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Discussion Starter · #1 ·
With the set valve on our bikes, is a muffler really needed? What I'm wondering is, is the muffler just for sound control or does it give and performance benefit? I would think all of the back pressure and performance comes from the set valve opening and closing and Suzuki and other builders put a muffler on to control the decibels(sp?). Just wondering, not advocating anyone tear your mufflers off.
 

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There are enough exhaust threads on here it make your eyes hurt and your head spin, just look around you will find plenty to read on the subject :bigthumbsup:
 

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ppridgen1 said:
they are there for noise reduction ,back pressure (mostly )is provided by the set. But removal of both is when the HP. really starts to come on
thats why i tell people to unhook the set, but nobody believes me. ::)
 

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If you were to remove BOTH (and not replace them with anything) that would give you virtually "0" back pressure -- and that can't be good for power.
 

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Discussion Starter · #5 ·
ppridgen1 said:
they are there for noise reduction ,back pressure (mostly )is provided by the set. But removal of both is when the HP. really starts to come on
That's what I thought. When I get some time, I want to investigate this thing a bit. There's gotta be a better way to make an efficient exhaust system and not add cross-overs and bulky mufflers and all the other stuff. I don't know why all of the aftermarket systems have a cross-over and claim that it helps all that much. The set valve is what gives the appropriate backpressure when needed, and it you're wide open, then you don't want any restrictions.
 

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montoya32 said:
That's what I thought. When I get some time, I want to investigate this thing a bit. There's gotta be a better way to make an efficient exhaust system and not add cross-overs and bulky mufflers and all the other stuff. I don't know why all of the aftermarket systems have a cross-over and claim that it helps all that much. The set valve is what gives the appropriate backpressure when needed, and it you're wide open, then you don't want any restrictions.
I think the crossovers and or collection chambers are there to have the exhaust pulses cancel each other out or something like that. I kind of guarantees that both cylinders get the same back pressure I guess.
Others here will know for sure.

Sledzep
 

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To try to answer JR's "question"

I know that dragsters run pretty much straight open -- but they've only got ONE job to do: run straight ahead, at full power, and high rpm.

The real world of riding a bike around the countryside requires a lot more variation, and mid-to-low end torque may be just as important to a rider's performance under some conditons, than total HP at 7,000 rpm.

If you want to be "scientific" about it -- I think what we want to maximize is "the area under the curve" of rpm vs HP (or rpm vs torque) -- I'm not sure which is more correct.

As you know -- a well-tuned exhaust can do a lot of things, like scavenge, and actually help suck A/F into the cylinder during the overlap phase of the valve timing. Unfortunately, it can only do this optimally at certain rpm -- because rpm changes the velocity of the gasses and everything changes pretty fast from "optimal" to less than optimal as rpm fluctuates.

Nonetheless, if you run "wide open" (I believe) you lose ALL of the potential for optimization (or near-optimization) that a properly designed exhaust has to offer.

::) :read: ::)
 

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You need some back pressure. I do run open pipes on my bike but do have torque cones installed at the head to give the proper back pressure load. If you run open pipes with NO back pressure you ARE robbing your bike's power band. PERIOD! And yes, I am sure!
 

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Isn't the best 1/4 mile time derived by the most HP over time, and not just total HP? Doesn't Mean HP win over Total HP?

I.e.

If your average HP were say 115 and your peak is 125, that can beat a peak HP of 130 if the average were say only 110HP. Of course the time duration for the averages and peaks here would be the key.
 

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J R said:
You make some valid points however a well engineered pipe for a given application dosent need bullschitz baffles and crap they sell on the net to help put a band aid over a poor design.I have worked around and on dyno,s since I was a little kid and have been around and worked with some of the best in the world as far as engine building and design and ive NEVER seen back pressurre make more h.p .I have seen poor designs and people compensate for poor designs with baffles and gain bottom end tq lost due to a crap pipe design but never have I seen a properly designed pipe need a baffle to make power ever in prolly 2 billion dyno runs ive did on everything from a briggs motor to aircraft engines. I got a set of dragsters here there stepped pipes there not straight like you posted and they make decent TQ with no baffles and hp and lose tq and h.p with the junk azz baffles they put in there pipes.But hey this is the internet and if sombody tells ya its better then it is right ;) The difference is I know putting washers in pipes and selling them as power adders is a lie and most dont... As far as pipe design goes each cyl should be treated differently and have its own needs just as the intakes but most people dont get it and think backwoods bullschit that " ya just gotta have a little back pressurre " and im glad those are the same morons that gave me recoreds and wins and jobs and the ability to retire in my 30,s and play and do what I want.Like they say, Ya cant fix stupid....Just look at the pipes out there now.Maybe the formula one guys and indy guys and nascar guys that spend millions a year dont know schit and all this time they just needed some backpressurre for low end ::) ::) ::) I think not. The only people that make these claims are the people selling the crap.Yea on the street ya need a way to keep the noise down for sure but thats not the way to make power or TQ a brain is..It like these morons that run supertrapps and think there "tuning" the exhaust ::) :a20:
:bigthumbsup: ;)
 

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heres something to make you laugh Jr. a well known shop around here that has been doing exhaust for years. tell me that on my turbo car that i need a smaller than 3" exhaust to make power. you know the words "BACK PRESSURE" i laughed so hard at him. and asked him what does the turbo do? all i know the bigger my exhaust on my car and the shorter it is TO A POINT. the more my dyno shows hp. and my baby four banger is well over 600hp now.. man i love turbos. same on my diesel. the bigger the exaust, the less bends. the better. well anyways i hope this made sense to somebody.. back pressure bad......
 

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Quote from a news item about the M109R:

"Spent gases pass through a catalytic converter, and the 2-into-1-into-2 exhaust system is also equipped with Suzuki's own version of the power valve called SET (Suzuki Exhaust Tuning). This is said to improve combustion at the low end of the rpm range, and seems to be doing its job just fine."

...tuning an exhaust for power, what were the engineers at Suzuki thinking, those morons. :dontknow:

On the other hand, there's this item from back in May:

http://www.m109riders.com/forum/index.php?topic=444.msg5151

LG
 

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J R said:
I dont think there will be any HUGE gains from ANY pipes maybe a little but nothin major.A stepped pipe and a crossover tube or a two into one with the right size primary tubes might do a little but.Nothin like some think.It would take sombody to build a pipe and put the bike on a dyno then build another set and put it on the dyno ect. lots of R&D not just making some pipes that fit and chrome them.BUT the weight savings will be where youll see some power getting rid of the truck exaust from the factory
I remember reading that a couple of days after joining the board. Now if I'm reading your new post correctly...

J R said:
Ya the set deal is good cause the bikes so darn lean down there.ditch the set valave and fatten the bike up and you can easily double the factory tq.
...it would seem that your journey has taken you far beyond that initial position. Brainstorming and experimenting as a collective is probably what I enjoy most about this board. The M has become a pet project of sorts to me and I do what little I can to further a couple of the main goals of this board. Sounds like you have at least two interesting dyno read outs to share.

LG :bigthumbsup:
 

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   QUOTE: "I got a set of dragsters here there stepped pipes there not straight like you posted and they make decent TQ with no baffles and hp and lose tq and h.p "

   When I mentioned "dragsters" I was referring to (like) A-fuel Dragsters (at the track) -- not the Cobra Dragsters.  You know, the guys with 8 open-ended pipes coming straight off the headers, with flames shooting out of them.
 

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   Just to stir this pot a little more:

   JR: I know you know this stuff -- but the garden hose analogy is not completely accurate.  There are explosions taking place in that garden hose, and IF you can coax a little more A/F INTO the hose -- then more will come out of it. 

   This is my understanding of a "well-tuned exhaust" -- (assuming that it is possible to "tune" it so that it works well throughout a good portion of the powerband).  If it works right, it will HELP suck the spent gases out of the cylinder -- and it may even suck a little more A/F into the cylinder, during the overlap phase of the valve timing.

   If that can actually be done -- then it should be better than open pipes, -- and there is that thing about backpressure for low end torque.
 

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I'm confused.

Lamont says he needs to lean his bike out to make power. JR says he needs to fatten his up (make it richer) to make power. Those seem to be opposites to me. What gives?
 
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