Eclipse232

Hey guys, probably another stupid question you guys are tired of reading which i apologize for now...

Can you supercharge a stock 454 magnum with a pair of emi thunder exhaust manifolds? I would think that i would need a new carb and i would have to reprop with a larger pitch to account for the higher rpm. Other than that I can keep the motor stock correct?

Another thing, ive heard procharging the motor is a little easier on the outdrive? Is this true? Would you guys go with a procharger or a roots style supercharger? What is the cheaper of the two?

Thank you guys for any of your help, I appreciate it

t500hps

The 454 mpi cannot handle the air pressure, but the MAG motor will be fine with 5psi or less. Everybody I know who has had Prochargers has removed them due to tuning issues (I bought my boat with them and removed them too). You likely will not need a new carb, but will need a new prop.

Eclipse232

What kind of tuning issues have people run into?

blue thunder

I would say efi tuning issues. I wouldn't attempt it with efi unless I had the software to be able to map my own fuel curves. A carb you can tune perfectly yourself and the engine will give great results. I run roots blowers (177s) with 9.5:1 static compression and 6.2 psi and hypereutectic pistons. Very strong combo. You just need to pay attention to detail on the setup. Things that might concern me on your application with existing engines are; head gaskets, top ring end gaps, exhaust valves and fuel system. Of course you need to change your timing advance curve as well. Other than that, you have a great platform.

getrdunn

iTrader: (7)

if you are thinking of doing this i would spec it out similar to that of the 525 sc. you could probably get away with a bit more comp. and down size the carb though. the 525's have the same internals to that of a mag with the exception of the pistons however they are balanced and blue printed at merc hi-perf.

ezstriper

if it's a carb 454, yes, no problem, a weiand 177 and good blower carb, fuel pump, and keep the boost at 5 psi you will fine as long as the engine is fine now....Rob

Eclipse232

Yes i have the 454 magnum that is carbureted. I dont plan on running too much psi. 5psi max.

"Things that might concern me on your application with existing engines are; head gaskets, top ring end gaps, exhaust valves and fuel system."

Do you think I should replace them just to be sure?

Sunshadow

I had prochargers on my 32' Baja. Stock 454 mpi, 5psi pulleys had to up the fuel pressure and pump volume. Managed to swing 28 pitch Bravos good for 70 mph + depending on load. Never had one problem. I only owned it for 50 + hours after prochargers and engines were freshened at the time.

blue thunder

I wouldn't, not until I had to. You do need to get a good flowing fuel pump and make sure you fuel pressure maintains above 6psi. Also a v-6 tbolt ignition module. Then only run a max of 30* total timing and an a/f ratio no more than 12:1. Also run no tstats and keep the engine coolant temps low, around 140f or so. Most of the 2 years on my engines were with pulleys that got me 5psi. I just went to the 6.2 and will probably go back to the 5psi once I get some new speed records

BTW I did like getrdunn said. Bought 525sc takeoffs and modelled thier build. All but the compression really. With the small 177cfm blower you need a little more static compression or you will spin the blowers too fast and create heat.

Eclipse232

So i would need an electric fuel pump. What would i do with the fuel pump that is attatched to the sea pump? Leave it connected and just disconnect the lines?

Also, it is a 1997 454 magnum, I believe it has the thunderbolt ingition.

Again, me being ignorant, if i were to get a 177cfm blower, what would i have to do to create more static compression?