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My R1 got eaten by a gixxer
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Discussion Starter #1
i was recently wonderin if a full exhaust will rob bottom end power with a power commander, i would think you would get a little more oomph with this combo but i have been hearing differently?

whats ur take on this question do u lose power even with a power commander? thanks for ur help in advance
 

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Need... More... Trackdays
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887 Posts
you only loose a little power down low cuz you remove the EXUP valve with a full system
 

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My R1 got eaten by a gixxer
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22 Posts
Discussion Starter #4
i know and i would want to loose any power down low you would think for nearly a grand some more you would get some improvement down low especially not a loss though, that kinda sucks
 

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Just when you thought . . .
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189 Posts
I went through this same agony (slip-on v. full system). If you look at the dyno comparisons, there is a dip from 3400 to 5000 rpm. On paper, it looks like a significant loss, but I am here to tell you, you will not be disappointed inthe full system. The "loss" down low is barely perceptible and can be ameliorated (but not completely eliminated) with the pcIIIr. But the gains up top are WELL worth it.
 

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GO CHIEFS!!!
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6,870 Posts
Yamaha didn't spend butt loads of $$ developing the EXUP for nothing. It definitely gives you more kick on the very low end of the power band... But, who cares?? It still has enough down low, and the extra boost up top is worth it (that is where you have the tach when having fun)...

- BA
 

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Action figure sold separately
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12,225 Posts
Retention of the EXUP is preferable on a street ridden bike. A full system is preferable for track and race bikes, where the substantial loss of low end torque will never be a hindrance.
 

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mmmmm...black bike
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1,856 Posts
Eyespy said:
Retention of the EXUP is preferable on a street ridden bike. A full system is preferable for track and race bikes, where the substantial loss of low end torque will never be a hindrance.

:iamwithst :iamwithst I totally agree.... for the street a full exhaust is a watse of money.
 

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Super Moderator
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8,670 Posts
That 2 hp you lose below 4k is nothing you notice. That 10-15hp you gain from 4k to 12.5k is definately noticeable.
 

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My R1 got eaten by a gixxer
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22 Posts
Discussion Starter #17
with a custom map, jetting, and graves slide stops and velocity stacks would you get some gain down low??? and with the custom map would you even need the graves stops and stacks???

thanks again for the repiles
 

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El Assholio Supremo del Mundo
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10,685 Posts
if you properly map any bike, it will gain responsiveness, and potentially power.
All motorcycles sold in the USA are by necessity lean running in the bottom of the rpm range. This is because that is where they are tested fro emissions compliance, and since random vehicles may be pulled for emissions testing by the government, you will find that all manufactureres err on the side of lean rather than risk having problems.
A properly mapped FI R1 with stock exhaust will have a tendency to run better, smoother and make more power than a none re-mapped one.
This theory also works when adding exhaust systems to the same bike. However i would like to point out that a completely stock bike, vs one with a full system that has been properlyu mapped, may actually show no decrease in powerin the lower RPM ranges on paper. Again due to initial settings of the ECU from the factory.

I would agree, that for street riding i would suggest a slip-on vs a full system, the reason being that the EXUP helps in the lower 5k of the power band to add more torque and HP. And since every strteet rider has to stop for red lights and other traffic control devices, they would benefit from this increase.
Most street riders do not need the extra top end power to be gained from thee full system.

My recommendation would be to take the money saved, and got to some track days to learn better bike control and to also enjoy the potential of the bike more.

Just my $.02
 

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My R1 got eaten by a gixxer
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22 Posts
Discussion Starter #19
so pretty much if i jet it and have it properly mapped(like custom mapped) i will most likely have some type of gain throughout the entire range or RPMS?
 

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El Assholio Supremo del Mundo
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young_R1rider said:
so pretty much if i jet it and have it properly mapped(like custom mapped) i will most likely have some type of gain throughout the entire range or RPMS?
actually mostly in the mid to low rpms, not much gain in top end, but better overall responsiveness.
 
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