Exhaust Myths vs Reality

[WarBaby]

WARBABY 4 x 2, 4 1, 4 2 1, now explain in more 4 x 2 vs 4 2 1? how does one get and who makes a seperate 4 2 system? without an X(cross over) is it an H with No connect the - part of the H just a piece to hold the tubes close for fitting purpose.[/quote]

A crossover or "balance" tube can be "X" style or "H" style depending on the designer's preference. In either case, it is a functional part of the exhaust, not just a mechanical support for the primary exhaust tubes. The "X" design is typically more flow-efficient and, when properly designed, both styles can increase low RPM gas extraction (scavenging) from the combustion chambers which, in turn, increases lower RPM torque.

[FAKK2]

Sorry for the stupid post here...



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[WarBaby]

I don't have personal experience with the HMF system. Theoretically speaking, "X" tubes should be optimal. HMF has an excellent reputation among Busa owners. Dual mufflers simply weigh more. If appearance is paramount, go for what your eyes like. If you're a performance purist, go for a power-proven, lightweight 4-2-1 system.

[FAKK2]

Sorry for the stupid post here...



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[WarBaby]

A properly designed 4-2 system is theoretically capable of making as much peak power as a 4-1 or 4-2-1. Exhaust design is largely about the kind of power you want. Peak power is not the only, nor even primary, goal of most aftermarket exhaust designers. The nature of the power band is MUCH MORE important for virtually all high performance purposes and different designs produce different powerband characteristics. Some people "poo-poo" the differences between exhaust systems but, to put it bluntly, they probably DO NOT UNDERSTAND as much about it as they think they do. This stuff is hard science, not speculation.

[FAKK2]

Sorry for the stupid post here...



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[WarBaby]

Understood. I salute your lust for knowledge... *I lust also.



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[FAKK2]

Sorry for the stupid post here...



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[FAKK2]

Sorry for the stupid post here...



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[MrHans]

Read it all twice and my eyes (and grey matter) are a lil bleary....
Thank you for the excellent read! I have a question about noise specifically and wondered if one of the pipe/can kits you rep are close to stock noise. I like stealth power mods and am looking for (at some point in the future) more ponies but not more noise. My tintinnus from power tools and rock n roll is bad enough...
Another question on a differing front:
Do you have any knowledge (or anyone else here for that matter) on active noise cancellation? Kinda like this only speakers on the outside to cover the noise made internally...
Again thank you for the excellent read, I'll go over it again until more sinks in...

[shortBoarder]

Originally Posted by [b

Quote[/b] (MrHans @ July 06 2005,18:26)]Do you have any knowledge (or anyone else here for that matter) on active noise cancellation? Kinda like this only speakers on the outside to cover the noise made internally...

That would be nearly impossible (with the exception being in a tightly controlled research environment) on a motorcycle, at least externally.

You could potentially do this inside the helmet, with an exterior microphone feeding speakers in the helmet a sound that's 180-degrees out-of-phase, but it's much cheaper to use earplugs

[MrHans]

Originally Posted by [b

Quote[/b] (shortBoarder @ July 07 2005,02:57)]

That would be nearly impossible (with the exception being in a tightly controlled research environment) on a motorcycle, at least externally.

You could potentially do this inside the helmet, with an exterior microphone feeding speakers in the helmet a sound that's 180-degrees out-of-phase, but it's much cheaper to use earplugs

Well yeah, think cockpit noise reduction systems and helmets that do the same. I already wear earplugs when I ride but this doesnt reduce or obviate the sound radiated by my bike.

[o-neg]

Akkk! I've got a D&D. At least a single can has made it easier to get into my tight parking space.
Some cars have active noise cancellation that works in conjunction with the stereo, so maybe the speaker in the helmet will work great too.
I've noticed that all of the Power Commander download maps take out quite a bit of fuel even with full race systems. I'm sure that at some RPMs you need to remove fuel, but I have a hard time believing that this should be true at peak HP. I've heard that inertial dynos will indicate that you need less fuel, not more since an acceleration curve in the ECU fattens the mixture. In one post, a guy from Brock said that he rarely adds more than 5% at WOT. I'm not sure how you can see an increase of 10% even with reduced pumping losses.
Any comments from the gallery about adding or subtracting fuel?

[WarBaby]

I'm not sure how you can see an increase of 10% even with reduced pumping losses.[/quote]

A 10% increase (say...15 HP) is very near the upper limit of available power gain with full exhaust, PAIR mod, air box mod, and proper mapping on an internally-stock Busa engine on gasoline. I've seen a lot of Busa dyno charts that range from 10 HP to 16/17 HP gains with the average being in the 12 - 14 HP area with these mods. Pumping losses are considerable with the factory exhaust. Otherwise, such gains would not be so readily possible. The factory exhaust is the result of several "compromises"... the visual desirability of (heavy) twin exhausts, EPA mandates, and cost being primary among them.

[Husky]

Have a 2002 Busa with 4-1 Micron system. Trying to get from a 11.139 into the 10's in the 1/4 mile up here in Colorado (6000 feet above sea leval). Would taking the slip on muffler do the trick or does it even have any benefit in doing this?

[WarBaby]

Would taking the slip on muffler do the trick or does it even have any benefit in doing this?[/quote]

Stock air/fuel mapping?

[Husky]

Yes its stock air, have 16 front sprocket, lowering links, running 100 octane unleaded gas. Kinda new to this, so what is mapping? I tried to just go around the block without the slip on muffler and it sure seems to be more throttle responsive. Just wondering if it will make any difference in the 1/4 mile ET's.

Thanks for any advice

[WarBaby]

The 100 Octane gas is not making more power for you nor saving your engine from detonation/pre-ignition. 87 works well for most of us with internally stock engines. 89 octane is reasonable during hot weather. No need for anything higher.

"Mapping" is the electronic tuning data that determines the air/fuel mixtures used by your fuel injection system under various operating conditions (like carb jetting except it is done electronically). To extract all available power from a full exhaust system, you should have your bike "remapped". Most of us use Dynojet Power Commanders for revised tuning (remapping). Do a search for "Power Commander" - "PC3R" - "PCIIIR" - "PCIII USB" and you should find a ton of info about that.

In your circumstance, I'm not sure what removal of your muffler will do for you except create more tuning problems. I wouldn't do it without remapping.*



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[Husky]

Thanks for the good information. Just FYI I took the bike to the track last night without the muffler and ran a 10.862 at 131.22. Not really sure if the muffler made the difference or just me getting more seat time on the bike.

thanks for the info.

[toybus]

awesome post. but what is a bde/hindle system? ...k