IMCO lower unit and water pressure...
 

Just looking for some clarification here. Been doing some reading and it's confusing at best.... I'm adding a -2" IMCO lower to my Bravo1 drive. It will be a 70mph or so boat. Will I need to install a pressure relief valve or is this just an issue on faster boats? Anyone have any "real life" experience/input?

Thanks in advance, Craig

I doubt there is a definite answer. You will most likely just have to test run and watch the pressure.

What Griff said. You just don't know until you try it

Most likely yes. I swapped from sportmaster lowers to imco’s on my boat and pressure went up 10 psi.

OK, thanks for the replies! I'm just gonna buy that stainless "T" fitting and the valve from CP Performance and install it. Better safe than sorry... This is correct, right?

https://www.cpperformance.com/p-976-...ve-12-npt.aspx
https://www.cpperformance.com/p-977-...se-12-npt.aspx

Looking forward to getting this little Cig 20 project completed!!!

Did you take the BH off?

I have them on the cigarette playboy. i have -1 imco. low water pickup. i have too much water pressure. simple valve. they dump out the sides. problem solved

Decided to go with a shorty instead.... Boat is getting painted now, then interior, hydraulic steering and installing the -2 Shorty lower...

By the way, I met some people a few months ago on the water (well, at a bar :D ) in Cape Coral that know you. They were telling me about your 20. I can't remember their names

There’s a nice ITS box in the classifieds that would look good on the back of your 20.

I used that exact dump and it worked great. -2 IMCO shorty on a 32' Sunsation running 90 MPH. It had plenty of adjustment and I had it set for 25 PSI for a non closed cool setup.