New muffler

[brackie1]

As mark recommended I have installed a flowmaster hp-2. I was surprised at the sound. I was expecting a somewhat high pitched sounded, but instead it produces a somewhat deep throaty sound. You can feel a slight vibration in the seat as you drive. It does produce a slight drone but not objectionable. It may be my imagination but it seems as though the old spider has a little bit more pep. I like it. It is not as wide so brackets will have to be made.

[michaelj]

Gene, were you going from the stock set up to the flowmaster? I modified my engine quite a bit and have been running it for about a year now. Runs great, but i get the feeliing it could do more. The other day i swung it into a local shop and had him put it on a lift to find a bumping noise. Turned out to be the idler arm was worn out. But while it was up there i started to eyeball the exhaust. The guy said it looked like inch and a quarter pipe. Seems small, but these are small engines I guess. Then he noted that coming out of the center muffler going to the rear muffler, that pipe was 1". It has to be a chokepoint.

That being said, I was wondering why you change the muffler, was your engine modified at all, and did you feel a difference in performance. I have higher compression ratio, bigger valves, hotter cams, lightened flywheel (best money spend right there!), electronic ignition. She runs great and i am thinking of dual carbs. BUt a 1" pipe sounds restrictive.

Mike

[brackie1]

Sorry for the delay in responding to you mike. I changed mine to get a less restricted flow thru the exhaust system. I honestly think it runs better certainly sounds better. My mechanic had to do some modification to the exhaust pipe going into the new muffler due to big difference in size, but wasn't that hard.

[chrisg]

so, you are talking about that muffler at the end of a stock system?

[brackie1]

Yes

[chrisg]

Many years ago, I used a 2" dynomax at the end of a 2" system I put together myself (at the end of a 4-1 header) and it flowed nicely & though loud it was an appropriate Italian sports car exhaust note. That particular setup was high RPM -friendly. Putting a nicer muffler after the more-or-less stock system I would think would have little actual VE benefit, though I'm sure sounds better.

[phaetn]

Putting a nicer muffler after the more-or-less stock system I would think would have little actual VE benefit, though I'm sure sounds better.

As an epistemology teacher I can't help but pointing out that perception = reality. If it sounds louder, and that's something you like (i.e. it's better) then, ipso facto, the car is faster.

Same thing with a new paint job. Forget drag co-coefficients, if it's a colour that turns your crank then it just goes more quickly.

Cheers,
phaetn

[brackie1]

So true. A recently washed car also drives better.

[chrisg]

You are correct. I have a wonderful was-NOS Abarth downpipe back system on my '71 (which you likely inadvertently heard at FFO last summer) that I'm most certain does not flow any better than an uncompromised stock system but sounds so nice.