B6 Exhaust Piping?

[bravekozak]

I am just beginning the exhaust install for my B6. I have decided to go with 2" pipe, based on pipe diameter guidelines. I have found a 2" resonator and a 2" muffler.

I have decided not to buy an expensive 2" cat, but just weld a pair of mild steel flanges on the stock cat for easy swapping for Drive Clean testing every two years.
So, I will need 4 stainless flanges + two copper flange gaskets. One of the stainless flanges will be required on the header. Two on the resonator. One on the rest of the exhaust pipe to resonator.

[blkfordsedan]

Why don't you check out Jones mufflers. They have tons of different sizes and styles, and they're cheap. - know they make a muffler with std. Inlet and an outlet on the side of the case.

[drddan]

Let's see if we can't get a turbo muffler to fit in the 'cat slot'.

My side outlet is progressing, but I'm probably going to have to stuff it with wadding to run as I am; without a muffler.

My next phase would be to design a side outlet that clamps directly to a glasspack. A glasspack will barely fit in the Festiva tunnel, if I can find one short enough. This would be direct fit cat back system. A turbo muffler instead of the cat, followed by my glasspack/side outlet would be a contender for ultimate Festiva exhaust (IMHO).

I am going with a .... "special".... cat, and a hi flow muffler, in the stock locations.

And hey..I like the moniker .... Dr. D

[Christ]

Okay

I'm building my side outlet today.

The actual exhaust openings will be cut in the bottom flat plate, with the exhaust flow pointed down toward the ground.

This will make the car seem quieter, in the sense that the sound won't be pointed at the neighbors' houses, or passing cars.

Aerodynamic flow in this area? I'm clueless. It's trial and error engineering.

The flow under a car in the area above the lowest point of the chassis is generally stagnant. I'm not sure about right at a transition edge near the rocker, though. That all really depends on the body's shape and vehicle speed.

I'm gonna end up doing a side-exit, too. I have about a million little tidbits of information stuck in my head at any given point in time, so if I some a situation where one applies, I just throw it out there. Whether or not the person is concerned about it, that's their call.

[BigElCat]

Okay

I'm building my side outlet today.

The actual exhaust openings will be cut in the bottom flat plate, with the exhaust flow pointed down toward the ground.

This will make the car seem quieter, in the sense that the sound won't be pointed at the neighbors' houses, or passing cars.

Aerodynamic flow in this area? I'm clueless. It's trial and error engineering.

[BigElCat]

Wait minute...what if I pull out to pass a semi on a two lane road...and some how a high pressure builds between the two vehicles. Just enough to cancel my acceleration, but not enough for me to figure out what's going on.

I'll be stuck there...no doubt with another semi comin' at me.

:banghead:

[BigElCat]

the difference is negligible.

negligible and mute...We have exactly one exit location for a side exhaust on the Festiva...is it a "stagnation zone"? It's our interface to the world!

Isn't there some research you could be doing on the surface of the moon?

[BigElCat]

Yo! Dr D

Let's see if we can't get a turbo muffler to fit in the 'cat slot'.

My side outlet is progressing, but I'm probably going to have to stuff it with wadding to run as I am; without a muffler.

My next phase would be to design a side outlet that clamps directly to a glasspack. A glasspack will barely fit in the Festiva tunnel, if I can find one short enough. This would be direct fit cat back system. A turbo muffler instead of the cat, followed by my glasspack/side outlet would be a contender for ultimate Festiva exhaust (IMHO).

[Christ]

Largest restriction to a side exit is the flow /outside/ the pipe. You've got to make sure it ends up either in a convergence zone (stagnation) or a high flow (low pressure) zone to avoid it.

But, again, the difference is negligible.

[BigElCat]

The front diverter spoon only protrudes into approximately 7% of the cross section. It will gain more than 7% of the flow due to turbulence, and any exhaust pushing back from the spoon behind it.

The over all cross section area of the rectangle is much larger than the cross sectional are of the 2" tube. This means no 'area' restriction, only the reluctance of the exhaust gasses to change directions.

I have this thing tuned to produced a very specific tone. Yeah right. I hope it doesn't sound like Bobstad's saxophone...the one without any key works.:p

I'm predicting a nice mellow rumble, without any reduction in power or driveability. Will it extract power? No, extraction is all over with after the head pipe.

[BigElCat]

This is a 2" 11g tube. It transitions to a 7/8"x7" rectangle, with an offset sweep that will clear the exhaust tunnel. The rectangle is divided into 3 equal ports.

The front two ports each have a diverter 'spoon'. The rear most diverter spoon covers about 40% of the cross sectional area.

[BigElCat]

TE...CH A...I...R, what's that spell?

[BigElCat]

hey mods - you're dropping the ball. EVERYTIME I post a ? about doing something to a festy you move it to "the proper section", usually the repair forum....then you pm me to let me know...is it any wonder why there is some confusion regarding the "general" forum post rules?...just sayin:p

This one should probly be it in the engine drive train column?

I super like FF.com! Don't want no trouble

[BigElCat]

The exhaust in front of the rear tire is not the best way to extract power

You ain't seen nothing yet, Hoss!:p

I'm starting with 2" 11g black iron tubing. I'm mean I'm building this thing to fit my car. Dr Dan could talk me out of the prototype, I'm building it now.

Pics are pending.

[loknlode]

hey mods - you're dropping the ball. EVERYTIME I post a ? about doing something to a festy you move it to "the proper section", usually the repair forum.

then you pm me to let me know.

is it any wonder why there is some confusion regarding the "general" forum post rules?


just sayin:p