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71 Berlina 74 GTV 17 Giulia Q4
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6,471 Posts
Discussion Starter #1 (Edited)
Made this quick video and even though it was damp I think it speaks well.
 

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Richard Jemison
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7,394 Posts
Muffler? A single chamber Borla mounted 30" from point where the collector goes from two to one.

Length before muffler mentioned is critical per Jim Steck. (30" or 60" no in-between)
 

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Premium Member
71 Berlina 74 GTV 17 Giulia Q4
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6,471 Posts
Discussion Starter #3
Yup, Everybody's got one.
full disclosure- I did replace with a glass pack at the back. I'm also very impressed with the Alfaholics 84.6 pistons. Also had crank and rods balanced. Stock rear drive.
1615579
 

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Premium Member
71 Berlina 74 GTV 17 Giulia Q4
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6,471 Posts
Discussion Starter #6
I appreciate that. The road was more dry than wet so it's not as bad as it looks.
 

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Premium Member
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Length before muffler mentioned is critical per Jim Steck. (30" or 60" no in-between)
That is for high end power. 30" and 45" were the same at 5800 rpm with 30" primaries on the chart that Jim gave me.

To use the muffler to behave like the end of an open pipe it needs to be large and of the chamber type. Borla is a glass pack type which looks like a straight pipe to the acoustic waves. I analyzed my exhaust - Shankle headers and straight thru mufflers and the headers are tuned for 4600 rpm and the complete system is tuned for 5600 rpm. I intend to modify the headers so that the tuned rpms are 6000 and 5600. My peak torque is at 5600 and my peak HP is at 6500 but I don't go over about 7000.

Your car sounds great Mike. What rpm were you shifting at?
 
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