FormulaM2Formula

I am upgrading my Bravo XZ drives to Bravo XR uppers and IMCO lowers. My boat is a Formula 382 w/ HP500 engines. With the XZ drives, the boat typically tops out around 72 mph.

Is this combination likely to generate excessive water pressure? I've read all the other posts on the topic, and my guess is that this will generate high pressure, but some of the posts are talking about boats doing over 100 mph so I want to make sure before spending the time and money.

If it is even remotely possible, I will go ahead and add a pressure relief valve and water dump as well as a strainer.

Thanks,
Garrett

Steve Zuckerman

Garrett,
The Imcos will significantly add water pressure to your existing setup. I tested one against my stock dual pickup XR case (standard length to standard length). It blew my housing apart on the stock water pump on my 575! I did pick up one mph for my trouble. My boat was running low 80s at that time.
After adding an intercooler running off my water pump, I lost about 5 PSI with the XR, making my engine water pressure marginal. Adding the Imco brought it right back to stock, and fed the intercooler nicely.
A friend here added them to his Fountain with 502 mags, and got a nice increase in MPH, but had to add pressure reliefs to his system. He is running high 70s. Speed close to your application, so hopefully comparable information.
Depending on your application, I would estimate you'll pick up from 5 to 10 PSI with Imcos, so add those pressure relief valves.
Regards, Steve

monstaaa

wii defineately pump up the psi. i machine the cases to except a screen to a) stop debri. and b) lower the psi.

good luck

Elite Marine

What is considered normal water pressure and what is excessive?

FormulaM2Formula

Thanks everybody for the feedback. I'll order the parts tomorrow.

monstaaa

20 p.s.i is about the mark, your pushung it at 30. a lil hi

Island Hopper

I have the same set up on a 353FT. I have added strainers, relief valves, still not enough. I am currently re working the drives, and plan to leave the water plugs out of the top of the lowers to see if this will drop it further. If this is not enough I will weld up the water intake, and reduce the hole size.

Steve Zuckerman

Monstaa,
Great idea on the screen. They WILL vacuum the lake. I also added a strainer to keep trash out of my intercooler and motor.
How much for the screen mod?
Regards,
Steve