what would you do first?

like the x idea, just sucks i have a single in dual out muffler. bought the muffler and y this off what hammer had on DF. figured the newer engine would need the back pressure and that the y and muffler would be better. good thing i don't get paid for thinking. wanna say with cherry bomb because it is loud. and it went through inspection here once(delaware does decibel tests) should again.

well, last time i was under the truck the muffler looked like **** probably how i have it ran. all the paint came off and it's started to oxidize. hell with it. gonna go x pipe and dual mufflers

matt99 said:

False. It will give less backpressure but no real change in torque. Better mpg though!

I had straits and got better MPGs than with this Magnaflow but not anything worth ranting about. The torque "feeling" is the engine recouping the pressure with gas. I dont remember the specifics though.

Click to expand...

I don't want to start a debate with you, but I've been hotrodding cars longer than you've been alive. Open up your exhaust too much and you wlll definitely lose torque. If you tow at all, you will regret duals.

RubberFrog said:

I don't want to start a debate with you, but I've been hotrodding cars longer than you've been alive. Open up your exhaust too much and you wlll definitely lose torque. If you tow at all, you will regret duals.

Click to expand...

The truth about exhaust backpressure and torque

now i agree that my truck feels more torque-y with this magnaflow instead of duals. But the increased A/F ratio would account for the loss in mileage also. BTW Frog, that thread I started last summer about getting rid of this truck just came up in my head. I did end up getting a great paying job right outta school, but I'm going to keep the truck due to yall's and my dad/grandpa's advice. It would be a waste to get rid of it and I would lose out my ass.

OP, have you thought about a cutout? I have only heard one guy say he didnt like his cutout, and hundreds on these sites have them. Ive been debating on getting one. You could run duals to two chambered mufflers giving you the "torque feeling" and open em up for a great sound and a free flowing exhaust

I've read articles like that a thousand times. They're always written by some tech geek that is describing back pressure in a static environment. They always make the same mistake- they ignore the effects of scavenging and low exhaust velocity.

Low exhaust velocity (caused by too large of an exhaust pipe) reduces scavenging. Scavenging helps to pull exhaust gases out of the cylinder. It sounds counter intuitive, but you need need a smaller (and appropriately sized) pipe to ensure sufficent flow speed. Too big of a pipe and your exhaust travels at a snails pace and loses scavenging ability.

According to your theory, he could run straight 8" pipes right out the back and everything would be great. Of course, we know that's not true. Proper exhaust pipe size increases exhaust velocity, increases scavenging, and creates back pressure.

You could argue that back pressure is merely a side effect, and I wouldn't disagree with you. But nonetheless, you can not have proper scavenging with out some amount of back pressure.

On to the street/strip, a more open exhaust is beneficial for WOT track driving because higher rpms need less scavenging. On the street, with rpms between 1500 and 4000, back pressure/scavenging play a HUGE role in performance.

And as a practical application of it, guys that run cutouts always report slower 1/4 mile times with the cutout open. Why is that?

Hmm I've never heard that. But it does sound probable. When the exhaust is leaving, it creates a high pressure vortex around the wall of the pipe and a lower speed and more turbulent flow in the Center. It would create a sort of a vacuum, so it would actually pull the exhaust out from the valve

So if you put the two theories together, you pretty much come to the fact that your exhaust has to be tuned to your engine and mods. But the "backpressure" and running 8" pipes doesn't really go along the same lines. Exhaust pipe diameter is obviously going to create resistance, but the lay of the exhaust and muffler is going to create the backpressure we are talking about. A perfectly strait but right sized pipe is going to scavenge better than a curved one with backpressre (its allowing for more velocity).

I don't know a whole bunch about cars. I'm just thinking of ut how we were taught in school about vein and artery flow (with the exhaust being an artery). I'm not arguing, and love to learn. Any info on this is great for the thread and for us to read. If I'm totally wrong then let me know, it's not a big deal

You're absolutely right with your analogy. And you're also correct about a tuned exhaust.

It's quite possible to have a free'r (?) flowing exhaust with better scavenging and lower back pressure. That's what headers do. The runners are tuned to maximize scavenging, increase exhaust velocity, and decrease back pressure.

Dual exhaust really shines with headers. But it can cause a low end power loss with he stock manifolds.

Anybody else's head spinning? Lol, lovin all the info tho guys. Personally don't want to do a cut out. Need the exhaust out from right under the the cab. Might in the future do headers bit it would be shorties or mids to keep the cats. So if im getting everything right, the y with a single in dual out is gonna be best for my application? Since pipe size came up, what would be better 2.5 or 2.25 from the muffler back? The y is 2.5 in 3 out, muffler is 3 in 2.5 out. Wish it wouldn't be a huge pain and costly deal to try different set ups to see what worked best.

For your situation, go with 2.5 back.

awesome, thanks man.

bigtigga84 said:

so i went and talked to the shop about my exhaust. gonna be about 125 to have it dumped before the fender. was just going to do that until i decided on how i was going to lift a little more. while i was there, the guy at first wanted to argue with me about how many cats i had. he swore up and down i only had one(had worked on earlier models). after that got straightened out, we started talking back pressure and torque. he suggested that i run a dual set up with two mufflers. i already have a magnaflow y and cherry bomb extreme. want the magnaflow y put in (had to persuade him there was room to fit the y). so new y to cherry bomb single in dual out. duals 45'd out the back. which set up do you guys think would be best?

Click to expand...

Sorry, haven't read the whole thread, but this popped out at me and I feel the need to pass on some of the experience I have had with dealing with this type of shop. In a word "don't mess with them". If a shop is not on the same page as you, then move to a shop who fully understands what you want. These guys who think they are the experts on everything with wheels are full of themselves and you will not be happy with the out come. Never drop your truck off and at the end of the day expect it to be anything like you expected from a conversation you had with them from a few days before. Look the shop over and put your truck on the lift and go over the work you want done. IF you are satisfied the answers and attitude then set up an appointment and stay with your truck as the work progresses. Anything else and you stand a very good chance of being unhappy with the end resolute. Good luck...

thanks greg, they came recommended by a guy that works at advanced auto in town. the advanced people take pretty good care of me and my friends that go there fairly often. think after the little discussion about what i have and know can be done with the exhaust he knows i'm not some ******** that just says put stuff on it. i might shop around some more. there is another place about a half hour away, but from what i hear just labor is 300 bucks. little high if you ask me just to do that work not including parts, which i have all the parts.

George, I see some interesting conversations in the future. I love it when the engineers set out with their computations and start figuring mass flow through piping. Basically between the wide operating band of engines (volume) and the changes in thermo energy (heat) and the resistance encountered in the various bends and muffler that make up the exhaust piping it all goes out the window. Not even counting the regulating or dampening effect of a catalytic converter on the exhaust port pulses. All of the headers I have seen offered, none of them say they are tuned, actually most say "not" tuned. Meaning they are only less restrictive then the OEM manifolds and do nothing to actually assist in scavenging the gases. My conclusion is that LT's are reported as working best because they generally are not being used with Cat's and flow with excellent velocity across the broadest rpm band. Three inch pipes are best from the collectors to muffler(s) as they are less restrictive with the higher header temperatures which results in increased gas volume. RPM and higher temperatures both increase the volume of exhaust gases. If cats are installed it is all further degraded. Muffler back I like 2-1/2" piping, which maybe is over kill as the gases are cooling and the overall volume is decreasing. Anyway the point I'm trying to make is that there is no way an exhaust system can be tuned from idle to WOT. The best we can hope for is a compromise that best supports our driving needs.

bigtigga84 said:

thanks greg, they came recommended by a guy that works at advanced auto in town. the advanced people take pretty good care of me and my friends that go there fairly often. think after the little discussion about what i have and know can be done with the exhaust he knows i'm not some ******** that just says put stuff on it. i might shop around some more. there is another place about a half hour away, but from what i hear just labor is 300 bucks. little high if you ask me just to do that work not including parts, which i have all the parts.

Click to expand...

Tyler,
When pricing, just consider what it will cost to have it done a second time to make it right and you happy.
I took my RED to a highly recommended body shop for work and sat with the truck everyday while the old girl was being massaged. At the end of the week I pulled her out and found another shop. The shop just wasn't on the same page as I was and it simply wasn't going to work. Now the second shop was a great time and RED came out looking good.

well now with everything matt and george were saying, im considering getting headers and doing an x pipe and two mufflers. well see how good the tax man is to me this year. according to the calculator on hr block it should be pretty descent so we'll see. are black powder coated as good as ceramic coated and chrome?

bigtigga84 said:

well now with everything matt and george were saying, im considering getting headers and doing an x pipe and two mufflers. well see how good the tax man is to me this year. according to the calculator on hr block it should be pretty descent so we'll see. are black powder coated as good as ceramic coated and chrome?

Click to expand...

Why is a ceramic coated finish better than chrome for headers?

Ceramic coating originated in the aerospace industry, where it was used to coat the exhaust nozzles of jet engines. The coating was found to not only protect the nozzles from corrosion, but also helped reduce operating temperatures and increase the nozzles' life span. Adapting this coating technique to automotive headers provides the same results--high corrosion resistance, reduced underhood temperatures, and longer life. Chrome plated finishes look good initially, but will tarnish and turn colors during normal operation. Also, chrome will rust if not cleaned regularly

Why is a ceramic coated finish better than chrome for headers? – SummitRacing.com

what headers would u go with shorties or mids

mids are gonna flow a little better i would assume. just gotta make sure it won't mess with the cats to much, damn inspection lol. i know lt's get rid of the cats, and we can't have that now can we lol.

hmmmmmmmm PaceSetter Performance 70-1375 - PaceSetter Headers - Application - SummitRacing.com

this is for the mids on the 3rd strike site. so it should mess with the cats right.

•Manufactured using mandrel-Bent 1-5/8" primary tubes. Includes 2-1/2" headers extensions to mate to stock converter or custom exhaust. Mild steel tubing and CNC Machined, 3/8" Thick Steel Flanges
•Welding required at catalytic converter; A cut will need to be made in front of y-pipe at cat. for supplied 2-1/2" downpipes to be welded on




Pacesetter 04-05 Dodge Ram HEMI Ceramic Mid Length Headers Pacesetter 04-05 Dodge Ram HEMI Ceramic Mid Length Headers, Pacesetter 72C1374 Headers [Pacesetter 72C1374 Headers] - $379.95 : 3RD STRIKE PERFORMANCE, Your site for Late Model Performance!

for you yeah, you only have one cat. only thing 3rd had for me was shorties. thinkin im goin with lucky's. was checkin out their site. looks like they have their **** together. better than the jack hole in selbyville. might ride over there tomorrow.