A good friend of mine designed and built pipes for bikes and formula cars - and believe me, a good pipe can make a LOT more power - but it can also be pretty quiet - and a lot of loud pipes waste more power making noise than turning wheels.
There again it depends on the truck, and speed, and a whole lot of things (like what's in the box)
Under some conditions, ie. high temperature,and heavy load, the 2 cars referenced will detune due to mild detonation on regular gas. Rhis WILL cause a (possibly small, but measurable) decrease in power output and fuel economy. It will not show up much on thir tests, but load the car to capacity and drive up independence pass, or any other long hard grade and it WILL be noticeable.
The difference between "premium recommended" and "premium required" is "premium recomended" can compensate for low octane by detuning and not cause any damage, while "premium required" cannot compensate enough. Under "normal" driving you may get away with regular gas on either car
One problem with my older car is that the headliner and pillar-liner material tends to flap in the wind when I use the windows.
What do you use to glue that back on anyway?
Just to let you know, my car "requires" premium (91 I believe) and yet, it works just fine on 87 (yes, it has knock sensors so it retards the timing "if" it knocks).
The question I've always wondered is how can I ever tell if it *did* have to retard the timing.
I am told if I had better equipment, I *might* be able to read that out of the ECU. All I have is OBDII stuff, so, that's beyond my capability.
I'm not gonna agree with you 'cuz that gets me into trouble.
Looking up the most common types of fatal motorcycle accidents, it seems that cars almost never rear end a motorcycle (5%).
About three quarters of the fatal accidents occur as head-on collisions, with the other quarter being mostly the motorclists losing control of their bike on their own.
Half of the accidents are when cars turn left into the motorcyclist.
There's nothing there about loud pipes but obviously visibility is always a critical factor.
If you look at common causes of crashes, almost none of them would be avoided by loud pipes (e.g., losing control of the bike).
I did a quick skim of the common types of motorcycle accidents
Where most, if not almost all of them, wouldn't make any difference with or without loud pipes. Given that light moves faster and further than sound (so to speak), one has to wonder if someone doesn't "see" you coming the other way (which is the most common and most dangerous crash), are they really going to hear you while they're in their luxurious cage?
Doubt it. But I'm open to research that says otherwise.
It's interesting that I looked at about a dozen articles, almost all of which suggested how to avoid the accidents, where none suggested loud pipes.
Of course, there are plenty of articles titled "Do loud pipes save lives"
Yikes! Look at just that *last* article. "The truth behind such a claim disproves this myth on so many levels: simple, common physics, common sense or plain reason can bring in countless reasons because this is just a myth. Let's tread the path of physics a bit and analyze what's happening from a strictly mechanical point of view."
You can read them, but I skimmed them, with the result being it's a myth.
I'm not going to argue because all I know is what CR said, which is...
"Tailgates and tonneau covers We tested a 2013 Ram V8 on the highway at 65 mph with the tailgate up, tailgate down, and with a factory soft tonneau cover. The tests were performed following our usual procedure for testing highway fuel economy, including making runs in both directions. We found that adding a tonneau cover or lowering the tailgate hurt fuel economy, rather than helped it.
With the tailgate up and no tonneau, we got 22.3 mpg. Dropping the tailgate decreased efficiency to 21.5 mpg. That 4-percent difference means that driving the Ram all year exclusively on the highway could cost the owner an extra 20 gallons of gasoline. (In reality, this big workhorse is likely to see a mix of driving and a variety of chores, limiting the potential penalty.) We found that covering the bed with a soft tonneau cover was even more detrimental, dropping fuel economy to 21.4 mpg."
RAM test:
Assuming the same outside rolling diameter, going from I.E. 15x6" wheels to 17x8" wheels:
- More stopping power
- More responsive steering
But:
- Less straight-line tracking
- Lower fuel economy
These can be overcome by:
Did you really expect there to be something about loud pipes? The only way you'd find that was if there was an actual study.
Yet you just said that half of all accidents occur with cars turning in front of bikes. If the bike is loud, it seems that there is a better chance the car driver might notice it coming, from 100 ft ahead, instead of turning in front of it. That happens very frequently, a car is waiting to make a turn, a bike is coming in the opposing lane, and they just turn in front of it anyway, as if the bike did not register with their brain.
Give it up already. Don't you have anything better to do? Now your trying to read tea leaves. You don;t have any valid data to even begin to work with.
Given that light moves faster and further than sound
Well then let;s remove the sirens from emergency vehicles and just go with the lights.
Good grief.
Yeah, and you know all about physics, right? So tell us by what physics are you able to determine that a noisy bike isn't more noticeable to others than a quiet bike?
From idiots like this:
"With the air/ gas jest directed towards the rear of the bike, it's there where all the noise goes. "
Who should I believe, that idiot or my own ears. Sure more of the noise will go behind the bike, but anyone who's been around a hog coming at them on the road knows that you can hear those loud pipes coming at you. Sirens would be of no use on emergency vehicles if that were the case. In fact, what we again know from physics is that this guy is an idiot. What you actually have is the doppler shift. There would be no doppler shift from a noisy vehicle coming towards you, only silence if the above BS was true.
What you have there are pure opinion pieces, laced with factual BS. You're one of the sad cases that thinks whatever they find on the internet on some jazzed up websites must be true because someone posted an article. Yet when someone tries to explain the actual physics to you, like I did in the earlier part of this thread, you just ignore it and go on to the next fluff piece. Sure, you're a "scientist". ROFL
common sense or plain reason can bring in countless
How far did your common sense and intuition get you in the earlier part, about wheel size and torque and work/energy?
Let's tread the path of physics a bit
It would be nice if you were a myth.
If mom and pop are not taking advantage of readily available data from the on-board computer systems they are either driving a 1972 Old Cutlass or they are not part of the conversation. This is 2017, not 1917 when you measured the tank level with a stick.
The physics of loud pipes saves lives shows it to be a myth.
"I almost broke Google looking for a large-scale, objective, scientifically conducted, peer-reviewed study showing that users of loud pipes have a lower mortality rate compared to other motorcyclists."
"On the surface it seems obvious that the noise emitted by loud motorcycle exhaust systems would aid in conspicuity and cause more watchful driving by other motorists. Yet not a single thoughtful study has been done that supports the theory."
See also numerous articles on "Do loud pipes save lives"...
And you probably wouldn't have much scavenging of the cylinder either. Best case you have a very low pressure node at the right place in the exhaust plumbing. The problem with that is it tends toward a narrow power band, hence the two strokes 'coming on to the pipe'.
We won't even go into rejetting the carb for older bikes or reprogramming the profile for FI bikes now that you've changed the flow characteristics.
What's the accuracy & repeatability of the dashboard reading you speak of?
As you must already know, the tach isn't all that accurate on today's cars. The temperate gauge isn't accurate on current cars either. Neither is the speedometer (to a few percent). Nor the fuel gauge.
Why would a purely informational dashboard mpg display be accurate? Or repeatable?
Maybe it is - but there's no reason for it to be accurate to +/- 2% of the indicated reading. Even the $360,000 EPA tool, as I recall, wasn't accurate to any better than that.
What's the accuracy & repeatability of the dashboard reading you speak of?
No argument. When you ride the best approach is to consider your fellow motorists to be utter assholes who, if not outright homicidal, do not see or hear bikes.
Loud pipes have one good use. When you're stopped at a light next to some soccer mom yapping on her cell phone revving it up to 5000 rpm might ruin her conversation for a bit.
Be a toss... I haven't read the rag in a long time but years ago I was amused by their car rating system:
inexpensive car -- a used Honda Civic is a better choice midrange car -- A new Honda Civic is a better value expensive car -- you could buy two Honda Civics for that
After reading the reports about items I had some knowledge about I concluded they were going plain vanilla, middle of the road, safe bets like the old saying 'nobody ever got fired for buying IBM'. With that in mind I didn't really trust their recommendations about items I know nothing about like digital cameras.
While I question pop's back of an old receipt calculations, the question isn't what the mpg would be for a known quantity of fuel at STP, but how many real world miles were traveled with that quantity.
For example, when I was driving a truck I would often get close to 7 mpg going east on I94 in North Dakota. Going west with the same load I would be lucky to get 6. If you don't know why you've never been to North Dakota. However, as far as planning my fuel stops, standard atmospheric conditions didn't count.
Assuming the same speed and frontal area what would be changing in the equation is the drag coefficient. Unless you have a handy wind tunnel, predicting the coefficient can be counter intuitive.
Back in the '30s automotive engineers were well aware of drag and its effects.
There were some beautifully sleek designs and you could even see the after effects in the Bonneville streamliners. Then in 1938 a German engineer by the name of Kamm made a discovery. Take a design that smoothly transitioned into a boat tail, saw the tail off, and you had the same Cd. You'll still see cars designed around that principle. Some of them aren't all that pretty but they do have low drag.
Like I said, you don't understand the difference between an actual study and opinion pieces. You take anything anyone puts up on a website as "data", even when it's obviously just opinion. Yet when someone takes the time to explain the physics of something to you, like I did with that whole endless BS about torque and work/energy, you just ignore it, don't even comment on it and it's off to the next internet fluff piece, which you treat as gospel.
Is it detached or just loose? What's the material? Steaming used to work with fabric headliners.
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