Quote from: Chuck on December 11, 2006, 12:29:32 PM

Quote from: AlphaFire X5 on December 11, 2006, 10:30:04 AM
The GS moves 244cc of gas at a time, while the R6 moves right around 300cc. It wouldn't be considered that much more "free flowing" especially since it is a stock muffler and has to conform to the same emissions and noise standards that all the other bikes do.

That's the kind of talk I was looking for.  Thanks Alpha, that gives me a way to think about it.  Now if I go (for example) from a 127.5 jet to a 150, that's theoretically about 18% more fuel.  Even with those numbers, the R6's 600cc displacement is 20% more than the GS's 500, so it seems about right.  Additionally, the R6 has a higher compression, which increases the amount of uncompressed air that has to exhaust.  Higher RPM also increases the volume of air that needs to pass through.

Once again, I could be missing something that makes this analysis completely wrong.

That actually kind of gives me more reason to think it would work.  Maybe it's my civic duty to try it and report the results.

Unfortunately that's not how it works. Just because you have a freer flowing exhaust doesn't mean you're increasing the air being drawn into the engine. Remember, exhaust valves are (for all practical purposes) entirely closed when air is being drawn into the engine. Therefore the effect of an exhaust change is not nearly as beneficial without an intake change. Stock headers on the GS also restrict most of the gas flow out of the engine. Just changing the muffler is going to do little to no good if the header pipes stay the same diameter.Also, higher RPMs don't necessarily mean higher volumes, just higher exhaust gas speeds, meaning how fast it needs to travel through there. Let your bike idle one day and stick your hand at the ned of the muffler. You should feel a distinct puff puff puff. Rev the engine and feel it smooth out into one continuous stream.

Quote from: AlphaFire X5 on December 11, 2006, 03:28:15 PM
Unfortunately that's not how it works. Just because you have a freer flowing exhaust doesn't mean you're increasing the air being drawn into the engine. Remember, exhaust valves are (for all practical purposes) entirely closed when air is being drawn into the engine. Therefore the effect of an exhaust change is not nearly as beneficial without an intake change.

That's a great point.  I didn't think of it that way.  (I am planning to run a lunch box, though.)  I also didn't think about the fact that it's the pressure exerted in the exhaust stroke that drives the exhaust gas out.  The R6 just plain has more power, and can use more of it evicting exhaust gas without it being a problem.  So an exhaust from a higher displacement bike could very well be more restrictive, and it wouldn't really matter for that bike.

That blows my theory out of the water, then.

Quote from: AlphaFire X5 on December 11, 2006, 03:28:15 PM
Stock headers on the GS also restrict most of the gas flow out of the engine. Just changing the muffler is going to do little to no good if the header pipes stay the same diameter.Also, higher RPMs don't necessarily mean higher volumes, just higher exhaust gas speeds, meaning how fast it needs to travel through there.

I meant volume-per-time, which is necessarily more when the RPMs are higher.

In all, it sounds like you believe there's no performance benefit to be had from replacing the can, then?  That would sure save me a few bucks, and a few decibels.

Quote from: Chuck on December 11, 2006, 03:55:02 PM
In all, it sounds like you believe there's no performance benefit to be had from replacing the can, then?  That would sure save me a few bucks, and a few decibels.

No matter what bike you have, replacing just the muffler/silencer/can makes little difference in performance. On most bikes you'll only see a 1 or 2 HP gain at the most from a slip on/bolt on can. Replacing a stock muffler with another stock muffler is just wasting your time, I feel.

dang you are smart!!  (not trying 2 be a smart A$$)

A little off the subject, but I'm wondering how my '89 will do with the new lunchbox I'm getting, matched with the Cobra F1R muffler that's on it.  It sounds pretty rowdy, but it isn't a straight-through baffle design...  Maybe I'll start with a 140 main jet to see how that works?

Quote from: Chuck on December 11, 2006, 03:55:02 PM

Quote from: AlphaFire X5 on December 11, 2006, 03:28:15 PM
Remember, exhaust valves are (for all practical purposes) entirely closed when air is being drawn into the engine. Therefore the effect of an exhaust change is not nearly as beneficial without an intake change.

Unless, as in the case of almost any stock Mazda running around on the street, the stock muffler is so horribly restrictive of flow that it merits a change even if the rest of the setup remains stock. 

My sister has a '01 Protege 2.0L that picked up 5-6mpg in city and highway, freed up the top-end rev range and although it hasn't been on a dyno in its life, seat of the pants tells me it is 5hp or so. 

Parents have an '02 Miata 1.8L that has similar effects from a muffler swap.  Adding a high flow foam element with an entirely redesigned "cold air" intake scheme mainly added noise, it was the muffler that changed the characteristics.

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The R6 just plain has more power, and can use more of it evicting exhaust gas without it being a problem.  So an exhaust from a higher displacement bike could very well be more restrictive, and it wouldn't really matter for that bike.

I disagree.  Wasted power is wasted power.  R1 headers are bigger in diameter than R6 headers because the R1 is always moving more air.

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In all, it sounds like you believe there's no performance benefit to be had from replacing the can, then?  That would sure save me a few bucks, and a few decibels.

I'd suggest waiting until you get up the gusto to go to a full system exhaust.  Anything that retains the stock GS headers, be it Wileyco, mak's "custom" high- or low-mount or an R6 stock muffler, is not going to do much for you. 

Another point, as has been pointed out in this thread before, the R6 can (in like new condition) is not going to be much, if any, louder than a good condition GS pipe.  A blown out GS pipe may, in fact, be louder if the baffle is rusted and leaking.

Quote from: Mk1inCali on December 12, 2006, 10:19:13 AM
I'd suggest waiting until you get up the gusto to go to a full system exhaust.  Anything that retains the stock GS headers, be it Wileyco, mak's "custom" high- or low-mount or an R6 stock muffler, is not going to do much for you. 

Another point, as has been pointed out in this thread before, the R6 can (in like new condition) is not going to be much, if any, louder than a good condition GS pipe.  A blown out GS pipe may, in fact, be louder if the baffle is rusted and leaking.

I actually like how quiet the GS exhaust is.  I was going to reluctantly accept an increased noise output in exchange for a slight improvement in power.  However, if the improvment is so slight I'll never notice, then I'll just wait for the gusto, as you suggest.  I bid $1 on just about every R6 pipe I found on eBay, so if I get one of them, I'll probably try it out.   

My current GS header is dented, so it's probably somewhat more restrictive than most.  I suspect that will be a problem anyway.  For now, I'll see what I get out of a lunchbox and rejet, and punt the exhaust question for a few months.

Also, if I want more HP, I suppose I can ride my FZR. 

Why not try an FZR muffler then? 

Hey chuck or wondertwin have any of you drilled holes in the stock muffler? I was wondering how would it sound or where in the can you drill it at

Everyone who's tried drilling their stock muffler has said it was utter crap.  And then, they can't un-drill it.

Funny thing about the FZR, I bought it with a V&H supersport on it.  It's so freakin loud I was thinking about going back to stock.  (I have the stock can, but no stock headers right now.)

can you put 2 exhaust in a gs500f 2006 instead of one? i was looking at the sv1000s with custom exhaust i was like wow

....................................



 

It's been mentioned:

http://gstwins.com/gsboard/index.php?topic=30565.0
http://gstwins.com/gsboard/index.php?topic=25605.0
http://gstwins.com/gsboard/index.php?topic=7472.0
http://gstwins.com/gsboard/index.php?topic=14203.0
http://gstwins.com/gsboard/index.php?topic=4407.0

Quote from: Mk1inCali on December 12, 2006, 10:19:13 AM

Unless, as in the case of almost any stock Mazda running around on the street, the stock muffler is so horribly restrictive of flow that it merits a change even if the rest of the setup remains stock. 

My sister has a '01 Protege 2.0L that picked up 5-6mpg in city and highway, freed up the top-end rev range and although it hasn't been on a dyno in its life, seat of the pants tells me it is 5hp or so. 

Parents have an '02 Miata 1.8L that has similar effects from a muffler swap.  Adding a high flow foam element with an entirely redesigned "cold air" intake scheme mainly added noise, it was the muffler that changed the characteristics.

I had totally forgotten about this fact until you mentioned it.  Also, in regards to the gen 2 rx-7 there can be as much as a 15hp increase just from the mufflers and cat change.  With headers it can be as high as 30hp depending on the engine.  It is unbelievable how much they had to choke up the rotaries.

Yeah but rotary engines are notorious for incomplete combustion.  Not as bad as a 2-stroke, but that cat does a lot of work.

chuck how can you remove the baffle in the stock muffler? NVMD lol

ok the 2006's exhaust, is it diff to drill than older models?

Quote from: GON on December 13, 2006, 12:54:49 PM
ok the 2006's exhaust, is it diff to drill than older models?

No.

Ok, don't drill your pipe, I did, sounded like a lawnmower fighting a swarm of hornets. If you do drill it, drill holes small enough to put screws in when you decide you hate it!
Wileyco sounds much much better!
As for the debate about the header of the gs, seems like the pipe is plenty big to handle the exhaust flow. The motor can only make so much flow, stock. Dollar per hp seems as though its not at all worth it. Just my opinion though.

I'm not trying to be a jerk or anything but anyone looking to add major hp isn't going to get it unless they modify the engine, and I mean bore/stroke or add spray to it (which can be done for about the same price as a top end exhaust). 
If you get two staws: a thin coffee stiring straw then a bigger staw and attach the larger straw to the opposite end of where you blow through  the thinner straw.  Does it make it any easier to blow through the thin coffee straw? 
The restrictive part to the exhaust is the header, then the pipes, and then finally the exhaust.  So any significant gains would be found getting a wider exhaust header, tubing, and then a muffler.
I'm not that familiar with motorcycle engines but I have worked on cars a little, so i'm just chipping in my $.02 so no need to flame.