Performance exhaust is it hype?

Question

Seven motorcycles later and i still wonder if it actualy does anything other then make noise? Yes i did exactly what the Jet Kit says or the exhaust manufacture says. Id assume since you go up bigger on the main jet that yes it does do something. Iv never felt a difference other then the noise! Modifing the intakes on bikes i notice a difference but not exhaust! Or could it be such a small gain in power its not noticable? Im starting to think exhaust systems are a waste of money and hype!!!! What do you think?

vance&hines/muzzy. Full performance exhaust systems! header,mid-pipe,muffler "complete systems" just thought id clear that up.

Answer 1

It depends completely on the bike.

There are many models which come from the factory with excellent exhaust systems, which are perfectly tuned to the engine setup, the carburetion/injection settings and the air intake. Installing any aftermarket exhaust on one of these may lose a few pounds off the bike, but won't gain anything but noise.

Other models are purposefully restricted from the manufacturer - whether due to emissions standards, or simply as a 'safety' measure, these bikes can benifit from a well-tuned exhaust AND ecu/carb rejetting changes. Sometimes they also require a more free flowing intake.

Then there's the in-between models - those that weren't really designed very well from the factory. The pipe is restrictive, but so is the cam grind, the head, and the entire intake and carb/injector setup. Bore and stroke aren't optimum for the desired rpm range, and maybe even compression isn't quite right for the bike's selected use. Putting a different pipe on one of these beasts is a crap shoot - sometimes a pipe that actually has less flow will increase horsepower. Then a very well designed exhaust that has perfect flow and backpressure will run like crud on a model without other modifications.

I've always had the best luck with any aftermarket parts when I buy from a performance company - not just a 'pipe manufacturer'. Most pipe manufacturers will make an exhaust system for EVERY model - regardless of what it does to the power. The performance shop usually does a ton of testing on my particular model, then offers the parts that really make a difference - sometimes a pipe, sometimes not.

Hope this helps!

Answer 2

Frist of all, there is no better pipe for a v-twin than a Vance and Hines 2 into 1 system. As for re jetting the carb, there is more to it than just changing the jets. On the cv type carb, you will need to reset the slide rings . And modify the vaccumn operation of the slide by drill a larger hole in the top. The slide need to have the incoming corner belveled and blended. When all that done you then go do plug cuts to see if you have the correct jets in the bike. Run the bike up to 80 mph and the without touching the throttle again coast to a stop shut off the bike , pull the plug and check for fat or lean condition. You want to get a plug that burns a nice choclate (mike) brown. Not black and not gray. Hope this helps.

Answer 3

Yes. Sure you can get a couple HP from and exhaust system but you are paying for the looks and the sound on a Harley or cruiser.

On sport bikes like an 02 GSXR 1000 that came with 138hp to the wheel I can install the top of the line $1800 system, power commander, and Ill custom map it. this will get 11 hp jump which is huge!!

Mind that this is 11HP on a 138HP bike that has a race system. Or consider that %8

A harley/cruiser starting at 70 HP will get just a couple. Again the sound and looks are what you paid for. Best case is about 5 hp which is also about 8%.

With a complete rebuild of the harley engine, cams, big bore, etc it might get to 85HP and that is being nice. If you want real HP in that cruiser you will need to get a Turbo. We have installed them on the V-rod to get 120HP.

The same goes for sport bike cans/slip-ons, they might add 1-3 HP but that is only by accident. You are really buying the sound and looks. nothin wrong with sounds and looks though.

I have read and seen some amazing HP numbers but these are what I have actually witnessed.

Answer 4

A lot of people answered this before me so I'll be brief. Look at the science of it. If you replace the main jet with a bigger one to keep the unit in the same air/fuel ratio then you are getting more air and fuel into the engine at wide open throttle. More air and fuel = more bang. On some units once you have installed a performance exhaust you must now upgrade the intake and camshaft(s) to really take advantage of the increaced scavenging. When in doubt pay the 100 hr it costs to rent usage of a dynometer and see the power difference you probably aren't feeling.

Answer 5

most modern cycle exhausts are already tuned pretty close by the factory when you buy them that any performance gains will be very small. unless you go down hill. remember that the exhaust is part of a complete system and all parts MUST work in harmony and balance to get the best performance.

Answer 6

most of these pipes are designed for wide open throttle like you would use it in a rece setting. The only thing you are doing on your harley is making it louder and saving some weight.

Answer 7

Personally, I don't like the Harley noise level. However, I wouldn't mind my pipes being louder than they currently are, if not for the sole purpose of letting people know that "I am right here... don't run into me."

Answer 8

unless your racing you probably won't notice any
difference. on most bikes you give up some weight
and makes alot of noise.. but the preformance
difference is marginal.. unless you are riding with
the tach on the red line all the time..