Muffler Options

YJJPWrangler

YJJPWrangler

Well-Known Member
Joined
Jul 19, 2005
Location
Charlotte
Need some input. After spending a LOT of time under the Willys tonight I think I've decided that it would be a hell of a lot easier to run true duals rather than tie them together. I really have no clearance between the driveshaft/anti-wrap bar to run a crossover. No option to tie the pipes together over the transfer case either. About the only way I see it, is to run dual exhaust down both frame rails, over the rear axle and then dump them out each side. Round mufflers would be the ticket for this as there's about 18" or so of room between the rear crossmember and the bottom of the tank.

I found these.

https://www.summitracing.com/parts/gib-bm0113/overview/

Not too expensive. But I can also go the way of the mullet and get two glasspacks for about the same cost as the gibson.

https://www.summitracing.com/parts/sum-630805/overview/

Thoughts? I don't think I've ever heard a "new" glasspack, I've only heard them when they are old and they don't sound to great and I know they don't last as long as a regular style muffler.
 
R Q said:
I had a glasspack on my Jeepster for a few minutes...sounded like shit!
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I was hoping you would chime in...thats good to know.

@JSJJ388, I love the price but am needing something small and compact.

@83oldyoda4x4, why these? Are you running them?

Any other options besides saying fuck it and running them through the hood?:driver:
 
IMO, It kinda depends on what you want to hear. For me, I like a quiet one that gives a decent sound when in throttle, but no so loud that you can't have a conversation.
After I had mine linked, had to have new exhaust. The one that was put on there was way too loud. Had another man work onit and ended up with one that would have went on something like a Ford Ranger. A lot quieter, but with 8 cylinders pumping into it, it sounds pretty decent.
 
I hate the raspy popping noise under heavy throttle. I wouldn't mind a slight rumble at idle but definitely want to be able to talk around it while its running.
 
Why are you so set on duals? I had a carb’d 4.3 in a S-10 blazer (TBI and wiring was shit). Long tubes and a Ypipe to a single 2.5” through a magnaflow out to the back. It sounded great at idle and a nice throaty sound getting into it.
 
skyhighZJ said:
Why are you so set on duals? I had a carb’d 4.3 in a S-10 blazer (TBI and wiring was shit). Long tubes and a Ypipe to a single 2.5” through a magnaflow out to the back. It sounded great at idle and a nice throaty sound getting into it.
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Space constraints. Right now there is no good way for me to have any kind of crossover tube due to the drive shaft, rear crossmember, and anti-wrap bar. I cycled the rear suspension and under compression there is no room at all for a crossover tube. There's about 18" of space between the rear crossmember and the gas tank so not much room there either.

I would LOVE to run a dual into single setup as I have all the pieces already. I just don't see it happening with the space constraints.
 
YJJPWrangler said:
Space constraints. Right now there is no good way for me to have any kind of crossover tube due to the drive shaft, rear crossmember, and anti-wrap bar. I cycled the rear suspension and under compression there is no room at all for a crossover tube. There's about 18" of space between the rear crossmember and the gas tank so not much room there either.

I would LOVE to run a dual into single setup as I have all the pieces already. I just don't see it happening with the space constraints.
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can you run the y pipe under the the bell housing and run a single pipe? Keeps both banks equalized and only have to use 1/2 the pipe
 
any chance you can run around the front of the pan like I did? I don't have room for 2 mufflers under mine. I'll try to find what muffler I bought. It's generic from summit or jegs and has a really mellow good sounding tone. Not loud, but talks good when you romp on it.

upload_2019-10-10_11-24-25.png
 
skyhighZJ said:
can you run the y pipe under the the bell housing and run a single pipe? Keeps both banks equalized and only have to use 1/2 the pipe
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Negative. Im running a SM420 and a Dana300. While there is room between the bellhousing and the transmission for a crossover, there is no room between the transmission and the front driveshaft at ride height much less front axle compression.

@justjeepin86, I had seriously considered that but again, space constraints. There really isn't any room between the framerails for a Y pipe. I have about 3.5" of space between the frame rails and the transfer case on both sides.

My original plan was to run duals down both frame rails, then to Y pipe over rear axle. But the crossover pipe is the issue. I have about 8" of uptravel from leaf spring pack to bumpstops in the rear. There is about 9" between the rear crossmember and top of the axle. Over the rear yoke of the transfer case there is about 3.5" of space. I had thought about running the crossover right over the rear yoke/first couple inches of the driveshaft but am concerned about driveshaft compression(up/down) and heat soak into the floorboard as it will be just about touching it(battery sits right over the same spot in between the front seats).

I see 3-4 options for keeping a Y pipe but there are drawbacks to every single one. The only drawback I see to true duals is the added cost of two mufflers and the possibility of less back pressure as its essentially a straight shot from the motor back.
 
Go back and look at my build. I don't want to fill up your post with pictures. You don't need a Y pipe to run them into each other. I used a 2.5 that I egg shaped. I had the same problem and needed to put them together near the collector. I understand that it works for you to do duals though. You may get a lot of popping when you let off the gas with that short of exhaust in true duals. I don't guess that will hurt anything though.
 
justjeepin86 said:
Go back and look at my build. I don't want to fill up your post with pictures. You don't need a Y pipe to run them into each other. I used a 2.5 that I egg shaped. I had the same problem and needed to put them together near the collector. I understand that it works for you to do duals though. You may get a lot of popping when you let off the gas with that short of exhaust in true duals. I don't guess that will hurt anything though.
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Just looked at your build again. You have a LOT more room than I do. This is what I have currently mocked up.

Driver side. Has to clear the slave cylinder.

LYgRDKcbgpB8LKVRHKIgxOpRInslu7-p1xH2DA-KhbbUXsKiC_TLiPq8uqtiz0DkZW-8XNFsMGJzhHKAT8UkunZFp6sIMZEhzt9YmyaYcr2O4Xkd04qUy4ehHN96-hyI1CNh6-g1D_zQI7PBx-iDByH0HS6zUBVmpXv4lcSttG6nASTTTpNXyCMtXveCwdjNTJttxA63o9qj2nm6uegVOqoS6saLivxALq0qOUOcMH-Sxn3K2rzc6ihpKrReY5F_K8UgRVf-7Fxwawde-zacpeWJ_5K2K1h2vOiNm9J5wgY8DkOdna-rsjeyHFxRGW2uXfD_zRr4zyIWpgMj0fI17aSZtnGq7pRxNpvvU7eKPkkR3i6aSst8D_n6F6gPSM3UiuZVN2e6aJ-BvzS0eHsXqowbpQyd8hH6JlLC_aqnhnfZijFQuRrhgnnh-KYXi_ETRIukiEGoWRJ0K_ZhxsktKWj0D1bopoRY4IWP3muN3fasNsB_Ks7vqpv6d55-vtRB344xj7VMixLgUZ4v1a_rLrQH4FWhKEjokavmO_NPQSvzLWhilXDgjRt11DaoO0YJOw4j3OnGQUNl3zeGgwcWSgCMxjps8v6Et5jOmsDiSMKRmX__13CahoGRkaDE2-XKME0-x19A0HDiwfuo6dSms01a2nCs6VLBeMOxGLvr_0v3i0HipKE5sGA=w1250-h937-no


Passenger side

_SB3ocyDsP6jYULis5tQBa0Cf3SVBOq_AmPth755uejEBhQ769kUbhE12SOvhWRYHCeMrjyxouzzyO4ySaDc3gQOzZzQEzj-FpJY0bkJLVaCdfeEhvnTULteS-eEME8pSIIzjpSngwMpOMBtcriNP5Ot-TxndI-LsIJS7nJzdDwk3uhowTl7azm5ZFJv4eTBQDfxwGzHfgdWmR7eJqJ6btwllUfq2stJdZfVQFb7jU2PpP5Pd071Ayww_PsZ6_vhFvKUXNe-yi3pk5lalnsGQ0_qK3oLbM2y7Kozlxy8tEdT_Ljb13MuWMzGPG-X-Oidr6XNCRouxR08JCnWuEKXiz3XY1EhBZhJm3QCEHdNSGV-GDGAYN_p7UirThJbeimgmByqI2u922Qoram4MrjdjFJs0M6tC4HQtpISrh6CiHAO6A_hd10YzIuzX822ihqSq9XXVy64JVpay-GA70jiqJzzt1SaeeAks4XvMHErLpJDZmfm-hW7bkin2V9dP0THVd0lpvKSSYsfVIc9g8olzuXt61oxRlm_tJUc_HDNvuaiKVzR6mx_mYKPsGEnwtps1geN5F-drFwPNBdjTelwhlU-uYnTKGdcSzEcCzoXZIvAzdtzDg0tuoNfO0pmyyDB22d88xH0dMkeAcLbILydkdzxDLvaMU9nmI3wIB_kpWx8ZDpTu9qIC-g=w1250-h937-no
 
You dont need 2x2.5s on a 4.3, imho.
Id stick to 2 or even 1.75 if running duals. That will also free up (a litttle) room.
 
YJJPWrangler said:
Stock exhaust was 2.25...

But I understand what you're saying
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2.25 in a 2-into-1 configuration. For a single exhaust 2.25 is probably right. Especially with the added restriction of a CAT which Im assuming you ditched.
But 2x1.75 would probably flow better than 1x2.25...the math would require a few more variables like pressure and length...Ill leave that to @Fabrik8
 
one last post and Ill abandon.
The 4.3 in my old buggy wrapped the pass side around the front to the oil pan, Y'd at the driver header outlet and left single exhaust. Even with the (short lived) turbo it had no problem breathing through a single 2"...but it was very straight.
it had a dynomax turbo muffler and it sounded like ass.
 
I went back and looked at your build thread and from what I can see from the pics, it looks like you should have enough room above the bellhousing to route the Y pipe. You would likely need to modify the header to point straight back, etc, but that should be reasonably easy.
 
@getstucksome came over last night and offered another set of eyeballs. We decided to route the driver side around in front of the oil pan and tie it into the passenger side. I have just about got it mocked up and it looks pretty good. I did have to take into account the front driveshaft and the Y pipe connection kicked my ass for about 1.5 hours but I have it tacked on now.

Final plan is to route everything down the passenger side framerail, dump into muffler right behind axle and then a simple turndown. This keeps the exhaust away from the fuel lines and allows me to use everything I already have.

I appreciate all the responses and ideas. Thanks!
 
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