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Midrange horsepower loss with AM exhausts?

2K views 9 replies 7 participants last post by  Pandaman 
#1 ·
I was told by the guy at the dealership that adding an aftermarket system will increase high-rpm horsepower but will reduce low-midrange horsepower - is this true?

I was asking him what he thought about adding an AM exhaust and he told me if I was planning on running the Z1k around at like 9k rpm a lot it would be a good idea, otherwise it would reduce the low-midrange grunt..

Is this correct? I don't see how backing up the air flow would help low-midrange horsepower but maybe it does?

Does an AM pipe increase torque also, or just hp?
 
#2 ·
For a full system, you might loose a little on the bottom, but it shouldn't be very noticeable with a tune. Having had both on several bikes I would say go ahead and get it, you won't be disappointed. Slipons shouldn't change the bottom end at all.
 
#3 ·
Any aftermarket exhaust is going to reduce backpressure, which will reduce low-end responsiveness. BUT, it really shouldn't be super apparent, like Kzin says, with a proper tune.

I'm sticking with my stock system because I like the bike quiet. But if you go aftermarket, you wanna sell me your cans? I want to experiment with a set. :)

Rob
 
#4 · (Edited)
If you are interested...

You can go to most AM pipe mfg. websites and they have dyno results for all of the pipes they sell, on each of the models they make them for. You can SEE what it does to HP and torque across the whole curve.

You also see that AM pipes give you about 3-4 HP... :(

For example, here is the Yosh R-77 for your bike... looks like you def. lose some HP below about 3,000 RPM. You dont really start adding any torque until about 5,000 RPM. The gains are so small though. I have not seen a mfg. that does NOT post this info. FWIW

 
#5 ·
I've had a wide range of exhaust on my first gen Z, from 4 into 1 D&D full system, to dual jardine slip-ons, to zx9 header with custom midpipe. The full D&D exhaust lost me some bottom end, I'm sure a custom tuned power commander would have helped, but the pipe was just too loud to deal with.

The dual slip-ons however, didn't result in any noticable loss. I think slip-ons would be fine, but a full system would require a custom map.
 
#7 ·
If you are going to do headers, get the cans too. You'll probably need a custom tune with that setup. Akro has quiet inserts I believe if sound is what you are after by keeping the stock cans. If you just like how they look, then I don't think they'll be much different from a AM cannister since the Z has a prechamber exhaust. Either way you'll need a tune to get the most out of it with a header.
 
#8 ·
I really like the the stock cans - certainly fits witht he overall style of the bike...

I also like the induction noise and I heard that if you get AM pipes you can't hear the induction sound well anymore - is this right?

I'd like a sweet looking AM exhaust that was lighter, gave more power, and was just slightly louder...

But, is the sound of an AM exhaust even better than the sound of the air induction? I've never rode a 4-cylinder sportbike with aftermarket pipes - I know my 650r twin engine sounded WAY better with AM pipes - but stock it just sounded lame all around - the stock Z1000 sounds great while riding it due to that intake/induction sound!
 
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