The Prophet

Here's one to muse over:
Butt Dyno's - I say they are seriously affected by the wallet, time spent performing the task, noise, and also ego.
Wallet - Spending hard earned cash on "wonder" products that promise "instant horsepower" usually convinces the buyer that they work. Example: Spending $1000 dollars on a straight through exhaust, then elaborating on how it vastly improved low-end torque. Easier to make these claims than to explain to your buddies that you blew a grand on nothin'. Sounds good to some though!
Time - after having spent a full Saturday in the garage hacking off the Airbox with the sawzall results in great gains in "power". "It's unbelievably better" sez the hamfisted perpetrator, "Those Engine Design Engineers are idiots!"
Noise - "These straight through shorty drag pipes are great, I've increased my horsepower by 25%!" ...Or is it just louder?
Test: Six stock bikes pass a group of ladies on the street corner. The ladies are asked to guess how fast the bikes were going. Note the results. Change the six bikes over to straight pipes. Same test, bikes past the ladies. What do you think they'll guess now. Yes, louder always seems faster.
Ego - of course. None of us like to admit that we were taken. Any time we are convinced enough to make a cash or time commitment, it's going to be very challenging to admit defeat if it doesn't really make any difference. Savvy bikers make better, well calculated decisions beforehand, and don't allow themselves to be forced into questionable alterations by pushy peers, or midnight internet experts.
Track times and timing slips tell the best story, as even dynamometers are limited by the operators set-up skills, and lack of wind, aerodynamics, etc.
Lastly, the most powerful, best set-up bike in the world is useless in the hands of an unskilled rider. Better to have a stock bike and a highly skilled rider.
My first qualifier when conversing with someone about bike motors is how often he says "Torque" Vs. Horsepower, and if he first asks specifically what the rider will use the bike primarily for. Many just want YOU to build another bike like THEIRS, hopefully validating their mechanical attempts.
I state all this as I so often see unfortunate newbies being pressured or convinced of ridiculous modifications on other sites, very seldom taking into account the owners riding style, budget, and experience. Most just result in "Loud", and accept it for "Fast".
I understand passion, and fanatacism, but to purchase a new bike for say $10K, then invest another $15k into to have the fastest "X Brand" arounds borders on... huh? Kinda like being the tallest midget in Des Moines, Iowa. Why not just buy another brand or model bike that already has these features, for say $12 K or so?
Interesting point to ponder: If all of these recommended modifications are so great, and so wonderful, how come the bike now uses significantly MORE fuel than before, and when, if ever, do I get to use that additional 5 horsepower at 10,500 RPM? What happened to good design practices, and designed efficiency.
There ARE high torque, very fast stock bikes that also obtain very good fuel efficiency, and are quiet and very comfortable to ride. What a concept!!It IS possible to build a great, efficient, reliable, and respectfully quiet motor, but only the very super-skilled and very knowledgeable can achieve this, and it is done via a well devised plan, tailored specifically for the distinct individuals needs. Plan your work, and work your plan.Your thoughts?

SidecarFlip

......If you want the 'lowdown' on engine and exhaust modifications, just ask a Harley Davidson owner......

You'll have to yell for them to hear you. Most are deaf from the modified exhaust..........

The Prophet

Just a week ago - as it is deer season here - a fellow biker very, very seriously informed me that I MUST have loud pipes, as the deer will hear me coming from miles away and run for cover. He has loud, straight pipes, and as proof has never hit a deer.

Based upon that theory, I always wear black socks when I ride, and have yet to hit a deer, therefore...

Serious about the statement from a friend, but otherwise, just foolin'. Point is/was: Advice is almost ALWAYS worth exactly what you paid for it. Actual engine experts, in constant demand from the racing and building world, would obviously find little, if no time to be constantly surfing the net, handing out unrequested advice. Real-world high quality builders are out there, but extremely hard to find, and undersatndably swamped with work. Many, many others have hand-me-down tribal knowledge and opinions, unfortunately few have fact based, mechanically sound, common sense, up-to-date technical ability. Those of us that have been around for a while, have heard some real doozies. Excellent for belly-laughs in the Pub re-telling, but extreme time and money wasters for the unaware.

Me? I'll stick like glue to the writings of Kevin Cameron, Des Hamill and others who have real world experience in the racing and experimental world, and who cater to street bikes by toning down the tuning aspects for reliability and ride-ability. Having a basic understanding of mechanical engineering foundations, physics, thermal dynamics and chemistry helps tremendously as well. I also frequent a dealer who is also very heavily involved in racing, and we have good laughs over some of the stuff touted on the internet.

Having said all that, I would never in a million years call myself an expert, far, far from it, although I've done my share of rebuilds and mod's. The fact is that the technical world changes constantly, and the rate of improvement in stock bike offers is snow-balling dramatically. Many new bike offers are ions better than very highly modified bikes from just ten years ago!

The day we stop learning and asking, and start doling out advice unasked for, is the day we should give it up! Nothing worse than a know-it-all preacher with ancient, or grossly incorrect advice. I always told my two sons - the better answer when you are unsure about something is: I don't really know, but I'll find out as soon as I can. As the old saying goes: Learning is done best with the mouth closed, and the ears open.

By the way, Cameron has a new updated version of his venerable classic - Sportbike Performance Handbook - coming out this month (November). Get it - the absolute best read, and by far the best unrequested advice I could give out to anyone. The book's suggestions and recommendations are eerily the exact polar opposite of what you might read in many of these open, untechnically moderated forums.

Caveat Emptor!

Speedtrip

Coming from the Sportbike side loud pipes mean nothing to me, show me a pipe that cuts weight then we can talk. I'm with Prophet as far as horsepower is concerned any 600cc modern Sportbike is probably more power than most riders can handle or need on the street ( though I still lust for RR liter bikes).

Right now I'm going in the opposite direction of the Bling& loud pipes crowd as I'm on a naked black bike with stock pipes, when I leave for work all the neighbors hear is the garage door.

The Prophet

I hear ya' Speed - no pun intended. To me, loud pipes translate as - Look at me, look at me, look at me! Beyond that, they do relatively nothing more than force additional noise legislation against ALL bikes.

With the straight through pipes, performance wise, you will gain at best a few HP waaaay up there in the RPM range, where you rarely, if ever, use it. Low end torque is compromised considerably, but the rev, rev, rev while blipping the throttle at the stoplight helps resolve this.

I agree, no need or wish to wake up the whole neighborhood and aggravate people. Also, long trips - >4-6 hrs on the bike - are no fun with a blasting exhaust. You'll arrive in much better spirits and hearing health with the quieter pipes.

I've done numerous modifications to my bike that easily enable all the power I need, and I can very easily obtain 115+ MPH if / when I wish, and also get 48-50 MPG to boot. I have no doubt I could easily achieve 50-55 MPG, if I rode slightly less aggressively.

All this on a relatively quiet, stealth appearing bike. I'm certainly not done yet, as I'm a habitual / serial tinkerer, but I am planning on trading her in within the next 1.5 years.

To me, a good modification mechanical-wise, gets you better fuel economy along with the torque increase, and does not compromise longevity, reliability or comfort. Volumetric Efficiency, and/or precise and effective Cylinder Filling capability via high velocity intake is where it's at. Too many sadly confuse more air volume with high velocity intake, and pay the price with the sudden loss of low end performance, and fuel economy as a result of larger and larger jetting requirements to compensate for innefficient combustion.

Uh-oh, now I'm giving out unrequested advice - sorry, just my personal slant on engine building. No need to take any of this seriously, as I'm certainly no expert as I offered earlier. Just enjoy the mutual banter.

stusaman

In the Vdub diesel world the "Butt Dyno" is a fact based report on horse power and torque. Chec the link below for more info.

http://www.ross-tech.net/andy/vwfiles/dynoplot6.xls

And this one to view an actual graph.

AudiWorld Forums: "Butt Dyno" Instructions

Here - here - LOUD does not equate to fast!

Jerry T

The Prophet

Thanks Stusaman, fantastic stuff, and good to hear from ya'. I love these charts and spreadsheets.

An easy arguement quencher concerning "loud pipes" is the fact that many, many bikes in stock form - Hyabusa, BMW, Triumph Triples, an so on, make fantastic Torque and Horsepower with stock, quiet exhausts. There are many aftermarket exhaust systems that increase performance, yet maintain a sensible, but "fun" decibel level. That said, there are no excuses for being loud, selfish and rude other than a lack of decent upbringing and a base education.

Actually, since this thread was originally started, our prophecies came very true - See Myrtle Beach, Daytona, and many other cities who are now aggressively cracking down on excessive noise from motorcycle exhausts. Thanks guys, nice going.

I, and I'm sure everyone else here, am all for having fun, and all for making modifications to our bikes. No arguement here.

What I'm not into is selfishness that results in more and more "babysitter" legislation to make child-like adults get in line. Acting like a fool never really results in anything good...

On a lighter note, thus far this year, I've lost 6.2 pounds (I have an Excel Spreadsheet Chart that I fill out every morning!), therefore my Butt Dyno should be more accurate? More sensitive? More portable?

At any rate, without touching my bike, it'll go slightly faster now!