engine horse power

Am I to assume this engine is normally aspired? Turbocharged? Supercharged? At what RPM would you like to know the horsepower?

The information required to calculate the horse power of an ICE:

1. Mean effective pressure in PSI (P).

2. Length of stroke in inches. (L)

3. Area of the piston (square inches). (A)

4. Number of power strokes per minute (N)

The formular as I remember it PLAN divided by 33000. This gives you the answer in horse power.

If you use standard metric units you just use PLAN, no 33000 division required.

I learned this at sea in 1976 and i 'm just working on memory.

The hard one to get is the mean effective pressure as this is required to be graphed as the cylinder fires. We used a Dobbie McKinnes Indicator for this. (Not sure I spelt this correctly) This indicator gave you a graph which you attacked with a planimetor to fined the average or mean pressure.

It was great fun climbing on top of a large diesel while we were rolling and bobbing along.

Two stroke, Four stroke, Diesel or Rotory? ICE engines vary starting with the answer to this question.

150 +/- a long threaded spark plug

From experience, maximum horse power can be made most efficiently, albeit short lived, by way of an 'over-square' ( bore dia. exceeds stroke length ) 2-stroke, 4 cyl. in-line, nitro burning, directly-driven internal combustion engine. This is "Dyno" H.P. not "to the wheels" H.P.

Sorry, I don't have a clue as to the math calculations but the above descibed motor will, indeed, scare the crap out of you.

I have calculated the horsepower of your engine to a very precise figure. It is exactly the same as the torque at 5250 rpm. It was a lot of calculations, but it is all worth it if you are happy now.

I have calculated the horsepower of your engine to a very precise figure. It is exactly the same as the torque at 5250 rpm. It was a lot of calculations, but it is all worth it if you are happy now.

My engine has 197 FT LB Torque @ 2,900 RPM. What is it's HP at 2,900 RPM?

Oh no Mr Chevy. The formula is only good at 5252 rpm, not 5250 as I posted before. According th the formula at the below site, HP and torque are equal at 5252.

http://www.vettenet.org/torquehp.html

Oh no Mr Chevy. The formula is only good at 5252 rpm, not 5250 as I posted before. According th the formula at the below site, HP and torque are equal at 5252.

Hi Bob,

It's MrChevy as in www.MrChevy.com ... the "Chevy" part is about Chevy cars/engines that I have played with over the years. Woody Dark stuck that name on me 30 years ago with:"Ask MrChevy about that." (regarding their and other race cars at the time... But I suppose Mr Chevy would work for the Ken Chevy part, eh? LOL

Ah, but you should have said, (besides correcting your mistake) the HP would be 109 at 2,900 RPM. (that is what the formula is for!)

It has worked good for me for 40 years or more (learned it a long time ago) and one nice thing about it...it doesn't change!

I have all kinds of HP formulas for drag racing I have used over the years, use them in an HP 200LX http://en.wikipedia.org/wiki/HP_200Lx (they came out in 1994 and I bought one of the 1st ones available from a friend who worked at HP/Corvallis for $660.00 cash, delivered to me at the shop) with its Solver Function (HP's Solver is one of the coolest things for figuring things out I have ever found. I think the first time I used it was when I bought their 18c in 1986), have 9 of them (200 LX's) lying around the house and shop that I use on occasion, but bought a PPC PDA in 2003 that I had to buy a $100 software program http://www.infinitysw.com/home/ to get the same (sort of... it is missing some of the 200LX's solver functions) type of solver in a PPC (Pocket PC), on my notebook computers and the desktops too. A very well spent $100.00.

I have some formulas I have converted to Excel spreadsheets too. Here is one for calculating compression ratios in an engine:

http://www.kensdms.com/CRCalcMrChevy.xls

Save it to your HDD and pull it into Excel. Any of the bright green data boxes can be changed and the spreadsheet automatically changes where it needs to change. Fun to play with. Originally made it in 1991 in Lotus 123 which was on the HP 95LX I was using back then.

All in fun, of course. Learning is fun

Thanks for the link, Bob, the info is well written by Bruce. Enjoyed it.

Ken

Click our sign to go to our website...

We are an Automotive Machine Shop

http://KensDMS.com

Thank you. Now you have given me another toy to play with.