Whp vs. Engine hp?
 

Ok, just curious about if there is any real conversion to tell what the engine hp is when knowing the whp? Here is my logic but im sure its not accurate. For example, when comparing the sport vs nismo, we see there is a 19 engine hp difference. From what ive read, there is approx a 5 whp difference (19 bhp) between the two cars (this is not a nismo vs sport thread or anything of the sort, so please dont bring it to that level. If my info is wrong, i appologize). So my logic tells me the whp to engine hp is 3.8 =(19/5). So for add on parts that get dyno'd, can you simply take the dyno whp and multiply it by 3.8 to get the bhp? Make sense? Lol, im sure thats not accurate but very curious...

I don't think that math is correct.

I think MT cars take a 17%+/- drivetrain loss

so a 100hp car = 78whp give or take

something like that, cause using your math of whpx3.8=CRAZY

With your 3.8 factor, people who dyno 300 whp would be making about 1100hp at the crank.

i like those numbers:icon18:

I test it the old fashioned way. I line up at the drag strip next to a sled with X horses tied to it and the same weight in the sled. I haven't reached the point of testing whether we really get 330 horsepower, because I only got as far as 30 before running out of space for all the horses, and quite frankly, I'm tired of cleaning up the poops.

Haha good point above. Didnt think about that lol. Stupid me... Wonder if there is a conversion just cuz when i get parts on, id like to be able to say i have about x amount of hp...

Converting from whp to bhp always involves some fuzzy math, but we can assume on a Dynojet the average 370 loses about 17% of its power through the driveline in stock form.

But this number can change from day to day and especially dyno to dyno.

Lol

Also depends if is RWD or FWD car for the loss in WHP...

I just meant for our cars. Haha when can we say we have a 400hp car? Lol

I only talk WHP numbers. Only the domestic guys talk in terms of crank HP. Guess it makes them sleep at night.

Bhp = whp*(1+.17)

Whp = bhp*(1-.17)

Estimation Obvsiously. Its not perfect.

My main thing is if a nismo only has an exhaust and slight tune to give it a bhp of 19 more, how much bhp do hfc's and an exhaust add, ya know??

whp stands for whip hp, the amount of neck whip you get when you mash the gas in reverse and forward. you have to do 3 cycles and take the average to get the most accurate numbers.

:icon17:

[QUOTE=Econ;1103368]well if HFC's and a CBE net around 15 whp

then

15 * (1+.17) = ~18bhp

about the same as a stock nismo

if you have a nice dyno and you get 20 whp

then
20* (1+.17) = ~23.4 bhp[/QUOTE

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...

Must be that "New Math".

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...

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...

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))

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

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...:(

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)

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

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.

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.

Its not wrong. Is the sport 331 hp? Is the nismo 350? Difference of 19 hp. That has been dynod as approx. 5 whp from people who have put on a nismo exhaust on a sport. So thats where my info is comin from...

Also, wouldn't an AT loose more than the MT

So you're telling me that the only thing thats giving the NISMO edition the 19hp advantage is the exhaust? Aren't there other things to the NISMO that gives it that extra 19hp?

It would add more than 4 hp to the 24 whp that is dyno'd.

It's not adding 4hp, it's adding 28.........

Its 24whp or 28bhp. Take your pick.

Again, it looks like you're basing your "facts" off that 19bhp 5whp BS. There is no f'ing way that 19bhp is only going to give you 5whp, that is a factor of 3.8x like someone mentioned. If i had a 300whp care and converted with that 3.8 factor, my god..... I'm pretty sure there is more to that 19bhp than an exhaust. You're getting the 5whp from just an exhaust, or converted roughly to 6bhp.

:bowrofl::bowrofl:

Probably 25whp for the frame, and an extra 10 for the black powdercoat. I've found the license plate frames give almost as much whp as the nos stickers on my windshield.

1 hp =

http://www.ridelust.com/wp-content/u...horsepower.jpg

This as far as math equations go is correct, as far as the specific problem I can't say how accurate the equation is. The previous posts were really bothering me, yes, I am an engineer....