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I have been wondering about this: It has become apparent that straight pipes are the most efficient way to go concerning motorcycle exhaust tuning, given its prevelance in MotoGP on four-stroke machines. Now, how would one set out to optimize the EFI for their bike with MotoGP-style straight pipes? Would a PCIIIR with ignition advancing do it? Would it require custom engine work? Would it require a custom pipe designed to have a little back-pressure? How would one go about doing this to maximize power delivery???

:confused: :confused: :confused:

:twofinger
 

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Discussion Starter #2
How about this: anyone know how the MotoGP guys did it?
 

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The PC111 would be a must,the stock ECU,as good as they are,just won't have enough range.

Back pressure is a whole nother can of worms.Take a look at Microns full Serpent system and all the R&D that goes into finding that sweet spot to knik the pipe to give it the max HP.

I'm running str8 pipes on my VTX and it has removable baffels.Sometimes I'll run without them and I can feel the power loss.Not that it's alot but enough that I know it.

On the track where 1000's of second count,it could matter.
 

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Discussion Starter #4
Interesting, why do you think MotoGP went to straight pipes then? To actually de-tune the bikes? I know it's possible, but I don't know if that was the reasoning...
 

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It's pretty much common knowalge in the v- twin world that str8 pipes give better HP gains.It's just that getting that perfect amount of back pressure is the trick and harder to do on a inline.

With the PC111 and a good Dyno tuner,I think you would be able to achieve the goals you seek.
 

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Take my VTX.

In stock form,95,96 HP and roughly 110ft/lbs of toruqe.I added a PC111,Vance&hines str8 pipes and a open air 3 1/4" K&N air filter.All of this with a custom map.

I'm now at 101HP and 121ft/lbs of tourqe.This bike weighs 750lbs and will now pull the front wheel in 3rd gear at 70 mph.
 

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wescoas1 said:
I have been wondering about this: It has become apparent that straight pipes are the most efficient way to go concerning motorcycle exhaust tuning, given its prevelance in MotoGP on four-stroke machines. Now, how would one set out to optimize the EFI for their bike with MotoGP-style straight pipes? Would a PCIIIR with ignition advancing do it? Would it require custom engine work? Would it require a custom pipe designed to have a little back-pressure? How would one go about doing this to maximize power delivery???

:confused: :confused: :confused:

:twofinger

The Short ANswer - Buy a PCIII, install it, then take your bike to a good tuner, and have his tech do lots of dyno runs to optimize the fuelling.


IOW - No different than anything else.

Scott :D
 

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My question is, you running track only on that bike, or running street too. Personally if your running street and you pulled up next to me on your bike with str8s on it. I might kick you over. The sound is annoyingly loud, and down right crappy sounding. But thats my opinion. But if it's for track then I understand. Like my buddies Katana750 Has a full race D&D system. I hate riding with him because of it. :twofinger
 

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what R you lookin' at?
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world of difference from moto gp to a streetbike........basically no comparison.
 

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Discussion Starter #10
I would not say that there is no comparison, although of course they differ in many significant ways. And yes, I ride straight pipes on the street sometimes. Some people hate it, some people love it. I love it. The sound at 12,000 RPMs with straight pipes is brilliant, as is the idle. No louder that a Harley with straights on either, so why split hairs?
 

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straight pipes

The first mistake is to think the pipes on moto gp are straight pipes. Straight pipes mean exaclty that straight to open air.... meaning no collector. On exhaust the collector is last factor in power delivery. I have never seen a bike make more than negligible power without the muffler. I dont build pipes so I couldnt get too techy on the subject so I wouldnt be a really great help in the math part. My suggestion? leave the muffler on as even if it was for track only, most tracks enforce a decible limit.
 

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Discussion Starter #12
I believe that they actually are straight pipes these days without collectors. M1, RC211V, Desmosedici, you name it.
 

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A straight-pipe is different from a straight-through muffler. The muffler, while flowing the same, would dampen the exhaust pulses decreasing noise and usually brings back some of the low end torque that would be lost with a straight-pipe.
 

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if it was straight pipes on moto gp then the honda would have five outlets, no? No for it to have two outlets it must run through a collector to chamber into one pipe. Hence they are not straight pipes. Anyways I didnt answer this thread for speculation on what a race bike has on it. I was stating that straight pipes are for a very very narrow power band such as a top fuel drag car. Even the damn F1 cars are run into collectors, it is the easiest way to fool mother nature into thinking it is a longer pipe than it is, and still have the short pipe for high rpm. That is why you now have tapered head pipes on some exhaust they also use crossover pipes. So enough with the speculation and get over it. It would be a bad idea to use straight pipes okay?
 

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Discussion Starter #15
By straight pipes I meant pipes with no muffler (aka, end can or slip-on), not without a collector, those are two different things. Perhaps my wording was off, but you know what I mean. So why is this such a bad idea? Sounds like it works for F1...
 

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its not a bad idea, but in GP i presume the cam profiles are different, and the abscence of backpressure in the exhaust would allow some of the power creating pressure to escape in a street driven engine, at least at lower rpm, whereas in MotoGP the exhaust probably opens just a bit later, and they run much higher in their power curve, so low end loss doesn't really matter to them,

bottom line: the engine is a big air pump with harmonic resonant tendancies on both the intake and exhaust sides, and any changes to either changes the opertion of the whole unit significantly, so a PCIII is a must, and custom mapping is a neccesity.
 

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Discussion Starter #17
Interesting, thanks Cerberus.
 

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yet another misconception, a loss of power just about everywhere is what would happen. I cant believe you guys think that Moto GP runs straight pipes. It is an open pipe after the collector. Run your bike without the muffler and almost nothing changes. run it without the collector and you'll see the problem. Moto GP is not a drag race, you need torque in the middle to pull from the corner. Thats why honda never raced an inline four in superbike. A "V" style motor offers more torque without the tr***** of the inline four.

Look I'm not flaming anyone but I did this for a living with the factories, Im telling you guys, dont get caught up in your fantasy gimmick. Making power is nothing more than math. No doodad is gonna help you no matter what you think. Do you think the new Gsxr1000 has a set of straight pipes into the Moto GP style muffler? No but people like you will think it is the newest badass thing since a digital tach. They have had the technology to make the power they do since the 70's, the limiting factor was chassis and tires. Nowadays the power increases you see are from thousands of dollars spent massaging parts that they found were not cooperating with the rest of the system. Not some magical doodad or trick pipe. Read some books guys, the magazines here are shit and biased. Who in their right mind would bash one of your biggest advertisers?
 

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hybrid said:
yet another misconception, a loss of power just about everywhere is what would happen. I cant believe you guys think that Moto GP runs straight pipes. It is an open pipe after the collector. Run your bike without the muffler and almost nothing changes. run it without the collector and you'll see the problem. Moto GP is not a drag race, you need torque in the middle to pull from the corner. Thats why honda never raced an inline four in superbike. A "V" style motor offers more torque without the tr***** of the inline four.

Look I'm not flaming anyone but I did this for a living with the factories, Im telling you guys, dont get caught up in your fantasy gimmick. Making power is nothing more than math. No doodad is gonna help you no matter what you think. Do you think the new Gsxr1000 has a set of straight pipes into the Moto GP style muffler? No but people like you will think it is the newest badass thing since a digital tach. They have had the technology to make the power they do since the 70's, the limiting factor was chassis and tires. Nowadays the power increases you see are from thousands of dollars spent massaging parts that they found were not cooperating with the rest of the system. Not some magical doodad or trick pipe. Read some books guys, the magazines here are shit and biased. Who in their right mind would bash one of your biggest advertisers?

someone had already straightened out the issue of wescoas1 mis-stating what he meant, which was basicly open exhaust after the collector.
I replied with the assumed understanding that that was what we were talking about.

now, about your statement:
Run your bike without the muffler and almost nothing changes.
Bull frigging Shit. modern exhaust systems are created with concerns for EPA regulations and create way too much backpressure. Aftermarket pipes with a proper retune will often net you a nice improvement in power(which i know for my own experience). If the cam timing had been optimized for the stock exhaust system that would seem impossible, but it seems clear to me that they (most manufacturers) expect us to open up the flow path.
Making power is nothing more than math. No doodad is gonna help you no matter what you think.
True and False. You presume to know every influencial parameter in the huge equation that is my bike? Guess again bucko. With some exhaust mods and a redsigned tune (of my own design) I was able to pick up at least 15% more horsepower and torque @5500 RPM and a few HP at the top end on my bike. See my profile for the chart.

people like you will think it is the newest badass thing since a digital tach
People like who? ME? I don't care who you work for or did work for, coming along and waving around your resume as if that means you know it all is a bit arrogant, don't ya think? I am an ASE certified Master Auto Technician, and I've been working on engines of all kinds all my life. Does that mean I am always neccesarily right?
No fucking way, but my experience proves you wrong, at least in my case.

And yes, they may have had the technology to create huge horsepower for many years but no factory anywhere is going to impliment it all in one big shot. if they did, there would be no reason to buy next years model, until some new power creating breakthrough comes along (don't hold your breath).
That being the case, there is always room for us to extract a little more.
 

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well mister ASE, how lovely. I can take a test get the car degree and what of it. Now if you want to misquote me be my guest. Go get a bike with an exhaust on it and take the muffler off. If you were so smart you would know that the exhaust can from the factory is do damn bid just to muffle the noise and not create a back pressure, hence the size creates an illusion to being straight thru. I doesnt work well but it does, now my resume doesnt mean I know it all but this isnt the mustang forum is it? No sir its not, so take what you want from it but I have done and you obviously have not. So what if you got 15%. Any monkey with a power commander and a pipe can do that. Typical gains from removing the factory fuel and exhaust management do that. Always has and until the little guys in Japan figure out how to beat our EPA it always will. If your so damn smart figure it out, I'm sure honda is interested in buying your patents on this crazy technobabble youre selling.

Now I am sure your a smart guy and we would probably get along just fine but the fact of the matter is your twisting a dumb question into a battle of wits. I am done with it, just trying to spread the knowledge I was fortunate to learn. Maybe someone who isnt as special as you could use it. Then again maybe you could make a bunch of money selling straight pipes to sport bike riders. Stranger things are bound to happen
 
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