[HELP] Calculate Horsepower

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[HELP] Calculate Horsepower

Postby Chiptls » Thu Sep 06, 2018 1:37 am

Hey guys! I'm pretty new to tuning and i have a little doubt and maybe you guys could clear it up for me.

I'm currently looking at how to calculate the maxium HP a vehicle can do

I've done some researching and appears that the formula is:

(RPM * Torque) / 7120 = HP

However looking at manufacturer specification for lets say,Honda Accord 2.2 ctdi, the maxium HP should be 140hp @ 4000rpm.

Looking at the Torque Limiter map (stock), 4000rpm is 314 nm.

So (4000 * 314 ) / 7120 = 176 HP which is not correct by manufacturer specifications.

Maybe im misunderstanding something?

Thanks in advance.
Best regards,
Ruben Teles

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Re: [HELP] Calculate Horsepower

Postby jurebv » Thu Sep 06, 2018 9:14 am

internal engine torque and wheel torque are not the same thing...there are losses

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Re: [HELP] Calculate Horsepower

Postby TurboTim » Sun Nov 25, 2018 7:31 pm

I also think its 5252 and not 7120

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Re: [HELP] Calculate Horsepower

Postby jurebv » Sun Nov 25, 2018 8:17 pm

5252 for torque in lbft , 7120 for torque in nm

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Re: [HELP] Calculate Horsepower

Postby dadoom » Tue Nov 27, 2018 2:37 pm

Formula is in attachment.
Manufacturer Horsepower is measured on wheels
where this formula gives HP at crankshaft.
You do not have permissions to view the files yet. You have to be registered and you have to make at least 3 quality / unique posts.

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Re: [HELP] Calculate Horsepower

Postby jurebv » Tue Nov 27, 2018 2:50 pm

5252 / 0.73756 = 7120 as i stated above for NM, your formula is just longer but same

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Re: [HELP] Calculate Horsepower

Postby lsdlsd88 » Sun Dec 02, 2018 11:51 am

dadoom wrote:Manufacturer Horsepower is measured on wheels


wrong, manufacturer always claim flywheel numbers.

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