dcass72 Posted April 24, 2013 Share Posted April 24, 2013 Alrighty, getting ready to do some exhaust work, as the muffler has officially fell apart on my 96 pathy. My question, is there any reason not to go with a bigger diameter pipe compared to the stock system? Also, true duals or 2-into-1? Has anyone noticed a loss in MPG by going bigger? Thanks for any info! Link to comment Share on other sites More sharing options...
Rebelord Posted April 24, 2013 Share Posted April 24, 2013 Without getting into a bunch of technical jargon. The factory dual 1.75" into the muffler provides more than enough flow for our trucks. The factory dual 1.75" pipes have the same flow rate as a single 2.5" pipe. (Actually 0.639 cfm less). To keep the same flow rate for a dual in, single out muffler. Would be to find one that has dual 1.75" in, 2.5" single out. But a single 2" out is fine. Here is a chart to show you: 1 Link to comment Share on other sites More sharing options...
dcass72 Posted April 25, 2013 Author Share Posted April 25, 2013 Any preference of muffler brand? What sounds good? Link to comment Share on other sites More sharing options...
Rebelord Posted April 25, 2013 Share Posted April 25, 2013 Through all my years doing hot rods. I have had Napa, Dynomax, Thrush, Flowmaster, Magnaflow, Borla, etc etc mufflers. By far my favorite has been Magnaflow mufflers. They seem to have a nice idle tone, that is noticeable but not obnoxious. Yet when at full throttle. Open up nicely and have again, a nice tone. Plus with most others I always had drone and rasp sound problems. 2 Link to comment Share on other sites More sharing options...
Precise1 Posted April 25, 2013 Share Posted April 25, 2013 While I don't have the same amount of experience with exhaust, I agree with the above. My first Pathy had a good sound with a cat back system and a Magnaflow, but not too loud and obnoxious. My current header/custom system with a Flowmaster sounds great at idle/low range but gets loud and raspy at 3k+ rpm. B 1 Link to comment Share on other sites More sharing options...
Muddyr50 Posted April 30, 2013 Share Posted April 30, 2013 I cut my stock exhaust off. It just dumps off the header. Sounds awesome on the vg. ESP when you drop a gear and give it. Link to comment Share on other sites More sharing options...
dcass72 Posted April 30, 2013 Author Share Posted April 30, 2013 I cut my stock exhaust off. It just dumps off the header. Sounds awesome on the vg. ESP when you drop a gear and give it. I had it like that for about a week, but was a bit much for me. I ended up getting the stock resinators (short glasspacks) and tips off a 2012 SS Camaro and used those as mufflers. Actually came out pretty well, has a great tone at idle, and not too raspy on accel. I'll try and post some pics tomarrow. Link to comment Share on other sites More sharing options...
shoesandsocks Posted April 30, 2013 Share Posted April 30, 2013 the muffler on my 01 is kinda rusted just thiking of getting a muffler and double rolled tip to give it a lil but of agression but i have to many projects on this thing so that is total back burner Link to comment Share on other sites More sharing options...
River044road Posted May 8, 2013 Share Posted May 8, 2013 Can we run true duels on these? Won't hurt anything? Link to comment Share on other sites More sharing options...
dcass72 Posted May 8, 2013 Author Share Posted May 8, 2013 Can we run true duels on these? Won't hurt anything? I did on mine, haven't noticed any issues, but did get a little better acceleration I feel. Gas mileage is about the same, which is kind of a bummer. Link to comment Share on other sites More sharing options...
pathfounder Posted May 8, 2013 Share Posted May 8, 2013 (edited) It's not possible to compare the areas of the pipes to compare the flow rate. There is friction along the walls of the pipes, and a single 2.5" pipe has way less wall area (29%) than two 1.75" pipes. The diameter of the primary pipes is very sensitive (the manifolds) but after the cats (the secondaries), it is much less so. Generally from there onward, bigger+shorter is better. Edited May 8, 2013 by pathfounder 1 Link to comment Share on other sites More sharing options...
Rebelord Posted May 8, 2013 Share Posted May 8, 2013 The theory craft of exhaust flow rates has been done over and over. Easy to find on hot rod forums. Especially Mustang, LSX engine forums etc. <br />There is actually a formula to calculate it the flow rates of pipe comparisons. But I dont know it off the top of my head. To say the wall friction will make that much of a difference is null. The amount of friction is next to nothing. <br />Where you get the greatest difference is the velocity of the exhaust gasses as they exit. Which needs to be balanced with the needs of the engine. <br />Check out the exhaust section of LS1tech.com<br />Tons of information there on exhaust and its corresponding theory craft. With proven results showing gains and losses. <br /><br />Sent from my Galaxy Nexus using Tapatalk 2<br /><br /> Link to comment Share on other sites More sharing options...
pathfounder Posted May 15, 2013 Share Posted May 15, 2013 I didn't say that a 29% increase in wall area means a 29% decrease in overall fluid flow, but to say that the wall friction doesn't matter is completely wrong. Anything that moves past anything else will encounter resistance. If you look at velocity profiles of pipes, the velocity is always greatest in the centre, and slowest at the wall. Link to comment Share on other sites More sharing options...
shoesandsocks Posted May 15, 2013 Share Posted May 15, 2013 Link to comment Share on other sites More sharing options...
Rebelord Posted May 16, 2013 Share Posted May 16, 2013 Nah. No popcorn needed. His point is valid. Just that IMO the size piping needed for our engines 3.0/3.3/3.5 the difference is close to null. Considering we dont need full 2" dual for proper flow. Getting a little technical. But has anyone ever determined the Volumetric Efficiency of our engines? Cant imagine its much higher than 80% at best. (Someone needs to shoe horn a LSx engine in one of these!) Link to comment Share on other sites More sharing options...
shoesandsocks Posted May 16, 2013 Share Posted May 16, 2013 screw an ls coyote swap for the win lol Link to comment Share on other sites More sharing options...
Bluewulf73 Posted May 16, 2013 Share Posted May 16, 2013 (edited) Well, kind of...what do S/C Xterra's use? I mean, they can't be using piping much larger than what we have, especially given the "modest" HP bump. If one uses the stock configuration with 2" piping all the way back from the headers, (assuming one gets headers) then it should provide a decent increase without losing much torque, if any. In my 4-bangers, I always changed the puny 1 7/8" for a 2.5" from the header back and although I did lose some low-end grunt, the gains were well worth it. Also, believe it or not, I did see an increase in MPG while cruising on the hwy. (Note that I said cruising, please) Having said that, In this truck, I would not want to lose the low-end grunt and would be happy with just a tiny bit of increase at higher rpms. So, I'm still voting for stock configuration with 2" piping. Magnaflow muffler and either no resonator out back or a cherry-bomb, just to quiet things down...a bit. I am currently running stock everything, except for the end resonator. Just straight piped that one and the sound is great. Not loud enough to hear while driving but loud enough to hear it at idle and low speed cruising in alleyways. Edited May 16, 2013 by Bluewulf73 Link to comment Share on other sites More sharing options...
thorpe991 Posted October 8, 2013 Share Posted October 8, 2013 so not trying to jack his thread but if i was to run a single inlet of 2" to a dual outlet of 2" would i be ok or no? i would be runing the stock 1.75 pipe to the 2" inlet of the muffler then running 2" for the tail pipes Link to comment Share on other sites More sharing options...
Karmann Posted October 9, 2013 Share Posted October 9, 2013 I realize I have a different motor (VQ35) but I have the dual in/single out 2.5" Magnaflow 18" muffler, removed the resonator, and love it. Little more power, little bit better mileage, and the perfect tone- not obnoxious at all, but a nice hum. 1 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now