Gibson Cat-back Exhaust Quickie Review

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RacerZX
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Gibson Cat-back Exhaust Quickie Review

Postby RacerZX » Tue Aug 21, 2007 11:09 am

Hardware: Nice mandrel bends, well crafted y-pipe, 3" from the cats all the way back past the muffler where it necks down to 2.5".

Install: Kinda a PITA, slip fits on each side of the asymmetrical muffler makes it a bear to properly align.

Sound: It's all resonating bass annoying you at cruise and no thrilling raspy highs when at WOT. Not my taste, though I guess glass-pack aficionados may enjoy it.

Power: Lost 1HP and 4lb-ft of torque at the wheels. Doh. Waiting for an email back from Gibson for "input".


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Postby SHAWNATGERBROCK » Wed Aug 22, 2007 8:55 am

Yea, I kinda like the quiet ..... as for the power loss ... wow .... Mabie the computer has to learn it ?? ..... Curious what it does in a couple weeks ...

One thing I would be curious about ...does it look like the Gibson tail pipe would go onto the stock muffler ?? .... Like if someone wanted to just upgrade the tailpipe .... ?? I was thinking something like using the gibson setup , but with the stock muffler for quietness ....

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Re: Gibson Cat-back Exhaust Quickie Review

Postby blink32 » Wed Aug 22, 2007 9:17 am

RacerZX wrote:Sound: It's all resonating bass annoying you at cruise and no thrilling raspy highs when at WOT. Not my taste, though I guess glass-pack aficionados may enjoy it.
You still have the stock intake and the supercharger correct? I don't hear the resonating bass at my cruise (typically 50-65mph) but I do get it when slowly accelerating in the sweet spots. Oh, and was this before or after the BFG upgrade?

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Postby RacerZX » Wed Aug 22, 2007 10:14 am

I went out and did a g-tech 1/4th mile run late last night, and then disconnected the battery. Will follow up again tonight and see if the ECU reset made any difference. Still no response from Gibson, I may have to give them a call. Their website has vauge claims about HP gains, but nothing hard, no dyno charts or antyhing, so I'm starting to think snake oil.

Only other power mod is the supercharger, still running OEM Nissan paper intake filter. All testing is being done with my 33" BFGs, so that's all consistant.

The Gibson muffler is 3" in and out, while the stock muff is more like 2". Anything can be made to fit of course, but it wouldn't be ideal.

The drone isn't massive, just having the radio on a bit loud will mostly mask it, but it is always there when I'm on the gas at all and the RPMs are under 3K, it would bug me on a long road trip. I need to climb back under there to double check there's no touching against the body anywhere, but I spent hours being quite anal about the angle of the muffler and it's slip fits to get it aligned just right so that's a long shot at best.

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Postby mtbpath » Wed Aug 22, 2007 1:46 pm

so if there is a potential power loss, is that due to a larger size muffler and 3" in/out outlets?

maybe the pipe that has the tight bend under the drivers side was to help create more lowend power.

I am still planning on doing an exhaust system, I'm just going add a Magnaflow with a dual in and dual out. maybe single.

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Postby RacerZX » Wed Aug 22, 2007 2:22 pm

It's possible to go with too large a tubing diameter in hopes of reducing back pressure and therefore improving flow rate, but what you actually end up doing is reducing flow velocity & intertia which can screw things up. I've seen it before on 350Z exhaust systems when the magazine did a big dyno tested shootout, some of the systems gave no or less power.

The truck feels nice and peppy today after the ECU reset, but it may easily be wishful thinking, I'll see tonight.

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Postby blink32 » Wed Aug 22, 2007 4:23 pm

I did a little test earlier on the way to see Super Bad and there is a drone around 2500rpm but 2200-1500 is very quiet on mine. Nothing like vehicles I've driven with 'packs.

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ralphwiggums
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Postby ralphwiggums » Wed Aug 22, 2007 6:40 pm

i wasn't really happy at all with my Gibson.
was a PITA to install, if you don't get it EXACTLY aligned correctly going over the rear cross member, it will either chatter on the member or if it's up too high, hit on a bolt from the seat.

i don't know if it's just my setup, but when you close the doors, you can hear a tinny sound from the exhaust and anything over 2500rpm starts to get annoying when you are talking to passengers.

then again...there's nothing else available.

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mtbpath
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Postby mtbpath » Wed Aug 22, 2007 7:49 pm

ralphwiggums,

notice your up in Seatlle, Vancouver area.
you ever checked the dealers in Vancouver to see if they can get the rear cargo cover for the 2005+?

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Postby phantom2 » Thu Aug 23, 2007 4:48 am

ralphwiggums wrote:i don't know if it's just my setup, but when you close the doors, you can hear a tinny sound from the exhaust
My exhaust system is stock and I get that same clanky sound when I close my doors,does anyone know what that comes from?

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Postby RacerZX » Thu Aug 23, 2007 8:32 am

In spite of the air temp being 5 degrees cooler, I was .1 seconds slower in a pair of identically simulated 1/4th mile runs last night after resetting the ECU the night before. Sorry guys, this Gibson system is DOA.

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SilverGhost
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Postby SilverGhost » Thu Aug 23, 2007 6:22 pm

RacerZX wrote:Sorry guys, this Gibson system is DOA.
Carl -
You speak with such authority :) Personally, I'm glad you're the team leader here!

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V8Pathy
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Postby V8Pathy » Thu Aug 23, 2007 6:24 pm

OT: SilverGhost, where did you get that rubber mat for your trunk ?
dealership ?

thanks

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Postby SilverGhost » Thu Aug 23, 2007 6:35 pm

V8Pathy wrote:OT: SilverGhost, where did you get that rubber mat for your trunk ?
dealership ?

thanks
Nope . . . it's a Weathertech. I'll PM you with the info. I can't remember at the moment where I got it, so I'll have to check my records. It's nice, but kinda pricey.

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ralphwiggums
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Postby ralphwiggums » Sun Aug 26, 2007 9:53 pm

MTBPATH--> no, that cargo cover is a mystery. no one in this area has it on their list. friggin NISSAN, the put knock outs and notches for it and every other one of their SUVs has a cover.


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