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Exhaust Sound
Hi all got one of pop up messages that reminded me I haven't posted in a while so why don't ask a question or something. Well here it goes.I have a 351w crate motor with what I would describe as a mild cam and not very loud side pipes.When I accelerate It sounds great! When at idle it's disappointing.What Im specifically concerned with is,there is a very distinct puffing sound coming out of one side. What if anything,could it be?
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Thanks Pete
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... I have about the same motor.
And I am not nuts.. but I did put in Synthetic the last time I changed the oil. (have a lot sitting the shelf for another motor that loves it) .. The cobra the motor does NOT like it.. and it smokes. (Yes this sounds nutso.. but i will be changing it back to regular oil) |
I also had a great sound at speed, but a disappointing sound at idle. I also had a huffing or puffing sound, more noticeable on one side. Last winter, I pulled the iron heads off, had them completely rebuilt and put it back together. The mid-range sound is the same, but the sound at idle is much better, even with my mild cam. Trouble was that I had a lot of recession of valve seats and wearing away of the valve faces to where there was almost no margin. New seats and several new valves helped. In the end, I probably could have gotten about the same results for a little more money with new heads, but I wanted to keep the ones I had.
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hard hit at idle is all in the cam and sidepipes.
I installed the Classic Cobra Pack on my Cobra. My small block sounds like a big block. Classic Chambered Exhaust Inc. - Cobra Dwight |
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A lot of cam "and compression" together, will really make your engine hit hard at idle. You may not like some of the other attributes entirely, however. :) |
Yes I forgot about compression.
I think you can run more lobe separation and less compression and still get a hard hit at idle. Best to check with someone who understands cams. I run Comp cam in my 354 (347) Cobra motor with .590 / .595 lift and a lobe separation of 112. Compression 10.67. My stock Ford computer with a piggy back SCT chip makes it all work. 350 rwtq at 2500 rpm great street motor but rough on the rear tires:LOL: Dwight |
Thanks Dwight
Checked out Classic Chambered Exhaust. That's what I need. |
Classic Cobra Pack
With my old side pipes I could be heard a mile and half away when I rev'ed to 6000. Got pics to prove this.
Very loud pipes. I changed to the Cobra Packs but I bought 28" (4" longer) and 3" I.D. My old pipes were 24" x 2 1/2" I.D. I wanted them to breath easy at 6000 but have a good sound at idle. The longer pipe is quieter at idle. Not a tested theory but with 6 or 8 of my Cobra buddies who are around me every week, we all agreed. Sounds like a big block at idle and good mellow sound at 2000 rpm cruising speed. I can talk to my passenger without screaming. Best of everything. I also install a pair on a KC 408 and a KC 427/487. Great sound for Cobra! Dwight you can not see the large chunk of my butt that is missing. He was four blocks away and heard me. No ticket. http://www.clubcobra.com/photopost/d...80DSCN1717.JPG |
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Seems very optimistic? |
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I picked up 80 HP by changing to classic chambered 2 1/2" muffler. I also changed intake manifolds at the same time from a 390 performer to the RPM performer on my 390fe. I dynod before and after and was pleased with results. Classic chamber was great to deal with as well. My stock mufflers were very restrictive.
John |
Looks like I'll be picking up a set of these before summer
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I don't think I picked up 80 or 100 hp maybe 15 or 20. But I'm running a small block and I had 2 1/2" I.D. pipes with equal lenght headers and the correct lenght pipes for my motor / hp. So my HP/TQ gain was smaller.
Dwight |
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Definitely on the list of mods if you can even pick up 20hp, more than that would be icing.
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