straight piping it

[Baddad12]

What are the pro's and con's on running a 6.5 subaru/robin engine with a 12" straight pipe?? It will bend at a 45degree off the exhaust port and then end up 12" to the tip. I was planning on cutting the tube 3 times like a slit end and then bending the slits out like a shotgun barrel that exploded. Has anyone seen this done or something like this before? This is my first BSR and need help.:hammer:

[Woodchuckscustoms.com]

well it would sound good this way but it might burn the velves prematurly. to prevent this weld some kinda plate inside the tubing to create a little back pressure, that might even give it a better tone

[moto1fast]

Woodchuck is right you need at least 18" of open pipe to keep from burning valves. Baffling will work on a shorter pipe and give it a deeper tone also as woodchuck said!! Not Only back presure but reduces the the chance of cold air hitting the valves and causing them to warp and burn to! When you let off the throttle from high RPM to Idle it creats a drawing of air to the valves from exhaust! The longer pipe keeps enough hot air in it that it will not draw cold air! Good Info Woodchuck!!:thumb:

[CritterBuddy]

Some racers *tune* their exhaust pipe by determining the optimal length for best performance and proper back pressure. They clean the exhaust pipe down to bare metal and paint it with regular spray paint. Any color is fine just don't use a high temp paint for testing. After painting they would do some runs and then look at the pipe to see where the burned paint stopped. At this point is the optimal length for the exhaust pipe. Any additional length added to the exhaust pipe from this point should be of a larger diameter pipe in order to not add any additional back pressure to the motor and can be used for adjusting the sound of your exhaust.

[Baddad12]

Thanks guys!! I did a calculation on the internet on the optimum length per cc's. And it landed at 10.45 inches. That seemed short to me, but what do I know. I will make a baffle of some sorts and give it a deeper, throatier sound as you have suggested. Since it is chrome I will not be testing it with paint but I will take the calculators optimum length and adding a few inches with a baffle of some sort.

[Dmanrider20]

What ive done in the past is welded a washer in the pipe to create the back pressure.