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HI all, has anyone installed a full exhaust on a M8 that has enough back pressure that the M8 needs or installed a full exhaust and not had any problems? I have a 22 blacked out heritage 114 and would prefer V&H pipes. Thanks for any help.
The M8 engine idiosyncrasies aside, I believe any pipe with baffles will be at the mercy of the abilities of the person who does the tune.....
IMHO..... if the pipe has baffles, it can be tuned to run well... obviously some pipes will be harder to tune than others, and the design of some pipes (back pressure just one aspect of the design) will ultimately perform better than others... but I feel a good tuner can make a baffled pipe run well in a street application...
I have Vance & Hines pipes on two of my Twin Cam bikes... an '01 88" Stage I carbed bike, and an '03 95" big bore w/headwork and EFI bike. I tuned the carbed bike and had a dyno tune on the EFI bike. Both run very well....
I'd say get the Vance & Hines pipes and find a good tuner....
Last edited by hattitude; Dec 17, 2022 at 10:53 AM.
HI all, has anyone installed a full exhaust on a M8 that has enough back pressure that the M8 needs or installed a full exhaust and not had any problems? I have a 22 blacked out heritage 114 and would prefer V&H pipes. Thanks for any help.
P!ease explain this NEED for back pressure? Something you read on the internet?
Last edited by 60Gunner; Dec 17, 2022 at 03:10 PM.
It's not as much the tuning device you use, but the people/shop making the tune that you will download....
Obviously the best tune you can get will be from a good tuner (person), performing a dyno tune on your exact bike. If the tuner is knowledgeable and experienced, he/she should be able to dial in just about any pipe for good, smooth, and efficient street operation...
If you have it dyno tuned, find a good, reputable, highly recommended shop and then buy the tuner or tune license from them for the tuner they recommend...
Next best choice would be to get a flash tuner from a reputable shop who does a great job with their tunes...
I use a PowerVision from FuelMoto. I use FuelMoto or DynoJet for my tune maps.... Both DynoJet and FuelMoto have supplied me with some really good tunes. If you buy your tuner from Fuelmoto, they will not only give you a map, but if it's not perfect, they will tweak it if you send them a data log and tell them what your issue is. That's probably the next best thing to an actual dyno tune on your bike. I don't hesitate to recommend FuelMoto..
I have no experience with the Vance & Hines tuners or their tunes.... But I have used and do like their exhausts.... I have read posts from many people who are very satisfied with both their tunes and customer service..... Since I have no personal experience with their tuners/tunes, I won't personally recommend them based only on second hand info..
Good luck with your decision...
Last edited by hattitude; Dec 17, 2022 at 05:00 PM.
To 60Gunner, I watched a video by Matt Laidlaw from Laidlaw Harley Davidson. He was explaining that the M8 utilizes the back pressure for low end grunt and the back pressure is built in the headpipe and not the muffler like the twin cam engine.
To 60Gunner, I watched a video by Matt Laidlaw from Laidlaw Harley Davidson. He was explaining that the M8 utilizes the back pressure for low end grunt and the back pressure is built in the headpipe and not the muffler like the twin cam engine.
just stating his opinion. Its not the gospel. A whole different beast. Lot of silly opinions on the M8
From OP: "HI all, has anyone installed a full exhaust on a M8 that has enough back pressure that the M8 needs or installed a full exhaust and not had any problems? I have a 22 blacked out heritage 114 and would prefer V&H pipes. Thanks for any help."
The factory M8 Heritage has the catalytic converter (and baffles) in the mufflers (slipons), not the head pipes. Unless you are going with a 2 into 1 or "true dual" system like Bassanis (I saw a Bassani setup at my local Indy recently) there is probably no reason to get rid of the head pipes. There are many slipons available for the new Heritage from Vance and Hines as well as others. Some of the higher priced slipons have a catalytic converter in them, others don't and are less expensive. Some have baffles, others don't. Be sure you are getting what you want rather than just buying a name. I just put Rinehart 3.5" slipons on my 2022 Hertitage and am pretty happy with them, although I am modifying them a bit.
Back pressure is bit of a controversial topic and opinions are like ******** (everybody has one). Most people (like me) believe that a free-flowing exhaust (little back pressure) is better for power than the highly restrictive stock pipes on an M8 motor. These have very little back pressure. There is a problem with "reversion" with straight pipes, however, that can be at least partially overcome with baffles or "lollipops". Reversion robs power from performance a low to medium rpm.
Look up Thunder Torque Inserts (like a lollipop) from DK Custom Products for a discussion on this matter. It's winter. You have plenty of time to investigate pipes before riding season.
OP; What's your end-goal here? Are you looking for better sound, or performance?
Either way, I'll know more in the spring, as I have a brand new Freedom Performance true-dual system in garage waiting for spring. I can tell you, from experience, a muffler swap definitely helps w/ sound as I swapped stock for Thunderheader slip-on's in 2020. Also true is cats are in pipes...check out my before & after pics:
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