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-   -   Whp vs. Engine hp? (http://www.the370z.com/nissan-370z-general-discussions/36254-whp-vs-engine-hp.html)

onzedge 05-11-2011 11:44 AM

Quote:

Originally Posted by Econ (Post 1103362)
Bhp = whp*(1+.17)

Whp = bhp*(1-.17)

Estimation Obvsiously. Its not perfect.

Must be that "New Math".

Econ 05-11-2011 11:45 AM

Quote:

Originally Posted by Pelican170 (Post 1103386)
Nah thats not making sense. For example, fast intentions claims their hfc's with exhaust net a whp of 24... But a nismo with its exhaust and tune get 19 extra bhp? You see what im saying or not? No way a boost of 24 whp is only getting you 3-5 bhp... If you lose power at the crank than the bhp number is going to a good jump higher than the whp...

your right,

i just based the formula off stock Z's 332 bhp vs 275 whp, which is a 17% decrease.

The formula would have to be weighted, so if you were doing individual mods you would have to increase the .17 (17%) to maybe .25 or .3


300whp would be around 351bhp using the 17% formula which sounds about right

Pelican170 05-11-2011 11:49 AM

Quote:

Originally Posted by Econ (Post 1103417)
your right,

i just based the formula off stock Z's 332 bhp vs 275 whp, which is a 17% decrease.

The formula would have to be weighted, so if you were doing individual mods you would have to increase the .17 (17%) to maybe .25 or .3


300whp would be around 351bhp using the 17% formula which sounds about right

Gotta be higher percentage than that since the nismo at 350 bhp isnt going to dyno at 300whp...

Econ 05-11-2011 11:51 AM

Quote:

Originally Posted by Pelican170 (Post 1103425)
Gotta be higher percentage than that since the nismo at 350 bhp isnt going to dyno at 300whp...

you're right it won't

350 * (1-.17) = 290whp

which sounds right (although i have no idea what a stock nismo whp is)

Pelican170 05-11-2011 11:58 AM

Quote:

Originally Posted by Econ (Post 1103427)
you're right it won't

350 * (1-.17) = 290whp

which sounds right (although i have no idea what a stock nismo whp is)

Actually, thats right around the mark. Ive seen around 284-286 average on dynojets from what ive read...

Pelican170 05-11-2011 12:06 PM

Quote:

Originally Posted by Econ (Post 1103427)
you're right it won't

350 * (1-.17) = 290whp

which sounds right (although i have no idea what a stock nismo whp is)

But its gotta be different for when bolt ons are being added because if you use that formula, the whp to bhp between the nismo and sport dont add up, unless im doing my math wrong again.

Econ 05-11-2011 12:39 PM

Quote:

Originally Posted by Pelican170 (Post 1103463)
But its gotta be different for when bolt ons are being added because if you use that formula, the whp to bhp between the nismo and sport dont add up, unless im doing my math wrong again.

well if you take a stock sport Z and add intake/exhaust netting you 25whp

you end up with around 351 BHP (300*(1+.17))

if you did the same to a stock nismo Z

you end up with around 364 BHP (311*(1+.17))

Pelican170 05-11-2011 12:59 PM

Quote:

Originally Posted by Econ (Post 1103565)
well if you take a stock sport Z and add intake/exhaust netting you 25whp

you end up with around 351 BHP (300*(1+.17))

if you did the same to a stock nismo Z

you end up with around 364 BHP (311*(1+.17))

Wait im confused. Where did you get the "300" and "311" numbers from?

eksigned 05-11-2011 01:06 PM

I'm not entirely sure if I understand your post, but I just skimmed through it. Edit: I don't understand your post. Despite :) as some mentioned, drivetrain loss is mainly to blame for the difference you seen in crank versus wheel horsepower. Typically it's around 15% loss for RWD (has to send it all the way to the back), and a bit lower for FWD cars (less distance to travel).

I think someone mentioned whp from mods. Individual mods add a good amount, ie intakes, tps/hfc, exhaust. Put them together though, and they unfortunately don't yield the given whp added together. Understand? Stillen Gen3's add...what? 20 whp...supposedly? Pipes and exhaust add 27 whp (let's just say). The total gained doesn't equal 47 whp.

No idea if that even answered your question...:(

Dizon248 05-11-2011 01:10 PM

Quote:

Originally Posted by Econ (Post 1103362)
Bhp = whp*(1+.17)

Whp = bhp*(1-.17)

Estimation Obvsiously. Its not perfect.

You can't do that. When you use the 17% drive train lost, you can't convert back up 17%, you are using a different baseline and it will give you a different value.

So Whp = bhp*(1-.17) is right, but when you do Bhp = whp*(1+.17) you are multiplying by a different baseline. Try it. Say I have 300bhp and I multiply that by (1-0.17), I get 249. Now use 249 to multiply by 1.17, you get 291.33. You just lost 9HP from converting like that.

The right way is this, Whp = bhp*(1-0.17), solve for bhp now. bhp = whp/(1-0.17).

Summary

Whp = bhp*(1-0.17)

bhp = whp / (1-0.17)

Pelican170 05-11-2011 01:10 PM

Quote:

Originally Posted by eksigned (Post 1103658)
I'm not entirely sure if I understand your post, but I just skimmed through it. Edit: I don't understand your post. Despite :) as some mentioned, drivetrain loss is mainly to blame for the difference you seen in crank versus wheel horsepower. Typically it's around 15% loss for RWD (has to send it all the way to the back), and a bit lower for FWD cars (less distance to travel).

I think someone mentioned whp from mods. Individual mods add a good amount, ie intakes, tps/hfc, exhaust. Put them together though, and they unfortunately don't yield the given whp added together. Understand? Stillen Gen3's add...what? 20 whp...supposedly? Pipes and exhaust add 27 whp (let's just say). The total gained doesn't equal 47 whp.

No idea if that even answered your question...:(

Nope lol but thats ok. I agree with what your saying. To put it simply, if you add hfc's and exhaust that show dynos of 24 whp, what bhp does it convert to?

Dizon248 05-11-2011 01:15 PM

Quote:

Originally Posted by Pelican170 (Post 1103673)
Nope lol but thats ok. I agree with what your saying. To put it simply, if you add hfc's and exhaust that show dynos of 24 whp, what bhp does it convert to?

24whp converts to this, bhp = whp / (1-0.17). bhp = 24 (1-0.17) = 28.91bhp

Pelican170 05-11-2011 01:21 PM

Quote:

Originally Posted by Dizon248 (Post 1103685)
24whp converts to this, bhp = whp / (1-0.17). bhp = 24 (1-0.17) = 28.91bhp

Sorry but no way. As mentioned, if the nismo exhaust and small tune adds 5whp and 19bhp, a 24 whp gain isnt going to add only 4 more bhp. Its going to be way higher than that....

Dizon248 05-11-2011 01:33 PM

Quote:

Originally Posted by Pelican170 (Post 1103712)
Sorry but no way. As mentioned, if the nismo exhaust and small tune adds 5whp and 19bhp, a 24 whp gain isnt going to add only 4 more bhp. Its going to be way higher than that....

Ever figure that the 19bhp figure is wrong? Did you even think about how the hell can 5whp give you 19bhp? Yeah, that's right.

We already pointed out that your figure of 3.8x is totally whack. Why are you still assuming that the 19bhp is right?

Or the 5whp figure is wrong, something is wrong. There is no way there can be more than 300% differences between whp and bhp.

And what do you mean 24whp is only going to add 4bhp?. It is 28bhp. Your logic is confusing the crap out of me.

m4a1mustang 05-11-2011 01:37 PM

When you guys finish sorting this out I'd like to know how many whp and bhp my NISMO plate frame buys me. It's stainless steel powdercoated black if that makes any difference... super durable.


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