Thunderheader Modification
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Cruiser
Joined: Apr 2010
Posts: 243
Likes: 3
Thunderheader Modification
I ran across some information on modifying the baffle of a Thunderheader to all but eliminate the Thunderheader dip in TQ at the low end. The edges of the baffle are bent, which direction is not clear. Anyone do this mod? Here is a pic of baffle inside my Thunderheader. Any input is welcomed, I'm hoping I can figure this out so I can get it done tonight 
Grand HDF Member
Joined: Dec 2012
Posts: 3,782
Likes: 1,202
From: river
I agree hazyboy. I've had a lot of guys recommend this when I ran a th. BUT NOBODY had any proof. I don't do azz dynos or assumptions. What did it do to the rest of the power curve? It might have fixed a blurb at lower rpm, but created something worse at a different rpm. My th experience was always the same. Starts a touch late, pulls hard then falls off very soon in upper rpm. Even though I still like, own and enjoy the pipe
Road Warrior
Joined: May 2010
Posts: 1,953
Likes: 1,170
From: Northern Colorado
TH's are very touchy to being messed with. Fiddle with the baffles you might get a little down low, but it's costing somewhere else, remove the cone, kill power everywhere, shorten the length of the primaries.. looks better but gonna hurt TQ on stock motors. There's better pipes for power, better pipes for fitment and better pipes for durability, but they all lack that one thing, the sound lol. I like my Bassani RR but would trade it a heartbeat for a TH no questions asked.
Cruiser
Joined: Oct 2014
Posts: 120
Likes: 4
From: California
Diggin up old stuff here but......
I will have my '12 Super Glide on a dyno in two days. I made a custom TH muffler to fit my V&H Propipe, and I cant tell you on the butt dyno.... I lost bottom end torque for sure! Once I take it to my Dyno, I'm going to let him do the baffle mod (bending the end out) as he sees fit one tab at a time. I'm sure my bottom end will come back, without sacrificing too much, if any, on the top end. I'll keep you guys posted with numbers and results.
OH! And he tunes for rideability. Not just trying to squeeze peak numbers and claim 115hp/tq. So it may dyno out at 85hp, but its all useable power. Not just peak power. essentialy my "lower" HP bike should be all around faster than a peak HP bike with similar mods.
My set up is: 96CI, Mackie 575 Cams, SE plug wires, V&H headers with TH muffler, Arlen ness Big sucker, and that's it for the engine. I'm contemplating port and polished heads down the line... My tuner makes a ridiculous stealth kit that add MINDBLOWING power, but I don't wanna get too nuts. She's my everyday rider/long distance hauler. wanna keep it manageable.
I'll keep you guys posted in the next few days!
I will have my '12 Super Glide on a dyno in two days. I made a custom TH muffler to fit my V&H Propipe, and I cant tell you on the butt dyno.... I lost bottom end torque for sure! Once I take it to my Dyno, I'm going to let him do the baffle mod (bending the end out) as he sees fit one tab at a time. I'm sure my bottom end will come back, without sacrificing too much, if any, on the top end. I'll keep you guys posted with numbers and results.
OH! And he tunes for rideability. Not just trying to squeeze peak numbers and claim 115hp/tq. So it may dyno out at 85hp, but its all useable power. Not just peak power. essentialy my "lower" HP bike should be all around faster than a peak HP bike with similar mods.
My set up is: 96CI, Mackie 575 Cams, SE plug wires, V&H headers with TH muffler, Arlen ness Big sucker, and that's it for the engine. I'm contemplating port and polished heads down the line... My tuner makes a ridiculous stealth kit that add MINDBLOWING power, but I don't wanna get too nuts. She's my everyday rider/long distance hauler. wanna keep it manageable.
I'll keep you guys posted in the next few days!
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Grand HDF Member
Joined: Dec 2012
Posts: 3,782
Likes: 1,202
From: river
OH! And he tunes for rideability. Not just trying to squeeze peak numbers and claim 115hp/tq. So it may dyno out at 85hp, but its all useable power. Not just peak power. essentialy my "lower" HP bike should be all around faster than a peak HP bike with similar mods.
Sounds like you're setting up for a good excuse for low power bike lol
Last edited by Madnss; Apr 25, 2017 at 07:22 PM.
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Cruiser
Joined: Oct 2014
Posts: 120
Likes: 4
From: California
I haven't the slightest idea what numbers my bike puts out now. The point I was trying to make was even with a lower HP number bike, it can be faster than a higher HP bike. It's alllllll in the tune!
Last edited by Rusty19MCSFV; Apr 26, 2017 at 10:22 PM. Reason: Missing text at end