Is a turndown exhaust louder?

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Hi guys, I'm looking at adding a couple of MPG, switching the entire drivetrain to synthetic and adding a catback exhaust.

I'm thinking about a round canister style muffler with a decent length, maybe magnaflow or flowmaster, and adding a turndown spout under the truck bed.

Are turndows usually louder or quieter than a rear or side exit exhaust....quieter is okay'er.

Thanks,

Ryan
 
Possibly more in cab noise? I guess that would make sense. I always wondered if it'd be quieter outside of the truck. The sound is going straight into the ground.
 
I doubt the cost of all those fluids and a new exhaust system is going to pay for itself in fuel savings
 
I hacked my f150 with a cheapo thrush muffler and a 90 degree elbow pointing down, albeit cocked about 20 degrees toward the passenger side. This was all installed immediately after the catalytic converter to stay legal for the absolutely cheapest price.

Doesn't sound any different/ louder.

I did the same thing with my dodge dakota albeit without a turndown and it resonated off the bed and sounded horrible.

MPG didn't change any for me, and I really really doubt it will for you, either.

However the syn all over, particularly the rear diff, should get you a tiny boost. If you have a belt driven fan look into going electric.
 
None of what you're about to do will have any meaningful effect on fuel economy. Different fuel formulations (regional,seasonal and brand), less junk in the trunk and a gentler driving style will have a far more profound effect on fuel economy. A tune up never hurts either.

That "cat-back exhaust" will set you back $400-1000 depending on how fancy you get. How much less gas must you burn to pay for that exhaust work? It WILL be louder, more apt to leak and will most definitly rot out sooner than the factory system you sent to the scrap pile.
 
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When i had my 97 Rodeo, the exhaust was dumped over the rear axle. It wasn't so much louder farther away as it was right besides it. Sitting inside with the door open it was definitely louder than far away. Also louder inside as a result. But it did sound great.
 
Some folks like the noise. Thats all you're gonna get. That and a thinner wallet. The next owner might not like the noise.
 
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Thanks guys, all things I've considered. Honestly, If I do it, I'll be doing the fabrication myself....the fluids, I was heading in that direction anyway.

Interesting though. Thanks for the replies.
 
MPG is more about adjusting the nut behind the wheel than anything else. Tires can have a noticeable impact too. Going wider and/or taller than OEM will negatively impact MPG. Training oneself to be a more efficient driver is the biggest bang for the buck. Having realtime feedback like a ScanGauge II or Ultragauge to optimize the fuel efficiency in many different driving situations really helps. Practice now when gas is cheap, so that when it's expensive the re-learning curve will be much shorter.
 
There's also a theory that dumping exhaust under the vehicle generates more heat and can make rubber suspension bushings deteriorate faster. That's a bit of a stretch though.
 
It doesn't make a difference, since the muffler will have already done its job before the exit pipe
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Originally Posted By: ryan2022
Hi guys, I'm looking at adding a couple of MPG, switching the entire drivetrain to synthetic and adding a catback exhaust.

I'm thinking about a round canister style muffler with a decent length, maybe magnaflow or flowmaster, and adding a turndown spout under the truck bed.

Are turndows usually louder or quieter than a rear or side exit exhaust....quieter is okay'er.

Thanks,

Ryan


The drone is usually the killer in those setups.
 
Thanks guys, I'm actually leaning away from it. I think you're right, plus the sound with these 2.3 litre four bangers and a more open exhaust isn't the most pleasant to begin with.

I bought the truck with a series higher tire than stock...not much difference at all, but they're also snow tires. They're drying out a bit so I may swap to the proper size in the spring. I'm heading to synthetics anyway to start stretching out the drain intervals. And I'll start easing off on the use of the right foot!

DoubleWasp, that's a great Porsche btw. The Carrera S is a favorite of mine. I prefer it over the GT3 for street use. Years ago I was involved with the local Porsche club with a friend of mine and had regular hot laps at Mosport in Ontario in a few of them. Amazing cars.
 
Thank You.

When I went shopping, I wanted one I was actually going to be both willing and able to drive on a daily basis. I was not out to buy a garage queen. The GT2, GT3, and Turbo were on the short list, but I had the feeling that those were going to spend more time being coddled in the garage than being used. I already have a super fast car that rarely sees the road. I don't need two of them.

This car has treated me quite well, aside from a cheesy sun visor that took 4 months to replace.
 
That's great. yeah the 911's have just gotten so good. Just amazing. The wider body of the S is quite nice. I've been around the track in both, and we didn't lose much speed at all to the gt3 on the back stretch, and theyre much more streetable. Great choice!
 
Originally Posted By: Ifixyawata
There's also a theory that dumping exhaust under the vehicle generates more heat and can make rubber suspension bushings deteriorate faster. That's a bit of a stretch though.


It can definitely heat the fuel in the fuel tank and make the vehicle more prone to vapor lock, depending on where the tank is located.
 
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