18'' donzi, 500 hp possilbe to run 75??
#21
Registered
Joined: Mar 2010
Posts: 491
Likes: 0
From: Cowichan Station BC
Settle down Carl...........
In reply to the OP, I once owned, seems like many moons ago, an 18C with a 377 Scorpion, I put an Imco 2" shortie on the Bravo upper, 17" Dana tabs mounted horizontal to the hull (still taking flak for that) hydro steering and ran a 25P Mirage Plus and saw mid 70's on a regular basis....IMO the secret to the Donzi 18 hull is BALANCE.........decent power (small blocks with high HP seem to work better than big blocks, I guess due to the weight and CG...?, suitable outdrive, hydro steering and tabs.....I learned early on that the 18s can be a handful but with seat time they are a treat to run.....good luck if you proceed with the build..............

In reply to the OP, I once owned, seems like many moons ago, an 18C with a 377 Scorpion, I put an Imco 2" shortie on the Bravo upper, 17" Dana tabs mounted horizontal to the hull (still taking flak for that) hydro steering and ran a 25P Mirage Plus and saw mid 70's on a regular basis....IMO the secret to the Donzi 18 hull is BALANCE.........decent power (small blocks with high HP seem to work better than big blocks, I guess due to the weight and CG...?, suitable outdrive, hydro steering and tabs.....I learned early on that the 18s can be a handful but with seat time they are a treat to run.....good luck if you proceed with the build..............
#22
#24
Registered

Joined: Mar 2010
Posts: 1,821
Likes: 6
From: morehead n.c
#25
Registered

Joined: Dec 2001
Posts: 3,922
Likes: 393
From: Indianapolis, Lake Cumberland
#26
Registered

Joined: Mar 2010
Posts: 1,821
Likes: 6
From: morehead n.c
#28
Registered

Joined: Jul 2007
Posts: 220
Likes: 0
From: Lake Winnebago, MO, 43MM LOTO
These lil boats are a blast to run, however when you go past 70 in the 18 Classic set up and seat time becomes very, very important, and you had better respect what they can do!!! I've transformed my stock 70 mph 18 into a well handling 90 mph boat, just remember to always wear a good life jacket and lanyard and respect what they can do!!!!!
#29
Registered
Joined: Jul 2005
Posts: 340
Likes: 0
From: Southeast
Tried to drum up interest on another site, but fell flat. Whoda thought...

Thanks in advance.
Last edited by GB; 01-09-2012 at 05:55 PM.
#30
Registered
Joined: Aug 2005
Posts: 6,306
Likes: 1
From: Between A Womans Leggs in IL
77 x-18 here,will run 68 mph no matter how many people on board with a full tank,,72 in 2-3'chop lite on fuel and just me and 77 with a 100 shot of nos in the past,,,was a hand full with the nos so i removed it years ago..oh 434 hp sbc and a tweaked volvo 280 and a labbed ultra prop..



