Quick tuning question
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Road Captain
Joined: May 2015
Posts: 633
Likes: 42
From: Charlotte NC
Quick tuning question
2015 SG Special
If I swap slip ons from 4" to 4.5" after bike has already had headers, air cleaner, tuner and dyno'd for the 4" setup, do I need to tune it again?
Basically I want to swap slip ons. Any issues just swapping out?
Sorry if this is a dumb question.
Thanks for info.
-smalls
If I swap slip ons from 4" to 4.5" after bike has already had headers, air cleaner, tuner and dyno'd for the 4" setup, do I need to tune it again?
Basically I want to swap slip ons. Any issues just swapping out?
Sorry if this is a dumb question.
Thanks for info.
-smalls
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
pertinent is what is the internal diameter of the mufflers? the outer is less important.
if the internal core is similar then flow will be similar and your "tuning" or settings should work about as well.
if the internal passage is larger- then exhaust gas flow will be slower through the mufflers. you will likely loose torque ( low rpm power) but you will pick up power at 6000 rpms*. Possible you will be a little rich at low rpms.
high gas velocity through the headers is good for power.
but this is a whole big ball of inter-related factors.
mike
* this is a joke- kinda...many of the awesome performance products enhance power at an rpm range we typically don;t use...at the expense of power in the rpm range we use 90% of the time.
if the internal core is similar then flow will be similar and your "tuning" or settings should work about as well.
if the internal passage is larger- then exhaust gas flow will be slower through the mufflers. you will likely loose torque ( low rpm power) but you will pick up power at 6000 rpms*. Possible you will be a little rich at low rpms.
high gas velocity through the headers is good for power.
but this is a whole big ball of inter-related factors.
mike
* this is a joke- kinda...many of the awesome performance products enhance power at an rpm range we typically don;t use...at the expense of power in the rpm range we use 90% of the time.
Last edited by mkguitar; Sep 5, 2015 at 02:52 PM.
Tourer
Joined: Jul 2014
Posts: 496
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From: MA
Cruiser
Joined: Nov 2014
Posts: 171
Likes: 7
From: Royal Oak, Michigan
You didn't specify what tuner you have, but I have a PV2 and was thinking about moving from 4" to 4.5"s at some point as well. Jamie from Fuel Moto said I would not need a new map...that a basic auto tune session with my current map would take care of it.
Thread Starter
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Road Captain
Joined: May 2015
Posts: 633
Likes: 42
From: Charlotte NC
pertinent is what is the internal diameter of the mufflers? the outer is less important.
if the internal core is similar then flow will be similar and your "tuning" or settings should work about as well.
if the internal passage is larger- then exhaust gas flow will be slower through the mufflers. you will likely loose torque ( low rpm power) but you will pick up power at 6000 rpms*. Possible you will be a little rich at low rpms.
high gas velocity through the headers is good for power.
but this is a whole big ball of inter-related factors.
mike
* this is a joke- kinda...many of the awesome performance products enhance power at an rpm range we typically don;t use...at the expense of power in the rpm range we use 90% of the time.
if the internal core is similar then flow will be similar and your "tuning" or settings should work about as well.
if the internal passage is larger- then exhaust gas flow will be slower through the mufflers. you will likely loose torque ( low rpm power) but you will pick up power at 6000 rpms*. Possible you will be a little rich at low rpms.
high gas velocity through the headers is good for power.
but this is a whole big ball of inter-related factors.
mike
* this is a joke- kinda...many of the awesome performance products enhance power at an rpm range we typically don;t use...at the expense of power in the rpm range we use 90% of the time.
I called RC Components and was told the 4.5" slip on baffle is tapered, ending up the same diameter as the 4". My bike is stock motor wise and honestly...I'm going for sound. The power is fine the way it is. I barely go over 4k RPMs.
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