True dual question
Our system will bolt right on your '09 no problem.
Pretty sure I'm gonna like you, I appreciate your professionalism in discussing different points of view. I see you are also a tuning center, so I assume you tuned your pipe prior to the dyno run you posted, but did you also put the same effort into tuning the Thunderheader or is that run as the customer's bike came in the door, tuned by someone else? What are the details of this build, particularly displacement and cam? The peak numbers are about the same but the curve is considerably wider by 500 RPMs, it is impressive, but you'll have to forgive me for pursuing a properly designed 2:1, just as you have obviously properly designed and developed your true duals. Nice to see an honest perspective on exhaust manufacturers from an exhaust manufacturer. It's like an industry gentlemans agreement to not have a legitimate unbiased review to prevent revealing to the public that most of them are subpar, from a performance standpoint. The one thing that has always bothered me about exhaust manufacturers is that they don't publish primary tube diameter and length. I understand its unreasonable to ask the exact length of each section of a stepped header, and precision details, but it would be nice to know the section diameters and overall primary length. I'm pretty well occupied at the moment but I plan on building a 2:1 tuned to the sonic wave of a stock to mild cam. I want to play with the lengths to get the pulse spacing to alternate evenly when they meet in the collector. Getting closer to retirement every day and I'm looking to get into the cycyle aftermarket myself. I don't have a dyno but I do tune by O2 datalogging, although I can't quantify it, I can feel the difference when I make changes, and so far the 2:1 has made the most useable power for me. I look forward to your participation on the forum, thanks for your sponsorship.
First of all, thanks for the comments. To answer your question about tuning the bike beforehand with the Thunder Header, no we didn't tune it, as it was already tuned by a dyno-tech with a power commander already on it by another shop. We were actually impressed with the numbers when it initially came in. Not very many bikes make that kind of power. It was a 2003 Road Glide with 103" displacement and a 510 S&S cam. It had the Thunder Header, an air cleaner and tuned power commander. All we did was swap out the Thunder Header with our MGS True Duals. The dyno-sheet explains the rest.
No forgiveness needed, power is power, if you manage to do it with a 2-into-1, more power to you. We weren't able to realize the broad power band we were after with 2-into-1's and decided to go the True Duals route, besides we personally like the symmetry of 2 pipes with 2 bags.
We wish you luck in your pursuit for more power and welcome you into the game of motorcycle performance. Enjoy it, we sure do. Thanks for participating.
Outstanding HDF Member
Joined: Jan 2010
Posts: 2,916
Likes: 31
From: earth
Don't want to drag this out forever but I do enjoy the discussion. At a glance, and this is an assumption because like I said before, the real critical dimensions are not published by the MFRs (and no means to contact them to verify), the Thunderheader primary tubes were probably standard 1 3/4 OD, which would make them a little anemic for a 103 application, and it would cause a steeper curve. Speculating the results of a larger primary Thunderheader would be wasted energy, but that is where I would start if I were validating this particular comparison. Still yet, commendable results from your duals, and I would seriously consider your system if I were looking for duals. Thanks again.
Elite HDF Member
Joined: Jun 2007
Posts: 3,873
Likes: 13
From: NW Arkansas
I agree, a great thread! I would like to change exhaust one more time and be done with it. These may be "that" exhaust system I'm looking for.......they look good so far.....still looking for more information on them.........I've changed twice from the stock exhaust, I want the next time to be the last time!
Intermediate
Joined: Dec 2008
Posts: 35
Likes: 0
From: Deer Park, TX
I'm about 90% sold on these pipes but I would realy like a good look at the left side also. I've seen more pics of Big foot . A dedicated sound clip would also help.
Tourer
Joined: Jun 2007
Posts: 351
Likes: 1
From: Arizona/Colorado
MGS. I'm a little concerned about the heat on the left side of bike, given the location of the pipe crossing across the top of the transmission and then down in front of the passenger. Any comment or is this a concern for the bike or passenger?
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider
Verdad Gallardo
The Best and Worst Harley-Davidson Moves of 2025
Verdad Gallardo
Heat is less than stock. The hot exhaust gases are flowing out of the exhaust system with less restriction, thus creating less heat. If the bike is tuned properly, heat should not be an issue for your leg or your passenger's leg. The only complaints of heat we have had (only a few) were due to an improper tune, once tuned heat went away and rider was happy.