EXHAUST (COMPLETED: 08/23/2005)

My manifold pipes were about to fall apart, so I got headers and progressively replaced the rest of the exhaust line with 2 1/2" diam. piping to allow greater exhaust gas evacuation, and support future modifications to the intake. The general consensus of those folks that I've spoken with is that 2 1/2" diam. exhaust pipe is the largest that should go on a normally aspirated MX-6 V6 engine. Most MX-6 turbo or super charge mods I've heard of are using from 2 1/2" to 3" diam pipe.

Random Technology Catalytic Converter

Installation time: 10 minutes. Perfect fit!

This is a high flow converter. The direct fit replacement part for the MX-6 (#822233) is 2 1/4" diam., but will restrict flow with the new 2 1/2" diam. headers. Luckily Random Technology also has a converter made for a Toyota pick-up (#822537) that is exactly the same length as the stock MX-6 converter, but with 2 1/2" diam. front and rear flange openings needed to mate with the custom header and new cat-back.

Bosal/Brospeed Cat-Back - Stainless steel, 2 1/2" diam.

Installation time: 20 minutes. Again, a perfect fit! I had been warned about the need to tweak a few bends, but fortunately that was not necessary at all. These parts slipped right in like they were there all along.

Had a pretty impressive improvement in HP and torque as shown in the dyno run... just from the addition of the cat and cat-backs alone!

Part #112-201. Purchased from SFX Performance Parts at a reasonable price. Unlike the Bosal headers I previously ordered from NOPI, these parts we're properly wrapped in several layers of bubble wrap and arrived in great condition, despite the fact that the box UPS delivered it in was practically shredded.

And, despite my previous disgust with the Bosal headers (see below), the consensus by buyers and sellers alike is that Bosal makes the best performing cat-backs... that is, for folks who like a quiet exhaust sound. And these are very quiet. During the dyno run, I stood behind the car next to the pipes, and at idle the exhaust was barely a whisper and they had a tight burble like (dare I say) a Ferrari when under heavy acceleration. They're almost unnoticable at highway speed.

SSAutochrome Headers - Stainless steel, 2 1/2" diam. exit.

I had bought new Bosal headers at a great sale price from NOPI Online, however, I was extremely dissatisified with the product I was sent. Click here to read about it on my thread at MX-6.com (you'll have to drill down into the thread a bit to find my post). I don't know if it was just poor manufacturing or if the distributor was sending me a "new" set of used headers that were dressed up, or both. Either way, they both got a lengthy letter of complaint with plenty of pictures.

After starting but unsuccessfully completing a custom header project, I got tired of waiting and finally decided to purchase headers directly from SSAutochrome in Creedmoor, North Carolina. These headers are often referred to as knock-offs of the headers from HotShot, which I had also considered buying due to their reputation. But the headers from SSAutochrome are made of stainless, instead of the mild steel that HotShot uses, and they are light-years better quality than the Bosal headers that I returned. Note that these headers came with the "XSPower" label attached. I'm not sure why...

Installation time: 8 God awful hours... working in tight spaces at odd angles, at the peak of mosquito feeding hour in my garage. And for all my scrathes, cuts, and mosquito bites, I still had to take it to a muffler shop.

There were two minor (but nonetheless frustrating) misalignments in the Y-pipe:
1) The rear down pipe flanges were radially misaligned and would only let me drop a bolt in 2 of the 3 bolt holes.
2) The Y-pipe was about 3/4" longer than the OEM Y-pipe, pushing the rest of my exhaust back and jacking it all out of whack.

And there was one major problem... the new EGR line. It was too short. No ifs, ands, or buts. The local muffler shop had to add a couple of inches and rebend it to reach and align with the connection on the back of the engine block. Happily, they did a damn fine job of fixing all these problems.

Even more happily, the manager at SSAutochrome offered to refund my entire purchase cost in trade for a few pictures of the headers in my car! How sweet is that?! I got the Jesse James price... Zero, zip, NADAAAA!!! 

Click here to see the dyno run results from this upgrade.

DENSO Oxygen Sensors - OEM type. 

These were installed with the new headers. $51 each from Sparkplugs.com. The '93 MX-6 year model does not use the pre-catalytic converters, so it only has two sensors vice four; one on each down pipe just below the manifolds.

And there it is.... my exhaust modifications are complete!