Exhaust Myths vs Reality

[Haywood]

Originally Posted by [b

Quote[/b] (WarBaby @ May 26 2004,04:59)]Haywood - I'll take a quick stab at it. Although nobody ever does it this way with stock cams, stock compression, etc., a "proportional" increase of bore and stroke relative to the stock bore and stroke dimensions is a matter of scaling if the related components (valves and ports) are equally scaled up to match the increased flow demands. By "scaling", I mean a 10% proportional bore/stroke increase in total displacement would yield an approximate 10% power increase: 1300 cc (160 HP) X 10% = 1430 cc (176 HP). A 20% proportional bore/stroke increase: 1300 cc (160 HP) X 20% = 1560 cc (192 HP). As mentioned, it is never done this way but a realistic power estimate depends upon too many variables--cam profile, compression, air/fuel ratios, head mods, revised timing, and so forth. There are many dyno charts on display at various Busa sites that show the results of the myriad "big motor" modifications available. *Such a question...

Thanks WarBaby... I got a million questions just like that one!! And since you liked THAT one so much, here's another... j/k.. thanks again for a great post.

[Let 'er eat!]

This one should be pinned it took me a minute to find it again

[HayAbuseD]

Thanks for the info..... Now i'll just need to spend the next lifetime digesting the stuff.......

May i assume therefore..... the bigger the pipe diametre the better?

[WarBaby]

May i assume therefore..... the bigger the pipe diametre the better?[/quote]

Not necesssarily. It depends on what kind of power enhancement you want from an exhaust system. If you install tubes that are very large in diameter, you may have great peak power but the low-to-mid range portion of the powerband will suffer because the gas flow velocity will drop severely. It might help if you focus on the part about flow velocity vs flow volume in the original post. It's all about design compromises to achieve a given performance objective.

[GJoker]

Excellent read... very informative~ Now could you please break it down with little words that I don't have to get out my dictionary to understand~
j/k.. Great post, thanks for the lesson!!

[ghosthawk]

WB--Nice summary and organized well too
That factory cross-over area does look particularly nasty...

[jfksmith]

BY THE WAY, DID YOU STAY AT A COURTYARD MARRIOTT RECENTLY. THAT WAS A MOUTHFUL OF INFO WHICH FOR ONCE IS ALL USEFUL. THANKS FOR YOUR TIME , INPUT, AND DEDICATION TO THE SPORT. WE COULD ALL USE YOU AS OUR PERSONAL SWAMI. TAKE CARE RIDE SAFE................. JOHN

[atticdog]

jfksmith i rode my busa the other day in newport to the jobsite

[WarBaby]

Thanks for your generous comments folks!

jfksmith:
BY THE WAY, DID YOU STAY AT A COURTYARD MARRIOTT RECENTLY?[/quote]
Not recently.

[gsteve]

Hes the short way to ask this question .. Warbaby , if you were to buy a pipe set for all around riding and riping up your buds on the hiway... what pipe would you buy? sj

[gsteve]

OOPS!!! Just read wbs profile... IMADORK!

[atticdog]

[atticdog]

[dezzy7]

Dang thats one DETAILED AND INFORMATIVE post.. Thx for taking the DA to write it !

[Orange_Busa]

Originally Posted by [b

Quote[/b] (WarBaby @ May 25 2004,15:19)]Item # 3 - This is the primary design bottleneck of the factory design. Suzuki uses an "X" collector/crossover which generates substantial turbulence (resistance) as opposed to the BDE merge collector which maintains a more laminar gas flow for reduced pumping losses.

OK, since the X-pipe in the factory design was a bad idea, what would you say about the HMF X they use in there dual systems? *Bad idea or a better design? *Thanks.

ps. Great post also, has alot of people thinking now I would asume.

[TorontoBusa]

Wow!! Thanks for explaining all that!

I have a sound questions for you I have the full titanium 4:1 pipe, and it works well but sounds to quite, I can't hear it on the highway.

I plan to open up the can and wrap 1/3-1/2 of the internal perforated tube with sheet metal, this should make it sound louder.

If I cover the section near the tip, or near the engine would it have any change in sound??

Thanks in advance

P.S. Any other idea's using my existing can?

[bbbsleeper]

WOW, So basicly exhaust velocity and volume will make my bike go faster, cool, OK.

[sageronin]

Originally Posted by [b

Quote[/b] (Orange_Busa @ July 12 2004,18:07)]

OK, since the X-pipe in the factory design was a bad idea, what would you say about the HMF X they use in there dual systems? *Bad idea or a better design? *Thanks.

ps. Great post also, has alot of people thinking now I would asume.

Tom ... I have this same question. When the tuner mapped my HMFs, he commented that their X design was an improvement over the stock pipes. After reading your excellent post, I'm starting to get a clue about exhaust now. Thanks much !!

Brian ... your bike is Sweet !!

[atticdog]

TorontoBusa
is it a BDE gen3?
and how many miles on the pipe?
Mine got abit louder after some miles on it

[WarBaby]

Sorry for being slow to respond. For some reason, I haven't gotten email notifications about the last few posts.

OK, since the X-pipe in the factory design was a bad idea, what would you say about the HMF X they use in there dual systems? *Bad idea or a better design? *Thanks.[/quote]

X-Pipes have their place in the scheme of exhaust designs and, on dual muffler systems, they can broaden the powerband (more power below the HP peak). The factory crossover design was probably a cost-induced compromise.

Wow!! *Thanks for explaining all that! I have a sound questions for you * I have the full titanium 4:1 pipe, and it works well but sounds to quite, I can't hear it on the highway.
I plan to open up the can and wrap 1/3-1/2 of the internal perforated tube with sheet metal, this should make it sound louder. If I cover the section near the tip, or near the engine would it have any change in sound?? Thanks in advance
[/quote]

Yes, covering some of the sound-absorbing holes inside the muffler should make it louder.

Tom ... I have this same question. When the tuner mapped my HMFs, he commented that their X design was an improvement over the stock pipes. After reading your excellent post, I'm starting to get a clue about exhaust now. Thanks much !![/quote]

Cross over pipes can be a good thing for dual systems when properly designed and correctly located. I am sure that HMF's design is far superior to the factory X-pipe crossover. This can aid low-to-mid range gas scavenging which creates greater torque. More torque is always a good thing!

If you visualize an exhaust pulse as a colume of gases moving rapidly through the exhaust tubes, it is easier to imagine what is happening inside the exhaust system. Clearly, a gas colume just wants to get out of the exhaust. It has mass and therefore inertia. The fewer restrictions it encounters, the better. Imagine the gas colume having a smooth, tubular path with gentle bends, no collisions with other gas columes, etc. vs. sharp bends, baffles, and turbulence etc.