User Tag List
Thanks: 0
Likes: 0
Results 1 to 9 of 9
Hybrid View
-
10-07-2013, 04:32 PM #1
Comparing 245 ish horsepower Mercs: 225pm, 245, bridgeport
Ok so I pick up my new to me '97 2.5L 225 promax tomorrow night and apparently they dyno at 245 HP to the prop. This is very similar to the 2.5L carb nic motor's rating of 245 and that of the 2.4L 240HP Bridgeport EFI or the 252HP Carb Bridgeport Mod-VP. I realize that out of the three the promax is the only steel bore motor and that it likely has more low end torque as it can make its rated power without having to spin to the moon. 6800 vs 7500 ish. I would assume dock manners would have to go to the promax too. My question is: If each was put on the same boat and setup as best as possible which motor would be the fastest? Horsepower is simple a measure of work so am I correct in assuming that they would all reach the same top speed if prop'd correctly to reach their powerband and make their rated HP? How about acceleration? Just curious as my promax will be competing against a buddy next year who's similar boat has a 2.4 Bridgeport. Than again the 235 Johnson I'm taking off my boat already runs down his Bridgeport.
1989 21' Skater - twin 2.5s
1986 Cougar 21MTR, 15" 300XS - sold
2002 TUFF 21 (#0.1), 300xs - sold
1986 Valero YT, 225 Promax - sold
1987 Viper, 140 cross flow - sold
-
10-07-2013, 07:31 PM #2
Maybe I,m wrong but your math suggest that the 245 carb has the top end nod.If the PM is 245 and turning 6800 and the carb is 245 and turning 7500,they both should turn equal pitch wheels,That should give the top end to the carb.A drag race to 7000 would very likely go to the P MAX. JMO
-
10-07-2013, 09:01 PM #3
I own a 225 promax and a 245 nic. The 245 with the same setup as the 225 will out accelerate it and out top end it by 3 mph. Turning a 28 cut chopper.
2008 Mirage V-Racer 1983 2.0L Mercury 15"
2010 Mirage V-Racer 1987 2.4 Original SST140 Powerhead
1974 Hydrostream Viper
1977 Hydrostream Viking
1995 Mirage River Racer " Boat On Loan" Thanks Mike Mullins 2.5 245hp 15"
-
10-07-2013, 09:22 PM #4
Well there's my answer I guess. I surprised the 245 would have the low end torque to pull on the promax so far away from its peak power given that they are the same displacement. Maybe a 245 has more compression. Does a 245 dyno its nameplate? What about a 260 or 280... do they dyno their nameplates or are they under rated like the promax?
1989 21' Skater - twin 2.5s
1986 Cougar 21MTR, 15" 300XS - sold
2002 TUFF 21 (#0.1), 300xs - sold
1986 Valero YT, 225 Promax - sold
1987 Viper, 140 cross flow - sold
-
10-07-2013, 09:29 PM #5
It's been said many times, that the 245 gives up little to nothing against the 260 on top.Merc badged them differnt to justify the horn.
-
10-07-2013, 09:40 PM #6
-
10-07-2013, 09:48 PM #7
-
10-08-2013, 05:24 AM #8
The 225PM is an awesome and very reliable motor when built/setup properly, yes it will be a tad slower than a 245/260.
The only difference I found with the 2.5 245 nic and the 260 EFI motors is low end throttle response, they will run exactly the same up top. Personally I would take a 245 or a 260 any day.