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Installed the Gibson today

3172 Views 4 Replies 2 Participants Last post by  roostfactor
This afternoon I installed the Gibson SS single side exit system on my Armada. I haven't driven it enough to get any performace impressions but I will rate the system, 1-10 with 10 being the best.

All necessary parts included - 10
Quality of parts - 9
Quality of instructions - 7
Ease of installation - 8
Fit and clearance - 7

I will attempt to explain how I arrived at these ratings.
The big problem was that the overall length of the system is to short. There needs to be about 1 1/2" added to the length of the resonator, the muffler or the front end of the tail pipe. If I slid the resonator all the way on the Y pipe, and the muffler all the way on the resonater then the tail pipe would hit the splash guard on the rear fender well. I had to assemble the system with just about 1 1/4" lap at each joint; the lap should be at least the diameter of the pipe (3") to make a good seal.
Also the tail pipe needs a little design change. It comes too close to the spare tire, only about 1/2" clearance. If you try to rotate the muffler to get more clearance from the spare (the inlet and outlet are off center) it then is too close to the floor or chassis parts.
The end of the resonator that connects to the Y pipe is expanded too much; it fits loose and there is no way the clamps furnished will tighten this joint. I tightened the clamp until it was bending and deforming, but it would not make a tight joint. I will buy a heavy duty clamp and see if it will do the job.
Overall the system looks good. Good welds, bends and the tip clamps on very secure. I will report back on sound and performance after driving more.
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Gibson system driving impressions

I have driven about 500 miles since I installed the Gibson system. Most of this distance has been highway driving. I went on a trip this weekend, 224 miles each direction. I make this trip every month, driving the exact same route and setting my cruise at 75 MPH. Over 100 miles of the 224 are on Interstate 10, with no stopping and staying on the cruise. I always have about 500 pounds of cargo.
My Armada is a SE, Big Tow two wheel drive. The only mods are the Gibson system and a K&N drop in filter.
Without the Gibson (with K&N) I always get 15.3 - 15.8 MPG. On this trip with the Gibson I got 16.27 on the way there and 15.67 on the way back. I don't think this slight increase proves anything yet; I need more data. I will be making another similar trip in two weeks.
I did notice a increase in throttle response and acceleration. Normal starts seem to require less throttle and there was a improvement in passing on the highway. I had to use less throttle to pass and the transmission didn't downshift as much.
Sound level is not much different from stock except there is a drone from about 45 - 60. The sound level at 70-75 MPH is no louder than stock. Reving the engine and accelerating produces quite a bit more sound than stock. I will try to get some sound clips.
Overall I am pleased with the Gibson system. Does the possible increase in fuel mileage and power justify the cost? Probably not, but what's that got to do with it. We boys got to have our toys!
If you are looking for a quality exhaust system that does give a performace increase in the lower RPM range (where we really use it) I think you will be pleased with the Gibson single system. :)
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I have now driven about 2,000 miles with the Gibson system. There has been no increase (or decrease) in mileage, but there is an increase in performance. Off idle response is better, and passing on the highway is much better. I have had no problems with leaks or rattles. Sound levels at idle and acceleration are higher, but it is a good sound. I have no raspy sound when accelerating hard. There is a little drone from 45 to 65 MPH, but crusing at 70 up is quite; possibly a little louder than stock. At 80 I can't hear the exhaust at all. If I was starting over with a aftermarket system the Gibson would still be my choice.
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