heatwave3

I have a Baja 272 running a 502 efi with a Procharger M1sc using a 4.25in blower pulley that generates about 4-4.5#s of boost at WOT. I'm running a 26" Bravo1 at about 4900rpms WOT. Top speed is 75-76 mphs. Currently I have an 8 rib pulley setup. The engine temp runs at 125degrees at cruising and about 150 during WOT runs. Running approx. 50 psi on fuel pressure. ECU done my Arizona Marine. I have stock 502 injectors, stock 502 heads and stock cam (due to Silent Choice which I want to keep). Upgraded to roller rockers, upgraded head gaskets and Stainless Marine Exhaust. Boat is currently running great with very little if any soot after a full day's run.

Of course I'm looking for more.... Talked with Procharger and they said I would be fine with the stock injectors if I upgraded to a 4.0" blower pulley.

My questions:

1) Will I be OK with the 8 rib pulley and belt setup once I install the smaller pulley? I have had no slippage to date on my current setup once it was fully tightened. Will I need a new belt or is there enough adjustment to acommodate the smaller pulley with the existing belt?

2) Will I be OK with the stock injectors?

3) How much more fuel pressure am I likely to need?

4) Will a 4" blower pulley (instead of the 4.25") generate 2-2.5 more #'s of boost (at the same rpms - 4900)

5) If the blower delivers 6-6.5#'s of boost and I upgrade to a 28" Bravo1, will I still be running at about 4900-5000 rpms?

6) How reliable with this setup be and will I be OK running mostly 94 octane but the ocassional tank of 89 or 91 with octane boost added?

7) Will I break 80mphs?

Feedback from the experts on this forum will be really appreciated as I was considering the pulley change-out in the next week or 2. Has anyone run a 6-7psi Procharger setup on a 502 efi with an 8 rib belt and how successful was the setup? Thanks for any and all feedback.

blownboat

off the subject ,what plugs are you running? Thanks

heatwave3

Blownboat,

I'm running Champion V63C's. Any feedback on the choice of plugs for my setup?

blownboat

There is about 2 million threads on here on plugs. Many swear that rapid fire plugs keep black soot off back. Just wondering what you were running. I am also running a seven pound m1 procharger on a 502 mag mpi. I also had mine reprogrammed by az speed&marine, 50 lb regulator. I have a computer program that I can hook my labtop to that looks at all the engine parameters. That way I can also make sure it is not running lean. Only problem I had is 2 blown headgaskets. I bought the boat with the charger on it and they did not change the headgaskets.

blownboat

What year is your setup and what state are you in?

heatwave3

I'm in NJ. The engine was a new crate engine in 2003. I bought the blower and boat separately from the same owner and had the blower installed by RW auto/marine performance in Harrisburg, Pa. We ran it on the river with his laptop hooked up to the engine to check all operating parameters. It's been a solid running setup and I hope by adding 2 more #s of boost I'm not pushing my luck and reducing my reliability, particularly if I'm stuck with some lower grade gas.

What boat are you running your setup in? Performance? Prop? Plugs? Timing? I'd be interested in more details on your 7# setup and how may hrs you have on it. Were you able to get your 7#s from the 8 rib belt or did you move up to 12?

Thanks for any additional input and any lessons learned.

blownboat

I think mine is the 8 rib, base timing 10degrees , the boat is a 25 eliminator daytona. 30 lab bravo 1 prop. ac 42ts plugs. Pulling heads tomorrow to do the head gaskets. My setup is a serpentene belt. I moved the intercooler over and plumbed it with stainless tubing and put the recirc pump back on with a 120 thermostat. I had a bad pressure problem with the way procharger had it set up now. I will see if I can attach a picture.

heatwave3

Here on the East Coast we typically remove the thermostat altogether. One less part to go bad. My mech than puts a restrictor after the water by-pass line (SS nut that tightly fits inside the water hose and held in place by a SS hose clamp on the outside of the hose), if the engine is running too cold without a thermostat. Once we placed the nut in the line the engine temp has been dead on 125-130 degrees at normal operating RPMs and no higher than 150 at WOT even for relatively long runs.

What do you mean by "bad pressure problem"?

blownboat

When I bought my boat the thermostat was removed and there was a restricter in mine also. I was going 80 mph and the hose on my oil cooler (main water feed) popped off. Filled back of boat up with water and luckily the computer shut the motor down. I put a pressure gauge on the block because I figured it had to be alot of pressure to do this and it was 50 pounds at 55 mph. Lots of people on this board have taken their recirc pumps off and there is lots of threads on this. Alot of guys are running a relief valve. I like the recirc pump because the water temp reaches 120 -125 before I am out of the no wake zone and then the temp always runs between 120-130. I think this is better for an injected motor. Just my opinion but I have had good luck this way. Moved the intercooler water feed before the motor and my intake air temp never gets over 120 degrees, and the air temp out here is already 110 degrees.

articfriends

Heatwave,i was running almost identical setup 2 yrs ago (272 baja,502,m-3sc),with the 4 inch pulley i had no problem running 4"pulley/8 rib drive as long as the belt was fairly tight. I went to a 3.85 and it slipped intermittently,changed to 12 rib drive then (its REAL hard to get the belt on because there is so little room between the back seat). Are your speeds on gps or speedo? I was getting 79 with 4"/28 pitch 4 blade at 5000 trimmed up high but i also had lightning headers,merlin heads and m-3 not m-1. The intercooler on m-1 is smaller so don't even think of running 89 octane gas at 7 psi boost(in your procharger manual you'll see the m-1 needs higher octane then m-3 because of smaller intercooler). Are you using a boost referenced fuel regulator? The one procharger sells is a real piece of JUNK and stuck all the time. I bought one from bell industrys in texas and run a nice aeromotive regulator to control my base presure then the bell industrys one on the return line from first one. This allows me to have a nice steady base presure then progresive raise pressure at higher boost. If you haven't put hydraulic steering on your baja it's time to think about it at these speeds also,mine was outright dangerous at 79 mph without it. If you going off your stock speedo,it's pretty generous too (about 6 mph faster then real speed when it shows 80-your going 72 or 73,at least mine did). I hope i helped you a little,if you want to call me,989-823-7319 after 5 0r 6 pm,and if your blower has same size shaft i have 4.25,4.00,3.85 8 rib pulleys i'd really like to sell,could ups you one in next day or two,Smitty