PDA

View Full Version : Best Prop for a 27 ZX twin step 500 EFI



Last Real Texan
08-10-2005, 09:16 PM
Tested today again and it had a tune up after de winterizing...much better I was wrong about the prop , it was a 24 4 blade Bravo one, turned it to 5500 and 67 MPH .... I am thinking it really needs a 26 pitch for sure now , they say you can figure 4oo revs down per 2 inches of pitch, correct? What do yout think ? I know Frank has tested every prop out there on this hull.......Hoping to pull at least 70 out of it.


Bryan

fasttrucker
08-11-2005, 07:26 PM
Iam using 26 pitch lab from throttle-up on my 1998 28zx w/500hp+

Last Real Texan
08-11-2005, 10:08 PM
Iam using 26 pitch lab from throttle-up on my 1998 28zx w/500hp+

What speed and how many revs....please.
Bryan

undertaker
08-12-2005, 10:10 AM
LRTexan shoot Frank a pm or email or even give him a call, he knows a lot of stuff about Donzi boats IMO and especially the 27ZX. Good luck :D

Undertaker :wavey:

The Hedgehog
08-15-2005, 09:44 PM
Iam using 26 pitch lab from throttle-up on my 1998 28zx w/500hp+

Did you ditch the MPI for a carb? If so are you happy?

fasttrucker
08-16-2005, 06:45 PM
Yes,went to carb.Had block and heads sent to machine shop.Put in larger s.s. intake valves,c+c,Decked block,ect. Put in the crane cam.msd ign.victor Jr. intake,holly double pumper.german timing chain.As far as the speed goes,my speedo reads up to 80mph.Ive gone that fast this spring in the cooler temps,alone with the wind+waves 1/4 tank.but normally get it to read 75 or 77mph :wavey:

The Hedgehog
08-16-2005, 08:35 PM
Yes,went to carb.Had block and heads sent to machine shop.Put in larger s.s. intake valves,c+c,Decked block,ect. Put in the crane cam.msd ign.victor Jr. intake,holly double pumper.german timing chain.As far as the speed goes,my speedo reads up to 80mph.Ive gone that fast this spring in the cooler temps,alone with the wind+waves 1/4 tank.but normally get it to read 75 or 77mph :wavey:

What kind of exhaust are you running? If the pipes are efficient you should be hitting 530+ hp! That in your boat should be pushing well into mid-high 70's. You should be able to run down the twin engine boats pretty good.

You ever think about putting a procharger and r-tech supercooler on that bad boy? That should put you solidly in the 80's on the gps.

Are you happy with the carb conversion? Did you run with a modified MPI for a while? If the fuel economy difference noticable?

Shanghied Again
08-17-2005, 03:02 PM
Try a 26 Pitch prop lab from throttle up, If this does not work sent it back to throttle up and have them shave it to a 25 Pitch first cut is free, you should see 69-70mph.

Last Real Texan
08-17-2005, 05:28 PM
Try a 26 Pitch prop lab from throttle up, If this does not work sent it back to throttle up and have them shave it to a 25 Pitch first cut is free, you should see 69-70mph.

Thanks Frank I will keepe you posted on the outcome.......

fasttrucker
08-17-2005, 08:25 PM
:yes: THATS WHAT i SAID "26 pitch throttle-up" :biggrin: I forgot in my post I added stainless marine exhaust with straight pipes out the back...sounds good!Iam running 5200rpm maybe a little more depending on weight.

fasttrucker
08-17-2005, 08:28 PM
I well SPANK :smash: the twin engine boats.....I love to run up next to a fast boat hit my throttle....then leave them behind. :outtahere

fasttrucker
08-17-2005, 08:30 PM
Oh yea! carb with the right intake is free H.P. I have my mech. tune it up every season.Starts everytime!idles great