I have a 2001 Classic with 502 mpi's - only 60 hours. I have added k&n filters, msd igintion, cmi headers, dart pro one aluminum heads, computer upgrade, and extruded intake manifolds. I have the stock 26 hydromotives 4-blades. I am turning 5,250 rpm at 79 mph gps. Great torque, but not enough top end.

Arizona Speed recommends two options: 540 upgrade - 630 hp or a supercharger (Vortech or Whipple), leaning toward the Vortech - 700+ hp. Any ideas on top speed with either set-up? They both cost about the same. I would appreciate any help.

I have no experience with Ariz Speed. Some OSO brothers have and I would contact them before you do the deal. Here is a recent thread.

http://www.offshoreonly.com/forums/s...=arizona+speed

i would whipple that is what i keep seeing around here and the run hard,,
seems from the blowchargers that have more issues.. i amabout as far from expert onthis as u can get.. but i was going to do that on my old 35 and i decided against.
and bought diff boat.. seems that its geographical.. here it seems maily whippleover vortech pro charger style blowers prob has something to do whti the guys that have shops in ea area......
i think i t comes downt to who is gonna set ip up and make it work right and not be a nightmare,,

I would definetely recommend either whipples or an upgrade to your existing engines. The whipple kits are great, and will make 700HP. Keep in mind that the top end of the engines need to be upgraded. Also, some port work would greatly help as well.
We also offer an upgrade package for you existing engines that would get you to 600+HP.
We can put together either package, dyno, and complete the engines and ship them to you ready to install. We also offer a warranty on all of our engines and rebuilds. Give me a call if we can help you in anyway.

Thanks,

Steve

Tyler Crockett can make a 502 MPI sing. He has his own cam and does some valve work and gets 100hp and 100 ft lbs. of torque. The major cost of his upgrade is the labor and good exhaust. You already have the exhaust. Hot Boat had a article a couple of years back on this upgrade to the 454/502 mag mpi by Tyler. You can call him and he will answer your questions. Best friend had a pair of zz502's built by Tyler, 610hp/650lb's torque. Motors were N/A and very turn key reliable, never had a problem in 2 summers.



Jan

We just installed Rtech supercharging systems on a 1996 35 Fountain single step with 502 MPI engines. We use the Vortech blower and our own design "supercooler". We are working with Arizona Speed & Marine to dial in the ECU. We will keep you posted or check out the thread "Rtech Supercharger on 502 MPI"

Results today were encouraging. We went 94 mph on GPS with three on board and 1/2 tank of fuel. But we only reached 4900 RPM and 4 psi, there is obviously room for more. We had the scanner tool hooked up and saw 30 degrees total timing with no knock sensor activity. Smaller pulleys are on order.

To answer your question about top speed, we figure the engines are only putting out about 625 HP right now. With the smaller pulleys we expect about 725 HP and over 100 mph.

(tom) tomcat, where are you conducting the tests??...do you still have your cat?

Speed is good Tom. Not real crazy on the box look but I guess they have to go someplace. Would that look any different on 502 carb's?

twinn29: Testing on Cook's Bay, Lake Simcoe south, boat is at my dock in photos. Sold the cat to my brother to help finance the supercooler business.

Downtown42: Form follows function; you wouldn't believe how important it is (to air flow) where and how you position the intercooler between blower and throttle body. The intercooler housing for carb engines is completely different because the carb is in a different place. You learn to love the looks when you feel the extra HP!

First picture shows relationship between blower outlet and throttle body inlet.

Second picture is how a pair of the carb supercoolers look. These went into a new 43 Black Thunder. They made 875 HP @ 5800 RPM on the dyno.

Third picture is a close up of the inside of the carb supercooler.