daniel475

also carbs?? its EFI

GPM

I'm not saying not to add the supercharger, just saying be careful, it may handle fine at 90 and kill you at 91. It's a small V hull, Just an opinion.

fireboatpilot

Might not have been hard but it sure was EXPENSIVE!

Man, I'm spendin thousands now just trying to squeak out 2-3 more mph. If you want to do more than 75mph, get a bigger boat. Even if you don't hurt yourself or someone else your gonna ruin the comfort and usability of the boat for example, cutting up the hatch to install a scoop and not being able to have the honeys lay out on the back.

daniel475

haha they aint laying on the hatch anyways lol ... well with the EFI i thought all you have to do is get it programmed? thanks alot for the advice guys im just trying to work all the bugs out im thinking of starting this in september .. for a winter project.. just want to know what to do first etc.. im sure there has to be someone out there that has messed with this hull or something similar at 75 it feels fine .. and i know with more hp i could keep the leg trimmed down more .. im sure it would handle 85 fairly easy ..

PS thanks for helping out the youngster lol im 25 getting old now

osur866

Find a 454 mag or 502 with the good internals add a EFI Whipple to it and be done! Cheap NO but would be the most reliable IMO.

I had a merc 6.2 done over the winter with head swap, cam, and piston change along with a EFI Whipple took boat from the low 70's to 89 and am still working with props and mines an 18' Donzi Classic, in that size hull every 10 mph past 70 feels like about 25! I've spent the last 5 years getting the boat dialed in with steering, shorty, and some other small moods in preparation for the bigger power along with nearly 400 hrs of seat time, just dropping in a bunch of HP in a fairly new to you boat without learning how it responds is prolly not a good idea.
If you really wanna run those speeds take baby steps and really learn the boat and it's limits, your friends and family will thank you later for it!

Steve

28Eliminator

The internals from the 454 mag EFI are good for the whipple system. Whipple comes with it own intake, fuel pump and injectors. You may need to change fuel line, water seperator and pickup in tank. Depending on the year it is and if it has MEFI 1, 2, or 3, Dustin Whipple can reprogram it. You may have to upgrade the ECU but Dustin can hook you up with what is needed. How many hours are on the motor?
If you add any supercharger, I can not stress enough about installing new head gaskets. Cometic are what I would use, but I have used Felpro and not had problems. Even if it doesn't have many hours the stock head gaskets will not hold up, and you will be replacing them within a year or 2, but could cause more damage when they blow out.
Sounds like to fun winter project. At 20' that thing will be a rocket.

Budman II

iTrader: (1)

Some good advice by 28Eliminator, as well as the other guys. Don't forget to upgrade the exhaust valves to a high grade alloy like inconnel or the Ferrea Super Alloy. Lots of threads on here that touch on the need for this. Also, with EFI, stick with a shop that has a lot of experience with EFI superchargers. Get the mapping wrong on this and lean it out and bye bye motor.

The stock Bravo will probably handle the power in a light boat if you use common sense. However, a light boat like that will have more tendency to get the prop out of the water, and the loading/unloading/loading is what kills drives.

Rule of thumb is take your initial estimate for the upgrades, double it, and then multiply by an additional 20% for all the little clusters that will bite you in the ass. Remember, BOAT is an acronym for Break Out Another Thousand, and this is especially true for the high performance variety.

daniel475

thanks alot guys great advice .. sorry for any confusion this is a 454 EFI magnum motor with good internals .. can someone provide me with some links on where to buy the whipple or supercharger as well as the exhaust valves? sorry for the conufsion also ive been driving this boat for years my uncle owned it before me and ive been running it for a long time aswell as running a boat all my life .. my dad has a 19 ft modified tunnel from cougar with a 2.5 racing merc ive been running since i was 13 lol ... thanks alot guys seems like im heading in the right direction .. also for hours the motor is at 450 right now and it isnt hard ran hours at all ..

eichhoma

iTrader: (1)

450 hours and your thinking of adding a SC?
I would seriously consider a complete refresh, add your SC, and all the extras... and consider upgrading to at least a Bravo 1 XR. No way would a B1 last... I spent 22k freshening up two 502's in my cig 2 years ago. already had blowers, and the XR drives... hope you realize how spendy of a job this will be... whatever you are budgeting - double it. Think I am kidding on that - ask some folks on here. Good luck!

daniel475

like i said the hours on the boat have not been wide open hours at all .. thing has been never really been pushed .. also we have done compression tests etc .. the motor is fresh .. and this boat would be for just cruising around the lake im not doing any hardcore driving etc.. I thought the leg would be fine? i wont be doing any hole shots etc.. anyways thanks for the advice aswell does someone have some links for the parts that i needed? also forgot to say the boat has only ever been ran in fresh water never been in the salt at all