I had my exhaust guy remove the resonator and it sounded great but there was too much flow causing the exhaust valves to rattle. He then put a hook on both the valves that left them open for a couple of days to see how it ran, well my MPG cut in half, and I had lost a lot of low end power, felt like a complete slug. Not worth it at all! So I went back they made the valves go back to normal and put the resonator back in place, all is well now getting normal MPG and great off the line acceleration and low end TQ once again.
Do not have your shop keep the valves open as you will eat a lot more gas and lose a lot of low end!
Mlarco...
Doubling your MPG means you get better fuel economy. MPG getting halved, means you lose miles per gallon.
I'm not trying to pick on anything, but I got excited to see you DOUBLED your MPG by cutting out resonators and thought that was one hell of a MOD.. LOL..
I'm curious if a tune would fix, but since that's in never never land, we'll have to wait for that answer just a bit longer.
Hey thanks Dotcom, however, I stood corrected, as I edited my earlier post I did make the mistake first with saying double. Only because I'm in Canada and we use L/100km and for my truck it read that the L/100km had nearly doubled so I mixed up the wording.
Did you think of maybe putting higher flowing resonators in place of the stock ones? That might still create enough resistance to keep the valves from rattling. Just a thought.
Hey no I don't have any videos I had one but my other computer got completely trashed and now its all back to stock, there was however, a lot of rasp at higher rpms and some popping. It sounded annoying to be honest at high rpm's, at low rpm's it sounded awesome but that didn't make up for the loss of power in my books.
Yes I did think of this but I didn't want to drop 1k on the higher flowing reso's with other stuff in place, what would be needed to stop the rattling is some reso's with a good amount of baffling inside and a x-pipe for sure and even possibly some larger piping up to the valves. This would cost a lot more for just a tad bit more noise, not something I want to waste my money on.
I have to say guys that the amount of overlap from system to system in the 2012 is MUCH MUCH worse then the WK1...In the WK2 you change one thing like the exhaust and it affects 10 other things.....Im very leary about just hanging parts on my 12 till I find out a lot more about overlap....
How does it not make any sense? I saw it with my own eyes as they cut and welded everything. The resonator provided a good deal of back pressure as the air had to go through the baffles and what not inside the reso itself. With it removed that extra flow from the reduced back pressure pushed through to the valves which are a couple of feet at most behind the resonators and they were attempting to open and close all the time rather than stay closed or open (as you accelerate faster), thus causing them to open and close and hit against the metal inside which made it rattle. Think about hitting a spoon against a small hollow pipe, that's sort of how it was as it just sat there in idle, I also saw the valves opening and closing slightly due to the increased flow from removing the resonator they were clapping making that noise, metal on metal.
Location is towards the end of the exhaust system near the rear mufflers (about 1 foot before the rear mufflers and exhaust tips). Their purpose is to open as more acceleration is applied and to release more pressure that way, and close up a certain amount when less acceleration is applied thus creating more back pressure. They are also used for the ECO mode and stay closed a certain portion when ECO mode is active in order to preserve back pressure that allows the vehicle to keep sufficient power in order to run on 4 cylinders and kick back into 8 cylinder mode as soon as it is ordered to.
Actually I'm sure its just a matter of coming out with a system that takes the stock valves into account and considers either replacing them with very similar setup just more hollowed out mufflers for a better sound. My 2012 seemed to have gotten a tad bit louder as I put more km's on it however I do understand its still not very loud. I however am happy with it because I'm no longer into driving a extremely loud daily driver.
I would hope that a good aftermarket cat-back would have more noise AND cooler exhaust tips that will be as attractive as the old center-mounted set-up.
While I do agree that there is tons of overlap on these vehicles, i have to disagree with not doing exhaust work. I've had the Corsa kit on mine for years and love it! it sounds unbelievable under acceleration and I've never had any issues with ECO, or even MPG. MPG stayed relatively unchanged, if anything it got slightly better. Once we got the shape of the mufflers just right (the first set from Corsa didn't fit well), it was amazing. I installed the kit and had my favorite muffler shop in Denver tack a few welds in just to be safe (don't trust clips).
I'd say my exhaust sound under acceleration rivals that of Cayenne's, but yet under light acceleration it's pleasant in the cabin. Maybe the difference here is that I wasn't just doing pieces, I did the entire catback all at once.
Why don't you just buy something like the Borla ATAK? I've had one since new and it sounds fabulous at wot, and the cabin is quiet at cruising speed. Love it!
Lol wow old thread back to life...I went with a Borla atak last year sounds incredible and the tips look much better than the goofy factory shrek ears.
I think some people might be confused, I originally thought you were talking about the engines exhaust valves in the heads.....not some butterfly valves in the exhaust pipes
Sure I'm going to sound like a dick but someone needs to say it. If you are driving a WK2 and cannot afford to easily purchase one of the numerous incredibly affordable exhausts for it, perhaps you should buy something different. I cringe when I see the cost cutting, ghetto rigged, things people do to these.
Go out and buy a real exhaust! You can get a Borla for $650 shipped, keep your valves, and lose absolutely no power.
Actually cost does have something to do with the SRT and exhausts. There has been no real evidence that full exhausts and such are giving major changes to horsepower and torque in the SRT. Very little real world Dyno figures from before and after. It's more to do with cosmetics and how they sound....
I wanted a GTHaus system for my jeep, but at nearly 5k here in Australia, that's a shitload of coin for very little gain. I went with a set of Mufflex Mufflers for 10% of the GTHaus system delivered to Oz. The other money has now been put to use upgrading the suspension and a SC which will both provide better value for money well and truly in the end, compared to a pretty sounding expensive exhaust system. Just my 2cents.
But when u mash it and the guy next to you cant hear his engine hitting rev limiter is priceless.... You have no idea the looks on there faces :lol::lol::lol::lol::lol: ive done it too mates and a Lamborghini gallardo last week. Never let a Jeep SRT with GT Haus pull away from you or sit behind it at the lights as they punch it, the sound is deafening...
I almost became deaf on weekend when I decided to go thru enclosed sandstone tunnel out from Woolloomooloo with the windows down :lol::lol::thumbsup:
The mufflex system is a good system, keeps most of the factory system, gives a nice boost in sound output, easily installed, and very cost effective,... Whats not to like, and $300.... Is far better than double that or more.... Oh yea, no drone also��....
I've removed the resonators and kept the original Shrek ear tips and don't have this problem at all. Looks factory. The sound is much better at all ends. The grumble when I slow down and the growl at WOT is quite satisfying. I've never experienced the rattling of valves and my fuel economy has improved, however slightly.
Performance is the same if not better. More responsive all over. I haven't done an 'official' 0-100 but my last was before the mod at 4.3 secs so I hope to shave at least a tiny bit off of that. I do get a bit of a fart at WOT but I reckon that's because the exhaust just isn't large enough to accommodate all of the exhaust gas in such a short amount of time.
I tend to drive in Sport mod most of the time, maybe that has something to do with it because the valves are never engaged.
Just an opinion, if I'm not wrong, the valves in the exhaust system are just butterfly valves operating by nothing but spring tension, so driving mode makes absolutly no difference as they work solely by force of the exiting exhaust pressure against them... More pressure more opening, less preasure less opening..... The greater the acceleration or rpm the more pressure
created by the engine exhaust..... During deceleration, less exhaust preasure is created so the valves close more as there is less pressure to over come their spring tension..... These exhaust system valves are not connected either electricly, or mechanically to any other system components, they are totally independant and operate solely from existing exhaust system pressures
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