Gibson On the Way

The Gas and Diesel Engines - VQ40De, VK56DE, YD25DDTi, V9X, Transmission, Transfer Case, Oil, Differentials, Axles, Exhaust...

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bender031
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Postby bender031 » Thu Apr 19, 2007 10:06 am

Yeah the gibson comes with a new Y-pipe (much needed) it is a full 2 1/2" system the whole way back, all mandrel bent, no terrible kinks like the stock system, gibson muffler is LONG...i think that helps keep the low mellow tone.


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RacerZX
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Postby RacerZX » Thu Apr 19, 2007 11:58 am

Does the muffler hang down below the frame rails?

bender031
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Postby bender031 » Thu Apr 19, 2007 12:40 pm

Maybe a little less than an inch, however it is not lower than the skid plates (OR model) in fairness, the tailpipe is more prone to damage than stock because it comes straight out the back and not slanted down, the stock tailpipe was tucked up under pretty good.

it was cold and rainy here, so i havent had much of a chance to get a good look...i will try to get some pics and vid up eventually.

bender031
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Postby bender031 » Wed Apr 25, 2007 10:38 am

Forgot to mention Mileage. I had reset my MPG computer for the first time in over a year (the last year's average mpg was 14.2) And i traveled about 160 miles on my trip. about 60 miles of back mountain roads and 100 on the pa turnpike. upon arrival at my destination, my MPG computer read 19.9 mpg...I think that is definitely up from what i used to get on similar trips.

Note- i run 87 octane, use mobil 1 synthetic, have an injen intake and bridgestone revo tires (265x75x16) in addition to the gibson.

On the return trip it was 18.9 with ac on and moon roof open.

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blink32
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Postby blink32 » Wed Apr 25, 2007 10:53 am

@ what speed did you get those numbers? I lost my inet connection at home but have been meaning to post that I was able to squeek out a 20.5mpg avg @ 65-66mph over a 3hr 45min trip to connecticut. 285/70R17's @ 46psi, gibson, Nismo intake, OME lift and Yakima rack removed.

Oh, and congrats on the smooth install.

bender031
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Postby bender031 » Wed Apr 25, 2007 12:02 pm

the backroad mountain roads were approx 50-60mph...the turnpike was cruise control at about 72mph. i have found that about 50-55 gets me my best mileage, but on the turnpike that isnt realistic.

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blink32
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Postby blink32 » Wed Apr 25, 2007 9:37 pm

bender031 wrote: i have found that about 50-55 gets me my best mileage, but on the turnpike that isnt realistic.
Tell me about it, 65 on the TP is practically standing still. But amazingly enough I was still passing people :-O .

bender031
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Postby bender031 » Tue May 15, 2007 12:18 pm

Any of you guys with the gibson have any squeeks or rattles still? i have a couple.
1) low rpm with load i get a metallic squeek

2) occasionally while stopped at a stop sign/stop light in drive i get a bad rattle/vibration

the system doesnt seem to be in contact with anything and i checked the joints to see if anything was loose...nothing obvious is causing the noise...

Any solutions?

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Postby Triffid » Tue May 15, 2007 4:24 pm

bender031 wrote:Any of you guys with the gibson have any squeeks or rattles still? i have a couple.
1) low rpm with load i get a metallic squeek

2) occasionally while stopped at a stop sign/stop light in drive i get a bad rattle/vibration

the system doesnt seem to be in contact with anything and i checked the joints to see if anything was loose...nothing obvious is causing the noise...

Any solutions?
I modified and re-installed the "damper" that was on the stock system also the ground straps??... I have not had this problem........ Triffid

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blink32
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Postby blink32 » Tue May 15, 2007 5:38 pm

bender031 wrote: 1) low rpm with load i get a metallic squeek

2) occasionally while stopped at a stop sign/stop light in drive i get a bad rattle/vibration
How much clearance between the rear Xmember and the exhaust do you have? If not much try putting a little marking compound (i use some lipstick i found in a beater car I bought once) and slather on top of the xmember and see if after driving it left a mark on the pipe. Other than that the only place I could think of that would make that noise is the muffler wasn't rotated properly and its hitting a heat shield or maybe the installers knocked a shield loose?

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blink32
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Postby blink32 » Tue May 15, 2007 5:41 pm

Triffid wrote: I modified and re-installed the "damper"
Triff,

what part was that? I don't remember seeing anything I could remotely call a damper on my exhaust and after going through the pictures I took of what I removed I don't see anything there either.

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Postby ralphwiggums » Wed May 16, 2007 12:27 am

i installed the Gibson cat-back about 4 months ago and have actually been pretty disappointed with it.

definetly noisier - noisy enough that it makes calls on my headset difficult.

once it heats up, there's definitely rattles and knocks. the pipe that transitions over the rear axle knocks on the axle - very hard to deal with this because the stock pipe is 'crushed' in that area to give clearance. The Gibson is not crushed and that area is very very tight for clearance. Also it's not a fully stainless cat-back system. unfortunately with the clearance issue, Gibson should probably have make a slightly oval pipe in that area. even when the pipe 'just' barely touches the axle, the rattling is very annoying and kind of makes you feel like you're driving a cheap beater.

all in all I think my intake made more of a performance improvement than the exhaust.

I'm going to look into the Stillen supercharger towards the end of the year - would like to find out if the transmission can handle that power and what the fuel mileage and maintenace will end up like.

bender031
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Postby bender031 » Wed May 16, 2007 5:35 am

blink- i think i have the answer to your damper Q. with the 05's we did not have the second large muffler/resonator near the tip (as i have seen in your pictures of your stock system. The 05's had a small in-line resonator and a 'damper' that was attached near the tip to control vibration etc...

I had discovered the difference when comparing my stock system to your pictures when preparing to purchase the gibson. i think they may have done this to lower the sound of the stock system as mine was particularly loud compared to other pathy's (prob 06+)

the rattle i have could be from the rear cross-member, however the squeek i get seems like it has to be from a joint or internal to the system itself as it only happens at around 1500 rpm and under load...

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blink32
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Postby blink32 » Wed May 16, 2007 6:50 am

Ahh, good point about the mufflers.

I would have had a rattle but to avoid it when I installed my system I used a piece of aluminum sign, bent it and ground it down to fit directly below where the tail pipe would rub on the xmember. Then I epoxied it to the top of the xmember filling the small gap forcing the pipe to slide on it. I figure it would wear out this smooth piece of scrap before rubbing through the tail pipe or the xmember.

That squeeking sound, is it a metallic squeaking or like the squeaking you get from an un-greased bushing?

bender031
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Postby bender031 » Wed May 16, 2007 7:28 am

more of a metallic squeek like a pipe joint is moving and rubbing on itself, without getting too crazy i did check all the fittings and they were all very tight....sounds as though it resonates through the pipe and out the back which leads me to believe it is the system itself.

another way to describe the noise would be a bird chirp noise...does that ring any bells? have any ideas?


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