Hi all, new to the forum and looking to put slip ons or change out the exhaust all together. Been going back and forth between V&H's and S&S. After much research I come across short exhaust systems (ex: short shots) being bad for the M8. Not enough back pressure resulting in loss of low end torque. Any truth to that? Also, was in my local HD dealer today and heard how good the S&S slash cuts slip ons sounded on a new Fatbob. I am so stuck on which route to go. Save money on slip ons or spend 3 to 4x's more on a full exhaust change. Recommendations appreciated. Thanks in advance

 

I'm happy with my Rinehart slip-ons. Once the warranty is through I may go with a full system and tune. Rinehart have a nice mellow rumble and great quality.

 

It's not the lack of back pressure, this is still a misnomer in this day and age, it's ridiculous. No engine need any sort of "back pressure", this has been debunked so many times its silly. What engines need are tuned length/sized primary tubes. If they're too short, it moves the tq peak way high in the power band where you're likely to never see any real benefit. The M8 unfortunately, as well as most all air cooled twins, Iike longer primaries to enhance the low to midrange tq they already make.

With this said, a full 2-1 system will be your best choice and Cobra makes the El Diablo system. It's not ridiculously loud, but plenty throaty. And the best part, if you shop around, you can get it for about the same as slipons cost. G/L!

 

Another vote for Rinehart. I just put these on the other day. Nice low rumble you can hear and feel, not loud and raspy.

 

It's not about back pressure. It's about anti-reversion.
If you want some Vance and Hines slip-on pipes, you can install some 118W Thunder Torque Inserts and get that low end torque back.

 

V&H Eliminator 300's. Sound awesome and didn't break the bank.

 

For what it's worth, the S&S are Fuel Moto go to mufflers for Softails. I'm happy with mine

 

...and scavenging.

Liquidswordz is right that people (even here on the forum) mis-use the term "back-pressure" way too much and don't understand the concept of what they are literally saying. Harleys like the longer primaries on the exhaust--which is why I think ANY short exhaust is practically stupid as it ends up hurting performance and having no real world benefit. I cannot remember specifically, but I think around 32 to 36 inches of length is where the benefits will be realized. I have first hand experienced this with a crappy short length TBR exhaust and literally seeing a drastic change in the VE's by adding a more superior exhaust.

 

I found some stock mufflers for my 21 Street Bob that had the baffles drilled out and holes drilled in the cats. I added some DIY baffles (curved washers and a few bolts) and I can definitely feel the difference between having the baffles removed or installed. Thunder torque inserts are always an option as well.


I enjoy how the exhaust sounds now (not overbearing but noticeable) but eventually I’ll go with a full on exhaust setup with cams and a tuner.

 

This is true. Every exhaust already has 14psi back pressure at sea level.