Mercury Engine Torque Ratings

[Glastron1987]

Anyone have any of the engine torque ratings for the 2.0, 2.4, and 2.5 135-280hp engines? For some reason it's always been hard to find these, but seems it should be basic information supplied by the manufacturer.

Curious to know how my 1988 XR4 2.4 would compare with my 1994 150 2.0, but also curious how these size up with the new 4-strokes that are advertised as having lots of torque. Hard to imagine more torque coming from an engine with less cubes and firing less frequently.

[KIRCHNER]

have to agree. you can even find peak h.p. at specific rpm. just an fyi, my 2.0 150 had just as good hole shot as my 87 2.4 220. the 4 strokes are using tuned intake, var valve timing and low gearing. lots of r&d on air flow, hi-tech stuff. my 175 suzuki 4 stroke specs just gives max rpm. a basic power curve graph would be nice. as for torque, the suzuki was unbelievable low end, i dont know how the jack-plate took it from a dead stop, instant power.all you need is deep pockets!

[Motv18]

If you have the hp x rpm just work the equation backwards since it takes rpm and torque and a constant to provide hp.

[mach351]

Yep you can always go back to engine 101 and get close.....

Horsepower = Torque x RPM / 5252

[Glastron1987]

Yep you can always go back to engine 101 and get close.....

Horsepower = Torque x RPM / 5252

Not sure it that will work to find the peak torque of an engine?

[Motv18]

Yep it will. Peak torque and rpm equal hp at that rpm.

[Glastron1987]

Yep it will. Peak torque and rpm equal hp at that rpm.

So for an engine rated at 150hp at 5500 rpm:
150 = T x 5500 / 5252
T = 150/5500 x 5252
T = 143

Something is missing, the peak torque of my engine I believe has to be more than 143.

[Gordon02]

Peak torque will always be produced at an rpm lower than and before maximum horsepower values are generated. As horsepower is calculated using the math shown, torque can go down while rpm goes up and the engine will have increased horsepower.

Peak torque is generated at the rpm where "maximum volumetric efficiency" is achieved (thus cylinder filling efficiency). It is only when torque falls off quickly that the calculations of horsepower drops with rising rpm. Gordon

[mach351]

Peak Torque May be more, but it’s not much. The math is a constant. Most of the time the hp curve and the torque curve will intersect at 5252rpm. There are abnormalities, but this usually runs pretty true. Your 143pound feet may not be far off for an engine less than 150 cubic inch.

[Gordon02]

Quote - "Most of the time the hp curve and the torque curve will intersect at 5252rpm

I respectfully disagree - I've done a lot of work with motorcycle engines and peak torque is more often around 2/3's of peak rpm. It's not surprising that this is where maximum fuel efficiency is produced. Peak torque is produced where the volumetric efficiency is at it's highest and the engine is operating at it's highest level of twisting force. I've got some old Land and Sea dyno charts somewhere in my library of articles, I'll try to dig some of those for scanning this weekend. Gordon

Update - here is an article from 2000 as measured from a carburetor model 1990's 200 horse Mercury.

[mach351]

Check what is said.....I didn’t say 5252 is peak torque.....that’s just where the curves intersect. Right where that mercury ad says. It’s hard to generalize engines as a whole, but horsepower and torque numbers are nothing but math. Horsepower is a function of torque, which is what is really measured then computed by a dyno. High output high rpm bike motors are going to be outliers obviously. High performance outboards might fall a little outside the lines, but the equations will get you close.

[Glastron1987]

Quote - "Most of the time the hp curve and the torque curve will intersect at 5252rpm

I respectfully disagree - I've done a lot of work with motorcycle engines and peak torque is more often around 2/3's of peak rpm. It's not surprising that this is where maximum fuel efficiency is produced. Peak torque is produced where the volumetric efficiency is at it's highest and the engine is operating at it's highest level of twisting force. I've got some old Land and Sea dyno charts somewhere in my library of articles, I'll try to dig some of those for scanning this weekend. Gordon

Update - here is an article from 2000 as measured from a carburetor model 1990's 200 horse Mercury.

Anybody have a torque chart like this for a 2.0L 150?

[David]

It would be wonderful if the engine companies published the complete torque and HP curves instead of one peak HP number.

One of the surprises (pleasant) of my life was that a 225 PM pulled a lot harder at low speed than the 150 XR4 it replaced. I had sort of expected that Merc shifted the torque curve up the rev range to get more power.

[Chaz]

It's TMI for most people. And what your's would make compared to the next guy could be up or down a few and then there's always some guy that's gonna complain. If it really matters that much, put it on the pump and tug on it ..

Garbage in - garbage out .. I got too much V.E. off the bottom, so that's artificially high, but you get the idea ..

Ok ,, so if a diesel makes 700 ft/lbs and only spins 2500 rpm ..

How much H.P. does it make ???

[mach351]

If you spun that 2500rpm cummins up to 5250 I bet that torque number would be way lower....mostly because the crank would be in multiple pieces lol