: Revolutionary (motorcycle) 'too quiet'



HotRodSaint
03-17-05, 12:17 PM
The world's first purpose-built hydrogen-powered bike could be fitted with an artificial "vroom" because of worries its silence might be dangerous. (http://news.bbc.co.uk/2/hi/europe/4353853.stm)

RBraczyk
03-17-05, 12:26 PM
Loud pipes save lives. I'll get a clip of the Termigioni pipes on my dad's Ducati 999.

Katshot
03-17-05, 12:39 PM
Loud pipes save lives. I'll get a clip of the Termigioni pipes on my dad's Ducati 999.

That's a load of crap. That's just an excuse for "hey, look at me" motorcyclists. Load pipes accomplish only two things, they disturb people, and draw attention as you drive by. They do virtually nothing to attract attention from ahead of you.

RBraczyk
03-17-05, 01:54 PM
You have no idea what your talking about.

Adumb
03-17-05, 04:12 PM
personnally i have never identified a biker driving by hearing him, it has always been by seeing him. the only time i ever hear the motorcycles are after they have passed, or if im standing by the road. i have never really been into motorcycles, anyways

BUILDINGCTSAMG
03-17-05, 06:23 PM
Maybe im different, but often I can hear motorbikes way before i spot them...i think it does save lives

90Brougham350
03-17-05, 06:25 PM
I thought one of the reasons they had "manufactured noise" or whatever was because driving an electric (or in this case, hydrogen) was just plain weird to most people, they wanted noise to tell them what was going on.

Brian

Katshot
03-17-05, 08:27 PM
You have no idea what your talking about.

I'm sure you'd like to think so. I was probably riding and racing bikes when your DAD was a kid! I started riding in 1968, I started racing in 1970. I've raced motocross, enduro, trials, hill-climbs, drags, and road racing. I've built and rebuilt more bikes than you've had sneakers, and I've had experience teaching AMA sponsored motorcycle safety courses.
If it wasn't for a crash in '94 that broke my neck in 6 places, I'd still be riding today. I had 7 bikes at the time of the accident, 2 of which I built from spare parts.
So if you want to tell me I have no idea what I'm talking about, YOU need to be able to back up your opinion. BTW, if you really want to understand why the sound of a motorcycle means little, if anything to on-coming traffic, either ask your science teacher to explain it to you or look up the physical properties of sound.

davesdeville
03-17-05, 09:35 PM
You can hear the sound ahead of the bike. The doppler effect will make it higher pitched, and unless you're riding 700 mph you're not going to outrun the sound. I don't like loud bikes, it makes me want to steer towards the annoyance... (not that I'd ever hit blah blah blah.)

RBraczyk
03-17-05, 10:00 PM
I'm sure you'd like to think so. I was probably riding and racing bikes when your DAD was a kid! .

My dad is older than you

Katshot
03-18-05, 10:22 AM
My dad is older than you
Regardless, I think you got my point.

Katshot
03-18-05, 10:31 AM
You can hear the sound ahead of the bike. The doppler effect will make it higher pitched, and unless you're riding 700 mph you're not going to outrun the sound. I don't like loud bikes, it makes me want to steer towards the annoyance... (not that I'd ever hit blah blah blah.)

True, but "hearing" it and having a sound level sufficient to actually provide any degree of "warning" are two different things. It would be like saying that mounting the horn(s) on your car under the rear bumper, facing rearward would still be effective. Somehow, I doubt that.
Without doing a lot of digging and graphing, I'd have to estimate that as little as 10% of the total sound pressure generated by a Harley with straight pipes is actually found at a point say 100ft straight ahead. Unfortunately, the rest of the population has to "deal" with the remaining 90% in the form of severe noise pollution.
On top of that, I bet you'll find that bikes with loud exhaust are involved in more accidents than ones with quiet exhaust. And you also need to consider what harm the loud exhaust can contribute to, either directly, or indirectly.

D148L0
03-18-05, 01:43 PM
A certain amount of noise will increase the chances of you being noticed.
But straight pipes are mostly annoying, a cry for attention. I found pitiful that people base their purchasing decisions on the amount of attention they'll get from them.

"Loud pipes save lives" is as valid as "There is no replacement for displacement".

Katshot
03-18-05, 01:47 PM
"Loud pipes save lives" is as valid as "There is no replacement for displacement".

Agreed, they're BOTH BS!

HotRodSaint
03-18-05, 02:30 PM
"Loud pipes save lives" is as valid as "There is no replacement for displacement".

Which means there is some truth to both and there are other ways to achieve the same results.

Can we stop arguing over whether deer whistles work or not. It's old now.

RBraczyk
03-18-05, 10:22 PM
Thank you.

cadydaddy
03-18-05, 10:35 PM
that bike aint got nothing on lance armstrong. lol and he pedels his.

90Brougham350
03-18-05, 11:51 PM
"Loud pipes save lives" is as valid as "There is no replacement for displacement".

Sorry fellas, but advancing the cam 4*, headers, and $300.00 chips only go so far. A modified 283 can make more power than a stock 350. A modified 350 can make more power than a modified 283, no matter how you look at it. Power is derived from the area under the torque curve, and since horsepower is derived from torque, what really matters here. According to Westechperformance,

"Displacement is the easiest way to achieve torque. Very large cylinders and a long stroke offer the greatest cylinder volume and overall piston area for the fuel charge to push against the crankshaft or lever if you will. Big block engines in the 400 to 500 cubic inch range deliver tremendous torque and they are easier on parts for the same amount of power output."
http://www.westechperformance.com/pages/Tech_Library/Understanding/hpvstq.html

Can anyone disagree? I don't want to start an argument, but when it comes to producing power, displacement is the option which provides the greatest yield. Other modifications can add to the benefit of increased displacement, but they cannot surpass it. Simply physics. There's a reason to build a Chevy big block with a long arm versus a small block with a long arm; the big block produces more torque. Torque spins the tires, not horsepower.
Here are the major ways that stroking (one method of increasing displacement) manufactures torque:


1. An increase in cubic inches creates more displacement, and more displacement means more torque.


2. A longer stroke is like a lever acting on the crankshaft; in practical terms it's like using a breaker bar instead of a ratchet handle.


3. More displacement facilitates a higher compression ratio without resorting to outlandish piston domes that disturb flame travel.


4. A longer stroke creates faster piston speed, so the piston can create more of a pressure drop to fill the cylinder more completely at low rpm. 5. It is thought by some that increasing stroke without increasing the length of the connecting rod builds torque because piston-speed dynamics and the rod ratio create more cylinder pressure at maximum rod angularity, at which point the rod has the greatest mechanical advantage over the crank. In a street engine, lengthening the stroke without changing anything else usually favors low-end torque, not high-rpm horsepower.


http://hotrod.com/techarticles/50997/
http://chevyhiperformance.com/techarticles/148_0312_stroke/

THERE IS NO REPLACEMENT FOR DISPLACEMENT.

Brian

BANK
03-19-05, 12:59 AM
I can only say that I have been alerted to the presence of a bike by its sound. However, it is open for debate as to if saving motorcyclists lives is worth the annoyance of loud pipes.

davesdeville
03-19-05, 04:31 PM
There still is no replacement for displacement. Name something that can be done to a smaller displacement engine that can't be done to a larger one.