Fiat Spider custom stainless exhaust.

[ClarkTheShark]

Rather than link all the images, ill just link the album

http://imgur.com/a/Mw57V

The idea here was to make a 100% 304 stainless system from header to muffler tip. Columbia River Mandrel Bending sells the flange and bends. I ended up going with 1 5/8" primary tubes (16" +-1" long ) and 1.75" inch secondaries (18" long). I finished the last of the welding last night. I have yet to even crank it up.

Making the headers was a giant geometry problem. I found that designing them was more of an art than science. Regardless - I used a couple programs online to help determine optimal primary and secondary size and length. Croft will tell you in his book that these formulas really cant be trusted and that real world trial and error is really whats needed. I didn't have the luxury. Croft has a range of lengths fro primary and secondary tubes that he says should work fine. These fall within those parameters as well.

I used 2.25" exhaust pipe from the headers back. I wanted to be able to disassemble the exhaust system if i needed to, so i utilized these cool clamps called V-Band clamps. They are nice to weld up and grip like a bear.

The muffler is a Borla Boomer Thumper. Its also 100% 304 stainless.

What do you yall think?

[cormac]

Kudos...looks great, am impressed, red caliper as well

Dave

[burgandy81]

Hi Clark,

Nice work.

I have been thinking about something similar although not as high end. My starting point will be an existing header. The custom unit will start at the 4 -2 section and will be 2.5" aluminumized steel.

I appears you followed the existing pipe routing. Any changes or words of caution for fitting the larger system?

How did you decide on the muffler size? My plan is for the longest resonator I can fit and the largest 'Turbo' style muffler that will fit under the car.

What machine are you using for welding? I am considering an off-shore TIG machine although budget will likely dictate a Craigslist MIG will inhabit my humble garage.

Best,

Jordan

[ClarkTheShark]

Yes - the pipe does follow the exhaust pipe tunnel under the car. No reason to deviate from that path.

The 2.25" inch pipe fits fine. And actually, fits much better than my previous system that was custom bent by the local exhaust shop. CRMB (columbia river mandrel bending) sells U bends in 2.25" that you can cut sections out of to make the perfect bends. This is not easy though. definitely a two man job. The problem with 304 is that its NOT magnetic, so you cannot use magnets to hold the pipes in place when you go to tack weld them. Also, because most of the pipe sections are butt joints, you must have a high degree of precision when cutting. I made a jig that clamps the pipe in, and used a sawzall to cut the perfect straight lines. then filed any burrs off.

I'm using a longevity 200sx for TIG welding. Some joint i Purged with argon on the backside, other i did not. Next time i will get a nitrogen tank and used that to purge to save a little money. All in all, materials cost me about $1k - tools cost about $1500. but of course i can use the tools over and over!

I may be wrong, but attempting this project with a MIG welder would be nearly impossible. there just isnt enough room in between the header pipes to get that mig torch into..

[ORFORD2004]

The only bad part with SS is that it crack.

[ClarkTheShark]

Never heard of 304 stainless having a tendency to crack.

here is quick video of crank up and fitment:

https://onedrive.live.com/redir?resid=7 ... ideo%2cmp4

[BEEK]

i want to know how the car is running with out a air flow meter?

[FiatMac]

i want to know how the car is running with out a air flow meter?

Just guessing that he is running Megasquirt.

[ClarkTheShark]

Megasquirt/Ford EDIS.

No Airflow Meter, No distributor!

[v6spider]

Nice work Clark! I like the German Shepard photo bomb s!

Merry Christmas!
Rob

[ClarkTheShark]

You should see him ride in the front seat.

Thanks Rob.

merry christmas

[nelsonj]

looks great. I have a custom "partly stainless" exhaust. That is the resonator rusted out, the pipes cracked and needed a joint, and I needed to hang a non-standard muffler. Also those "new parts" are stainless, but I like yours a lot better.

[ClarkTheShark]

It was all for a good learning experience. The next one i build will be much better I think. It does seem to perform very well.

I will have to take the header off the car again because i believe the flange is slightly warped from me welding it (slight leak at flange). The copper gasket i bought really requires a very flat mating surface for the proper seal. But hopefully i wont have to take it to the machine shop to have the flange decked a few k's.

[DieselSpider]

I like it an would like to do something similar to the Turbo Diesel in mine. The prior owner who did the Diesel conversion did not follow the exhaust tunnel very well and put a bolt through the trunk floor instead of attaching the OEM Fiat hanger to the Diesel muffler so there are a lot of rattles and buzzing coming from the exhaust where he made up a Rube Goldberg series of connecting pipes.

Is there a good pictorial that shows how the factory exhaust exited the engine bay and originally wound its way to the tail pipe showing the hangers in-between? I am presuming that the front pipe exits under the front frame inside the wheel well. The Diesel is a SOHC Isuzu 4FB1 1.8L engine with a flow through head having the intake on the right and exhaust on the left so the front pipe crosses under the engine and comes short of the tunnel becoming a real hodgepodge from there.

[ClarkTheShark]

Is there a good pictorial that shows how the factory exhaust exited the engine bay and originally wound its way to the tail pipe showing the hangers in-between?

Not aware of a pictorial. But my car has a nice aluminum shield that runs the length of the cab. the pipe is meant to ride right close to that tunnel.

I am presuming that the front pipe exits under the front frame inside the wheel well.

The pipe exits down towards the back of the oil pan/transmission. then takes a turn towards the back of the wheel well to meet up with the previous mentioned tunnel. check the video for a little illustration. Because the headers I designed have a bigger secondary pipe diameter, the factory "routing" had to be slightly changed as the pipe exited the engine bay. not much though.

exhaust on the left so the front pipe crosses under the engine and comes short of the tunnel becoming a real hodgepodge from there.

Left hand exhaust manifold is fine. You may have issues with the larger steering unit on the driver side. But f you are going to make custom headers, you can get around just about anything.

What I would do is remove the tunnel that the fiat factory installed and fabricate my own aluminum tunnel on the left side. The exhaust would switch over to right side over the chunk at the rear end - you have plenty of room.