I have a set of the hardin manifolds with the tall risers

I plan to install a dual O2 system this spring and after some research it looks like the FAST 170602 will work best for me. I also read - I think it may have been Eddie Young - a method for the bung install consisting of drilling through the inner and outer pipe, using a couple of ball piens to close the gap between the two, weld inner to outer, then weld the bung to the outer.

My question is location, where on the riser is optimal? I have three ideas:


My thinking is 1 is best because it is farthest from the water? 3 is closer to the water dumps, but can not have a gravity effects of water running towards it should any get in the riser.


Opinions?

TIA,
Ryan

He installed them on mine at position 2, but I also had straight runners. My guess is you don't plan on leaving them in, and there shouldn't be any reversion so either should work for tuning

I was told that as long as they are reading the average of all cylinders you are ok. Also water kills the sensor quickly. I would say #2.

the further you can get away from the water dump the better shot of them living !!! i have them in the header tube of my lightnings, only way they would live more than 15 mins

I have wondered about putting an O2 spacer that goes between the manifold and the riser and having it milled on an angle to help realign the riser with the original point in the back of the boat.

Tom what kind of exhaust are you running?