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-   -   28 donzi w 350s (https://www.offshoreonly.com/forums/donzi/168879-28-donzi-w-350s.html)

joejohn 09-16-2007 09:00 PM

28 donzi w 350s
 
was looking at getting a 28 skater, but now i'm looking at a 28 donzi with a pair of 350 mags...bit less money, and lower insurance.

soo...what I want to know, is what can I do to the motors, to get more speed, 75MPH just doesn't cut it, wouldn't mind hitting 80 or 85 MPH+...but not sure I want to get involved with prochargers...thinking some simple engine mods with bigger props...looking for advice...

Undertaker 09-17-2007 06:49 AM

28ZX twin 350 will run 72 MPH GPS all day long...75 MPH is a little on the high side... I owned a 2000 28ZX 350's (stock) ran 72 MPH never saw 75...


If ya want more speed I think superchargers would be the ticket would make that boat a sweet ride and would get you to your speed goals....good luck:D:D


Undertaker:D:D

Undertaker 09-17-2007 06:50 AM

Props that come from the factory on the 28 are the fastest props for the boat IMO...I believe they were 23P Mirage + boat ran great with those props...

LAKESIDE RESTORATIONS 09-17-2007 08:22 AM

28 is a great boat. Sc's would be the hot ticket in there. We have done our fair share of them. I am also doing a whipple in my new Donzi.. They are wave crushers. If you get one & want to upgrade it whether you want Sc's or just more power without em give me a shout.. However exhast alone wont make much difference. You will need to do a lot more to get the speed without using an sc.. :) Jamie / Lakeside

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joejohn 09-17-2007 08:41 AM

Now...if I want to mod some engines, am I better to go with the scorpion 377 motors, or the twin 350's? What do SC's do to the motors? What I've been told is that SC's are engine killers, and to stay away from them. There is no doubt they provide the power I'd require. Any suggestions on SC's I should look at?

Has anyone added SC's to a 28?

Thanks!

joejohn 09-17-2007 08:47 AM

what sort of power would I be looking at with a set of whipples? Now...the next question, how do I go about finding the right props?

LAKESIDE RESTORATIONS 09-17-2007 08:58 AM

If you dont want to do any mods go with the scorpions, otherwise steer clear & stay with 350 mags.. They are difficult/costly to modify & improve upon.. Also any Sc that you would add to it would be a custom install.. The 350 mags are easier to get stuff done on & find things to upgrade even though they are still both small blocks. ;)

As far as Sc's eating engines, that is a myth. However if they are set up wrong then yes they will definitley shorten the life of an engine & give you a lot of problems above & beyond any normal initial tuning quirks.. Also FyI do not go very heavy on the boost, everthing in moderation. A little bit goes a long way.. :)

As far as props genrally you jump about 2 full sizes or more..

Jamie / Lakeside

joejohn 09-17-2007 09:03 AM

Great!!! That helps out a lot!!! Now...how much boost should I be looking at for these? Any idea what kind of horsepower I will getting, along with a top end?

Another quick question, I've been doing some reading, and my understanding is that DONZI changed the profile of the 28 in 2002? What exactly did they change? Can someone post some pictures of the different profile of the boat?

LAKESIDE RESTORATIONS 09-17-2007 09:05 AM

HP will vary on quite a few things.. However either SC will make a noticable difference.. I would say boost levels should be in the 5-6 psi area. ;) Jamie

joejohn 09-17-2007 12:04 PM

what SC should I be looking at? A whipple or a Procharger?


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