Donaldson Muffler Installation

[BElliott]

Hello,



I have an 06 megacab and have a question about the installation of the 51" Donaldson muffler, which I am considering purchasing.



My stock muffler is not a straight in and out design, it is offset, the outlet is probably 4 inches above the the inlet. The Donaldson is a straight thru design.



How have you delt with this?



Any pictures of an installed donaldson would be great!



Thanks in advance for any help.

 

[jmccart]

I have one on my truck. It was not straight through, but I made it straight through. The megacabs also have an extra muffler just aft the axle. My entire exhaust is a straight through and it is no louder than stock. Here are before/after photos of the muffler before I installed it.

 

[brista]

Hello,



I have an 06 megacab and have a question about the installation of the 51" Donaldson muffler, which I am considering purchasing.



My stock muffler is not a straight in and out design, it is offset, the outlet is probably 4 inches above the the inlet. The Donaldson is a straight thru design.



How have you delt with this?



Any pictures of an installed donaldson would be great!



Thanks in advance for any help.

I installed the 51" Nelson and it is straight through so I these pics might help. I noticed the CAT dropped the pipe and the muffler brought it back up. Since I was removing both it was real easy. It took one slight angle change where the tail pipe goes into the new muffler to make it line up perfectly.





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This is looking down the exhaust from the front. The crossmember you see in the bottom of the picture was where the cat used to be positioned directly above.





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You can see the weld where I made the slight angle change.





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Not a great camera angle but you can see how the cat has a drop in the pipe built into it and the muffler design brings that back up.

 

[BElliott]

Perfect, that is what I was looking for.

Thanks,

 

[jmccart]

Hey Brista, did you have an EGT gauge before you did your exhaust? I am always curious what the EGT drops are going from a completely stock exhaust to a 4'' striaght through.

 

[brista]

Hey Brista, did you have an EGT gauge before you did your exhaust? I am always curious what the EGT drops are going from a completely stock exhaust to a 4'' striaght through.

Yup... dropped 25-50 degrees.

 

[BElliott]

Yup... dropped 25-50 degrees.

If this only dropped you egt's buy a few degrees I am not sure it is worth the investment of time and money to switch, especially considering that I am not taking the cat. off and probably will not get as big a drop as you did.



Were there any other benefit, besided the sound? Better mileage?



Thanks,



Bret

 

[brista]

I was hoping for a bigger drop, but this is only cruising EGT's. Unfortunately I am just getting into the towing season now so will have a better idea how that is affected soon. Mileage gains are hard to track as we were just going from summer to winter fuel when I switched it. My mileage stayed the same on winter fuel so it did help. We are just getting back into summer fuels now and I expect an immprovement.