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3rd Cat Bypass Flex Pipe

Thanks to Randy Smith:

Stock design:  3rd cat and flex pipe.

Well, I finally got my bypass pipe on yesterday.  Mine is one of the early birds that Vadim replaced.  I was able to acquire it from one of the early bird buyers (thanks Jim!)  Anyway, I had the flange holes turned into slots on the end mill at work.  Got home from the drags (didn't run my car) Sunday and decided to put the pipe on Monday.

Removing the 4-15mm bolts to remove the old pipe wasn't as bad as I had suspected (I hate exhaust work!)  Getting the back of the cat out of the rest of the exhaust was the first challenge.  We just took a heavy 1" pipe and kept wacking the front flange on the cat (not the flex section) until it would wiggle off.  Then I pulled the new pipe out and held it in place.  Too long.  Got a new blade in the hack saw and cut it in no time.  Under the car again, no dice, the bypass pipe wouldn't go inside the rest of the exhaust, and was just a little too small to go outside it.  So we had some special tool to re-round exhaust pipes that just happened to be the right size.  So we opened the pipe up as far as that tool would go and proceeded to strip the threads on the tool.  Doh.  Still wouldn't quite go on.  We started filing away at both pipes and then my dad thought about a little "piston" that he had.  Luck was on our side again, perfect fit!  So, using out fine tuning hammer (read, BMF!) we opened the pipe up until I could get it on far enough to get a clamp over it. Oh, before I bolted the front up again, I fired up the car just to hear the sweet V8 uncorked.  It sounds quite healthy, though probably a bit too raspy to drive around.  So I bolted the new pipe in place, made sure my alignment was good to avoid leaks.  Reset the battery and fire the beast up!

Before, I could hear the V8 if I got down on my hands and knees behind the car.  Now I can hear it nicely just standing behind the car.  On the road, I can hear the exhaust a bit more in the low revs, and at higher revs (read, with secondaries flowing) it takes a bit away from the intake side and lets you hear the exhaust a bit.  As for performance, it's hard to say it made a huge improvement, but I can notice a difference.  I still can't spin the sticky rubber from a stop, but I can get it to slip now!  All in all it was pretty easy and the results were good.  I plan to get the car at the strip either with the Great Lakes folks down at Milan with friends, or in late October down in Norwalk, Ohio.  I was turning 15.5 or so on the G-Tech with just the K&N.  We'll see how I do now.



SHO Shop's bypass flex pipe!
After the install
Again after the install

 Update - My SHO Shop Bypass Pipe developed a crack which became a leak after less than two years of use. I had to replace it. I hoped it would last as long as the car because it is stainless steel. Those with Bypass Pipes - from any source may do well to inspect them on a regular basis.

 Tim Wright  12/24/00

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