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Old 04-06-2015   #1
XfireZ51
 
Join Date: May 2007
Location: Chicagoland, IL
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Default Possible help on exhaust drone?

Installing C6Z brakes pretty much makes the stock ZR spare tire worthless. So my spare tire carrier was removed to lower some weight. Didn't have much to do for winter projects, but I thought about a way of reducing exhaust noise intrusion into the hatch area. My hypothesis is that with the tire carrier removed, the hatch floor is pretty much exposed to road and exhaust noise causing a bit of a boomines at certain engine rpms. So I decided to "repurpose" the tire carrier
and bolted it back on, but now rather than holding the spare tire, I'm using layers of fiberglass insulation to soak up resonance that would make its way into the hatch area from underneath. Took the ZR out yesterday for a test drive and doing some datalogging checking results of new Injector Bias values.
Just to refresh everyone, my exhaust has no resonator but it does have an
SW Xpipe after the Watson headers. I do have DynaMax 3" inlet UltraFlows w Z06 exhaust valves and tips installed controlled by a console rocker switch.
I was actually able to drive with the exhaust valves open at cruise without noticing they were open. What I heard was a "purr" coming from around the back of the car and not through the hatch area. At idle, you will hear the exhaust in the cabin but it's mostly the bass note. At cruise, it reminded me of the exhaust note I got w the MagnaFlow cat back system installed, which I liked quite a bit.
Be interesting to have someone else try this and see what their results are like especially if you still keep your spare in the tire carrier.
For now, I'm going to keep running around like this and see if I continue to like it. First impression is that it really helps.
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Old 04-06-2015   #2
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Default Re: Possible help on exhaust drone?

Don't let it get wet!

Last edited by BigJohn; 04-06-2015 at 10:49 AM.
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Old 04-06-2015   #3
XfireZ51
 
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Default Re: Possible help on exhaust drone?

Quote:
Originally Posted by BigJohn View Post
Don't let it get wet!
John,

It's in a heavy duty garbage bag that I'll be sealing w duct tape.
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Old 04-06-2015   #4
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Default Re: Possible help on exhaust drone?

Cool!
Did you get my dues yet?
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Old 04-06-2015   #5
XfireZ51
 
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Default Re: Possible help on exhaust drone?

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Originally Posted by BigJohn View Post
Cool!
Did you get my dues yet?
John,

I have a pic of your Membership Renewal and see you paid by check. However, our Treasurer, Dennis would have gotten that.
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Old 04-06-2015   #6
Paul Workman
 
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Default Re: Possible help on exhaust drone?

INTERESTING!!!
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Old 04-11-2015   #7
XfireZ51
 
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Default Re: Possible help on exhaust drone?

Guys,

Been driving around w the fiberglass in the spare carrier and so far I'm giving it a thumbs up. It's definitely worth a try. The drone, even at 1200rpm in 6th, is very much reduced. Actually, it's more like the boominess is gone. Of course, I don't have a spare tire in my carrier, so I am able to use about 5 layers of the insulation. A roll cost me $9 at HDepot. You may want to try a layer or two below and above the spare if you have one.
I'd be interested in hearing how it works for someone else. But I would encourage u to give it a shot. It's cheap enough.
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Old 04-12-2015   #8
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Default Re: Possible help on exhaust drone?

Do you put the insulation in a plastic bag to prevent from water saturation.
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Old 04-12-2015   #9
XfireZ51
 
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Default Re: Possible help on exhaust drone?

Quote:
Originally Posted by nelson007 View Post
Do you put the insulation in a plastic bag to prevent from water saturation.
Nelson007
Yes it's in a black heavy duty garbage bag and sealing it w duct tape.
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