Side pipes with cat converters

Aussie Mike · #1 (**permalink**) 10-26-2003, 06:31 PM

Hi All,

Thought you might be interested in my environmentally friendly sidepipes.

Our emissions laws in Australia are pretty strict and there are big fines for not having cats installed. So part of my criteria for my sidepipes was the inclusion of cat converters and being able to easily replace them and repack the mufflers.

I built the headers and sidepipes from scratch and after much machining and welding I nearly finished the right hand side on the weekend. I always liked the traditional steped "hot dog" style sidepipe rather than a straight 4" pipe, they always looked too much like a truck stack for me. These pipes are 2" primaries into 3.5" collectors to a 4.5" muffler body and then back to a 3.5" tip. The muffler body slips off at the collector so the whole thing can be serviced. The cat has a flange welded to it that slots into the a flange on the collector and is retained with a couple of recessed grub screws. The muffler body will be retained onto the same flange with either countersunk head cap screws or a hidden clamp, I haven't quite decided yet. The joint will be almost invisible and the whole thing will just look like a fatter version of a regular sidepipe.

I've still got to make the baffles and the rear mounting bracket but here are some progress pics.

Cheers

kountzecobra · #2 (**permalink**) 10-26-2003, 07:33 PM

Looks good! Isn't the heat going to be excessive from the cats? I always thought they ran a lot hotter than a normal pipe? I have no nothing to base it on, just what I heard in the past.

Aussie Mike · #3 (**permalink**) 10-26-2003, 07:44 PM

Yes the cats do run hotter (the hotter they are the better they work) and this does concern me too. There is a small airgap between the cat converter and the inside of the side pipe so hopefully that will reduce the radiated heat. I'm also going to get the whole thing HPC coated and might even get the outside of the cat done.

foothills gary · #4 (**permalink**) 10-26-2003, 09:36 PM

Mike,this is truly some beautiful workmanship!It looks like a product that a lot of Cobra owners could incorporate into their cars.It sure beats the shorty header with inline converter to the sidepipes commonly seen. It might be the answer as to how you can pay for that Daytona or GT40 if things take off for you.Keep us posted as to how they work.

Aussie Mike · #5 (**permalink**) 10-27-2003, 02:39 AM

Thanks Gary,

I'm keen to see how they go myself. From talking to a few pro engine tuners down here the cats don't have much affect on HP and might have a few benifits other than emissions. One that I can think of is that they would act as a flame trap and stop exhaust flames on deceleration. This could be a good or bad thing depending on how you look at it

I agree, the traditional cat converter isn't the pretiest looking thing to have in your engine bay. I can't imagine the shorty headers help performance either. The header manufacturers were reccomending between 28" and 34" primaries for my LS1.

Don't let my wife hear you mention GT40 or Daytona. She knows I'd love to do one or the other but would probably kill me before I laid a spanner on one.

Cheers

Rebel1 · #6 (**permalink**) 10-27-2003, 04:49 AM

Mike..you got wayyy too much time on ya hands....and talent.

Now..where's the phone??

Hello Mrs Mike. Do you know........

Curt C. · #7 (**permalink**) 10-27-2003, 12:30 PM

That is some impressive work. Where do I place my order?

Aussie Mike · #8 (**permalink**) 11-06-2003, 04:30 PM

Thanks Curt & Les,

Despite having a really bad cold the past week I pretty much got the drivers side done. The baffles are all built and the whole thing is pretty easy to strip down and work on. Now I'm happy with it I've just got to build the matching setup for the other side of the car and get them HPC coated.

Not sure whether I should buff out the welds and blend it all together or leave it as welded. I kind of like the welds being there on display.