Maximum WOT RPM for 454 MAG??

[Essex502]

Does anybody know what the Mercruiser maximum recommended RPM is for a 454 MAG at WOT?

[powerplay230]

Might be wrong but I remember it as being something like 4600-5200 rec' operating range for the magnum, and 4200-4600 (800?) for regualar BB. I am thinking of the carb engines I don't know if changed with FI engines.

[Essex502]

My 502 MAG MPI is 4800 - 5000 but my buddies 454 came in the boat that he boat used. There's no manual available and Mercury Marine doesn't have the older motors specs on the website. We think his 21P prop is too small a wheel for this motor but want to be safe.

[kevnmcd]

Isn't there a rev limiter on there? If so, I would select a prop that just touches it at WOT.

[rivercrazy]

I always heard that 5,200 is the safe limit for the 454 mag

[1stepcloser]

4600-4800 is the manufacturers recommendation.
5150 is the factory rev limiter.

[Essex502]

Originally posted by kevnmcd
Isn't there a rev limiter on there? If so, I would select a prop that just touches it at WOT.
kevin...he hasn't run it yet...we're trying to get the parts together to get it to the lake with what we think is the best combination so we don't have to dick around with it too much

[Sun burners]

My buddy's Placercraft with a Bravo 1 22' prop gets about 5100rpm's with a light load and ideal conditions,
Thats a 22' 454 mpi all stock

[duffster]

Essex 502 what is the top speed on your Sterling with the 502? And are you running a Bravo-1 or 3 if so what prop and pitch.
My Sterling with a 454 mag Bravo-3 running 28’s tops out around 65-67 full.
Also have you ever though about adding trim
Tabs to keep it from getting wild over 60?

[Relaxalot]

I have a 454 mag(385hp) with a 24 p Bravo one and a Carrera 257. It will run 64 mph with a stock prop at 4600 rpm. I labbed a prop and it runs 69 to 70 at 5100. It hits the limiter (5150) if the boat is light in cooler weather. What hull are you running with? I don't think this is a good comparison for a vee hull but I hope it helps.

[Essex502]

Originally posted by duffster
Essex 502 what is the top speed on your Sterling with the 502? And are you running a Bravo-1 or 3 if so what prop and pitch.
My Sterling with a 454 mag Bravo-3 running 28?s tops out around 65-67 full.
Also have you ever though about adding trim
Tabs to keep it from getting wild over 60?
We're banging the rev limiter with full tanks and a crew of two and all of our stuff. That's with a 23P Mirage Plus on a Bravo 1 @ a shade over 70 MPH and at Lake Mohave which is higher altitude than LHC. We also have tried a 24P Bravo 1 but there's way too much stern lift and the boat is squirrelly at speed. great out of the hole and midrange efficiency but chine walks and porpoises on the big end. Trying a labbed 25P Mirage Plus this weekend and expect good results from it.
The boat with the 23P Mirage Plus is rock solid at WOT. No need for tabs. With the 24P Bravo 1 it's another story. Very, very different driving experience.
duffster - you going to the Regatta later this month? We are.

[Essex502]

Originally posted by Relaxalot
I have a 454 mag(385hp) with a 24 p Bravo one and a Carrera 257. It will run 64 mph with a stock prop at 4600 rpm. I labbed a prop and it runs 69 to 70 at 5100. It hits the limiter (5150) if the boat is light in cooler weather. What hull are you running with? I don't think this is a good comparison for a vee hull but I hope it helps.
I believe it's 98 Ultra 21' but don't know the model. Previous owner claimed the boat ran 74 MPH but according to the prop calculators that's a little out of line with a 21P prop and given the RPM rev limiter settings mentioned.

[rivercrazy]

Originally posted by Essex502
Trying a labbed 25P Mirage Plus this weekend and expect good results from it.
Try to get out early this weekend. I hear its gonna crack 110 degrees! :eek:

[duffster]

Essex 502 - Yes we will be at the Regatta at the end of June. The name on the back of my Sterling is “To The Shore”.

[cjordan]

You can turn a Mag bottom end 6000 with no problems all day. I wouldn't want to turn much more than 6300 for any sustained periods. Your valve train will puke out before you hurt the bottom end of a MAG motor. I had a 502 Mag motor (stock bottom) solid roller motor I turned that hard with no problems and several buddies run stock 502 Mag bottoms in the 5800- 6,000 range with no problems in 250+hrs.

[MrScarabRacer]

i turn a 27 mirage and hit the rev limiter on my 7.4 carb engine. i have a question for everyone though. Can i disable or change the rev limiter to a higher rpm? i would like to be able to turn 5500 rpms to see what the boat will run. any help? thanks