Doug Thorley Cat Back Install

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I just ordered a Doug Thorley cat back last night to replace a rusted out muffler. I was hoping someone would have tips on installing it. Or even a link to a build thread of an install? I tried searching but didn't turn up much related to the install.

I've never installed a cat back before so I'm wondering if I need to put the cruiser on jack stands or if AHC 'high' will be high enough. Any tips for removing the current muffler from the hanger, etc...

Thanks!
 

gregnash

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Sawzall or angle grinder with cutting wheel. Buy all new flange bolts, nuts, and gaskets too if the kit doesn’t come with them.
This... just good measure to do it that way you don't have to worry about it if you end up having to cut a bolt off..
I was thinking of using something like this when I go to do my own custom exhaust.
 

gregnash

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I’ve never used one of those. Looks cool. Wonder if it works as good as it looks?
Yeah that is what I was wondering... I have used sawzall and diegrinder with cutoff wheel in the past and my only gripe is it is a bitch to get a straight cut. Figure if this works similar to a copper line cutter like I have used when running line for swamp coolers (looks like same principal) this would give me a much "cleaner/straighter" cut.
 
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Thinking of doing this, subscribed. A part list when you are done here would be helpful.

Thanks in advance.
 
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If this CBE doesn't drone on the highway (?), this just jumped near the top of my to-do list. $500 sure seems reasonable to solve the rusty muffler issues.
 
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If this CBE doesn't drone on the highway (?), this just jumped near the top of my to-do list. $500 sure seems reasonable to solve the rusty muffler issues.
Some other thread says it does result in some droning
 

ga12r1

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I get drone around 55-60 in OD. Anything much faster or when towing with OD off and the drone disappears. It is so much more fun to drive with the DT. I highly recommend it. The joy of the sound far outweigh any drawbacks imo. It's not obnoxious at all, just sounds so good.
 
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I keep crushing my mufflers.... first time cutting it "sort" of got me going. This time I totally crushed the muffler can. It sticks out way too far and the borla tip would most definitively get crushed. I've seen this one in life it tucks in nice and would hopefully not get crushed on a rock.


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I'm really looking forward to it! I got underneath it for 5 or 10 minutes last night and got the tail pipe/resonator unhooked. It didn't slide out easy like I had hoped. I'm hoping to get it removed and the muffler loose this weekend so I'll be able to just bolt up the new one when it arrives.
 

ga12r1

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I keep crushing my mufflers.... first time cutting it "sort" of got me going. This time I totally crushed the muffler can. It sticks out way too far and the borla tip would most definitively get crushed. I've seen this one in life it tucks in nice and would hopefully not get crushed on a rock.


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Yup. I ran the stock exhaust with a V1 Dissent rear at HIH8 and had the exact same damage. I switched to the DT catback and had absolutely no problems at HIH9 or any other trails since then. It does tuck up nice and high.
 

geanes

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I simply cut off the resonator on the rear and terminated the pipe just aft of the axle. No more bashing the exhaust system back there for me. 2 years on and no issues. Slightly better sound when on the gas without any drone when cruising on the highway.
 
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I simply cut off the resonator on the rear and terminated the pipe just aft of the axle. No more bashing the exhaust system back there for me. 2 years on and no issues. Slightly better sound when on the gas without any drone when cruising on the highway.

Thats what I have as a temporary solution, but there definitively seems to be more heat under the truck. I've heard reports of hotter ps rear tire, and my result is slight smell of fumes at startup. I really do want the exhaust to exit the body of the LC. Currently having to make repairs due to to this incident including melted wires due to heat, crackled powder coating and melting of locking nut plastic on the dissent and worst the arm sliding pad warped and melted. Having Ben shuffle around for a spare on the v1. There is a lot of heat output under there and you def want it to exit the body. Learned the hard way.
 

geanes

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Thats what I have, but there definitively seems to be more heat under the truck. I've heard reports of hotter ps rear tire, and my result is slight smell of fumes at startup. I really do want the exhaust to exit the body of the LC. Currently having to make repairs due to to this incident including melted wires due to heat, crackled powder coating and melting of locking nut plastic on the dissent and worst the arm sliding pad warped and melted. Having Ben shuffle around for a spare on the v1. There is a lot of heat output under there and you def want it to exit the body. Learned the hard way.
Very good to know. I wonder if simply extending the pipe to just before the bumper edge at the rear would work. Could keep the pipe up high and then have an angled exit like the one the factory does aft of the resonator. I thankfully haven't seen any of the consequences you've experience, but definitely recognize the possibility and certainly want to mitigate that as much as possible.
 
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Very good to know. I wonder if simply extending the pipe to just before the bumper edge at the rear would work. Could keep the pipe up high and then have an angled exit like the one the factory does aft of the resonator. I thankfully haven't seen any of the consequences you've experience, but definitely recognize the possibility and certainly want to mitigate that as much as possible.

That would be close, the dissent sort of creates a pocket right at edge holding up all that heat. I have to take pictures to show you the damage is extensive. I can't believe how much heat collected in there. It literally cracked off the powder off the dissent. I think the pipe has to clear the edge to be safe. I'll plan on posting a thread on this to warn others as a "hot mess". The harnesses damaged were not necessarily essential as to leave you on the side of the road mostly rear ac and trailer plugs, but could definitively start some spark if this happens to anyone.

here to give you an idea:

1593199162763.png



To be fair this all happened at the peak of Moab heat and almost 2k miles driving with the crushed can. The exhaust tip was partially covered by the dissent and I mean just a tad bit.
 

gregnash

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Very good to know. I wonder if simply extending the pipe to just before the bumper edge at the rear would work. Could keep the pipe up high and then have an angled exit like the one the factory does aft of the resonator. I thankfully haven't seen any of the consequences you've experience, but definitely recognize the possibility and certainly want to mitigate that as much as possible.
Can you post a pic of how you have your setup now with the resonator cut off? I was thinking of doing the same thing for the time being on my stock exhaust just to add a bit more sound then extending to do a side exit just aft of rear tire on that side. I like side exit (what I had on my 60) more than rear because of the pics above. Much more likely to cut an ascent/descent short and bank the bumper than have something come up under that rear quarter enough to smash your pipe.
 
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Just going to throw this out there.....i had a muffler shop redo my y pipe, muffler, and tail pipe. They eliminated the resonator and tucked the tailpipe way up.
All this was only $330 including a Magnaflow muffler. Pix in my build thread. It turned out great with a better sound but not too loud.


 
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