I have been seeing HP figures all over the place here and have a few questions. Please excuse my ignorance or lack of knowledge on this topic. Here goes...

When a car is sold with a HP rating of 100 HP, I know the actual HP will be less depending on the tranny, accesories and other drivetrain parts that rob power from the engine. I am confused as to whether there is a ratio or a straight forward increase in power when power adders are introduced such as turbo, nitrous, SC. What I mean is this...

If I have a car that is rated at 100 HP and the actual HP is 90, if I add a 50 HP shot of nitrous, does this mean my power is now 140 HP?

I am sure this is how it works, because I can't see how a tranny will rob more power when more power is added to the motor. Does this make sense or not? Can someone elaborate on whether my theory is right or wrong?

 

parrasitic drag loss i think its called that or some thing like that, thats in the auto transmission little less in the 5 spd

i'm not sure if its rated at net hp(with all the accesories attached on the engine) or gross hp (no accesories)

 

Could you explain what that is? I guess my question is if I add 50 HP, it should be 50 HP to the crank AND wheel, correct? I am asking as far as general autos are concerned, not just 1 particular car.

 

I think CHP would win because they have Frank "Ponch" Poncharello. Mark

 

ummm...uhhh....CHP=Crank HorsePower. But yeah, Ponch is my hero too! I'm saving up right now to buy a timeshare from him!

 

did a little research, that 50 shot is only to the crank, you'll lose about 10hp due to parrasitic loss from the accesories and the transmission

 

I don't doubt you, but how can the tranny and accesories take away 'more' power? I am not trying to argue with you, I just am confused on the subject. I guess the way I'm thinking is that let's say the tranny robs 10 HP without nitrous, can it rob more power? I am having a hard time seeing how this is possible. Please don't take this the wrong way, as I am not trying to be an a$$, I'm just trying to learn...

 

rotating mass... robs you of that power

getting a lightened crank pulley would help get a small percent of that power back

http://www.goingfaster.com/spo/paras...ower_loss.html

 

But it's the same 'rotating mass' whether the HP is measured at the crank or at the wheels. I guess you don't see what I'm asking.

 

Generally speaking, the drivetrain loss will be roughly the same. But it also depends on quite a few things as far as dyno's go.

If you plan to put nitrous on the 1nz, please build prior to install of nit. because you will blow your motor in no time doing so.

So for instance, if you have a 1nz pushing 150hp (crank), you will have roughly 135whp. Of course, all this depends upon other situations but thats usually what happens.

I also might point out with the new SAE ratings its a 106hp, not 100hp. Without the SAE it was 108hp. Really not all that much of a difference but yeah, a little more than 10hp drivetrain loss.

Most stock manuals run around 88-93whp, most automatics run around 84-89whp. It really depends on conditions, if you were in high elevation, extremely hot out, with other things envolved you could only see 75whp for instance. So yeah.

 

I was just using the 100hp as a nice round number. I do not plan on putting nitrous on my car. This ws just a general automotive question. I think you answered my question and what you said is what I think too...that the loss doesn't increae as the power increases. I really don't see how it could, but I'm no rocket scientist and wasn't sure. THX.

 

Actually it can to some degree, it depends on too much to say it does or it doesn't. But, with the mods you can do to the xb, rather, what you can't do yet, you really wouldn't see more % in drivetrain loss.

Now, if you were to convert drivetrains to rwd or awd, you would see a huge difference. Night and day difference especially with awd. But, your welcome.

 

this is a good question and your point makes alot of sense. I totally follow.

If you have 100 crank HP and lose 10 hp through the car to the wheels you have 90 WHP.

The car stole 10 hp. thats all it takes for the car to spin turn whatever it may be.

Now if you increase the same car to 200 hp at the crank. and dont change drive train, clutch wheels or anything, you would have 190 WHP. IN theory of course the car shouldnt take more than the 10 hp originally to make the car turn spin and whatever.

Is this how it works? Or will the 200 hp car (same car as 100 hp) lose more than 10 HP?

 

Nick06tC...You see where i'm coming from! It may sound like a dumb question, but my initial question was whether the total parasitic loss stays the same, and frankly, I don't see how it would change, but I didn't know for sure. THX all!
I do understand slight differences here and there will affect the overall, but I was thinking if everything stayed exactly the same (air temp, humidity, tire pressure, etc.), the parasitic loss will not increase!

 

200hp on a 1nz would require significant modification, in the end you would loose more than 10hp through drivetrain. 200hp would equal some where around 180whp. It would be anywhere from 10hp-30hp drivetrain loss. A good example of this is a 210whp echo i've seen dyno'd on echo forums. He is pushing 245hp, and has a drive train loss of 35hp.

 

There are different issues regarding different losses.

In an automatic (for example), the loss is not a set hp number. It is a percentage due to the torque converter "to keep it simple". For example, if you have 100 hp and loose 10 hp due to torque converter...it has a 10% loss. If you have 500 hp at the crank....I assure you that you will loose more than 10 hp.

By design, an automatic will never give you 100% power transfer unless it is a lock converter (the tC does lock in overdrive).

 

^ so does the xB. Now I'm really fricken confused...So you're saying that there IS a gradual loss?

 

Well, there are specific issues when dealing with automatics, but for simple sake, it can be viewed as a percentage loss. For example, you will always loose 10% thru the drive train. 10 hp on a 100 hp and 50 hp on a 500 hp car. a simple rule of thumb to convert back and forth is usually, 21% on an automatic and 16% on manual transmission. Add another 5% loss with 4wd transfer case added.

 

But is it always a percentage? Or is it 10% of 100HP which is 10 HP...then when 400 HP is added, it's not 10 HP? but 50HP (or 10%)? I don't mean to be ignorant but I am having a hard time seeing it.

 

haha i just learned to live with some of most of the hard to believe things in life