Physics Lesson
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From: Knoxville, TN, United States
Physics Lesson
Alright. From a lot of the threads I've seen, I think a physics lesson is in order.
Big brakes:
A lot of you guys think that bigger rotors are the way to go. Although a bigger rotor probably won't decrease your 60-0 stopping distance by much, it will give you better braking control and won't fade as quickly. However, it comes at a cost. If you get a 2" larger brake disc, you'll lose about 5whp, even if it weighs the same as your stock rotor. Why? Because the outer edge of the rotor is farther from the hub (duh), and requires more power to move it.
Rims:
Replacing a 15" rim with a 17" rim can make a big difference in handling. With the bigger rim, you'd run a thinner tire, thus giving you less tire roll around corners. However, it also comes at a cost. The average 17" rim weighs about 7lbs more then a 15" rim. Some rims are classified as light weight, and can even weigh less then a stock 15" rim. However, just like big brakes, the same rule applies. Because there's more weight on the outer edge, it takes more effort to turn it. Average 17" rims can cost you 10whp, while light weight can cost you as little as 3whp.
Mugen twin loop exhaust:
This really isn't a physics thing, I just thought I'd mention it. I watched a dyno run on an RSX Type S where they tested it with the stock exhaust, then a genuine Mugen twin loop. Between the two, there was only a 5whp gain. However, Mugen's twin loop design cancels out both high and low pitch sound, so the Mugen exhaust had a much better sound
Big brakes:
A lot of you guys think that bigger rotors are the way to go. Although a bigger rotor probably won't decrease your 60-0 stopping distance by much, it will give you better braking control and won't fade as quickly. However, it comes at a cost. If you get a 2" larger brake disc, you'll lose about 5whp, even if it weighs the same as your stock rotor. Why? Because the outer edge of the rotor is farther from the hub (duh), and requires more power to move it.
Rims:
Replacing a 15" rim with a 17" rim can make a big difference in handling. With the bigger rim, you'd run a thinner tire, thus giving you less tire roll around corners. However, it also comes at a cost. The average 17" rim weighs about 7lbs more then a 15" rim. Some rims are classified as light weight, and can even weigh less then a stock 15" rim. However, just like big brakes, the same rule applies. Because there's more weight on the outer edge, it takes more effort to turn it. Average 17" rims can cost you 10whp, while light weight can cost you as little as 3whp.
Mugen twin loop exhaust:
This really isn't a physics thing, I just thought I'd mention it. I watched a dyno run on an RSX Type S where they tested it with the stock exhaust, then a genuine Mugen twin loop. Between the two, there was only a 5whp gain. However, Mugen's twin loop design cancels out both high and low pitch sound, so the Mugen exhaust had a much better sound
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From: b00sting my D16s, SoWis, USA
Re: Physics Lesson (InvaderTrax)
For some people, their cars already have more power than they can use, so all the extra crap only impoves performance. And what naysayers don't understand is that lowering a car moves the brake bias forward, overworking the fronts - in a car setup from the factory with front-bias. Meaning...most cars WILL benifit from better front brakes. Note that I said 'better', not 'bigger'.
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Re: Physics Lesson (HiProfile)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HiProfile »</TD></TR><TR><TD CLASS="quote">For some people, their cars already have more power than they can use, so all the extra crap only impoves performance. And what naysayers don't understand is that lowering a car moves the brake bias forward, overworking the fronts - in a car setup from the factory with front-bias. Meaning...most cars WILL benifit from better front brakes. Note that I said 'better', not 'bigger'.</TD></TR></TABLE>
I'm a bit confused on this last part. I was reading Stoptech's articles on front/rear biased brakes, and it seemed as if an ideal brake bias would be somewhat neutral. If by lowering the car, the front gets more heavily biased, wouldn't we want to offset that a bit by using better pads in the rear?
I'm a bit confused on this last part. I was reading Stoptech's articles on front/rear biased brakes, and it seemed as if an ideal brake bias would be somewhat neutral. If by lowering the car, the front gets more heavily biased, wouldn't we want to offset that a bit by using better pads in the rear?
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From: b00sting my D16s, SoWis, USA
Re: Physics Lesson (erikiksaz1)
Heavy bias on an axle means it's doing more of the stopping (and possibly getting overworked).
I'm also going to guess that most people don't break in their brake pads properly, mainly due to lack of knowledge.
I'm also going to guess that most people don't break in their brake pads properly, mainly due to lack of knowledge.
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From: SoCal
Re: Physics Lesson (HiProfile)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HiProfile »</TD></TR><TR><TD CLASS="quote">For some people, their cars already have more power than they can use, so all the extra crap only impoves performance. </TD></TR></TABLE>
There isn't a point in any power to weight ratio where there is enough power that weight doesn't matter. What some people don't realize is that real racecars change setups depending on track and track conditions. Meaning you can't just go with the biggest rotors and biggest rims and call it done.
There are some conditions where physically bigger brakes and wheel/tire combination would be more of a disadvantage, no matter how much power you have.
The general consensus is, weight is the enemy.
And can you explain how lowering a car changes brake bias? Brake bias is hydraulic and is set by the proportioning valve and, on some systems, the ABS pump. There will be less weight transfer with a lower cg, which equates to less weight bias change under braking (and cornering and accelerating for that matter).
Modified by L8apex at 10:41 AM 12/18/2005
There isn't a point in any power to weight ratio where there is enough power that weight doesn't matter. What some people don't realize is that real racecars change setups depending on track and track conditions. Meaning you can't just go with the biggest rotors and biggest rims and call it done.
There are some conditions where physically bigger brakes and wheel/tire combination would be more of a disadvantage, no matter how much power you have.
The general consensus is, weight is the enemy.
And can you explain how lowering a car changes brake bias? Brake bias is hydraulic and is set by the proportioning valve and, on some systems, the ABS pump. There will be less weight transfer with a lower cg, which equates to less weight bias change under braking (and cornering and accelerating for that matter).
Modified by L8apex at 10:41 AM 12/18/2005
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From: irvine, socal
Re: Physics Lesson (InvaderTrax)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by InvaderTrax »</TD></TR><TR><TD CLASS="quote">Alright. From a lot of the threads I've seen, I think a physics lesson is in order.
Big brakes:
A lot of you guys think that bigger rotors are the way to go. Although a bigger rotor probably won't decrease your 60-0 stopping distance by much, it will give you better braking control and won't fade as quickly. However, it comes at a cost. If you get a 2" larger brake disc, you'll lose about 5whp, even if it weighs the same as your stock rotor. Why? Because the outer edge of the rotor is farther from the hub (duh), and requires more power to move it.
Rims:
Replacing a 15" rim with a 17" rim can make a big difference in handling. With the bigger rim, you'd run a thinner tire, thus giving you less tire roll around corners. However, it also comes at a cost. The average 17" rim weighs about 7lbs more then a 15" rim. Some rims are classified as light weight, and can even weigh less then a stock 15" rim. However, just like big brakes, the same rule applies. Because there's more weight on the outer edge, it takes more effort to turn it. Average 17" rims can cost you 10whp, while light weight can cost you as little as 3whp.
Mugen twin loop exhaust:
This really isn't a physics thing, I just thought I'd mention it. I watched a dyno run on an RSX Type S where they tested it with the stock exhaust, then a genuine Mugen twin loop. Between the two, there was only a 5whp gain. However, Mugen's twin loop design cancels out both high and low pitch sound, so the Mugen exhaust had a much better sound</TD></TR></TABLE>
you're physics teacher should be shot
that is unless you drive around on your rotors. which according to your theory would be best since having any rims at all would cost you hp. so i can upgrade my brakes and wheel size and lose 15hp but then gain back 5 from a twin loop netting out to only a 10hp loss and only receive the middle sound pitch....where do i sign up?
Big brakes:
A lot of you guys think that bigger rotors are the way to go. Although a bigger rotor probably won't decrease your 60-0 stopping distance by much, it will give you better braking control and won't fade as quickly. However, it comes at a cost. If you get a 2" larger brake disc, you'll lose about 5whp, even if it weighs the same as your stock rotor. Why? Because the outer edge of the rotor is farther from the hub (duh), and requires more power to move it.
Rims:
Replacing a 15" rim with a 17" rim can make a big difference in handling. With the bigger rim, you'd run a thinner tire, thus giving you less tire roll around corners. However, it also comes at a cost. The average 17" rim weighs about 7lbs more then a 15" rim. Some rims are classified as light weight, and can even weigh less then a stock 15" rim. However, just like big brakes, the same rule applies. Because there's more weight on the outer edge, it takes more effort to turn it. Average 17" rims can cost you 10whp, while light weight can cost you as little as 3whp.
Mugen twin loop exhaust:
This really isn't a physics thing, I just thought I'd mention it. I watched a dyno run on an RSX Type S where they tested it with the stock exhaust, then a genuine Mugen twin loop. Between the two, there was only a 5whp gain. However, Mugen's twin loop design cancels out both high and low pitch sound, so the Mugen exhaust had a much better sound</TD></TR></TABLE>
you're physics teacher should be shot
that is unless you drive around on your rotors. which according to your theory would be best since having any rims at all would cost you hp. so i can upgrade my brakes and wheel size and lose 15hp but then gain back 5 from a twin loop netting out to only a 10hp loss and only receive the middle sound pitch....where do i sign up?
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From: Jasma
Re: Physics Lesson (HiProfile)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HiProfile »</TD></TR><TR><TD CLASS="quote">For some people, their cars already have more power than they can use, so all the extra crap only impoves performance. And what naysayers don't understand is that lowering a car moves the brake bias forward, overworking the fronts - in a car setup from the factory with front-bias. Meaning...most cars WILL benifit from better front brakes. Note that I said 'better', not 'bigger'.</TD></TR></TABLE>
How exactly is lowering a car moving the brake bias towards the front?
The correct answer is: It doesn't, it has nothing to do with brake bias.
How exactly is lowering a car moving the brake bias towards the front?
The correct answer is: It doesn't, it has nothing to do with brake bias.
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From: SoCal
Re: Physics Lesson (silver j)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by silver j »</TD></TR><TR><TD CLASS="quote">
you're physics teacher should be shot
that is unless you drive around on your rotors. which according to your theory would be best since having any rims at all would cost you hp. so i can upgrade my brakes and wheel size and lose 15hp but then gain back 5 from a twin loop netting out to only a 10hp loss and only receive the middle sound pitch....where do i sign up?</TD></TR></TABLE>
And YOUR spelling teacher should be shot. The original post was about the disadvantage of relatively heavier 17", or even lightweight 17" wheels vs. 15" wheels. Mass is mass when it's static but to rotate it and stop it, mass becomes rotational inertia, which obviously increases with speed and distance from the centre point.
Ideally, you should use the biggest brakes you NEED for your application, whether it be street or track or a combination of both. And use the smallest rims that will fit over the brake system.
you're physics teacher should be shot
that is unless you drive around on your rotors. which according to your theory would be best since having any rims at all would cost you hp. so i can upgrade my brakes and wheel size and lose 15hp but then gain back 5 from a twin loop netting out to only a 10hp loss and only receive the middle sound pitch....where do i sign up?</TD></TR></TABLE>
And YOUR spelling teacher should be shot. The original post was about the disadvantage of relatively heavier 17", or even lightweight 17" wheels vs. 15" wheels. Mass is mass when it's static but to rotate it and stop it, mass becomes rotational inertia, which obviously increases with speed and distance from the centre point.
Ideally, you should use the biggest brakes you NEED for your application, whether it be street or track or a combination of both. And use the smallest rims that will fit over the brake system.
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From: Eindhoven, Netherlands
Re: Physics Lesson (HiProfile)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HiProfile »</TD></TR><TR><TD CLASS="quote">For some people, their cars already have more power than they can use, so all the extra crap only impoves performance. And what naysayers don't understand is that lowering a car moves the brake bias forward, overworking the fronts - in a car setup from the factory with front-bias. Meaning...most cars WILL benifit from better front brakes. Note that I said 'better', not 'bigger'.</TD></TR></TABLE>
I'm not sure what he means by brake bias...but if anything there will be less of a load put on the fronts after lowering the car, because less weight gets transferred from the back.
However, because there's less load on the fronts, they will lock up sooner. If that's what he means by brake bias, then so be it. But, he contradicts himself, so I don't know...
Whoa...old thread. Just realized.
I'm not sure what he means by brake bias...but if anything there will be less of a load put on the fronts after lowering the car, because less weight gets transferred from the back.
However, because there's less load on the fronts, they will lock up sooner. If that's what he means by brake bias, then so be it. But, he contradicts himself, so I don't know...
Whoa...old thread. Just realized.
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