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2nd H-Pipe farther down "stream"

General engine tech -- Drag Racing to Circle Track

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73c34me
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Location: michigan

2nd H-Pipe farther down "stream"

Post by 73c34me »

Hello,

Current Exhaust on my 385 SBC. on my 73 vette so overall length isn't too bad. Header collectors (3") flow into 3" exhaust pipe for leading 4'. Then by the rear cross member, it tapers down to 2-1/2", which continues through FM super 40s and a short 2-3/3" tail pipe. All bends are mandril. H-Pipe is located up front as near the collectors as possible. 12:1 compression and the system is pretty quiet with no annoying drone. I am thinking of adding another H-pipe farther back, in front of the mufflers. I thought years ago, I read an article that tested this Jim Hand Pontiac Performance?) and there were measurable gains, along with a slight decibel reduction. I have the materials, car lift and equipment. I am I wasting my time? much thanks. Jim
F-BIRD'88
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Re: 2nd H-Pipe farther down "stream"

Post by F-BIRD'88 »

I'd swap the FM mufflers out for a better straight thru purfed pipe design muffler.
More power and less noise.
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Tom68
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Re: 2nd H-Pipe farther down "stream"

Post by Tom68 »

73c34me wrote: Fri Aug 05, 2022 12:25 pm Hello,

Current Exhaust on my 385 SBC. on my 73 vette so overall length isn't too bad. Header collectors (3") flow into 3" exhaust pipe for leading 4'. Then by the rear cross member, it tapers down to 2-1/2", which continues through FM super 40s and a short 2-3/3" tail pipe. All bends are mandril. H-Pipe is located up front as near the collectors as possible. 12:1 compression and the system is pretty quiet with no annoying drone. I am thinking of adding another H-pipe farther back, in front of the mufflers. I thought years ago, I read an article that tested this Jim Hand Pontiac Performance?) and there were measurable gains, along with a slight decibel reduction. I have the materials, car lift and equipment. I am I wasting my time? much thanks. Jim
Could go either way, but the extra volume should at least be a positive.
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