Comparing 245 ish horsepower Mercs: 225pm, 245, bridgeport

Printable View

10-07-2013, 04:32 PM
Fullthrottleguy

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.
10-07-2013, 07:31 PM
outasite

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
Ira Tindale

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.
10-07-2013, 09:22 PM
Fullthrottleguy

Quote:

Originally Posted by Ira Tindale

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.

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?
10-07-2013, 09:29 PM
outasite

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
Forkin' Crazy

Quote:

Originally Posted by outasite

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.

Same I heard and for a sales pitch. Doesn't a 225 PM have the same ports?
10-07-2013, 09:48 PM
outasite

Quote:

Originally Posted by Forkin' Crazy

Same I heard and for a sales pitch. Doesn't a 225 PM have the same ports?

I have sleeves for both sitting on my desk,The exhaust port is the same.The transfers on the 260 are a little healthier (wider)I think the chest is also different.Just breathes a little better.
10-07-2013, 11:42 PM
whipper

Quote:

Originally Posted by outasite

I have sleeves for both sitting on my desk,The exhaust port is the same.The transfers on the 260 are a little healthier (wider)I think the chest is also different.Just breathes a little better.

Yep chest work, SVS, tighter heads,higher revs to 8200 are supposed to really wake up the promax. You can spin 7500 every time out many times a day for a mile each time with a stock promax and live hundreds and hundreds of hrs. Im not sure to what rpm you would start hurting things though? Thats what I would like to know. Mines got close to 1000 hrs going to get freshened up and since this many hours and 8 years hasnt hurt anything at 7500 with 33cc heads I want to push this rpm range a little further. 40-1. I know guys saying they turn 8000-8200 regularly so that might be as far as I would try as its known for now without going bang on quite a few motors i know of. I like the 245 also but don't like the idea of nic for maintenance and cost reasons. Good oil and high quality materials should make the steel bores resistant enough to take some movement around them. But to what degree? Or degrees.:D In steel also side pinned or top. I would think what ever keeps the piston centered best at higher rpm will make the bores and piston last the longest at the highest rpm. That's another debate.:rolleyes: Im just discovering the real potential on these motors as I get closer to redoing one. As theres more displacement there's more potential for hp and torque. The 260 block is the same as the 200,225,all the same 2.5 block. Im not sure about the 280 though. I think they actually used a different block correct me if Im wrong on that. So basically starting with a 200 they all can be made up to 260 or even 300.:reddevil:
10-08-2013, 05:24 AM
tux974

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.