If a particular drivetrain requires lets say, 80hp, to overcome friction in a 400hp car, how in the world does it require 200hp to overcome friction in a 1000hp car?!!!!!

It's the same drivetrain!!!!!

I'd have to say that must be the "new math" at work.

 

The more power you make, the more friction you create and more power is lost as heat.

 

Yes, but not an additional 120 hp, no way.

I think to quote a fixed % is erroneous, as it would be to quote a fixed # of hp loss.

Sure, there will be additional parasitic drag, but not that much.

The only way to settle it is to run an engine on a dyno at different boost and power levels, then set up the same engine in a car and do the same.

We may never have an accurate idea.

 

So take ronnie duke's setup (big 9" and big glide) and put them in your average h/c motor. I bet they will lose a similar amount of power.

Friction does cause heat which causes a loss in hp. But you're not thinking logically anyway. The only added friction is their car turning 8000 rpms versus yours turning 6500. The extra piston speed and the like will cause extra friction because that's just plain and simple physics, but that's only the motor. But the extra friction to turn the rear end and tranny is what you're saying though right? The exact same rearend and tranny that would be in a head cam car is losing more power when it's behind a procharged car?

You're obviously entitled to your opinion but this is exactly how i see it. Do the math. The main reason you lose horsepower from drivetrain is trying to accelerate the mass of the drivetrain. Friction is a by product of that.

Force=mass x acceleration.

Nate

 

the percentage stays the same, or roughly the same

the reason the power it takes to turn the drivetrain goes up as the power levels go up is that is the higher power levels are turning the drivetrain faster (with more force of acceleration) which takes more power

 

6500 rpm is 6500 rpm in a 400 hp car or a 2000 hp car

 

Ya know, I can see that there will be additional loss in a higher hp application.

For instance, Nate, you are correct, to accelerate a given mass FASTER requires more power.

I think you and I agree that the additional friction is not going to be on the
order of 150%, as in the 400hp/1000hp example I stated before.

There will always be a question of just how much additional power is lost.

Not that it really matters, just TURN UP THE BOOST!!!


quick edit: I just want to say that it's the total mass of the vehicle being accelerated quicker that requires alot of additional hp, not the drivetrain.
I believe the drivetrain loss will remain "somewhat" constant, give or take a few ponies.
Just wanted to clarify my belief.

 

I am not saying that he would loose the same amount of power BUT he is going to loose the same amount of power due to the rotating mass of the parts. He will, however, loose more through his converter (if using the same converter as a 400hp car) I know for a fact that he is NOT using the same converter that my 400hp car is using... If he were to do so then it would flash at 7-9k if not more it would just push right through. Bottom line is there is NO way that you are loosing 20% accross the board.

What is 20% of a 1000hp? 200hp... and lets say that a 400 hp car looses 80hp from flywheel to the ground. A good converter looses NO MORE then 5% between locked and unlocked (gaurantee the big boys are using a good converter) so 5% of 1000 = 50hp lost. Now 5% lost on 400 = 20hp lost.

80hp-20hp = 60 hp lost in the drive train parts not including the converter(off the 400hp car). Now add 60hp and the 50hp that is lost through the converter and that myfriend is NOT 20% But more like 11%

 

good to hear from you Homie!

 

The viper that was built by SVS made 1725 through a glide. I saw the video on viperalley.com

 

just a question. wouldnt a motor with 400hp have to work harder than a 1000hp motor to turn a th400 or any other kind of tranny. just my .02

 

exactly,
the 1000 hp engine ACCELERATES the parts faster than the 400hp engine, therefore it takes MORE FORCE. mass obviously stays the same. the added acceleration of parts is your extra drivetrain loss.

 

Oh good God...welcome to the internet, where everyone is a mechanic and has a 10 second car.

Would you guys stop hijacking the thread and post up some numbers?

 

Im gonna go ahead and put in my .02... I dont think that a 1900hp car will lose ~400hp on drivetrain loss

 

what would happen if you hooked up a motor that only made 80hp? would it be able to run? yes because a smaller hp has a smaller drivetrain loss, and vice versa-larger hp=larger drivetrain loss.

anyway my car has a torque spike of 800, but that's already been drawfed by actual numbers, sorry i'm no real help.

 

Dang, I created a monster, soooo not what I was going for

 

I think you hit on something! Yes it would run with a 80hp motor. So the loss would have to be in the speed in witch the parts accelerate?

 

I know someone who made over 1200/1500 at the wheels. A little work to a viper and bam huge numbers

 

them vipers can be made to make some sick numbers,
shadowlight- sorry for bringing this back up.

 

There is a nice long technical thread on this somewhere....

It's percentage based. The more you make the more you lose, almost like taxes! Esepcially when you factor in the added loss of stronger drivetrain components and looser converters


Speaking of fast vipers: Anybody read the September road and track? It has an awsome test of 14 very fast cars (well, most are very fast) runing the standing ONE MILE.

The Hennessey venom 1000 twin turbo went 0-100 in 6.8 seconds, 0-200 mph in 21.3 seconds. And this was on street tires with a 1/4 mile of only 11.0 at 145.5.