I hear about guys procharging 496 Mags. Do they first upgrade it to a 496HO with a cam and ECM change, and then add the procharger?

-Craig

Hello,
I'm interested in doing the same thing. A technician at a performance boat shop near me said he would add the Procharger to the MAG and wouldn't waist the money on upgrading to the HO version. I'm still wondering if I need to upgrade my stock bravo 3 to and X version.

I had a neighbor that wanted to do this last year so while at PRI I talked to one blower Mfg of centrificals and they said no. Due to emissions OEM have modified the stock OEM pistons and in doing so have made them not blower friendly. Now some have done it and gotten away with it, but some have done it and had catastrophic losses. I would compare it to playing Russian Roulette with 3 loaded chambers.

I hear 4-5 lbs of boost and avoiding detonation at all costs aka Premium Gas is a must if supercharging 496's..the piston coating is brittle...thanks GM....that should get ya near the 475 HP mark...I personally like Whipples.

Check out the torque curve in the 496cu 375 HP engine...the 425HP is about the same...you will see that the max torque of 490 lb ft comes in at 3200 RPM...great for planing...however the 375HP is not seen until 4800 RPM and the torque curve is squat low at that point. A good torque curve for cruising at say 3500 RPM in a SeaRay but WOT in an offshore leaves you very low on torque.

A Whipple at 5 lbs or Raylar's heads..cam...intake and some Stellings can get you to 500 HP. But it is obvious from the torque curve that this puppy was not designed for what "we" have in mind whereas the 502's had much better power bands for offshore use at WOT and were more adaptable to modification from a parts and durability standpoint.

http://www.gm.com/automotive/gmpower...std_marine.pdf

To procharge a 496 the cam & pistons do not need to be changed. HOWEVER Low boost & premium fuel is recommended. If memory serves me correct about 3.5 psi & an injection modification. Once you put higher boost to the 496's it's hard on them. The only direct kits available from procharger are for the early 04 and prior(spin on water separator fuel system). The newer 496's have a integrated fuel pump/filter system in a black box instead of the spin on version. If supercharging one of these MoFo's currently the fuel system would have to be retrofitted to the earlier style injection. If it was my boat and an earlier 496 I would be comfortable in running one as long as the boost was low. On the new series I'd wait until procharger has some dyno time on one with the new fuel system... Jamie
www.LakesideRestorations.com

I had a 2003 496 375 HP 3.5 Procharger in an Advantage. I ran 93 octane and went from 62 mph to 76 mph GPs. My outdrive was a plain Bravo. I used a 28 Bravo One prop on a 1:5 gear. Nothing but good results. I did not thrash the rig but I ran it several times for 15 minutes at WOT with absolutely no problems. I had a total of 60+ hours on the rig when I sold it.

I believe the key to longivety on this setup is discretion in rolling on the throttle and no long trips at WOT. Whats new?

If I wanted an inexpensive way to make low tech HP it would be a 496 375hp with a 3.5 Procharger properly installed and set up. The 425 HP 496 is about $10,000 more than the 375. The Procharger on a 375 costs about $5000 or $6000 more and yields 500HP or better.

Thats 75+ HP for $4000 less money. { Whipple is (or was) good. Cost lots more. Maybe doesn't exist.}

Thanks everyone for the replies.

-Craig

The up-charge on the mag to the H.O. was 3,500..... not 10K