The Facts Behind Harley Exhaust Backpressure 

Wouldn't a big pipe possibly reduce the efficiency of the scavenging effect and not increase back pressure.

Glad you like the video! Thank you for commenting! MB

A big pipe does not increase backpressure, but it does increase reversion and slow down exhaust gas velocity, which will rob power, the same as backpressure robs power. KP

@@DKCustomProducts I hadn't thought of it that way but it makes perfect sense. Back pressure Myth goes way back. Water going through a radiator to fast is another.

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We agree! Thanks for commenting! 😎 MB

Sorry, thunder torque

That is awesome! Glad you are happy with the Thunder Torques and seeing the benefits of having them installed. Thank you for your business and for commenting! MB

Lollipops do work, but the Thunder Torque Inserts™ utilize a patented design that works 200% - 500% better than lollipops. The unique shape Speeds up Exhaust Gas Velocity, in addition to reducing/eliminating reversion. Two major keys to power. www.dkcustomproducts.com/thunder-torque-inserts-c57-337.htm

Glad you like the video and understand backpressure! Thank you for commenting! 😎 MB

Glad you like the video! Thank you for your support and for commenting! 😎 MB

Glad you like the video! Thank you for commenting! MB

We do now have Long Thread Thunder Torque Inserts available. Here is a video on them that you may find helpful- ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-naqPtEcDcU0.html If you go to the size thunder torque you need at the link below. Scroll down the description too the fitment notes. You will find a link to take you to the Long Thread TTI's. - www.dkcustomproducts.com/catalogsearch/result/?q=thunder+torque+insert Please feel free to contact us with any questions or help ordering; Support@DKCustomProducts.com 662-252-8828 Thanks for commenting! MB

Amsoil is a great lubricating oil! Thanks for commenting! MB

It depends on which aftermarket exhaust. The gutted OEM slip-ons supplemented with the TTI are better than most aftermarket slip ons alone... But keep in mind aftermarket slip ons can be equipped with the TTI as well. Reversion is Fresh air and spent exhaust gasses reverting back into the exhaust becoming a detrimental to exhaust scavenging. I agree with people mis-using the term but I think most are considering "backpressure" as bottle necking the gasses with a baffle. What you want is an open exhaust that you can see straight through with the TTI installed 1-2 inches into the exhaust. You will get the best performance this way. Here is a video on choosing the right exhaust that you may find useful - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-H681dl2X_f4.html And here is a LINK to a written report on setting up exhaust for best performance- www.dkcustomproducts.com/harley-exhaust-myths-and-facts.htm Please feel free to contact us with any questions; support@dkcustomproducts.com 662-252-8828 Thank you for commenting! 😎 MB

Awesome, I am glad you are well pleased with the TTI's and that you are feeling the benefits of having them installed! Thank you for your business and for commenting! MB

LOL 😂😂

Yes, some care more about sound than they do performance! Thank you for commenting! MB

Some people just can not understand no matter what terms you use! Thanks for commenting! 👍 MB

Glad you like the video! Thank you for commenting! MB

It certainly does not! Thanks for commenting! 😎 MB

I was one who was part of this myth for years. I think maybe what happened, whether it matters or not, is back pressure was something we dummies could "understand". Reversion on the other hand, was something we didn't understand and it was dropped from our vocabulary. But reversion is actually 1/2 of the formula, for the problem being discussed. And not understanding reversion is like trying to bake a cake without an oven.

Glad you like the video! Thank you for commenting! MB

Yeah, should be interesting. 👍😎👍 KP

The unique & patented design of the TTI's increase exhaust gas velocity speed with very little restriction. This increase in speed, results in an increase in volume, and also encourages scavenging. This results in a better fill charge on the intake stroke, which results in a stronger combustion stroke, which results in more Torque. Taking the baffles out or running open free flowing exhaust eliminates back pressure (restriction), but then you have reversion. That is where the TTI's come in and reduce reversion and speed up the exhaust gas velocity bringing back the torque. This video explains this subject very well - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-pr6z00gL5Yg.html Here is a written report where you can see pictures of how exhaust gases flow and where the TTI's come into play with preventing reversion that you may find helpful - www.dkcustomproducts.com/harley-exhaust-myths-and-facts.htm Here is the full video to this short that you may also find interesting - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-P5s8YKEb0gE.html Thanks for commenting! 😎 MB

Thunderheaders are great pipes, and they produce even more power when used with Thunder Torque Inserts™. www.dkcustomproducts.com/thunder-torque-inserts-158-model-family-dk-tti-158.htm KP

Glad to hear it! Thank you for your business and for commenting! 👍😎👍 MB

Thanks for your comment. Sounds like an interesting build.😎 MB

Great to hear you got your low end torque back. You may find the report at the link below really interesting. One of the things it shows is the progression we made from the lollipop design to the patented design of the TTI's. There is more power on the table to get. www.dkcustomproducts.com/harley-exhaust-myths-and-facts.htm Also, at the bottom of the above link is an interesting video on decel pop that you may like. Thank you for commenting! MB

Removing just the cat will make no perceptible difference in power, at any RPM. You might see 1-3% difference on the dyno, but you are not going to feel it in everyday riding. Removing the restrictive OEM mufflers (Slip-ons) will make a very significant difference, and is an entirely different subject than the catalytic converter. Here is a video on how to get the most out of an aftermarket (free-flowing) exhaust- ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-pr6z00gL5Yg.html And here is a LINK to a written report on setting up exhaust for best performance- www.dkcustomproducts.com/harley-exhaust-myths-and-facts.htm Thank you for commenting! 😎 MB

The packing dampens volume so removing the packing will help with the exhaust note. As will removing the CAT which will also help with felt heat. You can add the TTI's and that will improve performance in your low to mid range torque. Here is a video on the TTI's that you may find helpful/interesting - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-b2mN7lZ1CLw.html Here is a link to a report on exhaust that you may find helpful as well - www.dkcustomproducts.com/harley-exhaust-myths-and-facts.htm Here is a link to a report on how to choose the correct size TTI's - www.dkcustomproducts.com/choosing-the-right-size-thunder-torque-inserts.htm Please feel free to contact us with any questions; Support@DKCustomProducts.com 662-252-8828 Thanks for commenting! 😎 MB

You would see better results by removing the baffles and installing the TTI's You can see the TTI's at this link - www.dkcustomproducts.com/catalogsearch/result/?q=thunder+torque However you can leave the baffles in, you just will not get the absolute best performance that way. Here is a link to choosing the correct size TTI's that you may find helpful- www.dkcustomproducts.com/choosing-the-right-size-thunder-torque-inserts.htm Please feel free to contact us with any questions; Support@DKCustomProducts.com 662-252-8828 Thank you for commenting! 👍 MB

So with removing the baffles and installing the TTI. Will I need a retune? Tia

If you have a good tune right now, you will not need to retune if you remove the baffles and install TTI's. KP

Thanks for responding. Will placing an order for the TTI. I believe I will need the 2 5/8” for 4” slip on Rinehart.

Yes, you will need 258 if the opening where you will be installing the TTI is 4 inches. You can see the 258 TTI's at this link - www.dkcustomproducts.com/thunder-torque-inserts-258-model-family-dk-tti-258.htm You can see a written report on choosing the correct size TTI at this link - www.dkcustomproducts.com/choosing-the-right-size-thunder-torque-inserts.htm Please feel free to contact us with any questions; Support@DKCustomProducts.com 662-252-8828 Thanks for commenting! MB

That is because backpressure is bad for power. Backpressure is a power robber. It, literally, makes the engine work just to get the exhaust out. Additionally, backpressure prevents a full combustion chamber fill in the intake stroke. The Thunder Torque Inserts utilize a patented design that works 200% - 500% better than lollipops or cones. The unique shape Speeds up Exhaust Gas Velocity, in addition to reducing/eliminating reversion. Two major keys to power. www.dkcustomproducts.com/thunder-torque-inserts-c57-337.htm Here is a written report on exhaust that you may find useful/interesting - www.dkcustomproducts.com/harley-exhaust-myths-and-facts.htm Here is the link to the TTI's if you are interested in reading more about them- www.dkcustomproducts.com/catalogsearch/result/?q=thunder+torque+inserts Thanks for commenting! MB

Hahaha 😂😂😂I saw that video! Hopefully, since we haven't said anything to offend him and this video is about Backpressure he won't find the need to make a video about us. If he does I believe it would be a positive video because we also do our homework before making parts and deciding to sell them. Thanks for commenting! MB

Fishtails still have reversion. Here is a video that has some fishtails with the Thunder Torque Inserts™ installed that stop the reversion- ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-GuIgK-rc2s4.html Link to TTI's with details- www.dkcustomproducts.com/thunder-torque-inserts-c57-337.htm The longer the pipes, the MORE power...as long as the pipes have no increase in diameter as they get further away from the engine. The best power is to have the same size pipe as the headers, all the way to the back of the bike. Of course, most folks don't like that look, so they give up a little power to have the larger diameter slip-ons. KP

Yes, crossover pipes help scavenging and will speed up exhaust gas velocity, but still leave a lot of reversion occurring when using free flow slip on's. KP

The Thunder Torque Inserts™ utilize a patented design that works 200% - 500% better than lollipops or cones. The unique shape Speeds up Exhaust Gas Velocity, in addition to reducing/eliminating reversion. Two major keys to power. www.dkcustomproducts.com/thunder-torque-inserts-c57-337.htm Here is a video with stock exhaust with the TTI's installed (with baffles removed). Will not work with stock pipes with the baffles still in place. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-cOs1-bTPycU.html Here is a written report on exhaust that you may find useful/interesting - www.dkcustomproducts.com/harley-exhaust-myths-and-facts.htm Here is the link to the TTI's if you are interested in reading more about them- www.dkcustomproducts.com/catalogsearch/result/?q=thunder+torque+inserts Feel free to email or call with any questions: Support@DKCustomProducts.com 662-252-8828 Thanks for commenting! MB

I am sorry we only do testing and have knowledge about Harley's. We will be of no help to you about any car questions or car exhaust questions. You may want to find a forum or youtube channel that is for cars. Thank you for commenting! MB

I am sorry but we do not do any testing on cars. So we do not have any information for you! You may want to check out a forum or talk to a local shop! Thanks for commenting! MB

You would see better results by removing the baffles and installing the TTI's You can see the TTI's at this link - www.dkcustomproducts.com/catalogsearch/result/?q=thunder+torque However you can leave the baffles in, you just will not get the absolute best performance that way. Here is a link to choosing the correct size TTI's that you may find helpful- www.dkcustomproducts.com/choosing-the-right-size-thunder-torque-inserts.htm Please feel free to contact us with any questions; Support@DKCustomProducts.com 662-252-8828 Thank you for commenting! 👍 MB

No, that is not normal. There is nothing about the function of the Thunder Torque Insert™ that would cause a lower idle. In Fact, they should, very slightly, increase the idle on most bikes. Was there anything else worked on on the bike around the same time as the TTI install? I would look at an intake leak or exhaust leak first. KP

@@DKCustomProducts thanks for the help. I had taken the exhaust headers off to reconfigure the mufflers and found one bolt on the front header not tightened when I put it back on and it was leaking

Awesome! Glad you found and corrected the problem! MB

If you have a good tune for your bike as it sits, and you add TTI's, No retune is needed. Thank you for commenting! MB

That and all the misinformation you can get on the internet. It is easy to find information these days, what isn't easy is knowing if it is good accurate information. Thanks for commenting! 👍 MB

It really depends on the exhaust and how restrictive your DB killers are. For a more informed opinion on optimizing your exhaust's performance, please email us a photo looking into the exit of your exhaust and exactly what DB Killers you are using. Support@DKCustomProducts.com Here is a written report on exhaust that we've made that you may also find helpful - www.dkcustomproducts.com/harley-exhaust-myths-and-facts.htm Please feel free to reach out to us with any questions. Support@DKCustomProducts.com 662-252-8828 Thank you for commenting! MB

@@DKCustomProducts Many thanks,for the fast reply. Will email you,the exhaust details and hopefully,will not be a problem to run the bike without DB killer's. Once again Thanks

Awesome! We will be glad to take a look and help. Thank you for commenting! MB

We have done quite a few tests on torque cones and have never seen any measurable benefit from them. Here is a video explaining how reversion works that you may find interesting/useful (and it is not just traveling along the outer shell) - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-pr6z00gL5Yg.html The TTI are a universal item that will increase the exhaust gas velocity of any V Twin exhaust system... Long or short We have dyno charts showing the significant gains of low and midrange torque when using the TTI's. You can see some of them at this link- www.dkcustomproducts.com/thunder-torque-inserts-118-model-family-dk-tti-118.htm Thank you for commenting! 👍MB

Glad you like the TTI's! Thank you for commenting and for your business! MB

Reversion and back pressure kills torque... If you prioritize low-mid range power, those things must be addressed. Beyond 5,252 RPM is when HP is measured at at those RPMs things like reversion, backpressure, and exhaust gas velocity are not as much of an issue. You can see a written report on Exhaust that you may find useful/interesting at this link - www.dkcustomproducts.com/harley-exhaust-myths-and-facts.htm Thank you for commenting! 😎 MB

@@DKCustomProducts I was just curious. I do a lot of off roading and my machine has a V-Twin. I've seen on Dyno where they lose low and mid range torque but read higher HP with a more open exhaust, but just because the HP and TQ is higher the range moves to high to utilize your low end, and with more low and mid range (more broad tq range with a more tame exhaust. Kinda like a Harley. I'll be sure to read the article as well. Thank you.

I think you will gain a lot of understanding from the report above. Thank you for commenting! MB

@@DKCustomProducts I get what the article says. I forgot to type a line or so. More the difference between shorter true dual drag pipes vs 2 into 1 exhaust difference in braid low and high end torque of the 2 into 1 than the drag pipes which have more TQ and HP but at a more concentrated higher rpm. The 2 into 1 still has decent high rpm power as well. Is that because of the scavenging effect? That's what I run is a custom 2 into 1 on mine.

Yes, a good 2-1 pipe will have better scavenging, which is good for power thru out the RPM band, including high RPM. 2-1 exhaust still has a reversion challenge and will benefit in the low and mid range from the TTI's. Thanks for commenting! KP

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We do understand enough that we have a Patent on a design that reduces reversion, speeding up exhaust gas velocity, resulting in a better combustion chamber fill, which results in cooler IAT, more power, and better economy. Here is another video about a myth regarding exhaust that you may find interesting- ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-pr6z00gL5Yg.html Here is a link to a report that explains how TTI's work- www.dkcustomproducts.com/harley-exhaust-myths-and-facts.htm

Truth! lol Thanks for commenting! MB

Or something to that nature! lol Thanks for commenting! MB

Glad you are well pleased with the TTI's! Thank you for your business and for commenting! MB

We do have other videos that talk about more than one subject. Some subjects need to be talked about singularly as it makes it easier to understand! Here is a video on 4 things to do before changing your exhaust that you may find interesting - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-AE724ChBBLw.html Here is a video on how to choose the right exhaust for your Harley that you may find useful/interesting - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-H681dl2X_f4.html Here is a written report that you may find useful/interesting - www.dkcustomproducts.com/harley-exhaust-myths-and-facts.htm Thank you for commenting! MB

Removing the cat will make no perceptible difference in power, at any RPM. You might see 1-3% difference on the dyno, but you are not going to feel it in everyday riding. Removing the restrictive OEM mufflers (Slip-ons) will make a very significant difference, and is an entirely different subject than the catalytic converter. Here is a video on how to get the most out of an aftermarket (free-flowing) exhaust- ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-pr6z00gL5Yg.html And here is a LINK to a written report on setting up exhaust for best performance- www.dkcustomproducts.com/harley-exhaust-myths-and-facts.htm Thank you for commenting! MB

LOL not sure why you think he looks stoned, but glad you like the video! MB

There will always be some, no matter the topic.

There is so much misinformation out there. Sometimes people get their information from someone that believes they understand backpressure when they really do not! Thanks for commenting! 😎 MB

Those are some really good video links you posted. Thank you. In some of our other videos we have some clips from Engineering explained. 👍 Thanks for your advice on making videos. Most engine guys know Banks Power and Gale Banks, and if not, they are easily found with a google search. We cannot put everything in one video....but we have many videos with data and dyno charts and then you can look at the hundreds, if not thousands of comments by Customers using the TTI's with very happy results, hundreds on our website and thousands more of forums. NO, we cannot put all that in one video....it would simply be too long. That is why we reference the data/other videos with links. KP

Hi Dave, thanks for the comment. Please elaborate on "it all depends on tuning" -DS

@@DKCustomProducts seems like I answered it already…

@@davemeshamsr6000 Ah ok, Thanks again for the comment and thanks for watching -DS