need more speed zx33 donzi
 

I have donzi 33zx 2003 525x2 mercury racing .blue
Top speed 78 mph trim 3
Prop 30
I need more speed
??

Being a 98 i am guessing you have no steps in the hull, correct? If so, I would still think you should be in the 80's with 525's. Sounds like you need to pull up the anchor. If you trim any more, does she start slipping? what position are your trim tabs?

tom

So is boat 03' or just motors?

I am guessing the boat is a '98 cuz of his handle, q8donzi. I understand your point of the '03 motors (or newer) being 525's though.

98 first year for stepped hull..i think your correct.he needs to trim it out more to get more speed...a 38 with 525's will run 80+ all day long..

I think 98.5s were stepped...early 98 was not?

Soo, where did he go?

Could be 525SC no?

Thats what I was thinking, but couldn't confirm. Fixx knows his stuff so didn't want to doubt. I do have a friend in Toledo that has a '98 38ZX (not 33) with no steps either so that is where i was coming from. Pretty sure he has 500's in it but not sure what speeds he's turnin'.

tom

I don't think his boat is a 98 I think that is "Q"8 in his name... boat should be a 2003

figured he was making a play on numbers and letters and that the boat was updated. Okay, maybe a stretch :bong: . If he ever replies, we will get Paul Harvey's 'Rest of the Story'.

tom

My boat 2003

My boat 2003
Trim 3
5100 rpm
:(

ok,,so now we know what the real boat is and the real engines are..you need to go to a 32 p prop because your bouncing off the rev limiters...once you go to the 32 p props trim it to 5 or 7..that should put you over 80..

Thanks
I will try and tell you

q8 is indeed a play on words for Kuwait (his location).

I don't think moving up in props from a 30 to a 32 will help him, he is only revving 5100, Merc Racing 525's are set up ideally to spin 5200 and will not bounce off a stock limiter until 5400.
IMO 32's will kill his rpm unless they are worked over a lot.

Just trim that fat girl out until you break loose then down a notch from there....

525 rpm 4800 to 5200 not 5400 thanks

The little stickers that Merc put on the cooler read 4800-5200 rpm. Most people that own 525 EFI's like myself know that 4800 is way too low for wot. The Merc Racing 525EFI is an engine that should be run at 5200 rpm for optimal power, not 4800 rpm. The engine is very capable of turning 5400 rpm in stock form, not that i am saying to do this however....To each their own I suppose.....

verbi69 is correct the rev limiters are at 5400(maybe 5350) so that isn't the issue. In fact, you should be running them closer to 5300 as they make more power there.

they start at 5400 and take into consideration that some tach's do lie..

q8,,b4 you swap props you really want to see if you can get any more speed from the props you have,,i spoke to a friend and he said that you want to spin those engines at 5250 b4 they hit gaurdian mode..trim up and see what you can get out of it..dont be scared to over trim at a lower rpm,,get into a nice cruise at around and trim up until the props slip then trim back down until they bite again then ease into full htrottle and see what the boat runs for speed..i dont know your boat but they all respond differently..

5100 rpm with trim level 3
I go to trim level 5 more rpm I think up to 5300

I have a 2000 33zx poker run edition with 600's. i am pushing about 1300 hp. I top out at 85-86 mph GPS.
Trim - 5
Rpm - 5200-5300

I have extension boxes so I am sure that changes the situation..

I would have to say trim up more.

~PG

Thanks Thanks my friends
I will try and till you
Next weekend

Have fun!

Pgatso, you may a prop issue based on those speeds and that power. When my 575sci engines were stock I hit a best of 88mph on GPS with an average of 86-87 (freshwater). I have had some struggles dialing in a prop to keep me over 90, due to some bow and stern movement, but I'm going to have bblades try to lab that out.

My stock 03 33zx with 500 efi's runs 78 on GPS if that helps.

we have a 1998 33zx with steps