Exhaust system

Now I was ready to address the exhaust system. Originally, I was going to take it to an exhaust shop for this work, but a couple of friends who had made their own exhausts encouraged me to give it a try. And I thank them for that.

I ordered (from Summit of course) a few sections of 2 ¼" exhaust tubing (their thicker gauge to keep the sound down in the car, and to help accommodate my meager welding skills), some J-bends, and a couple of Hooker Aero-chamber mufflers.

This is a low car, so some careful routing of the exhaust was necessary. Bit by bit, I cut each section of pipe at the angle necessary (well, half the angle on each piece), then welded it together. I put some flanges in towards the rear so that the exhaust could be removed piece by piece. I also ran a cross-over pipe (with flange) between the two.

The exhaust system isn't light. Partly because of the thicker tubing I used, and partly because the mufflers are heavy. For those of you interested in weights, the mufflers were 14.7 lbs each, so with these heavy dogs on the end, the entire exhaust system (except the lightweight headers) weighs not quite 57 lbs.

It took me about a week to do the exhaust, but a lot of that was because I was learning along the way. Also I took the time to make calculations about necessary angles and offsets, and then carefully set my power hacksaw to each angle. Experienced folks can mark the angle and cut it on a band-saw freehand, then clean up the ends with a sander. "Next time" will be quicker.

Here's what it looks like, I put a slash cut on the rear extensions. It would probably look better had I used 2 ½" tips rather than 2 ¼" like the rest of the exhaust, but this is honest:

Had I used smaller mufflers placed flat rather than up and down, or round mufflers, I could probably have snaked the fuel filler line between them and the bottom of the car, precluding having the filler topsides.

Here are the headers back from ceramic coating:

You can see the indent in the driver's side pipe to give a little clearance for the steering shaft. In reality, it's not as severe as it looks in the picture. Maybe a quarter inch deep. It was made by heating the pipe with a torch, then holding a piece of pipe against the header at the desired angle and giving it whack with a hammer. Pretty sophisticated! If you buy the pipes new that are ceramic coated (cheaper then having them done later), it's questionable whether you can put this indent into them without damaging the finish.

How does the exhaust work? Well, it's got a nice sort of hyper sound to it that's about the right volume for me (although my wife thinks it's a little loud). No drumming in the interior, and it isn't even very loud from inside the car. All things being equal, I would prefer a little deeper sound, but I don't think you can get that unless you go to glass packs rather than steel-baffled mufflers like these Hookers, then it gets louder over time. I'm satisfied with the exhaust. And it seems to let a lot of power out of the motor as well while still being plenty legal. According to their promotional literature, these mufflers flow 95% as well as a straight pipe, and I can believe it – if you look into the rear tips, you can clearly see the pipes coming from the front of the mufflers. I had used one of these mufflers earlier on a Datsun 510 race car with good results.

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