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the TURD
September 16th, 2017, 18:38
Recently I redid my exhaust system, and found that it droned terribly between about 2600-2900 RPM. It was miserable to drive and I felt like an idiot teenager driving around. So I figured I'd try a something I'd read about called a 1/4 wave resonator.

It's basically a capped pipe that tees into your exhaust pipe, and what it does is cancels noise waves by sending an equal and opposite wave back into the exhaust pipe. The exact frequency it targets is based on the length as well as the chemical characteristics and temperature of air inside the pipe.

https://2.bp.blogspot.com/-lObZ1CUbkbs/WZbQADbt1dI/AAAAAAABCSM/oowqVoblK2QmBphUFp1GYg-MVqqmq73RgCKgBGAs/s400/DSC_1909.JPG

https://3.bp.blogspot.com/-qwqEfAWwa0E/WZbQAKJw4zI/AAAAAAABCSM/Nr8OoXGoAZkt8cJFxGNixCuytT9T3C-igCKgBGAs/s400/DSC_1908.JPG

This is what mine looks like.

As you can see, it's pretty simple to build and install. I made mine about 30" long and it worked wonders. The average sound level in the drone area was reduced by 11 dB, which is a 10x reduction in sound energy.

If you want more details, visit my blog: http://ironhydroxide.blogspot.com/2017/09/drone-warfare.html
Sorry, I just didn't feel like typing everything twice.

BTW, if you are wondering what my exhaust sounds like, this is it:

https://youtu.be/ArbPoxbWSog

comanche91
September 18th, 2017, 08:49
That's too loud for me.........

WB9YZU
September 18th, 2017, 10:17
Very interesting solution ! Cool!

It seems to me that a nice welded muffler with a couple of chambers would have solved your problem, reduced db level across the range, and have been NP/NF legal as a spark arrestor . But that's me. Everyone has a different vision as what they want their Jeep for :)

burntkat
September 19th, 2017, 06:34
That's too loud for me.........

Concur. Was that before the resonator? If it's after, it still has too much drone..

the TURD
September 19th, 2017, 12:37
Drone isn't something you can necessarily hear from the outside of the vehicle, since it's an interaction between the body and the exhaust. The nice thing is it's not as loud inside as you would think because the drone is gone. Outside, the volume level is about the same as your standard aftermarket exhaust.

WB9YZU, what are the requirements for a spark arrestor? I rarely get to actually go wheel but I'd be surprised if it's an issue here (just barely moved to Michigan).

WB9YZU
September 20th, 2017, 14:48
Spark arrestor requirements for Autos/Trucks/Jeeps are not seriously stringent.
Essentially, the muffler just has to trap a spark.

Here is the snippet from the NFS website.

During fire season (May 1 Sept 30) all vehicles on NFS (National Forest System) lands must be equipped with a baffled muffler, serviceable tailpipe and should contain operable fire extinguisher (2.5 lb capacity, 4BC rating).

So basically, no straight through mufflers and no missing tail pipes.
That still leaves lots of options for a nice sounding performance exhaust system that won't rattle your teeth :)

the TURD
September 20th, 2017, 19:06
https://1.bp.blogspot.com/-xp_jQUN6jd0/WZbQPDdDcaI/AAAAAAABCSg/DUoNmlmiOXYQTiAGmSJbLlYqUvY9MstUwCKgBGAs/s400/DSC_1888.JPG

So basically, no straight through mufflers and no missing tail pipes.

So something like this? This is a picture of the inlet of my muffler. It looks the same in the outlet as well.

That still leaves lots of options for a nice sounding performance exhaust system that won't rattle your teeth

I'm not sure if you are inferring that my exhaust is really loud. I promise you it's not, at least on the inside, though without the quarter-wave resonator it was loud inside.

Greenz
September 20th, 2017, 19:44
I like it. Good Job!

Nice to see some new XJ tech enter the forum.

burntkat
September 21st, 2017, 05:57
If that's like the normal glasspack, it's not a baffled muffler.
Baffles means that there is no straight-through path for things to pass through, to my knowledge. IE: you can't see straight through it.

That pic is as installed, correct? So the only reason we can't see through is that one end is closed off, visually.

burntkat
September 21st, 2017, 05:58
BTW, how do you bend your pipe? I need to fabricate a crossover and I really don't want to use crimped bends (even though from a performance standpoint it won't make a difference).

Green XJ Jeep
September 21st, 2017, 06:22
BTW, how do you bend your pipe? I need to fabricate a crossover and I really don't want to use crimped bends (even though from a performance standpoint it won't make a difference).
Any quality muffler shop should be able to mandrel bend exhaust pipe. If not then Jegs or Summit will have pre bent pipe you can ordered.
For a relatively low rpm motor an H pipe would be better than a x. They make more power in the lower rpm's than an x does

burntkat
September 21st, 2017, 06:57
That's not what this is for. This is simply to get a V8 to exhaust through one muffler. Might seem wasteful or shortsighted, but there's only so much space under an S10, and I am moving the battery and tranny cooler (as well as a filter assembly) to the space a second exhaust unit would have to go if I went to duals.

EDIT: ALTHOUGH, now that this is mentioned, if I was able to squeeze a true dual exhaust into the package, it would simplify a great amount of the exhaust work by way of not having to deal with a collector to merge 2 into one.... and then I could put that H pipe to work with a couple simple fishmouth joints and a bit of welding time. Hmmmmmm...

Green XJ Jeep
September 21st, 2017, 08:01
Seems like it would be easier to run the exhaust outside the frame rails and dump it before the rear tire than to mess around with 2 into 1. But is been a very long time since i have been under the cab portion of an s10

burntkat
September 21st, 2017, 08:22
It's actually an S10 Blazer, but quite similar to the pickup, with the added benefit that the fuel tank is behind the rear axle, giving more space.

Plus, I an running a 2" body lift (had to for tire clearance, and drivetrain clearance since I pushed the powerpack 2" aft), so I could very easily stand the mufflers on end.

Now that you have me thinking outside the box, so to speak, this may not be terribly difficult. Hell, I may be able to run the second pipe alongside the first and have just a 6" H-pipe betwixt them. Buy a second tailpipe the same as the 4.3 stock size, which was going to stifle the V8... but if I am only exhausting the one bank out of it, it's a non-issue.

Heck, weld flatbar between the pipes, and I can even use the factory hangers.

You have me thinking outside the box now, and I believe you've solved my problem!

burntkat
September 21st, 2017, 08:32
I alkso like how you've replaced the manifold flange with a v-band flange. I may do that in this application as well, as it's not sealing well (89 lo-po Camaro flanges. There is literally no gaasket, and red RTV hasn't done the job. I'm tired of exhaust leaks!

Anak
September 21st, 2017, 08:43
Any quality muffler shop should be able to mandrel bend exhaust pipe. If not then Jegs or Summit will have pre bent pipe you can ordered.


I have yet to see an exhaust shop with a mandrel bender. All that I have ever seen are press benders.

A mandrel bender takes up nearly as much floor space as an automobile.

Here is an example of what a mandrel bender looks like:

https://www.youtube.com/watch?v=gdtrTaY7yfk

That long bar that runs the length of the machine is the support for the mandrel. Around the 40 to 45 second mark you can get a decent sense of the mandrel itself. It is comprised of several jointed segments which are able to follow the bend and support the pipe from the inside.

I cannot see a mandrel bender making sense for an exhaust shop. Just the time to change over the tooling from one tube diameter/bend radius to another would be prohibitive, never mind the setup time to go between patterns.

the TURD
September 21st, 2017, 09:33
If that's like the normal glasspack, it's not a baffled muffler.
Baffles means that there is no straight-through path for things to pass through, to my knowledge. IE: you can't see straight through it.

That pic is as installed, correct? So the only reason we can't see through is that one end is closed off, visually.

No, it's not a glasspack. It's a Flowmaster Hushpower. I had a glasspack on it previously and it was way too loud.

This is not installed, and the reason you can't see through it is because you are looking into a perforated cone, and there is one in each side of the muffler.

https://www.rx7club.com/attachments/1st-generation-specific-1979-1985-18/274721d1199612809-best-muffler-custom-exhaust-size-hushpower.jpg

http://cdn.shopify.com/s/files/1/1290/3221/products/hushpower_images_grande.jpg?v=1468941381


BTW, how do you bend your pipe? I need to fabricate a crossover and I really don't want to use crimped bends (even though from a performance standpoint it won't make a difference)

I get my bends from Columbia River Mandrel Bending. They are consistently the best prices I've found. http://www.mandrelbends.com/

burntkat
September 21st, 2017, 10:11
I have yet to see an exhaust shop with a mandrel bender. All that I have ever seen are press benders.

A mandrel bender takes up nearly as much floor space as an automobile.

Here is an example of what a mandrel bender looks like:

https://www.youtube.com/watch?v=gdtrTaY7yfk

That long bar that runs the length of the machine is the support for the mandrel. Around the 40 to 45 second mark you can get a decent sense of the mandrel itself. It is comprised of several jointed segments which are able to follow the bend and support the pipe from the inside.

I cannot see a mandrel bender making sense for an exhaust shop. Just the time to change over the tooling from one tube diameter/bend radius to another would be prohibitive, never mind the setup time to go between patterns.

This has been my experience as well.

Looks like I'm off to Summit!

burntkat
September 21st, 2017, 10:15
No, it's not a glasspack. It's a Flowmaster Hushpower. I had a glasspack on it previously and it was way too loud.

This is not installed, and the reason you can't see through it is because you are looking into a perforated cone, and there is one in each side of the muffler.

https://www.rx7club.com/attachments/1st-generation-specific-1979-1985-18/274721d1199612809-best-muffler-custom-exhaust-size-hushpower.jpg

http://cdn.shopify.com/s/files/1/1290/3221/products/hushpower_images_grande.jpg?v=1468941381


I get my bends from Columbia River Mandrel Bending. They are consistently the best prices I've found. http://www.mandrelbends.com/

GREAT info!

Your truck is a bit loud for my tastes (each their own, I'm old! :) ), but putting resonators (glasspacks work as well) upstream of the main muffler will reduce that.

I did some research a few months back about this sort of issue, there was some interesting stuff on youtube about getting a quality tone (quiet at cruise, with a WOT bark) with cheap parts-house pieces. I think it's time I start burning steel and see what I can do.

Green XJ Jeep
September 21st, 2017, 10:29
I have yet to see an exhaust shop with a mandrel bender. All that I have ever seen are press benders.
A mandrel bender takes up nearly as much floor space as an automobile.

Here is an example of what a mandrel bender looks like:

https://www.youtube.com/watch?v=gdtrTaY7yfk

That long bar that runs the length of the machine is the support for the mandrel. Around the 40 to 45 second mark you can get a decent sense of the mandrel itself. It is comprised of several jointed segments which are able to follow the bend and support the pipe from the inside.

I cannot see a mandrel bender making sense for an exhaust shop. Just the time to change over the tooling from one tube diameter/bend radius to another would be prohibitive, never mind the setup time to go between patterns.
I know of half a dozen shops within 50 miles of me that have mandrel benders.
Maybe i am just lucky to have that resource

RCP Phx
September 21st, 2017, 10:49
I have yet to see an exhaust shop with a mandrel bender. All that I have ever seen are press benders.

A mandrel bender takes up nearly as much floor space as an automobile.

Here is an example of what a mandrel bender looks like:

https://www.youtube.com/watch?v=gdtrTaY7yfk

That long bar that runs the length of the machine is the support for the mandrel. Around the 40 to 45 second mark you can get a decent sense of the mandrel itself. It is comprised of several jointed segments which are able to follow the bend and support the pipe from the inside.

I cannot see a mandrel bender making sense for an exhaust shop. Just the time to change over the tooling from one tube diameter/bend radius to another would be prohibitive, never mind the setup time to go between patterns.

While that's a true mandrel bender, a good tubing bender doesn't "ripple/indent" the pipe

Anak
September 21st, 2017, 11:33
While that's a true mandrel bender, a good tubing bender doesn't "ripple/indent" the pipe

That is mostly a function of bend radius and degree of bend.

As long as you don't need to re-shape the pipe much you don't need as much support in order to keep it round.

Once you really get into mandrel bending you might as well start viewing it as an extrusion process.

JohnX
September 21st, 2017, 11:50
I checked every shop within 10 miles (which is over 100 shops) nobody does true mandrel bends. I ordered mine from summit, jegs, etc.

RCP Phx
September 21st, 2017, 12:13
I just had the muffler shop down the street do my entire system from the header back with a new downpipe/cat/muffer/tailpipe and all the bends were beautiful !!!

Green XJ Jeep
September 21st, 2017, 12:24
In lines 4, 5, and 6 on your spread sheet, how did you come up with your numbers?

the TURD
September 22nd, 2017, 09:29
In lines 4, 5, and 6 on your spread sheet, how did you come up with your numbers?

Just did a little internet research to find those values. They are based on the physical properties of exhaust gas.

burntkat
September 22nd, 2017, 09:35
Thanks for posting this, and the link to your site. It's very interesting, and I see you have the education to back this stuff up.

Now I just need to find a good muffler with a nice tone at idle and cruise, but a bark at WOT.

Flowmaster need not apply...

Green XJ Jeep
September 22nd, 2017, 10:09
Thanks for posting this, and the link to your site. It's very interesting, and I see you have the education to back this stuff up.

Now I just need to find a good muffler with a nice tone at idle and cruise, but a bark at WOT.

Flowmaster need not apply...

That would be Borla

burntkat
September 22nd, 2017, 10:15
That would be Borla

Yup, that's my thinking, or maybe Magnaflow.

But then I get to thinking how outright comical it is to weld those nice mufflers to aluminized pipe.....

four_shot
September 23rd, 2017, 12:53
I liked the sound my Dynomax ultra-flow welded made on my '86. (It would even shoot flames when I had it on the test pipe! lol)

The can was aluminized so it didn't look stupid when welded onto aluminized pipe.

burntkat
September 24th, 2017, 04:52
Yes, but that's pretty much just a flowmaster. Pass.

Green XJ Jeep
September 24th, 2017, 08:06
Yes, but that's pretty much just a flowmaster. Pass.

Cant go wrong with either Borla or Magnaflow.
I prefer Borla's on 4 and 6cyl engines and Magnaflows on v8's

Green XJ Jeep
September 24th, 2017, 08:22
Just did a little internet research to find those values. They are based on the physical properties of exhaust gas.

I am assuming that the temp is for exhaust gas and is there a reason you used the incorrect value for 2E?

Speed of sound is 340.29m/s and with the correct value entered it does change the length.
After playing with google docs it looks like anyone can modify the doc so you might want to include your values you used on your blog

burntkat
September 24th, 2017, 10:32
Cant go wrong with either Borla or Magnaflow.
I prefer Borla's on 4 and 6cyl engines and Magnaflows on v8's

To a degree, that is true. Even borla makes some stuff that sounds like Joe Dirt would be a fan.

the TURD
September 25th, 2017, 06:48
I am assuming that the temp is for exhaust gas and is there a reason you used the incorrect value for 2E?

Speed of sound is 340.29m/s and with the correct value entered it does change the length.
After playing with google docs it looks like anyone can modify the doc so you might want to include your values you used on your blog

Speed of sound depends on the temperature in the pipe. Coming out of the head, it will probably be between 300C and 500C. Inside a catalytic converter, the temperature is upwards of 500C. Of course all of this depends on the engine and the exhaust setup. There is no actual flow through the resonator, so it's going to be cooler than the flow in the actual exhaust pipe. I don't recall what I used as an assumption, I could find it in the original excel sheet I created for this.

I want to allow others to modify the doc so they can use the tool themselves. can you do me a favor and verify that you are ONLY able to input target frequency and temperature. I want it to be useable, but I don't want anyone to be able to screw up the calculations for others.

burntkat
September 25th, 2017, 13:17
So I'm seriously looking into replacing the flanges on my exhaust manifolds with v-band flanges, but I'm finding there is apparently a serious issue with warping of the flange during welding, in which case you'll never get them to seal.

How do you address this when you weld? It certainly seems as though there isn't much to the flanges to keep them from distorting during welding- and the suppliers I've found say the flanges are guaranteed leak free, unless they've been welded.. This seems rather stupid, what am I supposed to do, glue them on?

Apparently there is a solutin- the Marman flange. It was literally invented by one of the Marx brothers.
Info here: http://www.gbemandrel.com/marman-flanges.html

I know nothing of the company, but the flange does seem to be more robust and a better product.

the TURD
September 25th, 2017, 17:06
I just use Summit or Columbia River brand. Never had any real issues with warping. Just extend the pipe a little bit through the joint as shown below for extra strength and sealing.

http://www.spdexhaust.com/images/Secondary/ExhaustFlanges/V-Band/V-BandDetails.gif

I've heard of Marman flanges but never used them. I'm sure they are great, but v-band works really well for me.

Green XJ Jeep
September 25th, 2017, 17:18
Speed of sound depends on the temperature in the pipe. Coming out of the head, it will probably be between 300C and 500C. Inside a catalytic converter, the temperature is upwards of 500C. Of course all of this depends on the engine and the exhaust setup. There is no actual flow through the resonator, so it's going to be cooler than the flow in the actual exhaust pipe. I don't recall what I used as an assumption, I could find it in the original excel sheet I created for this.

I want to allow others to modify the doc so they can use the tool themselves. can you do me a favor and verify that you are ONLY able to input target frequency and temperature. I want it to be useable, but I don't want anyone to be able to screw up the calculations for others.

I can edit target freq. temp and speed.

It is indeed useful and something I most definitely going to play around with and research further

burntkat
September 25th, 2017, 19:25
I just use Summit or Columbia River brand. Never had any real issues with warping. Just extend the pipe a little bit through the joint as shown below for extra strength and sealing.

http://www.spdexhaust.com/images/Secondary/ExhaustFlanges/V-Band/V-BandDetails.gif

I've heard of Marman flanges but never used them. I'm sure they are great, but v-band works really well for me.

How far would you say you extend the pipe through, about 3/16"? This makes something I ran across make sense.

the TURD
September 26th, 2017, 04:32
Yeah, 3/16-1/4 is about right.

burntkat
September 26th, 2017, 05:59
OK, thanks.

Got any brands to recommend?

BTW, that company doesn't offer anything under a 2.5" fitting. Those are about $25 per set. Not too bad...

What process did you use to weld to the cast?

the TURD
September 26th, 2017, 07:23
https://www.summitracing.com/parts/sum-694925/overview/

I was happy with this one. You can get it in stainless for $12 more, if that's important to you. The smaller sizes come only in stainless.

http://www.mandrelbends.com/v-bands-band-clamps/v-band-assemblies.html

These are a bit more pricy, but available in just about any size you could want.

My manifold was some grade of tubular stainless, and it welded easily.

burntkat
September 26th, 2017, 07:46
That will be the hard part on mine. Pretty sure it is cast iron.

the TURD
September 26th, 2017, 08:15
Maybe you could just do an LS swap, they have cast steel manifolds that weld nicely... :D

burntkat
September 26th, 2017, 08:37
Oh don't tempt me. ;)

Green XJ Jeep
September 26th, 2017, 10:12
Dont they have s10 v8 swap headers?
Pretty common swap one would think there is.

burntkat
September 26th, 2017, 11:10
Dont they have s10 v8 swap headers?
Pretty common swap one would think there is.

Yes they do- and without exception, they all suck.

Very few fit worth a damn, and I've pushed my engine 2" back from the standard location, making the issue worse.

Additionally, I'm running a stock(ish) 350, and so headers will get me very little for all the trouble.

Also, headers tend to rust out faster than manifolds. Namely- headers DO rust out. Manifolds don't.

Green XJ Jeep
September 26th, 2017, 12:12
Well then how something like this and just start cutting and welding a new one up the flanges back.
http://www.jegs.com/i/JEGS/555/30671/10002/-1?CAWELAID=1710598596&CAGPSPN=pla&CAAGID=39714413703&CATCI=aud-300525381059:pla-293995373017&CATARGETID=230006180039220954&cadevice=m&gclid=Cj0KCQjw9afOBRDWARIsAJW4nvxQXfOSq7-K-UtZZvM98DyaVwvHeJPgx1arsuK2rNP4LnLFbGq19SsaAhQvEAL w_wcB

burntkat
September 26th, 2017, 13:04
If I ever go to headers, that will be the way it happens.

But again, I am running a stock motor. I have no need of headers. Additionally, I have no love for them, having been there and done that with other cars.

I may consider a set of oldschool Ramhorn manifolds if I can find them that will work. Or I may just say to heck with it and while I'm cutting off the collectors on these, redirect the passenger side down instead of back/down, in order to give me some more clearance.

Meanwhile, this is my DD, so I'll practice on the old 4.3 manifolds I no longer need, and if I can weld them well I'll go that route with another set of the 89 Camaro manifolds.

Green XJ Jeep
September 26th, 2017, 17:52
If I ever go to headers, that will be the way it happens.

I meant use your existing down pipes off of your manifolds then start plumbing new exhaust from one of the available kits out there.
No real need to hack the end of your manifold off.
Welding cast sucks balls and personally I try to avoid it like the plague.

burntkat
September 26th, 2017, 18:20
Plumbing exhaust is the easy part. The problem I'm having is getting the old camaro manifolds to seal (I think).

It very possibly may be the crossover pipe. Half of it is the old 4.3 job and I saw some rust perf in it.

To that end I will be replacing everything from manifolds back.