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Old 07-13-2012, 02:08 PM
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What's the deal with the half-a$$ SRT exhaust valves???

Some of you might not know there's a valve on each side of the exhaust, right by the differential. How did I find out? Blipped the throttle just to see how the exhaust sounded with the door open, and heard this loud and rapid 'CLAK CLAK' under the truck. WTH? Blipped again and same thing. Awful noise. I knew right there I was dealing with exhaust valves, but never imagined what I found. They're SPRING LOADED. There're no actuators, like on the Vette.

My 2 questions are: Why the hell do we need valves with all those heavy a$$ mufflers under there? Have you seen them? And finally, have any of you found a way to keep them open, for a slightly throatier sound all the time, and most importantly, to avoid all that unflattering metal clanking? By the way, the spring is relatively weak (you can easily turn the valves open with 2 fingers), so it's obviously just for noise control (to meet federal levels, I'd guess), rather than engine tuning purposes. On the Vette, just installed a manual switch and now have the best of both worlds (quiet or loud). And they never make a noise on either setting. Was disappointed about this application. And no, don't want to change the exhaust like I did on the Overland (Corsa)... which sounded incredible, by the way. The SRT sounds really nice, and the tips are part of what makes it look great from the rear. Let's hear your comments.
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Old 07-13-2012, 05:17 PM
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Re: What's the deal with the half-a$$ SRT exhaust valves???

some have removed those valves and immediately had them put back in. Mlarco52 if Im not mistaken.
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Old 07-13-2012, 06:01 PM
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Re: What's the deal with the half-a$$ SRT exhaust valves???

They serve 2 purposes, reduced reversion to help performance when in MDS mode and muffling the horrid sound the engine makes in MDS mode. Remove at your own risk. If you must hear what it sounds like then it's pretty easy to rig a tie wraps to hold them in the open position.

You will not see any performance gain nor any change in the tone of the exhaust at idle or under acceleration.
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Old 07-13-2012, 07:18 PM
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Re: What's the deal with the half-a$$ SRT exhaust valves???

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Originally Posted by mjw930 View Post
They serve 2 purposes, reduced reversion to help performance when in MDS mode and muffling the horrid sound the engine makes in MDS mode. Remove at your own risk.
Never said anything about removing them; just opening them. But thank you for the explanation. I assume 'MDS' is the cylinder deactivation crap, right? No desire to keep them open now, but just wish they were quiet when closing. And no, you cannot keep them open with a ziptie. And even if it was possible, they'd melt right away. I'll just take a closer look to see if I can install a silicon cushion to avoid the clanking if somebody asks to hear the exhaust .

Related question: Why doesn't the 5.7L HEMI have those valves? And why never heard any bad noise after installation of the Corsa exhaust? Sounded awesome on the Overland. Both engines are very similar and have the same cylinder deactivation system, prompted by an 'ECO' dash icon, right? Or is there a difference I'm not aware of? Just curious. Thanks gang.
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Old 07-14-2012, 08:18 AM
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Re: What's the deal with the half-a$$ SRT exhaust valves???

The ECO light is deceiving, it's not an indicator the MDS is active, it simply means you are getting better fuel economy than your calculated average. There's no dash indication for MDS.

I haven't heard the 5.7 with the corsa exhaust so I can't comment but I believe they aren't included on the 5.7 because the exhaust is so quiet it's able to provide the muffling required to defeat the MDS drone.

According to Chrysler "To keep the gas mileage respectable, Jeep has employed a new active exhaust system that lets Chrysler's cylinder-deactivating Fuel Saver Technology operate over a wider rpm band". That, combined with the less restrictive exhaust is probably why the sound is worse on the SRT. It has also been reported that the valves help with the actual performance when it's in MDS mode but I'm too lazy to search that reference.

BTW I used SS tie wraps, no problem melting. I could have wedged something between the lever and the exhaust to hold them open but I didn't want to risk bending anything.
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Old 07-14-2012, 03:43 PM
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Re: What's the deal with the half-a$$ SRT exhaust valves???

Yep I had them opened up with the center suitcase muffler removed, there went my low end and my mpg. Went back to stock after that realized I did not want to drive around with a roaring exhaust anymore.
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Old 07-14-2012, 04:24 PM
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I know you mentioned not changing the exhaust. I just did a Borla ATAK from the rear axel back. Great sounding, no drone, quite in the cabin, and IMO way better looking tips than the stockers.


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Old 09-11-2012, 04:37 PM
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Re: What's the deal with the half-a$$ SRT exhaust valves???

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Originally Posted by Mongoose9400 View Post
I know you mentioned not changing the exhaust. I just did a Borla ATAK from the rear axel back. Great sounding, no drone, quite in the cabin, and IMO way better looking tips than the stockers.
Any pics? And how about a vid? I've bought Borla in the past, and all 3 times they droned like a 'MoFo', so haven't bought again. But if you're saying it drones nothing, then something must have changed. Could you please post the part number to investigate further? Many thanks.
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Old 09-11-2012, 04:40 PM
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Re: What's the deal with the half-a$$ SRT exhaust valves???

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Originally Posted by elp_jc View Post
Any pics? And how about a vid? I've bought Borla in the past, and all 3 times they droned like a 'MoFo', so haven't bought again. But if you're saying it drones nothing, then something must have changed. Could you please post the part number to investigate further? Many thanks.
Start around post 50
http://jeepgarage.org/showthread.php?t=44098&page=5
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Old 09-11-2012, 06:02 PM
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Re: What's the deal with the half-a$$ SRT exhaust valves???

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Originally Posted by Mongoose9400 View Post
Start around post 50
Thanks man. Sounds good. By the way, the xxxx6 system is the less aggressive 'S', and the xxxx7 is the 'ATAK', which you have.

My other concern with Borlas that I forgot was FIT. Tips never centered without using wire or other non-desirable options. Those seem to be 'okay'. That's why I like the stockers, because they don't move at all, therefore can be quite close to the bumper cutouts. The tubes are too visible, but might be a low camera angle. Found this exterior sound clip:

http://borla.com/products/product_de...prod_sku=11827

The tips should have been black chrome on the GC SRT systems IMO. And the inside of the tips scream for black paint, but it's not a big deal. Otherwise the soot would take care of that over time.

Glad to know there's no drone. They sound REALLY GOOD man. A little expensive for what they are, but better than stock. Cutting the stock exhaust is not the best approach, but that's the only way to keep the valves. Plus who keeps the stock exhaust? Not me . Thanks again for the help .
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Old 09-12-2012, 08:48 PM
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Re: What's the deal with the half-a$$ SRT exhaust valves???

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Originally Posted by elp_jc View Post
Any pics? And how about a vid? I've bought Borla in the past, and all 3 times they droned like a 'MoFo', so haven't bought again. But if you're saying it drones nothing, then something must have changed. Could you please post the part number to investigate further? Many thanks.
I can assure you: no drone. See my comments and pics at my thread "My new Borla ATAK"
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Old 09-15-2012, 12:20 AM
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Re: What's the deal with the half-a$$ SRT exhaust valves???

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Originally Posted by BigHemi2 View Post
I can assure you: no drone. See my comments and pics at my thread "My new Borla ATAK"
Hope you're right because just ordered it . By the way, the system is back-ordered even by Borla until October, but found TWO systems at a super price of $699 shipped. Since I just bought one, there's one left folks. Company is MarylandSpeed, and they're an official Borla distributor. Buy my Vette stuff from them; great folks. Hope to make somebody a happy camper .
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