forged rotors?
10-25-06, 09:11 PM
#26
I am the stig.
http://www.vetteweb.com/tech/0407vet...l_information/
Guess so. They mentioned the test was on an Inerta dyno, which I'm not familiar with.
11 seconds to 145mph. I wish my car could go 145mph. ****. 
I've heard the same thing about rims, "a pound on the rims is like 50 on the car".
Additionally:
http://www.se-r.net/engine/light_flywheels.html
Guess so. They mentioned the test was on an Inerta dyno, which I'm not familiar with.
Next, the stock pressure plate, clutch, and flywheel were removed and weighed. The three factory parts hit the scale at 51 pounds. The new Fidanza 12.5-pound aluminum flywheel (PN 198571, retails at $439.00), and the 14.5-pound Spec Stage 1 clutch/pressure plate unit (PN SC091, retails at $299.00) totaled 27 pounds--a savings of 24 pounds of rotating weight at the crankshaft!
...a gain of 9.3 hp and 8.6 ft-lb of torque. Maximum horsepower was achieved in 11 vs. 14 seconds with the stock parts, and maximum torque was seen in 9 vs. 11 seconds with the stock parts! Back on the road, Denny's Z06 revved a little quicker and required a lighter push on the loud pedal. We could feel the difference.
...A flywheel does not make any horsepower, but it shows up as a horsepower gain because you have reduced the inertia on an inertia dyno. So you need to look at the reduction in time to speed that was created by the reduction of inertia. We went from 14 to 11 seconds to 145 mph on the stock Z06. What that tells you is how the car is going to feel on the street. It is going to accelerate quicker to the redline.
...a gain of 9.3 hp and 8.6 ft-lb of torque. Maximum horsepower was achieved in 11 vs. 14 seconds with the stock parts, and maximum torque was seen in 9 vs. 11 seconds with the stock parts! Back on the road, Denny's Z06 revved a little quicker and required a lighter push on the loud pedal. We could feel the difference.
...A flywheel does not make any horsepower, but it shows up as a horsepower gain because you have reduced the inertia on an inertia dyno. So you need to look at the reduction in time to speed that was created by the reduction of inertia. We went from 14 to 11 seconds to 145 mph on the stock Z06. What that tells you is how the car is going to feel on the street. It is going to accelerate quicker to the redline.
I've heard the same thing about rims, "a pound on the rims is like 50 on the car".
Additionally:
http://www.se-r.net/engine/light_flywheels.html
Last edited by Twofer; 10-25-06 at 09:18 PM.
10-25-06, 09:50 PM
#27
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Originally Posted by Twofer
Well it all comes back to what "power" and "displacement" mean.
Horsepower is really a fictional number based on Torque and RPM....
(Torque x Engine speed) / 5,252 = Horsepower
High revving engines will have lots of "power". RX-7 and S2000 are good examples. High revs, high power, low torque.
An example of a low power, high torque engine would be a diesel truck. Some redline at 3k but have upwards of 800 lb/ft of torque. It'll pull anything out of anywhere, but it's not really fast.
It also has to do with the weight of a car... so power to weight ratio.... anyway.
http://auto.howstuffworks.com/horsepower.htm
http://auto.howstuffworks.com/question622.htm
On the topic of Displacement, it's measured differently for piston engines and rotary engines.
Piston engines rate the displacement by the maximum cylinder volume of all the cylinders. Rotary engines rate displacement literally. Rotor housing volume minus rotor volume. The difference comes up in racing classes, where they go by the "Double Displacement" rule... 1.3L rotary comprable to 2.6L piston.
http://auto.howstuffworks.com/question685.htm
On the issue of forced induction, the short of it is: More air, more fuel, more power, more stress on engine.
Could a 1.3L Rotary make as much "power" as a 7.3L truck? Sure, if the tuck only rev'ed to 1000 rpm.
The rotary engine isn't magical, it's just shaped wierd.
Horsepower is really a fictional number based on Torque and RPM....
(Torque x Engine speed) / 5,252 = Horsepower
High revving engines will have lots of "power". RX-7 and S2000 are good examples. High revs, high power, low torque.
An example of a low power, high torque engine would be a diesel truck. Some redline at 3k but have upwards of 800 lb/ft of torque. It'll pull anything out of anywhere, but it's not really fast.
It also has to do with the weight of a car... so power to weight ratio.... anyway.
http://auto.howstuffworks.com/horsepower.htm
http://auto.howstuffworks.com/question622.htm
On the topic of Displacement, it's measured differently for piston engines and rotary engines.
Piston engines rate the displacement by the maximum cylinder volume of all the cylinders. Rotary engines rate displacement literally. Rotor housing volume minus rotor volume. The difference comes up in racing classes, where they go by the "Double Displacement" rule... 1.3L rotary comprable to 2.6L piston.
http://auto.howstuffworks.com/question685.htm
On the issue of forced induction, the short of it is: More air, more fuel, more power, more stress on engine.
Could a 1.3L Rotary make as much "power" as a 7.3L truck? Sure, if the tuck only rev'ed to 1000 rpm.
The rotary engine isn't magical, it's just shaped wierd.
Torque is, IIRC, work done at the moment.
BC
10-25-06, 11:46 PM
#28
I am the stig.
For the purposes of automotive comparison, it's a relative measure. An approximation of what kind of performance you are going to get. It's something to brag about.
If I told you a vehicle had 100 hp, could you tell me how fast it could do a quarter mile? What if it was a 1.6 liter Civic, or a 650cc Sport Bike, or a turbine powered go-kart?
Now if we had the same car, with a 100 hp engine, and a 200 hp engine, we know the 200 hp engine would be faster, but still no exact time.
So back to the original point, horsepower is indeed a real number, it just doesn't mean much. Read any discussion about turbo sizes and there will be discussions about "usable power" versus "peak power". Terms like "properly sized turbo" and "dyno queen" come up frequently.
It's a number for the marketing guys to put on the brochure. Just like audio amplifiers that claim they're good for 1000000 watts. The real number to look for is RMS watts @ <= 1% THD.
If anyone was wondering, I was bored at work today.
If I told you a vehicle had 100 hp, could you tell me how fast it could do a quarter mile? What if it was a 1.6 liter Civic, or a 650cc Sport Bike, or a turbine powered go-kart?
Now if we had the same car, with a 100 hp engine, and a 200 hp engine, we know the 200 hp engine would be faster, but still no exact time.
So back to the original point, horsepower is indeed a real number, it just doesn't mean much. Read any discussion about turbo sizes and there will be discussions about "usable power" versus "peak power". Terms like "properly sized turbo" and "dyno queen" come up frequently.
It's a number for the marketing guys to put on the brochure. Just like audio amplifiers that claim they're good for 1000000 watts. The real number to look for is RMS watts @ <= 1% THD.
If anyone was wondering, I was bored at work today.
10-26-06, 12:42 AM
#30
Lives on the Forum
Brake rotors are cast iron, I don't know of any forged ones, but iron isn't usually (or ever) forged AFIK. There are steel rotors, but iron works better for most intents and purposes, because it's harder and resists abrasion better.
10-26-06, 01:28 AM
#31
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I had a lighten flywheel in my b16. I rev up very quickly, the car becomes very responsive, but on the same note, it revs down just as quickly too. My friends who are not used to driving it always stall the car and hate driving it.
It also makes engine braking almost non existent since there's alot less momentum. I can only imagine that it'll be the same with a rotary rotor; most likely more noticiable since its closer to the energy generating source.
It also makes engine braking almost non existent since there's alot less momentum. I can only imagine that it'll be the same with a rotary rotor; most likely more noticiable since its closer to the energy generating source.
10-26-06, 02:17 AM
#32
Lives on the Forum
Whatever the case, you're looking at a brand new design of the rotors.
Problem with forged components is that their heat expansion rates are different than cast items.
With the close tolerances of the rotor and rotor parts, I'd worry about tolerances.
All these forged piston owners bitch about "piston slap" until the engine warms up...
-Ted
Problem with forged components is that their heat expansion rates are different than cast items.
With the close tolerances of the rotor and rotor parts, I'd worry about tolerances.
All these forged piston owners bitch about "piston slap" until the engine warms up...
-Ted
10-26-06, 02:28 AM
#33
This is funny ****. It reminds me of one of the first local 7 owners I met when I got into 7s myself back in 99. IT was this young dumbass redneck kid who thought his s4 NA base model was the fastest **** on wheels. He had dual 3" straightpipes, and painted it bathroom aqua green with no clearcoat, "RE" written on the fenders (he said it stood for rotary engine, my girlfriend at the time said it stood for retard), and little purple "rotors" stenciled on it in random places all over the car.
Anyway this dude swore his car had titanium rotors and that is why it was so fast. HE also claimed to have went 170mph on the interstate even though the speedo in his car stopped at 150 and he had tires 3 sizes too small for the car. I just kinda shrugged it off and went on with life, though I did make fun of him from time to time.
Sounds a little bit like what we are dealing with here.
Anyway this dude swore his car had titanium rotors and that is why it was so fast. HE also claimed to have went 170mph on the interstate even though the speedo in his car stopped at 150 and he had tires 3 sizes too small for the car. I just kinda shrugged it off and went on with life, though I did make fun of him from time to time.
Sounds a little bit like what we are dealing with here.
10-26-06, 02:30 AM
#34
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Damn I'm learning chemisty and physics at the same time! haha! This is genius! haha! Who needs school! haha! j/p
I really didn't think that this would be such a hot topic! I was just wondering! haha!
Hasan
I really didn't think that this would be such a hot topic! I was just wondering! haha!
Hasan
10-26-06, 11:03 AM
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Originally Posted by Twofer
For the purposes of automotive comparison, it's a relative measure. An approximation of what kind of performance you are going to get. It's something to brag about.
If I told you a vehicle had 100 hp, could you tell me how fast it could do a quarter mile? What if it was a 1.6 liter Civic, or a 650cc Sport Bike, or a turbine powered go-kart?
Now if we had the same car, with a 100 hp engine, and a 200 hp engine, we know the 200 hp engine would be faster, but still no exact time.
So back to the original point, horsepower is indeed a real number, it just doesn't mean much. Read any discussion about turbo sizes and there will be discussions about "usable power" versus "peak power". Terms like "properly sized turbo" and "dyno queen" come up frequently.
It's a number for the marketing guys to put on the brochure. Just like audio amplifiers that claim they're good for 1000000 watts. The real number to look for is RMS watts @ <= 1% THD.
If anyone was wondering, I was bored at work today.
If I told you a vehicle had 100 hp, could you tell me how fast it could do a quarter mile? What if it was a 1.6 liter Civic, or a 650cc Sport Bike, or a turbine powered go-kart?
Now if we had the same car, with a 100 hp engine, and a 200 hp engine, we know the 200 hp engine would be faster, but still no exact time.
So back to the original point, horsepower is indeed a real number, it just doesn't mean much. Read any discussion about turbo sizes and there will be discussions about "usable power" versus "peak power". Terms like "properly sized turbo" and "dyno queen" come up frequently.
It's a number for the marketing guys to put on the brochure. Just like audio amplifiers that claim they're good for 1000000 watts. The real number to look for is RMS watts @ <= 1% THD.
If anyone was wondering, I was bored at work today.
Horsepower is a very helpful number. Moreso, in fact, than torque, since cars have a transmission (which multiplies the torque). Horsepower is a good indication of how you can take advantage of your gearing to produce more torque at the wheels (actual torque at the wheels, not engine torque measured at the wheels). A dyno measures wheel torque and engine RPM. Then, it uses wheel RPM and engine RPM to establish the gearing and applies that ratio to the measured torque at the wheels, which is usually higher than the torque at the engine. If two cars make 200 ft*lbs of torque at two different RPM, the one with the torque at a higher RPM will accelerate faster because the car can be geared lower (increasing the torque to the wheels) for the same speed.
For the car to maintain the same speed in first and second gear, the engine would have to be at a lower RPM in second, right? For example, if 8000rpm in first gear is 40mph, and second gear gives you 40mph at 4000rpm, then it would take twice the engine torque to accelerate the car in second gear at the same rate. So, imagine you have an engine that makes 200ft*lbs at 4000rpm (152hp) and an engine that makes 200ft*lbs at 8000rpm (305hp). The first car has a drivetrain producing a 1:1 ratio between engine speed and wheel speed, while the second car is a 2:1 ratio. For both cars to maintain the same velocity, the engine speed of car 2 must be twice that of car 1. So, car1 is at 4000rpm making 200ft*lbs, and car2 is at 8000rpm making 200ft*lbs. They are going the same speed. If both punch the gas, car 2 will accelerate much faster, because it's 200ft*lbs at the engine is now 400ft*lbs at the wheels due to the gear ratio. Coincidentally, that car has twice the horsepower.
That's why horsepower is actually a better indication of a car's ability to accelerate than torque. In a car with only one gear, torque would be the deciding factor. Since automobile manufacturers have the ability to choose gears to suit a car's powerband, horsepower is the deciding factor as to a car's speed. It takes into account engine torque AND the torque-multiplying effect of a car's gearing.
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