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Discussion Starter · #1 ·
To all you exhaust pro's. I'm thinking about building a 2 1/2" dual exhaust. Does it make sense to install an H-pipe?

I've heared an H-pipe is good for low end torque. Is it good for something else? Fuel economy? Better sound? Is there a negative point to tell about an H-pipe? I wonder why no one asked that before - there must be a negative point. Or does it just make no sense to install it in our low pressure, short exhausts?

Loaf
 

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Loaf,
Not sure about the H pipe scenario, I know HD says it adds considerable improvement to the twins, but not sure on ours. From what I've read the H is really only designed to eliminate the imbalance in systems with unequal length pies/mufflers. I guess that would equate to better flow???

I ordered a new set of headers from Marv at the rally, and they are the tri-y style that supposedly give you the boost in the low to mid range
.....about 30+ hp on Marvs' dyno tests. Not sure what they sound like either........but they bolt to the stock holes, utilize the stock header covers and have the same appearance as our stock system.

Tim
 

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Joe,

All I know so far is that Marv had a BH owner in AZ take his bike to the fabricator (we met the BH owner @ Osage) and they developed a set of bolt on headers for the two wheelers. They used the 'Tri-Y' configuration instead of the equal 4 tube design like Sanderson did for Adrian. The theory behind this (not new technology) is to match cylinders that fire 180 degrees apart to scavenge exhaust better. Obviously on most vehicles, space doesn't allow this to be done @100%, but they have developed a system that gets pretty close.

Actually, I had researched this style of headers for my motorhome through Thorley.........big increases in low to mid range, no detriment in the upper rpm band. Thorleys site and several others have dyno specs that say 'tri-y' style headers typically gain between 15 & 18% in HP & torque.............for a motorhome that is a bunch.

The headers are coated and plated, saw a set on a big at Osage, from a distance you can't even tell their different. Stock heat shields are adapted to fit and look pretty good.......did not hear them yet, but I doubt they will have the very distinctive sound that Adrians' have........if you have not heard Adrians' small block with his headers, you are missing something :)

I believe Marv said they were $1500 complete............bolt on, reinstall the heat shield, drive away. My goal is to continue to gain HP, but not affect the relliability of the engine..........i.e. NOS, headers, ignition, etc.....
so I can just get on and go every time I hit the starter..........

He had a few sets delivered this week and they were going to the ceramic and chrome shop. I'm going to stop by there tonight on my way home and should have more info Monday for ya.

You can look for Dougs or Headmans sites and they both have info on this configuration.

Tim
 

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Discussion Starter · #5 ·
Tim,
Marv's new headers seem to be very interesting. Can't wait to see pics. You said they are ceramic coated and chrome plated...? Are they coated inside and chrome plated outside, or did I misunderstood you?

Loaf
 
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