Sea Water Pressure of 496HO
 

What is the max sea water pressure of the Merc 496HO (closed cooling system) at WOT in a ~ 70+ mph sport boat with a dual water pickup Bravo X1 drive?

Nobody knows the answer?

30 psi,, roughly

Thanks Monstaaa,

My 496 is no longer stock but the sea water system is and the Diacom data is showing 43 psi at 5800 rpm and mid 80's. Just trying to get a handle on if that is a good number or not since it seems high. I am looking for any additional cooling capacity to include plugging the above water water intakes of the Bravo X1 drive. However if alreay at 43 psi more pressure may not be a good thing. Already have a much bigger oil cooler as well but still need more cooling.

Hey Bill, next time you're at your boat turn the key on without starting your engine and check if diacom shows any water pressure. What I have experienced is after Whipple reprograms the PCM that they will show about 20 psi higher water pressure. It will have a reading even without the engine running. So your readings may not be correct. I just tested a stock 496 and was reading around 20 psi at 60 mph on the Smartcraft. Dustin has not been able to explain why that happens, but it has on every one he's done for me.

Bob

Hey Bob,

Wow, that is excellent information. I'll do as you suggest.

Thanks,

Bill

I checked my stocker at 80mph with water picking up through the drive on a sport master lower. I was seeing around 25psi but, I was trying to drive at the same time.

Thanks for the input. Everyone is saying around 25 psi and my reading is 43 psi. Sounds like I have a readout problem.

Thanks

MERC says that anything under 60psi is ok. They want 25-45 at WOT

Well that is good to know. Thanks. I thought that this thread had died. Nice surprise.