Brand new at this please help !

[taper41]

I know I irritate you, so I'll get you a beer too. 

[tortoise]

I know I irritate you . . .

Not at all. This thread is fun. Thanks for your contribution.

[jl222]

Naw, just pump 75psig boost into the engine, and hope the body panels don't tear off.  

    

     JL222

[McRat]

Naw, just pump 75psig boost into the engine, and hope the body panels don't tear off.  

    

     JL222

Here's the thing ...

I just drove my "race" truck to work.  When nobody is around, I goosed it.  At a 50mph stab, the scream of the turbo drowns out the squeal of the tires, and it coats the road with two coal black stains at 1/2 throttle, 30 PSI boost.

Aerodynamics might be logical, more sophisticated, and cheaper, but truly stupid amounts of HP have a certain grin-factor that nothing can replace. 

Disclaimer:  I'm an idiot.  Do not do what I do.  Offer not valid in Alaska and Hawaii.  If you have an erection that lasts over 4 hours, your turbocharger is finally big enough.

I will never join the circus and get shot out of a cannon, or be a Navy F-18 pilot, but having 1000hp under the hood is close enough for now.

[Geo]

Pat, nothing says it like forced induction!

having 1000hp under the hood is close enough for now

Soon your hp will be the same as your vehicle number! 

Geo

[fastman614]

Naw, just pump 75psig boost into the engine, and hope the body panels don't tear off.  

I luvya Pat!!!!!

[fastman614]

Taper41...
Are you "getting it"? A few of the heavyweights DID "weigh in" on here.... You have information at your fingertips from many of the posts on here that you really ought to copy and file away, if you have not already done so..... Some time down the "road".... You may be able to restate some of this and make a class project just a little more practical..... or fun.... or?....

[taper41]

Taper41...
Are you "getting it"? A few of the heavyweights DID "weigh in" on here.... You have information at your fingertips from many of the posts on here that you really ought to copy and file away, if you have not already done so..... Some time down the "road".... You may be able to restate some of this and make a class project just a little more practical..... or fun.... or?....

waaaayyyy ahead of you fastman.......(ironic) lol

[taper41]

I think I have figured it out:
. . . at 50% or 2x change the difference is .00000000.

Larry

if  you decrease the aerodynamic drag by 25% 50% or add power by 25% 50% would the result differ or be the same, if it was on the same vehicle?

The vehicle with the reduced drag is now 10% faster than the other one.

if the vehicle with reduced drag is 10% faster than the other one, how do you agree that power and drag are equal, or are you talking about the vehicle that we started with in the beginning with no changes made

[tortoise]

I think I have figured it out:
. . . at 50% or 2x change the difference is .00000000.

Larry

if  you decrease the aerodynamic drag by 25% 50% or add power by 25% 50% would the result differ or be the same, if it was on the same vehicle?

The vehicle with the reduced drag is now 10% faster than the other one.

if the vehicle with reduced drag is 10% faster than the other one, how do you agree that power and drag are equal, or are you talking about the vehicle that we started with in the beginning with no changes made

Once again, this is as if CdA and power were the only factors.

If you decreased the drag 50%, and you went 100 mph before, you'd go about 126 mph.
if, instead of decreasing the drag, you increased the power 50%, you'd go about
114.5 mph. 126 mph is about 10% faster than 114.5 mph.

This is just a simple algebra word problem.
Hotrod just made a mistake. He was tired. People make mistakes.

This algebra problem has nothing to do with whether drag or power is "more important".

[Interested Observer]

Taper,
The ambiguity arises out of how the "modifications" are specified.  Since the velocity ratio depends on the ratios of power and drag,

(V2/V1)^3  =  (P2*CdA1)/(P1*CdA2)

if P2=2*P1 and CdA1 = 1/2CdA2, comparing doubled power to halved drag, obviously the ratio is 1.0.   However, that is a 100% change in power but only 50% change in drag.

[taper41]

I think I have figured it out:
. . . at 50% or 2x change the difference is .00000000.

Larry

if  you decrease the aerodynamic drag by 25% 50% or add power by 25% 50% would the result differ or be the same, if it was on the same vehicle?

The vehicle with the reduced drag is now 10% faster than the other one.

if the vehicle with reduced drag is 10% faster than the other one, how do you agree that power and drag are equal, or are you talking about the vehicle that we started with in the beginning with no changes made

Once again, this is as if CdA and power were the only factors.

If you decreased the drag 50%, and you went 100 mph before, you'd go about 126 mph.
if, instead of decreasing the drag, you increased the power 50%, you'd go about
114.5 mph. 126 mph is about 10% faster than 114.5 mph.

This is just a simple algebra word problem.
Hotrod just made a mistake. He was tired. People make mistakes.

This algebra problem has nothing to do with whether drag or power is "more important".

How does it not, isn't your math showing that the same change in aero is more significant than in power.
If you have a different result for each factor by independently changing them at the same percent like we are how are they equal but show different results.

Is hotrod's math wrong on that ? because he answered the question in both ways , including resetting the value, after the errors in the fractions were ironed out they came out exactly even.

[taper41]

hotrod answered the question in both versions.

your simple aglebra shows that drag has more of an effect.

so how can both answers be correct with different outcomes. Help me out here tortoise
If your algabra equation isn't showing whether drag or power is a more significant factor to top speed then what is it showing ?

[jl222]

hotrod answered the question in both versions.

your simple aglebra shows that drag has more of an effect.

so how can both answers be correct with different outcomes. Help me out here tortoise
If your algabra equation isn't showing whether drag or power is a more significant factor to top speed then what is it showing ?

  Drag is inportant but once the ultimate shape has been obtained only more power will make it go faster.

            JL222

  P.S. Taper...what is the CD of a flat plate?

[taper41]

hotrod answered the question in both versions.

your simple aglebra shows that drag has more of an effect.

so how can both answers be correct with different outcomes. Help me out here tortoise
If your algabra equation isn't showing whether drag or power is a more significant factor to top speed then what is it showing ?

  Drag is inportant but once the ultimate shape has been obtained only more power will make it go faster.

            JL222

The overall cd of a square flat plate perpendicular to the flow is apx 1.17

common tortoise i know your on here reply

  P.S. Taper...what is the CD of a flat plate?