ChitownRC

SixVi6-Camaro Wrote:HP plays a huge part in top speed. Its not all about gearing and aero. Its about matching the gearing and power to the drag of the car moving through the air and distance you have to reach top speed.

example.. 2 identical cars both geared to have a top speed in theory of 250mph with an unlimited distance to run with the same weight and drag coefficient but one has a 50hp engine the other has a 500hp engine.. I got my money on the 500hp car to reach a much higher top speed. The 50hp car will simply run out of power to keep working against the increasing drag from the air.

The 500 hp motor will only get to 250 faster. The 50 hp motor will reach it eventually! A motor can never run out of power if you have ebough speeds or gears to hit that speed.

the 50hp car would have to have an 18 speed tranny or something.... the 500HP car could do it with a 6-speed

squirrel Wrote:The 500 hp motor will only get to 250 faster. The 50 hp motor will reach it eventually! A motor can never run out of power if you have ebough speeds or gears to hit that speed.

you are adding varriables to my example.. I said 2 IDENTICAL cars with the same exact gearing. the only difference is the engines. A 50 hp motor won't have the power to get to the same top speed as a 500hp. as speed increases the power required increases exponentially to work against the atmospheric drag.

Lets try another example.. 2 IDENTICAL 1/8 buggies.. 1 speed.. same gearing lets say 18/46 with unlimited space to run but one has a .15 and the other has a .28. the .15 will never be able to reach the same speed as a .28 because the .15 will not have the power to work against the atmospheric drag, parasitic drag form the driveline itself.

SixVi6-Camaro Wrote:you are adding varriables to my example.. I said 2 IDENTICAL cars with the same exact gearing. the only difference is the engines. A 50 hp motor won't have the power to get to the same top speed as a 500hp. as speed increases the power required increases exponentially to work against the atmospheric drag.

Lets try another example.. 2 IDENTICAL 1/8 buggies.. 1 speed.. same gearing lets say 18/46 with unlimited space to run but one has a .15 and the other has a .28. the .15 will never be able to reach the same speed as a .28 because the .15 will not have the power to work against the atmospheric drag, parasitic drag form the driveline itself.

John I think there was some sarcasm that both you and I are missing out on in this thread. At least I HOPE so, other wise I wonder about the education system at times.

SixVi6-Camaro Wrote:you are adding varriables to my example.. I said 2 IDENTICAL cars with the same exact gearing. the only difference is the engines. A 50 hp motor won't have the power to get to the same top speed as a 500hp. as speed increases the power required increases exponentially to work against the atmospheric drag.

Lets try another example.. 2 IDENTICAL 1/8 buggies.. 1 speed.. same gearing lets say 18/46 with unlimited space to run but one has a .15 and the other has a .28. the .15 will never be able to reach the same speed as a .28 because the .15 will not have the power to work against the atmospheric drag, parasitic drag form the driveline itself.

Ok I missed the identical part. Then yes you are correct it could never attain the speed. But gearing has more to do with TOP speed.It's all correct yes horsepower has to do with top speed A LITTLE. I said it before.

Squirrel Wrote:horsepower has something to do with it yes but not nearly as much as gearing.

IT'S ALL RELATIVE!

Thirdgen89GTA Wrote:John I think there was some sarcasm that both you and I are missing out on in this thread. At least I HOPE so, other wise I wonder about the education system at times.

No sarcasm, and the educational system is fine. Otherwise I paid $26000 for nothing. Again 's all relative. You can't have top speed without horsepower or gearing. But with gearing a 50 hp motor can reach the same speed as a 5000hp motor just needing more distance. Also another variable RPM of the motor. 5000 hp does no good if the motor can only spin to 2000 rpm, thats where gearing comes in again. There is so much that has to do with top speed and acceleration. Hence why race teams have such a hard time.

I'm going to err on the side of caution and say you are being sarcastic. Because i don't believe anyone can be that ignorant.

I don't see the reason to put so much misinformation out there for any reason. Someone who truly doesn't know is going to come along and read it and take it as truth.

Let me restate it. There are 3 main things a car must have to reach a specific speed.

• It has to has to be as aerodynamic as possible, the more efficent the design the less power it takes to reach a given speed.
  
• It must have the power to overcome the aerodynamic drag at the specified speed.
  
• And finally it must be geared correctly so that at the specified speed the engine is generating the required power output.
  

If you don't have at least those 3 requirements met then it simply will not reach a given speed.

Why am I so insistent? Earlier it was stated in this thread that a 50hp engine could power the car to the same top speed as a 500hp car. If you take the new Z06 which is a near 200mph capable car and take its 500hp engine out then drop a 50hp engine into the car then its simply NOT going to reach anywhere near 200mph. It is impossible, 50hp is simply not enough. If you are lucky you'll get it near 70 or 80mph, but I don't believe its going to be capable of even 100.

Eracer76 Wrote:You got me by 1 mph....only because I backed out of it at 174mph due to things flying by much faster then my liking!
The scary thing is.....I was in my modded Crossfire SRT-6 and it was still pulling hard, as if I was still doing 110mph :eek:
Man I love this car!

Must be HEAVILY modified to even get close to that speed.

Perhaps you were reading kilometers?

squirrel Wrote:The 500 hp motor will only get to 250 faster. The 50 hp motor will reach it eventually! A motor can never run out of power if you have ebough speeds or gears to hit that speed.

Sure it will. It's about torque. Horsepower is only a calculated number based of torque which is actually measured.

50 ft lbs of torque wouldn't push you too fast regardlass of the number of gears you had. the load would bog the motor at some point.

Thirdgen89GTA Wrote:I'm going to err on the side of caution and say you are being sarcastic. Because i don't believe anyone can be that ignorant.

I don't see the reason to put so much misinformation out there for any reason. Someone who truly doesn't know is going to come along and read it and take it as truth.

Let me restate it. There are 3 main things a car must have to reach a specific speed.

• It has to has to be as aerodynamic as possible, the more efficent the design the less power it takes to reach a given speed.
  
• It must have the power to overcome the aerodynamic drag at the specified speed.
  
• And finally it must be geared correctly so that at the specified speed the engine is generating the required power output.
  

If you don't have at least those 3 requirements met then it simply will not reach a given speed.

Why am I so insistent? Earlier it was stated in this thread that a 50hp engine could power the car to the same top speed as a 500hp car. If you take the new Z06 which is a near 200mph capable car and take its 500hp engine out then drop a 50hp engine into the car then its simply NOT going to reach anywhere near 200mph. It is impossible, 50hp is simply not enough. If you are lucky you'll get it near 70 or 80mph, but I don't believe its going to be capable of even 100.

Change the gearing in the trans and whaa laa you have a 200 mph car. Everything you say is correct, not arguing that, but if you take that car and put in a 20 speed trans in it is possible to get it up to 200 mph. It would just take forever and a day to do it.

read all about the facts from those who know it all......

http://www.scta-bni.org/

1350cc class motorcycle
S-BF EZ Hook / Wheeler Kawasaki 8/04 332.410mph

That's haulin the mail on limited traction surface like Bonneville! or any surface for that matter.

Procharged5.0 Wrote:Must be HEAVILY modified to even get close to that speed.

Perhaps you were reading kilometers?

Eric's cars are SICK. I would not doubt for a second that it is that fast.

FreeRideFrosty Wrote:Eric's cars are SICK. I would not doubt for a second that it is that fast.

I think it's awesome if it's true! I just meet & talk to too many guys who think their cars can do more than they can...far too many.

I'd love to see pics of Eric's car if he's willing to share!

http://en.wikipedia.org/wiki/Drag_%28physics%29


Power
The power required to overcome the aerodynamic drag is given by:


Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome air drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW). With a doubling of speed the drag (force) quadruples per the formula. Exerting four times the force over a fixed distance produces four times as much work. At twice the speed the work (resulting in displacement over a fixed distance) is done twice faster. Since power is the rate of doing work, four times a work in half the time requires eight times the power.

It should be emphasized here that the drag equation is an approximation, and does not necessarily give a close approximation in every instance. Thus one should be careful when making assumptions using these equations.

This further supports the fact that it requireds more power to go faster not just more gears. That was obvious from the start.

yep, duh.

But it is funny to examine the corvette:
500hp to do 200mph translates to 22hp to do 100mph!! That's a slippery car.

Awesome isn't it. Wish I had the coin to pick a Z06 up!

heard that!

Procharged5.0 Wrote:I think it's awesome if it's true! I just meet & talk to too many guys who think their cars can do more than they can...far too many.

I'd love to see pics of Eric's car if he's willing to share!

He had a picture on here a little while back in stock form. I know he had a cobra with some work done to it, then a Dakota R/T with work done (I think it was supercharged, not sure), and an SRT-4 that was putting down 400-500 horsepower or something like that. His cars don't seem to stay stock for very long. You can take him at his word though. If he said it went that fast, it DEFINITELY went that fast.

Yeah, the Z06 packs quite a punch. it doesn't QUITE hit 200mph though. VERY close. I don't think it would take much to get it there. Removal of side mirrors, and headers would probably do it.

Here's a terminal run of the C6 Z06 on a 3mile long naval runway.
http://www.youtube.com/watch?v=I6EiNFiLhV0

Notice something funny about the speedo numbering? From 0-100 every major tick mark is 5mph, from 100-200 every tick mark is 10mph Its a non-linear speedo. Kinda cool, it explains why the vette seems to slow down so much after 100mph. Its not slower, just the way the speed is measured has been changed.

But watch how fast it hits 100mph. its like nothing.

Ok once again you are all CORRECT!!! I've said that like 5 times now. You are all to tunnel visioned to see that I guess.

Quote:Exerting four times the force over a fixed distance produces four times as much work

What happens if you exert .5 times the force does that only produce .5 times the work?

Vipers are better than Corvettes any day imho lol

Ponch Wrote:Vipers are better than Corvettes any day imho lol

I think we can all agree here! Same horsepower numbers but $30k less? Hands down CORVETTE!!

Ford Mustang GT500.... 18,000 less than a vette and in the new motor trend just a tick of a zo6 in almost all aspects

Except with Chevy you are paying for quality, with Ford you are paying for... well.....

FreeRideFrosty Wrote:He had a picture on here a little while back in stock form. I know he had a cobra with some work done to it, then a Dakota R/T with work done (I think it was supercharged, not sure), and an SRT-4 that was putting down 400-500 horsepower or something like that. His cars don't seem to stay stock for very long. You can take him at his word though. If he said it went that fast, it DEFINITELY went that fast.

The Dakota R/T wasnt supercharged, but it did have lots of engine work done.
I installed aftermarket ported/polished heads, cam, intake manifold, billet throttle body, headers, performance pcm and so on.....
it was 250hp stock, and Im guessing it was around 350-375hp when done.

It was fast, but still could only go 140mph because of the fact it ran out ran out of the 3 major ingredients to faster.
Not only did it hit a brick wall at the speed, it also didnt have the power to push though it, that and my tach was at 4,800rpm...redline was 5,200...so it barly had any gear left.

My SRT-4 had major mods done (bigger turbo and mods to go with it) it put down 420hp on the dyno, but would still only go 155mph just like it did when stock, due to taching out.


My Crossfire SRT-6 doesnt have as much done compared to my previous cars, but its much faster.
The car is supercharge from the factory and had 330hp stock, it only weighs 3150 lbs and I added....
Renntech Performance Package (custom pcm flash and pulley kit, about 40hp)
Magnecor plug wires
Denso spark plugs
K&N air filters
Sprint Booster
Rotex Gold brake pads
Eibach springs
Adjustable rear camber arms

So....its around 375hp now and the pcm flash removed the speed limiter which was around 155 -160mph I think.

This car is by far the best handling car Ive ever owned at those speeds, it just pulls down the road so smooth and quite that you dont realize your going 150mph (the SRT-4 was scary at that speed lol)
.
.
I know for a fact that I hit 170+ on the speedo one day, on the way home from Leisure Hours with all my R/C gear in the trunk to boot!