When I just added the Cycle Shack pipes, it did feel like the bike had more power, but it didn't really have more power. Four months later, when I added the Screamin Eagle Air Cleaner with K&N air filter. Pulled off the carb, drilled out the plug on the air/fuel mixture screw, re-jetted the carb and tuned it quite well. When I first went out of the driveway, the front was a couple of inches off the ground.

That is performance increase!!

You will be well satisfied with the Cycle Shack mufflers for increased sound and that was your original post. If you decide to move forward with performance increases, the Cycle Shacks will serve you well there also. They still work very well for me with the substantial performance improvements I have made to the Sporty.

 

Glad to hear it! And you have no argument here from me that intake mods are MUCH better than exhaust mods for performance gains. I just thought that there had to be something said for exhaust modifications too, even it's only a couple HP.

 

My personal experience is from buggies I messed with for years and older 4 cylinder jap bikes. I just recently got my first Harley. But on both the stock VW aircooled engine and the old jap bikes a high performance exhaust seemed to be a detriment to performance since they cause a lean condition. Might be different in the case of the Sportster because of the stock aircleaner and exhaust setup. I don't know I'm in the learning stage.

 

GWinkleman,

Technically exhaust systems cannot increase or decrease an engines power. However, and this is a BIG however, exhausts systems can have a profound affect on increasing or decreasing engine pumping loss.

You can loosely compare engine pumping loss with adding an extra 200 lbs weight to the bike. The engine still has the same amount of power, but with the extra weight on the bike it will accelerate slower...it will feel like it has less power than it would if the extra 200 lbs was removed.

Every engine will suffer to some degree from engine pumping loss. The goal of many exhaust systems is reduced engine pumping losses, resulting in more felt power at the rear wheel. If efficiency of the engine increases then fuel mileage may also increase because less throttle is needed to move the bike forward at the same speed.

There are Many design factors that can affect whether an exhaust system increases or decreases engine pumping losses, far more than could be put in a post here (by me anyway lol).

Generally most of us that ride Harley's want the most felt (rear wheel) torque in the low to mid rpm range as possible. Inertial scavenging has a major effect on that felt power.

The nuts & bolts of increasing inertial scavenging is the following-

When the exhaust valve opens two thing happen. A pulse (wave) of energy enters the exhaust pipe, generally at 1300-1700 feet per second. This can be understood as a shock wave from an explosion.

At the same time the spent combustion gases enter the exhaust pipe at 150-300 feet per second. (Generally the faster the exhaust gases travel, the better the inertial scavenging and the less engine pumping loss)

The energy wave that is heading toward the end of the pipe will get to a low pressure area faster (low pressure being a bigger area of the pipe OR the end of the pipe) WHEN that happens some of the wave will reverse direction and collide with the slower moving exhaust gases that are still traveling toward the end of the pipe. This will slow down the speed of the exhaust gases. This will produce the result of less felt torque at the rear wheel.

Exhaust systems that are are successful in increasing exhaust gas velocity (resulting in an increase in inertial scavenging and a decrease in engine pumping loss) will make the bike have more felt torque across the RPM band, especially in the low & mid range.

There are many other factors...the above just scratches the surface what can be involved in the design of a performance exhaust system. But is should give a basic understanding of how exhaust systems, independent of any other changes to the engine can negatively or positively influence felt power without really changing the engines actual power.


Ha! I tried to keep this short. Wonder if anyone is going to even read it.

 

Here's my 2010 w/ Vance and Hines short shots. Sounds good. This vid is actually in the garage so it is amplified a bit

http://www.youtube.com/watch?v=MykbY...&feature=feedu

 

The explanation is well appreciated. But I don't think anyone was saying (I hope not at least) that the exhaust increases engine power. But it can increase total power of the bike. From a thermodynamics standpoint total power = generated power - total loss. To incorporate your logic, we should be phrasing it as the exhaust systems help minimize the total loss which in turn increases the total power of the bike. Increasing generated power is accomplished by other means.

 

SportyPig, I don't want to beat a dead horse but I thought I'd make good on the claim I made before. Here is the post that Ryan from Rush made.

"We are 100% made in the USA.
You can expect about a 5hp gain with our 2.00" baffle slip-on. With any of our slip-ons or full systems, you will see a performance gain when properly tuned. Adding a high flow a/c and dyno tune will really bring the performance to life.
Our slip-ons are $359.95 and short system is $399.95. (black series)
http://www.rushracingproducts.com/blacksport09_10.html
http://www.rushracingproducts.com/blacksportfull.html

You will not see a huge difference in the performance between the two but there is a difference in the sound. The slip-ons will have a deeper tone than the full system and that generally applies to all manufacturers.
Most people are very happy with our 2.00" baffle slip on muffler, it has a deep aggressive tone and the best overall performance increase.

Let me know if you would like more info.
-Ryan
__________________
RUSH RACING PRODUCTS

www.rushracingproducts.com
email: sales@rushracingproducts.com
Ph: 866-994-RUSH

Available now: CYCLE PEDIC SEAT and SIDE KICKS
https://www.hdforums.com/forum/rush-r...ing-seats.html
https://www.hdforums.com/forum/rush-r...-4-wheels.html"

It doesn't matter anymore. I just don't like making statements that I can't back up.

Rubber side down.

 

just my .02 if you want loud obnoxious pipes cheap look for some Short Shots with the regular baffles.

 

Just installed the Cycle Shacks! They are SO LOUD. This sporty rivals other larger Harley's. Nobody will call it a "baby Harley" anymore haha I'll post a vid tomorrow when it's light outside again.

 

Really G? You got them already? Damn!! I havent ordered mine yet? Is it really a big difference in loudness?