Haybusa Parts and Service Member Support

Author Topic: **TECHNICAL QUESTION**Someone explain to me why removing cans&mids hurt hp/tq?  (Read 3119 times)

Offline N.SANE

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Reguardless if someone likes the sound or not, I'm mostly interested in why/how removing the stock exhaust cans & mid pipes will hurt performance. I figure that Suzuki R&D has spent countless hours and money developing the BEST exhaust for the bike (within state laws). I look at the fact that they incorporated the "X" design which is a BIG deal on Nascars and even Mustangs, so you think there must be something to it. The mufflers I understand must be the way they are to reduce noise emissions. I also noticed that Suzuki choose to go with dual exhaust on the GSXR-1000 which use to only have a single exhaust system.....WHY???  I'm not for or against those who just run tips with their stock header. I'm just simply trying to get a better understanding of why it is suppose to hurt performance as people claim. Couldn't you use a PC3USB and a DYNO to tune the bike better? I know some years back when I drag raced my Firebird (I know its not a bike), I only ran open headers which made a HUGE difference in my 1/4 mile times and dyno numbers. I was just hoping someone could explain to me why it is not a good idea to do.

Has anyone ever dynoed their bike with stock cans and then removed them and redynoed? If so, what data did you get?
Has anyone ever attempted to tune a bike that is only running the stock header and little exhaust tips? If so, how did that turn out?

I don't want this to turn into a bashing so PLEASE keep NEGATIVE comments to yourself. I'm just simply trying to get some hardcore data whether this is truely a bad thing or if it is just a buch of speculation.

THANKS!!
05' BUSA
WORK IN PROGRESS

Offline N.SANE

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I wish I had access to a dyno (cheap) I would like to play around with this idea and see what (if any) improvement I could get out of just some small tips and maybe a short baffle to create back pressure.

If you think about it.......all you would be doing is making a smaller higher flowing muffler in a sense and scaling in down to fit at the end of the headers. I can't see why it wouldn't be simalar to installing name brand slip-on except being much smaller and higher flowing.
05' BUSA
WORK IN PROGRESS

Offline Scary-Jerry

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The biggest improvement you can make is doing what you already stated:  Tune it up - More Fuel!
Manufacturers have to meet Noise & Emission standards.  This means quiet, small exhaust & lean fuel mixtures...

By opening the exhaust, you are freeing up the path of exhaust travel:  The more that goes in (Fuel), the more that has to exit (Exhaust)...
Keeping it bottled up helps low end grunt torque, but hurts peak high-end performance.

1999: RCC 'Custom' Stage II Intercooled Turbo System, AMS1000, GSXR Front End & Wheels, Trac Swingarm, Elka Shock, Cut Tank, & a lot of Carbon...

Offline N.SANE

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Also, wouldn't two 2" pipes (stock header) flow better than one 2.5" pipe (after market header)?
05' BUSA
WORK IN PROGRESS

Offline glenn71

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Its not just about flow and more about velocity.If the diameter is too big the gases flow more slowly hence are cooler and slower coming out the exhaust and make less power.Hmfs for example make much better power when the up pipes and cans are removed and replaced with dump pipes behind your foot.The gases at that point are still hot and fast and not causing a traffic jam at the end of the exhaust system.Not much good for your boots though. :lol:
Gen1 the original and the best
8.76@165.42mph so far