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Discussion Starter · #1 · (Edited)
I have always loved that sound of a straight pipe Cummins however the reality of having kids ride in the back seat and living in a neighborhood have driven me to quiet down my truck over the years. I finally found a great drone free combo of a Hushpower and a FTE resonator but always missed that great straight pipe sound. Well here is my solution. I had a couple Corsa silent choice 4" stainless exhaust valves sitting on the shelf so I used one to build a Custom Resonator and muffler with a 4" straight pipe bypass. At the flip of a switch in the cab, a solenoid valve is activated and the muffler/resonator are both bypassed. I attached a few pictures. I just installed it this weekend and it works great! I even used the stock tailpipe for a stealth look. Now the kids and neighbors will be happy, but at the flip of a switch it goes from being Dr Jekyll to Mr Hyde!:D
 

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Wow man you created a monster, I would get a patent on it quick. And how much for it? I want one.
 

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Discussion Starter · #4 ·
I am surprised that no makes something like this for our trucks. It seems like this Idea has been around for some time in the marine industry. Judging from the response of the friends who I have shown it to, I better get working on that patent!! :)
I will try to get some video up soon. If there is enough interest I may build more. If you send me a PM I can at least get you a ballpark price. Thanks.
 

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I am surprised that no makes something like this for our trucks. It seems like this Idea has been around for some time in the marine industry. Judging from the response of the friends who I have shown it to, I better get working on that patent!! :)
I will try to get some video up soon. If there is enough interest I may build more. If you send me a PM I can at least get you a ballpark price. Thanks.
PM sent man, let me know. and yea, lets see a video, your setup looks neat.
 

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it's been done a number of times... my problem is it's more restrictive, and it still doesn't sound exactly the same as straight pipe because you've still got a helmholtz resonator on the system with it "open"
 

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Discussion Starter · #7 ·
Drunk on diesel, are you referring to the fact that when the valve in the straight pipe section is open, that a portion of the exhaust will still be flowing through the resonator and muffler, and that will change the sound? I had thought about using 2 valves so that the flow through the resonator and muffler could be completely stopped when the straight pipe valve is open. Next on my list is to do a 2nd gen manifold swap. Hopefully then I will be able to test if adding a second valve makes much of a difference.
 

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yeah, it's the definition of a helmholtz resonator... don't get me wrong, it makes for a nice tone :D

but it's not exactly the same as true straight pipe

you'll LOVE the 2nd gen manifold :D
 

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Very nice work man! This will be next on my to-do list. I'm thinking a little different though. Using the "Y" style inlet pipe you have for both the inlet and outlet. And use a cheaper 4" ID/ID exhaust valve in the straight pipe section. Thoughts?
 

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so why dnt you put 2 valves on it one b4 the muffler and one b4 the starit pipe and put 2 switches where u can completly close the muffler and open the strat pipe corvette has this system perfected they call it mild to wild
 

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Discussion Starter · #12 ·
drunk on diesel, I looked up Helmholtz resonator and now understand what you are getting at. Seems like the only way to truly ovoid this is with a well designed flapper type valve located in each Y section that smoothly block off the flow into the which ever side of the Y is closed. I will have to get the 2nd gen manifold on first and then see how it compares to a true straight piped truck.

motocraneguy17, that was exactly my plan until I came across some used corsa marine butterfly valves. I have used several of the electric 4" valves over the years and they seem to work fairly well, however, I do like the simple and quick pull solenoid on the corsa vs the more common and slower electric geared motor. QTP sell a 4" butterfly valve for under $200 but I have not had the opportunity to look one over in person in order to evaluate the quality.

huddys2tonhunny Two valves are not necessary but may improve the sound. Downside is mostly cost, but the upside is you could close both like an exhaust brake to help warm up the truck in the morning.


I will try to get a little video of the sound difference up soon.
 

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Wow man you created a monster, I would get a patent on it quick. And how much for it? I want one.
must make 2 cause i so want 1 also cause i live in town also with a old couple that lives next door 2 me
 

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Why don't you just put the cutout a foot in front of the muffler instead of using a y? That's how I do it on all my cars and trucks... Hit the switch and it dumps it before the muffler then close the cutout and run it through the muffler?
 

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Not sure I follow you Mr.Hyde. Do explain more please.. I don't see how you can't "Y" it. Are you just trying to eliminate the Helmholtz acoustic properties Drunkondiesel is speaking of?
 

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Looks good, interested to hear this.

I agree with drunk and motocrane, you'll love the manifold swap :thumbsup:
 

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Like on my car and truck I just put the cutout a little before the muffler and when the cutout was open it dumped the exhaust right under the vehicle. When it was close the exhaust would go through the muffler and out the tailpipe. I would think it is a lot easier to do it this way. Just cut a little segment out of the exhaust in front of the muffler put your cutout in and weld it back up. Hope this helps
 

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That's kinda what I figured Mr.Hyde. I think I'm gonna rig it up like Md500e though since I got stacks and it would seem a bit funny to me dumping it under the truck...tit-for-tat.

Md500e, I saw the QTP valve you were talking about. Do you know if they make one or somebody that does offhand that has a 4" ID/ID so you could slip pipe into both ends of valve? Or would you get the valve you speak of and weld flanges onto the existing exhaust pipe to bolt valve up to? Thanks!
 

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Discussion Starter · #19 ·
blj184 and Blood, I have been asked by lots of people so I plan to build few more as soon as I have some time. PM me and I can give you a ballpark price.

Mr.hyde, I know just what you are describing. I have seen that on lots of street/strip cars. It would be a lot less expensive and simple to install but I plan on running it straight pipe around 50% of the time and would like to have the exhaust exit the tailpipe or it will soot up the underside of the truck. Another issue with the "dump valve" under the truck is the amazing amount of resonance it can produce. Not a problem for a few passes at the track but it can drive you nuts on the road. I once drove a Cummins truck a few miles that had the muffler disconnected under the truck and the resonance/drone was almost unbearable!
 

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Discussion Starter · #20 ·
Here is a link to some video to give you an idea of the sound. I need to make another video with some drive by passes.
 
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