looking to swap out exhaust

[jarod duane]

Looking to put on new exhaust, Ive got a factory 2 into 1 exhaust an looking at a set a of cobras any suggestions or opinions.

[Grum]

Make, model & year of bike would be helpful.

[Whoaru99]

They'll definitely be louder, but typically not much if any power increase. Maybe even a power decrease in some situations.

[upnorth]

A coworker just last year put a set of Vance and Hines 2 into 1s on his V Star 1300, sounds great and with the fuel reprogram got a good performance shot too.

[jarod duane]

Suzuki boulevard 07 you can see a recent pic of it on who rides what.

[Whoaru99]

Quite a few bikes these days don't show any meaningful improvement in performance until you do intake, exhaust, and fueling mods. Any of them on their own don't amount to much, if any, or maybe even a loss, generally speaking. Exhaust in and of itself can add lots of noise, which is fine and what I've done, but by itself it's often a loss of performance over the factory pipe(s).

[jarod duane]

Thanks whoaru for the info, this is kinda a personal preference deal, after time just didn't like the sound, my wife Honda shadow sounds better than mine, I want that blomp blomp blomp rumble. I have a FI programmer to adjust for loss if needed. Thanks

[Whoaru99]

Wasn't trying to imply you shouldn't do it, only saying what are the most likely results from doing it.

The Cobra pipes I have heard have been really loud. My V&H pipes can make some pretty good noise but the Cobras I've heard, well, they're too much for my liking. Could just be the certain ones the guys have had. I don't recall the models, only the brand.

[jarod duane]

I hear ya, thanks for the thoughts.

[CANOPY SAM]

So what were the results of the pipe trade out? I know some of the "other" brands of bikes just don't produce the true loping sound of a HD. If I'm not mistaken, I've heard the HD folks actually tried to "patent" that sound so no one else could copy it?

I'm really not much of a mechanic, but wouldn't that deep guttural lope come more from overall displacement and a slower RPM? Big jugs, and a slower idle...blop, blop, blop....

I'm sure one could change the "sound" of a bike with different pipes, but that's not gonna do much for the pace, or tempo of the revolution. I'd also be a little concerned about over-muffling the exhaust. Couldn't this potentially cause some damage to the engine, or minimally throw off the air intake ratio and screw up your gas mileage? Or perhaps that can be adjusted with the FI programmer you mentioned?

How many cc's does the Boulevard have?

[Dave S]

The sound of any motor comes from a couple things.

Suzuki's crank pins are at different intervals than Harley so you won't get that nice rumble we typically associate with Harleys. To some extent the air intake also has an effect on sound. There's more to it but typing on an iPhone is a pain.

[Whoaru99]

Yeah, you'll never get that "if it was anything but a Harley I'd bring it in for repair because it's not running right" sound from a metric V-twin, but you can certainly get a deeper, more throaty sound with some pipes (the sound I like) or the higher-pitched more raspy/rappy sound with other pipes.

[Grum]

all primary engine performance is based on how it can "breathe". How easily the engine can breathe will effect how much fuel you can push through it and how fast. By finding the the right combination of how fast and big a breath of fuel is determined by first you air filter, venturi size, intake manifold & intake valve area. Your cam profile will determine how how deep and long of a breath it takes and your exhaust valve area, exhaust gasket constriction into you final exhaust and muffler/baffle . If you change any of these, without changing the opposite side to keep the balance, then you probably are de-tunning the engine. ( I know I didn't get into the fuel delivery or the ignition side of it, but they don't dramatically effect how the engine breathes.)

If you have the option you might consider a tunable slip fit muffler, like a supertrapp

[Grum]

And if you already haven't, install a high flow air filter like a K&N.

[CANOPY SAM]

Thanks for the explanation. Like I said, I'm really not much of a mechanic.

[Whoaru99]

These days everything is much more closely matched than in the "good old days". That's why in most cases just changing one of the three (intake, fuel, exhaust) by itself doesn't improve much, or may even decrease performance.

It's not like back in the muscle car days when the hot rods had big cams, big carbs, high rise intakes and open air cleaners with dinky exhaust manifolds and pencil-like exhaust pipes. Just throwing a set of headers and bigger exhaust pipes on those could net pretty big gains.

[Grum]

But don't give up hope, remember the EPA always steps in and regulates the emissions and the manufactures must comply. Usually by detuning the engines with a restrictive exhaust system. A high flow air filter and tunable exhaust can give you a nice little boost, but it's not going to turn it into a track bike. But this may cost you some mpg.

[Whoaru99]

Modern bikes are tuned so lean to meet EPA that without a fuel tuner adding intake and exhaust is almost certain to result in a net loss, albeit with more noise that gives the impression of more power.

[Grum]

Modern bikes are tuned so lean to meet EPA that without a fuel tuner adding intake and exhaust is almost certain to result in a net loss, albeit with more noise that gives the impression of more power.

Good point, I will admit I don't know much about fuel injection systems and how to, or if they can be adjusted to lean/rich the mix. I still live in the carb era. ( my newest bike is old enough to vote )

[JOHNBIGDOG]

Good point, I will admit I don't know much about fuel injection systems and how to, or if they can be adjusted to lean/rich the mix. I still live in the carb era. ( my newest bike is old enough to vote )

New F.I. bike can be "tuned" either with reprogramming the existing PCM, or getting a box that plugs inline to the PCM and lies to it to do what needs to be done.