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Thunder Torque Inserts 258 for Increased HP & Torque

Availability: In stock
Item #: DK-TTI-258
Manufacturer: DK Custom Products

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Thunder Torque Inserts 258 for Increased HP & Torque


Increases Low & Mid Range Torque

Adjustable Sound Volume & Tone

For Your Exhaust


 MADE in The USA!


DK Custom Products


  • High-Temp Powder Coat Finish
  • Stainless Steel Studs (5/16" diameter)
  • Includes All Hardware
  • FITS 3" diameter & larger Slip-ons (other sizes available)
  • Increases Low & Mid Range Torque
  • Increased Exhaust Gas Velocity
  • Increased Inertial Scavenging
  • Adjustable Sound Volume & Tone
  • Option for only 1 TTI for 2-1 exhaust systems
  • E-Z Installation  Bolts into the end of the slip-on muffler (using the baffle bolt hole)
  • Patented Technology
  • Made in The USA!

Watch these videos on how to get a better sound AND increase torque!

Take a listen to the following sound clips of 5 Different Bikes that all have an increased amount of Power from Thunder Torque Inserts™ Being Installed.


***The Video Below shows how to Remove Baffles from stock OEM Mufflers that do NOT have a Catalytic Converter in them.  This process does NOT work on Mufflers that have Catalytic Converters in them.***


Do you want Louder Exhaust? 

Quieter Exhaust? 

A Deeper Tone? 

A More Aggressive Bark? 

Do you want More Torque?


The Video Below shows how to Remove Baffles from stock OEM Mufflers that DO have a Catalytic Converter in them. 


Another Video showing how good the stock exhaust can sound, and how much power they can have, with the baffles removed and replaced by Thunder Torque Inserts™.


All the Vance & Hines Systems and Slip-ons we've tested produce more power, and a bit deeper tone with TTI's Installed.  The V&H's respond particularly well to TTI's, with or without the baffles!

Without getting too technical, we've spent thousands of hours testing shape, size, thickness, & surface coatings to find the optimum combination that increases power across a wide RPM band, AND gives maximun flexibility to deliver different sounds.

The Increase in Torque is accomplished by reducing engine pumping losses, increasing exhaust gas velocity and increasing inertial scavenging.

More about how exhaust works at this LINK 


Thunder Torque Inserts™ are designed to perform well when used on slip-ons with and without baffles, drag pipes, shortys and 2-1 Systems.

The Patented design will produce a bit deeper sound/rumble all the way through the RPM and Throttle range. 


If you feel that your current exhaust is too loud, the Thunder Torque Inserts™ will noticeably reduce the decible levels.





The comparison may seem subtle but decible measurements are not linear.


For Example, 90 decibels is four times as loud as 70 decibels and 110 decibels is about 16 times as loud.



These particular results belong to a customer that had this to say...


"My impression of the sound is that it lost some higher pitched bark at roll-on and there was a reduction in low pitch reversion "echo" (kind of a flabby chuffing sound). To my ear, with these pipes, the tone isn't significantly lower but it is a bit cleaner or more refined sounding"


(Twin Cam at Full operating temp, mixture corrected, and idling at 1000 RPM.)



When ordering you have an option of getting just ONE TTI if you have a 2-1 exhaust system that has only One slip-on, or to choose TWO TTI's for exhausts that have Two Slip-ons.
The "Q" model is no longer being manufactured.

Click this LINK to see Pictures & Fitment Information, to Choose the Correct Size TTI for your Exhaust


A small change can make a BIG Difference!!!




"Amazing how much more power these gave my 103 down low.  The sound is raw power too." -Phil



"Just wanted to take a minute and let you guys know how pleased I am with the W258 TTIs.

 I'll be honest, when I first read about these things I figured it was somewhat gimicky so I didn't expect much. But, after removing the baffles from my Wild Pig slip ons and installing the W258's I was blown away by both sound and performance!

 It has the potato potato sound at idle (noticeably louder than before) and also sounds great at cruising RPMs. It actually reminds me of the way my old shovel head sounded.

 What really surprised me though was the very nice torque gain that you can really feel. After installing true duels and the wild pigs, I noticed a loss in torque. The TTIs brought all of that back, and maybe then some!

 Best money I've spent on my exhaust system for sure. Thanks!" -Dewayne





Customer Reviews

2007 Night Train w/TTI 258 = Snappier and better sounding ride Review by SGTMAJ
Quality product and an easy install. Bike feels snappier and sounds better. Product was installed in a V&H Competition Series 2-1 exhaust with baffle removed. (Posted on 7/10/2019)
Small change Review by LILFGR
Customer communication was ok. Took a couple times getting thru t actually speak to someone, but after getting my questions answered i was able to order what was needed. Installation was fairly simple. The insert did quiet my pipes down a little bit which is what i was hoping for. Overall satisfied. (Posted on 7/10/2019)
2018 fxlr w258 torque inserts Review by Kolt
I just got my w258 2 into 2 torque inserts for my 2018 harley Davidson lowrider, I drilled out the factory baffles on my bike and took all the packaging and everything out (catalytic converter) and put the inserts in and immediately fell in love head over heels for the sound and power I gained, with just 2 small inserts in a straight pipe its astounding the physics behind these to be able to do such a magic trick on a bike. Thsi honestly the best 30 bucks I've ever spent on anything. (Posted on 7/5/2019)
Great product Review by Hardwickbv
After calling and talking with Dwayne a couple times I purchased the 258s for my 17 Tri-Glide with Screaming Eagle Street Cannons. I ended up leaving the baffles and mounted them at the half way point of the tips.
I ride to work each day through the country with several hills and curves staying mostly below 50 mph. I have noticed that I am having to downshift less during my trip indicating A good increase in torque at the lower speeds.
I also believe they have increased my gas mileage both around the country where I normally ride as well as on the highway during a couple long trips I have taken since installing them. Recommend them highly!!! (Posted on 7/3/2019)
Excellent product Review by Nelly
I brought the thunder torques for my partners 2007 fat boy, he is over the moon with the sound and performance of his bike now, we totally recommend this product if you want a louder and better performance bike, best money we’ve spent on the bike by far, thank you DK customs (Posted on 7/1/2019)
2019 Iron 883 with 3" slip ons with baffles removed. Review by Jonathan P
Fast shipping. The W258 TTIs restored my lost torque and acceleration, and they got my bike sounding awesome! (Posted on 6/26/2019)
Awesome upgrade! Review by HisAngriness
I bought a 2012 Softail slim, bone stock. After looking into full exhaust systems I came across these insets and figured it can't hurt to try them for the price. MAN WHAT A DIFFERENCE! Removed the baffles and installed the 258's and not only can I HEAR the difference but I can FEEL it in my butt dyno when riding. I might just keep the stock pipes on it now! (Posted on 5/23/2019)
258s In My '12 Nightster Review by Rob
I recently purchased a 2012 Harley Sportster 1200N Nightster. It had stock mufflers on it that just didn't provide the "sound" you commonly associate with a Harley. This was evidenced by the 3 times I was almost wiped out by people changing lanes right in to me because they either weren't aware of my presence or just weren't using all their faculties to be attentive to the road, their actions, and other motorists. I looked around for ways to increase the sound output and mostly came up with completely different mufflers or ways to simply remove the baffles inside the stock mufflers.

Then I came across DK Customs TTI, Thunder Torque Inserts. Not only was it a reasonable means to increase decibels of exhausting, it gave the added benefit of back pressure for torque output. And the price was exponentially less than completely replacing the mufflers with something that was essentially going to do the same thing.

I reviewed the tutorial videos and collected data, watched the instructional, and set in to order a set after confirming with Dwayne which product I needed. Installation was simple enough, if somewhat exacting and delicate, and adjustments took no time at all. And the sound.... Holy Moley! "Thunder" Torque Inserts is right!!

My Nightster went from a gurgely, sputtery Kawasaki sound to the rumbling, throaty, bark of a Harley! And the low end torque increase is dramatic! It now pulls like my 1200XL Custom does! I honestly can't believe how vast of a difference, an improvement, was made by such a simple insert and at such an incredibly low cost. These simple inserts are well worth the price and I would recommend them to anyone who is on a budget, not afraid to make modifications, and wants a deep, growling bark for their bikes sound without sacrificing power by simply hollowing out their mufflers. Worth. Every. Penny! (Posted on 5/4/2019)
2016 XL883L OEM Tapered Pipes Install Review by NoSlackPatriot
These were installed in my wife’s 2016 XL883L. Her pipes are the OEM tapered exhaust. For this install, I used blue painters tape with military map markers and tape measure to evenly mark my cut line at the taper line, which measures 4 3/4 inches from the end of the exhaust pipe. When cut at the taper, tapping out the baffles is too easy!!

A band saw came recommended from Dwayne, which I purchased and then soon found out that I knew nothing about the required number of teeth for a smooth cut. I’m sure this method works fine, but I went with a Dremel and EZ Lock Metal Cut off Wheel and Adapter, about $30 in sum; and returned the band saw. This method provided a smooth cut all the way around. I then locked my angle grinder with a 40 grit flap disc in my bench mounted vise and evened up and smoothed the edges where I cut. Perfect finish!!

These do provide an increase in power and the sound is much deeper than my XL1200X with V&H Short Shots. It sounds great and my wife loves them! Her biggest reason for getting these was to be heard by cages. The increased performance is an added benefit that she thoroughly enjoys! (Posted on 4/22/2019)
05 ultra sounding sweet Review by KRi
As the title suggests I have an 05 ultra classic, the bike has a Reinhardt stepped header and Rush 3.5” cans with 1.75 baffles, the exhaust combination has always performed well but was just a bit loud and high pitched for my liking! I discovered the DK TTI and questioned if for this small price could these be the solution or is it just another BS product out there making big claims. I figured why not try a set since they are simple to install and if I don’t like them let’s be honest it’s the cost of a few good beers, TTI’s arrived quickly and nicely packaged, installation was quick an simple with the rush cans (I ordered 2 5/8” insert per DK)! Upon first fire up I instantly noticed a change in pitch and volume of the exhaust and all for the better, took the bike for a ride and same thing over all tone and pitch is now deeper, softer and just better, from a stop light the bike feels to have slightly more torque but it’s always pulled well on the bottom end, ran the bike just south of the rev limiter in 3 gears and it pulls clean and crisp all the way! Very happy with the TTI and I believe this is a prime example of often times simple is better! Great work DK. (Posted on 4/12/2019)
WOW game changer Review by pojobe
After many upgrades and age my E-Glide with cobra head pipes and DNA 4 in exhaust had lost it sound and became too loud for me, installed 258 and got back so much more, torque you can feel and see, the old Harley sound we love, and not to loud, this is a must have product if you have true duals, it will put in the back pressure in the engine. (Posted on 3/14/2019)
Sound and Performance Review by Johnny Bravo
I have a RGU w/ 4" slash cut Vance & Hines performance slip-ons. I removed the baffles to increase the sound and my safety. I lost torque and the sound was super loud. My buddy recommended the Torque Inserts and what an amazing difference in low and mid torque!!! I tried 3 different angles for the sound and decided to leave the inserts flat against the diameter of the pipes. Strong Sound! Deep and throaty. (Posted on 12/13/2018)
Good sound Review by Gray Biker
Removed the cat and installed 4" mufflers, removed the packing.. I knew my back pressure was going to be screwed up. So I bought the inserts. It has a lower tone to it now. More of the old HD sound. Dont know about any more power... Its to cold and sloppy on 1.5 miles of gravel to try it out. Easy install removed the bolt for the baffle and installed in the same hole. (Posted on 12/13/2018)
Nice product Review by Jim
I took a set of stock 09 dyna slip ons, cut 3 inches off the back, yanked the baffles out and installed these. Results were pretty spectacular. I ran it for a few days without the inserts and my bike was super loud but sounded like crap, excessive decel pop among other annoyances. Bike already had open intake and ViED’s. After TTI installation this bike runs great and sounds awesome! Deeper tone and decel pop was lessened. Perfect to my ear since I like loud bikes with a little deceleration noise. Bike runs cooler. One of the best inexpensive upgrades available! (Posted on 8/17/2018)
TTI W258 On Full System Review by Dave Fox
Hi DK,

Just wanted to drop you a note to let you know that I am on my second set of Thunder Torques on two different bikes and the results have been incredible. My first set of TTI's were used with V&H slip ons and they worked great. My second set are on Samson true duals with 4×30 inch mufflers. Results are fantastic, raw power. The young lady who helped out in customer service was great too. Thanks Dave (Posted on 8/13/2018)
W258s in stock 2015 Street Glide slip-ons Review by JMC87
After installing a set on my Sportster 48, I decided to try these on my stock take-off slip on mufflers. I originally had Screaming Eagle Street Cannons, but after I removed the cat from the stock headpipe the sound was terrible. Raspy, loud and blubbery sounding. I orginally got the W258s to try in the Street Cannons but they were a 4 inch inside with no packing or filler, so the TTIs were way too loud and lost a lot of the deep rumble I wanted. This is a design flaw of Harley’s in my mind - and that’s on top of the end cap design which was a nightmare to work around.

I put my stock slip-ons back on for a few months and it sounded okay with the de-catted head but I wanted more. I watched countless YouTube videos to see if I could get a deep rumble without too much volume and finally decided to try these on. Cutting out the stock cone baffles was straight forward. I used a cutting wheel with a power drill and cut right behind the weld inside the muffler. Once cut, a bit of wiggling and pulling took the cones right out. The next part was critical in getting the sound I wanted - leave the inners with the fiberglass wrap in the muffler! Mount the W258s as close to the end of the fiberglass packing as possible for the deepest sound.

I love the way my bike sounds FINALLY. It is deep and powerful without being too loud for a touring bike. It sounds like a hot rod to me. The only downside to this whole thing is a feel like an idiot for wasting time and money on Street Cannons.

Decat your stock header, use these to replace your stock slip-on cone baffles and ENJOY. (Posted on 4/13/2018)
Thunder torque inserts Review by Poolman
I just removed my baffles on my 2014 Harley Davidson Sportster xl1200 and inserted the TTI's and when I turned on the bike my jaw instantly dropped. The bike is loud (Posted on 1/20/2018)
Thunder torque inserts Review by Doug
Ordered a set of the 258 inserts expected delivery in 4-5 days recived them in 2 days install was easy enough. The sound is a really nice rumble, torque increase for the buck is fantastic.
Bang for the buck best thing I've every found! (Posted on 11/8/2017)

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