B6 Exhaust Piping?

[Safety Guy]

Since Zoomzoom's link to the calculator comes form a Cortina site, I bet it is configured to work primarily for non-turbo four cylinder applications. Probably SOHC, too.

So it might do just fine for NA SOHC engines like the B3 and B6.

On the other hand it doesn't take into account displacement. I wonder if that's important?

I might be wrong. Very wrong.

Karl

[BigElCat]

IIRC, the stock B6 downpipe is 1.50" ID. It looks bigger because of the double wall tubing. 6or a stock B6, I would stay with 2" or smaller. If you look at my build thread in the garage forum, I have pics of a custom 2.125" mandrel bent downpipe and a comparison to the factory diameter.

I looked for your build, wow, 500 pages of posts. How about a link, or a few hints. I'd like to see this. What was the title of your build?

[BigElCat]

Coool link Zoom.

1.5" gives a max of 92bhp.

Dan's efi B6 8-valve is about in this range. (Am I right, or wrong?)

I'd say "stay as small as possible" for torque, throttle respose, longer radius bends. No cat, easy to replace stock oval/big core muffler.

[zoom zoom]

this is kinda neat, http://www.mk5cortinaestate.co.uk/calculator5.php

[Movin]

Anybody ever ask Mandrel Exhaust Systems?

I just emailed them about a 1 3/4" down pipe back system. Should be a good size for a 1.6. They are very nice on price on their pre-bent setups, but not sure about the Festiva since they don't generally offer it.

I'll post up once I get a response. Would be FAR superior to a generic crush bend muffler shop job.

They are pretty!

[sketchman]

Anybody ever ask Mandrel Exhaust Systems?

I just emailed them about a 1 3/4" down pipe back system. Should be a good size for a 1.6. They are very nice on price on their pre-bent setups, but not sure about the Festiva since they don't generally offer it.

I'll post up once I get a response. Would be FAR superior to a generic crush bend muffler shop job.

[blkfordsedan]

IIRC, the stock B6 downpipe is 1.50" ID. It looks bigger because of the double wall tubing. 6or a stock B6, I would stay with 2" or smaller. If you look at my build thread in the garage forum, I have pics of a custom 2.125" mandrel bent downpipe and a comparison to the factory diameter.

[BigElCat]

I guess the appeal of 'sticking it to the man' is universal no matter how benign the 'powers that be'.

I agree 2" all the way is too much.

I'm not suggesting we lose the cat in order to defy the EPA. We lose the cat because we eliminate one potential problem. We lose the cat to save weight and gain room under the car...to gain better exhaust flow. It's a legal gray area because it's not enforced around here.

Any large displacement new vehicle, even with its emission controls, is going to polute more than a Festiva without a cat.

Maybe I'm reading too much into your statement. You are one of the 'benign powers that be' along with the rest of us, aren't you? It sounds condescending, if read the wrong way.

[Bert]

I guess the appeal of 'sticking it to the man' is universal no matter how benign the 'powers that be'.
But 2 inch pipes might get ya more air than the motor can handle if this is supposed to be a daily-driver.

Way back (mid 70s) I put a Chevy truck muffler and pipes on a sprint-modified Mini Cooper S and never regretted it. Never lost a race but that car never liked to sit still, or idle. But then the cam and other goodies in it likely never noticed the big pipes either. A few other idiots at the time stuffed steel wool in the tailpipes which would catch fire and make them look 'hot'. Didn't make them go any faster but did impress the ladies.

[BigElCat]

The sections would be removeable for maintenance work without running it up on a lift.

Here's what my 2" pipe from the cat back, no muffler sounds like.

http://youtu.be/QK03LP5OXY8

[BigElCat]

The 2.5" stock oval will serve as a expansion chamber for performance, and keep it quiet with a rumble...as much as a 4 banger will rumble.

The system would bolt together using 2 bolt flanges where ever necessary to get it to fit under the car.

I can burn 10g SS two bolt flanges for the primary pipe at a nominal cost (i'll pm you). You'd have to come up with some thin brass or copper gaskets. At the muffler, you'd have a 2 bolt flange the same size as the one on the primary pipe except with a hole large enough to weld over the muffler inlet.

[BigElCat]

Here's my 2" cat back no muffler. It's not ideal, but it's working.

I'd recommend 1.75" SS304 all the way back to the stock muffler position, then hang a cheap 2.5" core stock oval muffler. The smaller diameter primary will keep the exhaust velocity and torque up...in theory. Smaller diameter can use larger radius bends with out crimping the tube, a larger radius small diameter will out flow a big diameter, tight radius as well.

[drddan]

:p

Well...I think I know a little muffler shop... (heh heh) .... just down the street

No emissions here 1995 and later

[Movin]

Make sure you tell the exhaust shop this is for your new cornfinder machine..maybe
they will bend your pipe and swedge the ends. More likely you will need to buy
the cheap HF hydraulic pipe bender and the cheap pipe expanders and do your own.
You will need a pipe cutter and a good vice too.

[Festy46]

I used 2" O.D. for all my 1.6 and 1.8 engines. I would get a straight piece of 2" pipe and a steel brake line that was as long as my pipe. I would then hold the brake line up to the edge of the exhaust manifold and bend it to make a template to the correct angle for the exhaust pipe. Then take the bent brake line and your straight pipe to an exhaust shop or garage that has a pipe bending machine and have them bend your pipe to match the angle(s) of your brake line. I use a 3/8 piece of plate for the exhaust flange and make the pipe going from the bottom of the car to the exhaust manifold a little long so I can cut it to the perfect length to go through the 3/8" plate and just have enough clearance under the bottom of the engine. I used a good quality 2" metal cutting hole saw with plenty of oil and a drill press to cut the hole in the 3/8" plate and an exhaust gasket for a template for the mounting holes.