OdessitPashka

<div class='quotetop'>QUOTE (hamhead)</div><div class='quotemain'>Drivetrain loss on FWD is around 15%. The energy lost through heat is not included in Crank HP form as it isn't used at all, its just expelled. Heat loss is more than 5%, its more like 20%. Heat also creates more wear and tear on parts... thats why heat sucks, unless your outside in the winter.</div>

ham, if drivetrain loss was 15% then why do people gain power from exhaust and pulleys? There is some power loss within those as well. And apperently the power loss on our cars is no more than 15%, so it can't be all going to the drive train.

Dmitry

power loss can be:
-clutch
-tranny
-axles
-bearings
-wheels
-exhaust
-intake
-pulleys
-AC
-alternator
-water pump
-breaking pads that contact with rotors

Alex01tib

when you lighten pulleys and such your harnessing power that your engine already makes. when you get better airflow w. I/E, you allow your engine to make more power.

OdessitPashka

<div class='quotetop'>QUOTE (alex01tib)</div><div class='quotemain'>when you lighten pulleys and such your harnessing power that your engine already makes. when you get better airflow w. I/E, you allow your engine to make more power.</div>

I agree that when you add an intake you add power because you add more air, but when you add an aftermarket/custom/better flowing exhaust you just let your engine breath like it should. Stock exhaust is very restrictive because of the emmisions and sound police, so factorys must rob power by making restrictive exhausts.

What Dima said is right, and everything he said basically includes drive train, pulleys, exhaust.

Double_A

I look at it like this. The lost power goes to everything turned, pushed, pulled , etc. between the crank and the wheels. For example, if it takes 1 hp to turn pulleys, 2hp to run electrical componants, 5hp to run tranny and 3hp to push exhaust gases through the exhaust system, then youv lost a total of 11hp before you get to turning the wheels. So imagine you have an engine that has just the same amount of power (hp) you lose between crank and wheels on a given car. The motor would just just barely be able to run and move everything.

Numbers are just pulled out of the air. If im wrong, let me know cuz i dont want to give out bad info. But i think i got it.

Dmitry

Don't forget about aerodynamics. Faster you go more hp you lose.

OdessitPashka

<div class='quotetop'>QUOTE (Double_A)</div><div class='quotemain'>I look at it like this. The lost power goes to everything turned, pushed, pulled , etc. between the crank and the wheels. For example, if it takes 1 hp to turn pulleys, 2hp to run electrical componants, 5hp to run tranny and 3hp to push exhaust gases through the exhaust system, then youv lost a total of 11hp before you get to turning the wheels. So imagine you have an engine that has just the same amount of power (hp) you lose between crank and wheels on a given car. The motor would just just barely be able to run and move everything.

Numbers are just pulled out of the air. If im wrong, let me know cuz i dont want to give out bad info. But i think i got it.</div>

You are getting it right man.

hamhead

As you guys swear by Corky Bell, read the first few lines of his book... he outlines that one third of all the energy created by combustion goes out through the exhaust. I think its a little high, but its a generally accepted rule of thumb.

Exhausts make power simply because the small pipes disrupt velocity. Your freeing power that was already there and being lost simply because of the small piping. Has nothing to do with drivetrain loss, etc.

Pulleys make power in 1st gear... dynos are done in 4th gear on the Tib... whichever gear is the closest to a 1:1 ratio. A 1st gear dyno would show a crapload of torque. Did you know a lightened flywheel is equivalent to removing 300 pounds off your car in 1st gear, but only 50 in 4nd gear with the way the Tib and most cars are geared? Each gear makes different power... the comparisons your using don't mean anything in this case.

OdessitPashka

who you talking to ham?

01tibby

what the hell are you guys talking about? eyeroll.gif

he just wants to know where the power goes thats lost between whp and hp at the crank. to answer the question originally asked, it is transferred.

conservation of energy my friend. energy cannot be created or destroyed, only transferred. just like the energy of a falling rock is transferred to a little heat and sound, so is the hp that is lost between the flywheel and wheels.

heat, noise, vibrations...the list of variables goes on and on.

the exhaust has nothing to do with the energy lost between the flywheel and wheels.