Hello All,

I have V&H short shots on my 48 and I want to make my own exhaust. The bike has already been dyno tuned using Harley's super tuner. I know people say no tuning will be needed if you just change a stock exhaust to an aftermarket, but when you change the air cleaner and the pipes a tune is needed.

My question is, since I'm already tuned to aftermarket pipes, will installing new pipes with no baffles really change the map all that much? My dealer said removing the baffles from the short shots will require a re-tune, but I think that they are full of it. I understand how it will change back pressure and will affect the low end grunt, but I can't imagine it would be all that much.

Thoughts?

 

If you want it right it will need retuned imho. I don't remember exact term but the waves of flow through the exhaust will have a effect on the flow through the valves and may require a leaner or richer tune. If you aren't picky or paying a dyno tuner to do it, I would rethink the change or see how it runs. You may not notice a difference but the dyno results would as well as a possible performance loss and a drop in mpg is possible.

 

It will depend on how much you understand about exhaust system design and little (big) details like the effects of reversion.
If your intent is to build an unbaffeled set of "drag pipes", retuning probably won't matter much, as they will perform poorly on the street in the lower to mid range RPM's anyway. I suggest you give using some torque cones or lollipops consideration.

Just my 2¢

 

Thanks for the input. Its funny you said drag pipes becuase I either want to go with that or a shotgun style setup. I figured that worse comes to worse, if they perform poorly or I dont like them for any other reason, I can always throw the short shots back on.