Re: 496's vs 500 EFI's
 

Thanks for the tip Ray, I've never rode in one . I was considering it mostly from a looks point of view ,and having owned three Donzi's to date,but I certainly will take your advice and test one before purchase!!! Are all 500 efi's raw water cooled ???? :eek:

Re: 496's vs 500 EFI's
 

The 500EFI is standard with raw water cooling, what ever you run in gets circulated throught the engine and exits the exhaust.

the 496 is closed cooled meaning the raw water comes in and passes through a heat exchange (big black thing on front of engine) then it passes thru and out the exhaust. The engine block itself has coolant inside and isolated from the raw water. Similar to a automobile whereas the coolant is cooled by a radiator but saltwater is sill going throught the heat exchange and exhaust. The exhaust area seems to be the most effected bacasue of the high tempratures and salt mixture. These if they fail will take out your motor. They need to be flushed every time.

You can get closed cooling put on the 500's maybe 1K each. but you still need to flush to protect the drives exhaust and heat exchanger.

Re: 496's vs 500 EFI's
 

A wise old man once told me that you will burn out your motors before the salt corrodes them, if they are properly taken care of. No need for fresh water cooling.

Re: 496's vs 500 EFI's
 

If this is a cruiser, go 496 duo,

:drink:

However take Raypanics advise, drive it first and see if it has enough performance for you, sounds like they are pretty slow.

WILL :drink:

Re: 496's vs 500 EFI's
 

i took delivery of my donzi 38zx in 2003. the boat sitting next to mine was a holdover 2002 zsc with 500's and br 3's. head mechanic with the dealership for donzi told me the drives could not handle the 500's and it was going to go thru drives with that set up. my good friend has the 400 ss formula which is similar setup and it has 496ho's for 60k less than the 500's and runs within 3mph and never had a drive problem with his br 3's. i think i would do the 496's and add the raylar package before paying 60k or even 30k more if you are buying it new. just my .02. by the way i have had the old 454, 454 mag mpi, 502 mpi, and 500's and they are all great motors that need to be maintained.

Re: 496's vs 500 EFI's
 

The 39 that Ray rode in was definitely not running properly...some of those boats had the PWC lift extension added onto the back of swim platform, too; which is a huge performance-kill. That boat with 500EFI's should run into the 50's any day. We have customers owning examples of both power plants in that hull, and the truth is that there's not that great a difference in top speed. You will get a little higher cruise speed with the 500's, though. Having said that, Merc has made a BIII XR drive to handle the torque of the blue motors.
Hugh