>

I run down turns on two boats. One with mild power and the other wild power. Zero issues and no holes drilled.

THE HOLES WERE THERE AND STILL GOT WATER IN ENGINE
WITH BAD VALVE SPRINGS!

Brad,

the small holes come drilled from the factory on my gibson pipes . the problem came from defective valve springs
in one of my motors . I belive that without the downturns
no water could come to heads with dry exhust alone .

Howard

I was wondering if holes would work on a fountain given the fact the stock exhaust exit with 1/4 of an inch submerged. Nauti how big are the holes in your exhaust and what kind of motors and exhaust are you running?

I think the holes are 1/4 " , my old set up 650 hp 509's w/ b&m 250's , e tops with cmi dry tails into downturns.

Just to be clear the pipes worked great ,BUT when you motor
malfuctions look out ! the water could be coming in your engine like you have thru prop exhust .

Still waiting to hear from gibson about this

I've never used them but I like the concept. My only issue would be if you don't have a secondary water dump or water pressure guages, how do you know your circulating water properly? I always start the boat, watch for oil pressure and then head to the swim platform to watch for water out the exhaust. I can also get a good feel for when I have an impeller starting to go bad by the time it takes to get water and the volume of water by watching the exhaust.

Make sure you pressure test your headers it might not be your down turns.

I have never got issues with mine in about 120 Hours.