2.4 BP vs 225 PM

[msethsmile]

What's the comparison between a 2.4 BP (225 hp) and a 225 PM?

 

[bc's xtb21]

I have never run the 225 BP, I assume you are talking about the carb version, but I currently run a center horn efi BP on an xtb21. I have also ran a few pro maxes, to me I think the pro max, being a 2.5 liter will feel a good bit stronger on the bottom end but on top I think the BP would be hands down he quicker motor. I'm gonna guess and say the BP would be about 5 mph better on top. I really haven't answered your question though,since I have not run a 225 BP, I would think in that comparison the top end would prob be about the same but the pro max would be quicker on plane and mid range. Just my 2 cents, hope this helped.

 

[procomp]

I've owned a few bridgeport carbs and a 225 PM. Those old carb motors really work well on a light boat however the promax's start and idle so nice, less smoke and get way better fuel mileage. I don't see really any real advantage to the bridgeport except for maybe the cost to purchase.

 

[suicidealli]

The bp will eat. Pm up'!!!!!!!!!!!!! More torque in a pm, better fuel consumption too.
A good bp will turn 8000-8500. They last longer under 8000. I ran 104 with my old bp on a ss with no trouble...
A bp is 240-245 hp stock

Roy

 

[K.Kiser]

I think the promax will win it overall... I've seen some very quick and fast allisons with 2.5 prostock motors (no internal modded 200 fish)... These motors have pushed XR01's past 120 mph with a big prop... The Promax is gonna torque harder, and prop'd for the 1/4 mile turn over 9,000 rpm and 100+ mph @ 1400 lbs ... Just my non-factually based opinion...

 

[suicidealli]

A promax with a custom fuel curve is different than a stock fuel curve... My bp had some mods and would turn over 9000. Stock bp will turn 8500, and rev way faster than a stock pm. A pro stock motor isn't stock... I have a friend with a built to the Gils bp that turns 10,300.. You have to compare apples to apples... My bp was quicker than my stock 260.. But your right you can make a promax run, and turn over 9000 with just a little work. Bp pistons are way better than pm's. JMO

 

[K.Kiser]

The prostock motors are 200's, but promax's aren't much different and I understand and agree with what your saying... I don't remember what kind of performance numbers the superstock 2.5 motors run, but the 2.4 carb motors used to compete really well in that class... The 2.4's got a weight break, but still they are inherently good running engines and very durable... Some will argue that the 2.4 and it's basic engineering is a more sound engine that the 2.5... I don't have the super NASA knowledge to argue it either way, but the ol' 2.4 has given many boaters a lot of good memories for a long time...

 

[suicidealli]

Yeah... I was building a 2.4 last year for pro carb b/c of the weight break. They lowered the weight last year even more, and I couldn't get that light. Lol. I sold it. The pm will have a longer life. Your right the 225, and 200 is very little difference. Ruck can change it to a 225 for next to nothing.
I prefer the behind the liner design. That is what I was making my bp.
Bp don't live real long, but they pull very hard... On a fishing boat the pm would be the best choice, but a solid bp is a mean little 2.4! Jmo


Roy

 

[bigtis]

A good bp will turn 8000-8500.

Roy

Roy, a dsra legal superstock 2.4 200 will turn an average between 8300-8800 depending on setup. I've only played with efi bp,s but I found it to come on alot stronger at 6k and above compared to a 2.4 200. I think the bp would make hp higher in the rpm than the 200. I've got a bp I've been thinking of rigging as an until it blows warrior..... Gonna have to see what she,ll spin with a 660 setup. I think on squeeze the bp will make 9500-10k

 

[Larry D]

a DSRA prostock motor is not even close to a 225 PM. the 225pm has different sleeves, porting, 7 reed front half and the exhust at the bottom of the block is cut like 260 and rod slots are different. The only thing not stock on a prostock motor is the ecu and the 32 CC heads. a stock 2.4 at the same weight will not run with a prostock set up and a modified one at the same weight would have trouble getten around on. later Larry D

 

[patches]

I consider the PS 200 to be a stock motor. Just my opinion and everyone has there own definition but an untouched long block makes for a stock motor

 

[msethsmile]

I was referring to stock vs stock. By stock, I meant out of the crate. Btw, the 225 bp was a carb. I recently bought back, for the third time, a bp carb. The last time I owned it was about 10 years ago. Anyway, differences I see: Bp-five petal front, quicker? 16 amp system w/ steel flywheel-quicker..(efi version had alum flyuwheel) PM 7 petal, behind the liner, 40 amp w/ humungous flywheel, steel sleeve, rev limit (ok, don't count the rev limit or oiler). IMO, don't turn a stock pm over 7k (rod bolts,bearing cages)

reliability? Didn't the 'bridge' on a bp have issues from heat?

 

[bassracr]

I was referring to stock vs stock. By stock, I meant out of the crate. Btw, the 225 bp was a carb. I recently bought back, for the third time, a bp carb. The last time I owned it was about 10 years ago. Anyway, differences I see: Bp-five petal front, quicker? 16 amp system w/ steel flywheel-quicker..(efi version had alum flyuwheel) PM 7 petal, behind the liner, 40 amp w/ humungous flywheel, steel sleeve, rev limit (ok, don't count the rev limit or oiler). IMO, don't turn a stock pm over 7k (rod bolts,bearing cages)

reliability? Didn't the 'bridge' on a bp have issues from heat?

SUPPOSEDLY..... the efi was rated at 240 and carb at 225. there were rumors that mercury underated the carb to help justify the price differance for the efi. i beleive john marles said he dynoed the stock carb engines at 240. i had a mercury engineer tell me many years ago that the efi bridgeport was closer to 260hp. who knows ??? the later bridgeports ,did have top pinned mahle pistons that were relieved in the bridge area and had a black coating on them.. i purchased some new replacement pistons that were like this.. some guys were drilling tiny holes there, or machining a flat spot on the pistons where the bridge is to combat the heat in that area ... i had a warmed up bridgeport back in the early 90'S that seemed to run as good or better than most 2.5s that were coming out about then. its been along time ago..but from memory ,my 2.4 seemed to perform a good bit better than my 225 promax i had on there.

 

[msethsmile]

Bassracr-
Along those lines, I heard the reason the 2.5 carb was (under) rated 245 was to one up the BP efi @ 240. A merc mechanic from the factory in Oshkosh said he thought the carb would run with the efi on a BP. I never owned a bp efi. I did have 2 bp carbs and 2 2.5 carbs. Remember those? I think they even made a 2.5 carb ss.

I was pleased with those old 2.5 carbs. Mine ran a 11.03 bracket on a 600+ # xr2001 with the wrong jets on a 100 degree day carrying a 50# bag of salt as ballast.

 

[bassracr]

I do remember all of those.. Did a lot of informal racing against them and they all seemed to perform similarly . Back then we would go to dale hollow lake and there would be quite a few stv's ,Allison's,hydrostreams . With an assortment of those engines.. Less and less showed up each year untill they were all but gone . Those were the days you could line up 4 or 5 of those boats and hear all them mercs howling down the creek . Would have never imagined back then it would fade out as much as it has

 

[suicidealli]

A lot of talk on this thread.. A ps motor is a. Stock long block, but the fuel system is completely different.. A stock 225 pm won't run with a 200 ps motor.. Not even close.

The bp efi ,and carb were the same hp. Merc did lower the hp rating on carbs.. Who would pay 1200 bucks more for the Same hp... A lot of extra $ in a efi motor as we all know...
the same with the 2.5 245/260.

Never seen a factory top pined 2.4 piston. The bridge was a factor. The early version was the mod vp. Merc found out with a exhaust port that big, it was a matter of time til it hung a ring. They decided to put a bridge accross the port.
The bridge could crack. If the pistons got hot enough, also put put some extra wear on the ring from the bridge.. The answer was put the bridge diagonal across. The "Z" port was created, but never put in production the 2.5 was borned. You could buy a z port power head or block tho..

Roy

 

[bc's xtb21]

I was told by Jim Ruck a few years ago that the difference between a mod-vp and a BP was the bridge, obviously, and also the mod had 1/100" higher port timing. Also the early bp's were chrome bores whereas the last couple of years were nic motors. As far as a fishing motor I think the pro max would be the better choice, milder mannered, steel sleeve, longer lived, but man those old 2.4's sure would wind on up.

 

[msethsmile]

suicide--
Yes, I had a z port back in the day. Forgot about the cracking on BP's--good point.

Bassracr--
All those rigs are gone from Dale Hollow? That's too bad. I was there once, years ago, and saw some very fast rigs.---And I got lost. Don't ever admit to the wife that you're lost--just keep driving...

 

[msethsmile]

I bought my original 225 bp for $6700 in the crate. Add a new stv for 6200 and had a turnkey 100 mph boat for less than 13--all new. Those days are gone...

 

[procomp]

I bought my original 225 bp for $6700 in the crate. Add a new stv for 6200 and had a turnkey 100 mph boat for less than 13--all new. Those days are gone...

wow, you must be old! LOL :at the bar

I have a fresh 225 promax if your shopping but its not new in the crate and I'm looking for 6K. Not too far a drive.