PDA

View Full Version : safe h2o pressure for OPtimax?



stoker2001
04-16-2005, 09:24 PM
been playing with props and hyd jack plate levels trying to find optiman topend performance with 2000 225hp.this is 22 foot Stoker tunnel.when i surface prop at speeds pressure drops to 11 PSI.Al suggests ussing 15" diameter bravo four blade around 24 pitch and drill hub for ventilation.should i plug some of the side upper water intake holes to help with water pressure,this lower has the four holes in front tip of bullet.performance is pretty good with light fuel load and one person it hit best of 77mph ussing 25 small diameter four blade on the rev limiter.with full tanks and gear and two extra bodys the performance suffers drastically.was wondering how much more performance a new 250SX would give over the 225hp?thanks for any input

Gene K
04-17-2005, 10:47 AM
Carb/EFI 3.0 is a low pressure / high volume system. 10 psi is supposed to be minimum pressure. As far as I know the DI Opti 3.0 uses the same set-up.

225hp to 250hp should be about 5 mph. Assuming the current engine is about 230hp and the 250XS is about 270hp I would estimate around 8 mph.

Gene

bostoncan
04-17-2005, 11:08 AM
stoker ,I filled the top 4 or5 holes on the side of my 2003 225 Opti and with those plugged my pressure is about 21 psi ,I was pulling in air thru the top holes ..

stoker2001
04-17-2005, 02:29 PM
thanks for replys,did you use epoxy to plug holes or weld them up?i think i want to peddle this motor so i can afford a 250SX :cool:

bostoncan
04-17-2005, 04:51 PM
All I did was use some of that epxoy stick, sanded hole areas and when the epoxy was setting up ran my wet finger over the epoxy to feather out so you cant tell, smoothed out great then just touch up with black paint . You can use brass plugs and thread the holes but the epoxy stick seemed to work out good .

sosmerc
04-17-2005, 06:30 PM
Why not just drill and tap the holes and insert some allen head set screws? That way, down the road, it's easy for anyone to return to the stock setup?
Also, I believe that Optimax should have a water pressure tranducer and the ECM will trigger a warning horn and "guardian protection" if it doesn't see the correct block pressure for the particular rpm you are running at.

sosmerc
04-17-2005, 06:38 PM
According to my manual, the minimum block pressure the ECM is looking for is:
7 PSI @ 6050
6.1 PSI @ 5500
5.2 PSI @ 4950
and so on down the line....if it sees low pressure for more than 2 seconds it will activate horn, and warning light.
After 5 seconds it will also reduce engine rpm.
This system is only active above 1500 rpm.
Check to see if your engine is equipped with a pressure tranducer at the back of the block, just above the ignition coils.

mercpower
04-18-2005, 06:27 PM
my 200 Optimax ran 11psi at WOT and never had a problem :D

stoker2001
04-19-2005, 06:22 PM
thanks for replys,i just heard rumor from reliable source that merc will offer 300hp opti for 2006.now that got my heart pumping :eek: :D here is our new 2005 Stoker tunnel 224 first ever with outboard power.Al retooled around five years ago and to this date has not offered the 224 with outboard power ;)