# Thread: How many hp? formula calculator?

1. ## How many hp? formula calculator?

hi...

every days... someone ask me... how many hp is now my ski...
I really don't know. some says 300 some says 350...

no one know a formula for calculate this?

for example...

we know:
-dispacement
-compression
-psi

aren't these paramenters not enough to calculate approximatively hp rated for an engine?

thanks

2. 10 HP for every mile you gain, Julio...

3. ,

4. This is what i was looking for!
Thank you

5. Still a lot of factors that are not taken into account ( bigger intercooler, better intake or exhaust). I would give the hp number you come up with a plus or minus 10 percent.

6. Also compression ratio and the fact that a turbocharged motor will output about 50 more HP over a supercharged motor. The formula above doesn't take that into account.

I've always use 10HP for every mile an hour gained on engine modifications and I have come to the same numbers as a dyno tested motor give or take a few HP, Julio...

Also compression ratio and the fact that a turbocharged motor will output about 50 more HP over a supercharged motor. The formula above doesn't take that into account.

I've always use 10HP for every mile an hour gained on engine modifications and I have come to the same numbers as a dyno tested motor give or take a few HP, Julio...
yes ... it's an easy way... to 'calculate'...
but is affected on the ride plate, the prop size, the nozzle diameter and degree, the pump...

i think a good setted pump and plate could give 5 mph or more, over a worst setup...
I think the formula is more accurate....

I tried some combination...
and values seems to me correct...

8. ## +1 by:

9. Originally Posted by rplaster
Still a lot of factors that are not taken into account ( bigger intercooler, better intake or exhaust). I would give the hp number you come up with a plus or minus 10 percent.
bigger intercooler, better intake... = more rpm.
more rpm = more hp.

10. Originally Posted by Ale
Originally Posted by rplaster
Still a lot of factors that are not taken into account ( bigger intercooler, better intake or exhaust). I would give the hp number you come up with a plus or minus 10 percent.
bigger intercooler, better intake... = more rpm.
more rpm = more hp.
Exactly, which is why that hp calculator wouldn't be accurate.

11. How come? That HP calculator has inputs for displacement, boost pressure, and RPM.

Originally Posted by rplaster
Originally Posted by Ale
Originally Posted by rplaster
Still a lot of factors that are not taken into account ( bigger intercooler, better intake or exhaust). I would give the hp number you come up with a plus or minus 10 percent.
bigger intercooler, better intake... = more rpm.
more rpm = more hp.
Exactly, which is why that hp calculator wouldn't be accurate.