horses divided by cubes

[sunnen]

Any one got a opinon on how many horspower a good 4 cylinder or 6 cylinder should make per cubic inch in size? I heard some say as low as .13 x cubes and as high as .27 x cubes. This should start a good debate. forget the green and yellow I dont know how they figure in, some G's at 800 ci and so on.

 

[Dblair]

1 fore every 4 cu in that would make a 400 farmall about 70 hp for a good running stock tractor.

 

[RichB]

I think higher than .27 on a well built/designed 4 or 6 cyl. Oliver or farmall @ 200+ hp...try the math

 

[DiamondPuller]

Well they claim 150 hp out of a 426 M farmal.

 

[jd b puller]

All engines are different. RPM's play a huge factor, as well as efficiency. As a generic comparer I use the following that I derived from different people's dyno runs as well as stock data. usually pretty close, but no replacement for a dyno.

HP = RPM's * Cubic inches / Efficiency

Efficiency is a guestimate based on compression, carb, timing, cam, etc, all boiled down to a number.

Stock tractor with low (4-4.5:1 compression) = 10000

Built tractor = 7500.

 

[buickanddeere]

As others have said, figure rpms in there too.
Today a fairly modest two valve per cylinder, pushrod engine running on pump gas. Can make approx 1HP per cubic inch at 5500rpm in emission trim.
So by the same ratios. A well tuned, well built stock displacement, stock rpms JD G. Should make 75HP.

 

[Mike Bock]

4 cubic inch per horsepower is close for stock engines example ,404 in jd 4020 =100 horse,301 in 185 allis=75 horse

 

[Anonymous-0]

(quoted from post at 17:26:01 10/30/09) 4 cubic inch per horsepower is close for stock engines example ,404 in jd 4020 =100 horse,301 in 185 allis=75 horse

best way i know of for any engine is by cfms of airflow at 28''hg 301 allis got into the 100 horse way with a turbo.

 

[Anonymous-0]

Also where are we measuring the horsepower from . for instance at the flywheel or at the pto makes a difference.

 

[jd man]

So how would a guy get the most hp out of a older jd like an a or b that has the small pto on it and has been told that if you put the tractor on a dyno it will tear up the pto and things inside the trans.

 

[Anonymous-0]

(quoted from post at 17:51:19 10/30/09) So how would a guy get the most hp out of a older jd like an a or b that has the small pto on it and has been told that if you put the tractor on a dyno it will tear up the pto and things inside the trans.

what about the belt.

 

[Superih]

Baker build farmall, around 2.75 horse per cubic inch at the PTO.

 

[Superih]

yeah right, I wish, I ment 2.75 cubes per horse or 0.37 horse per cubic inch for a Farmall M

 

[jd b puller]

crank/belt

 

[mEl]

360 CID stock stroke DC Case, 120 Hp @ 1400 eng rpm. .34 HP - CID. mEl

 

[Mopower]

This varies with RPM and brand, but you can sort of figure for each type of engine. Baker's high h.p. per cubic inch on IH engines is evident by the speed capability and weight classes in which they pull.

If you figure LP gas compression or better on a healthy tight engine with correct carb, good fuel, and warmed up cam, figure .25-.27 h.p. per cubic inch in say AC, IH, MM.

Well ported high compression tractors with after market ignition systems and high grade fuels can make .30 to .37 h.p. per cubic inch. I don't know Oliver 6 cylinder numbers but four cylinder common engines hitting .35 are very good. Fords run far more RPM (3000 or so) and as such I would assume .40 per cubic inch is possible but I'm no Ford guy.

These are just observations because I take interest in monotoring this stuff. Our UB was .17 at best stock. Now it runs just under .25 per cubic inch. 9.5:1 compression, warm cam, 413 cubes, stock RPM, stock carb, stock heads. 100 h.p. at 413 cubes. I have observed good MM strokers at .34 per cubic inch. A little more in a 5-star because of extra RPM.

It's a neat thing to see. I wish more dynos were in use out there. Well, accurate ones anyway.

 

[Superih]

THAT is a good running case at 120 PTO hp.

 

[mEl]

Thanks. mEl

 

[Anonymous-0]

try .3970 for a ac i think that would be more realistic.

 

[Anonymous-0]

The promblem with doing horsepower for cubic inches is the head. to put it simply a head flowing say 160 cfm will make as much hp at 340 cubes as it will at 440 cubes if the bore size doesnt change only thing changed is stroke. the 340 cube will make its power at a higher rpm than the 403 cubic .you can trust me on this one.

 

[SingleFrontWheel]

yeah,...I remember when a certain one got put on the pto dyno.... Just had to rib ya...

 

[Anonymous-0]

(quoted from post at 19:30:37 11/03/09) yeah,...I remember when a certain one got put on the pto dyno.... Just had to rib ya...

We are getting close to hooking to the dyno for the 200 hp run. If it dont make it we will just fudge on the correction factor like everyone else so it does.

 

[jd plowboy]

take it to LW and put it on his dyno. it doesnt lie. it will tell you what you got