Do large diameter mufflers hurt low end ?
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Tourer
Joined: Jan 2012
Posts: 482
Likes: 14
From: Detroit
Do large diameter mufflers hurt low end ?
Just wondering if the larger 4.5'' mufflers hurt the low end torque ? Thought i might of read that somewhere and in interested in the 4.5'' Rineharts
Not according to the tech at MagnaFlow but they never provided documentation to prove it. With the new SGS 114" M8, Vance & Hines told me to use the V&H High Output with PowerDuals for a map on a stock exhaust so not thinking this has affected low end much. As far as seat of the pants, it feels no different than the stock did but sounds a heck of a lot better.
That being said, you are about to get about 50 differing opinions.
Good Luck!
That being said, you are about to get about 50 differing opinions.
Good Luck!
Thread Starter
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Tourer
Joined: Jan 2012
Posts: 482
Likes: 14
From: Detroit
Thanks. Im also wondering if i should even spend the extra money for their header or just gut mines, know im going to get even more opinions on that. I like the look of Rinehart's header but doubt if it or any of them are worth the money for a few more HP or torque.
The outside diameter doesn't matter, it is the size of the baffle that can hurt low end torque. The M8 likes some back pressure. I really don't know anything about the Rineharts. There are members running them so someone should be able to answer your question about that particular muffler.
Seasoned HDF Member
Joined: Jan 2008
Posts: 13,681
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From: State of Confusion
can't say in general or not, probably several different contributing factors..but I have 100 RW TQ at 2000 rpms and 105 at 3000 with the 4.5 " street canons which isn't bad for just a SE Stage 1..pulls strong from idle and plenty good enough for me anyway
Tourer
Joined: Jun 2017
Posts: 494
Likes: 220
From: Qld, Australia
I’m running 4.5 Rineharts with a Bassani Header........
100 ft/lbs @2.3 rpm
110 ft/lbs @2.75 rpm
119 ft/lbs @3.40 rpm (Max Torque)
100 ft/lbs @5.2 rpm
I’d say low Torque is just fine running the Rineys. Good luck with your choice.
100 ft/lbs @2.3 rpm
110 ft/lbs @2.75 rpm
119 ft/lbs @3.40 rpm (Max Torque)
100 ft/lbs @5.2 rpm
I’d say low Torque is just fine running the Rineys. Good luck with your choice.
Ultimate HDF Member
Joined: Oct 2016
Posts: 5,063
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From: On my bike!
For me personally, I will gladly give up a few torque numbers for the sound difference over stock exhaust. That being said, I ran a total of 6 sets of slip ons on my 2017 SGS which included 4 and 4.5's, I honestly couldn't tell any seat of the pants difference in any of them, stage 1 with a decatted stock header.
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As several here noted it's not the size of the muffler body, it's the size of the baffle. Baffle size & design greatly influence & affect the overall power curve, baffles that are excessively large affect low RPM performance, response, and tunability. The M8 engine is also more picky on what it wants compared to Twin Cam. The standard 2.25" louvered baffles in the Rinehart mufflers work well in most applications, the mufflers that typically cause issues are the larger 2.5" cores, tapered, or stepped baffles that are in some of the louder mufflers being marketed.
Below is an extreme example of a Twin Cam chart showing the effects the exhaust can make on a 100Hp 107" motor.
Below is an extreme example of a Twin Cam chart showing the effects the exhaust can make on a 100Hp 107" motor.
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Jamie Long / Fuel Moto USA
The USA's Leader V-Twin EFI & Performance www.fuelmotousa.com
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Jamie Long / Fuel Moto USA
The USA's Leader V-Twin EFI & Performance www.fuelmotousa.com
Contact 920-423-3309
Email jamie@fuelmotousa.com
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