I have a 2003 Dodge 3500, one ton, 4X4, duallie, quad cab with a 5 speed, 5.7 hemi in it. I bought it for towing a 5th wheel camper. I'd like a little more power for pulling over the hills and have a question on exhaust and intakes. If I put a 50 series muffler on the stock exhaust like I see some of you guys do, will it lower the torque? I NEED the torque and I have read changing exhaust can reduce torque. Thoughts? ALso, is the 50 series too loud or does it give a nice "tone"?

Question #2 I see some of you adding intakes. Any power increases? I added a magnaflow cat back exhaust and AEM true CAI to my Nissan 350z and although it sounded cool, I really couldn't detect any real power increase. Your opinions would be appreciated on the truck performance. Since my 350z didn't really get any noticable power gains, I don't want to go to the expense of doing these changes to the truck unless I get more bang for the buck!

 

The muffler wont do much to the torque that you would notice.

Though if you want more torque..look into headers or a cam!

 

Headers!?!?!?! that will certainly decease your low end hp and tq... and so will a cam! Look at the RPM where the HEMI makes peak hp and tq numbers... both are over 4000rpm. That's because these engines already have pretty hot cams in them. Unless you spend a lot of time between 4000rpm and redline, stay away from the above.

As far as the Flowmaster, you might loose a tiny bit of very low end torque due to lower back-pressure, but when you get up in the revs where these engines work best, you will see good gains in power and torque.
Do not get a cone filter unless you build a cold air intake box around it to insulate the cone from the heat under the hood. I would just put a K&N panel filter in the stock airbox as it is faily efficient and does a good job pulling cool air from the front right fender area.

That's my $0.02 anyway.

 

I agree w/ B12, unless you only plan on pulling only in the low RPM range then you really won't be doing any harm. Once you get into the upper RPM range (cruising speeds) you'll definitely get the extra "kick" from ANY aftermarket cat-back exhaust system. You should be OK.

 

Going to a small tube street style header on any application will not cause the engine to "lose" torque. It will change the power band at which average and peak torque occur. A small tube header and nice cat back system will actually help boost torque under 4000 RPM-good for towing. CAI help a little, not like the claims that are made.

 

I have a 2003 2500 with the hemi and the 5 speed manual. I bought the 50 series Flowmaster and had to take it back in about a week--too loud. I went with the 60 series. It's still pretty loud and has a little droan but it's liveable. No noticeable change in power or torque.