Quote:
Originally Posted by siggyfreud
Where does the exhaust exit? Is it a clamped or welded system?
Moving the exits as far back as possible will help. Welding up unnecessary clamped joints (keep enough to remove it easily though) will also help.
Short to long headers won't do anything IMO.
Something like dynamat + dynapad will help a lot.
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The exhaust is all welded except where it meets the headers where it has band clamps, no leaks and exits to the sides just in front of the rear bumper. I installed the Dynamat but haven't test driven it yet.
Quote:
Originally Posted by MARKDTN
Why do you still have cats? I would think you would have had them tuned out of the ECM when you had it done? Stock engine=no need for headers. Stock cast manifolds will be more than adequate for a 4.8 IMHO.
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I had the headers from another vehicle. The engine I got didn't have exhaust manifolds so I decided to use the headers. I agree they don't add much power but they look cool
. I have to run the cats because of environmental laws. If this was a factory stock truck I wouldn't need any smog equipment but it's modified and classed as a hot rod so It has to meet the emission laws at the time it was modified. It has a 2002 GMC engine in it so it has to meet 2002 rules. It also has a closed fuel system and evap cannister. I don't have to smog test it but It has to have the equipment.
Quote:
Originally Posted by Custom 68
I was gonna ask this as well. I kind assumed since you mentioned an exhaust "kit" it didn't just dump. If it doesn't exit somewhere behind he rear tires it will have even more chance to drone. I had mine exit right in front of the rear tire and it had a drone with my magnaflow muffler. I added a resonator it helped. Ultimately I ran it to the rear and that fixed it.
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It doesn't drone, It's just loud. A drone is a low tone but this sounds more like a roaring engine but is't running at 2100 at 70 mph. The sound is difficult to explain. Thanks for all the suggestions, I hope the Dynamat helps.