Posted: Mar 16 2008 at 10:54am | IP Logged

05FrontierSE

You can try running the mufflers on edge side by side in the same location or you can run them flat and stagger them one in front of the other but still side by side .....and then have custom tailpipes bent out the back where you want them.

My .02 is that everything you do the modify the performance of todays cars which have MILLIONS spent in R&D to optimize performance and mileage, you're going to end up losing somewhere.  It's like an algebraic equation, whatever you do to one side of the equation, you have to do to the other.  Whatever you do to the intake, you have to do to the exhaust to expell that extra intake and vis-a-versa.  Also  if you want more top end, you're going to lose bottom end........and vis-a-versa.  And the one gaurrantee is that your gas mileage WILL suffer.

Posted: Mar 16 2008 at 2:01pm | IP Logged

On the gas mileage suffering....really? I"m not trying to be sarcastic, but I've heard of others indicating that as long as they are staying out of the tall pedal, that they will see their numbers increase from opening up front to back. Granted, you might give up a little torque on the low end, however you might end up gaining in the peak torque numbers overall, it just might shift the peak up the rpm range. Whether or not that is fact or not, I do not know, just speculation.

One thing that comes to mind is that sometimes when people hear the new growl their vehicle is putting out with either an intake or exhaust upgrade, or both, that the sound is so inviting that people lean on the pedal more than they normally would, which would definitely affect fuel economy.

I will agree with Nelson on the fact that you could run dual mufflers in either of the configurations that he indicated as an alternative to the one I posted about. I have thought about those as well, when looking at the flowmaster hushpower II or whatever it is called, I figured they are fairly small mufflers and I could have them welded together with a bracket or something. In the end, I figured that having the dual in dual out muffler will still  give a bit of a choke point to maintain some backpressure instead of totally opening up the system.

Posted: Mar 17 2008 at 3:44pm | IP Logged

Frontyfan

You can possibly get an increase in mileage, but it will only be on the highway, and the increase will be minimal.  It just depends on how big you go with the exhaust.  You will definitely give up bottom end torque, which is why you'll lose the around town gas mileage.  You're right as for the torque moving up the RPM range. It will move anywhere from 500-1000 RPM depending on the system installed.  Yes, you could actually gain in peak torque, but probably at 4-5000 RPM.  Unless you want a race truck, that's not a very usable RPM range to be driving in, not to mention my 06 kc 4x2 4.0 ways 4000lb. so I would rather have more bottom end. 

You are definitely right regarding the people hearing their new exhaust and leaning harder on the long skinny pedal causing them to get worse mileage, but having installed hundreds of exhaust systems on all kinds of trucks including my own, though not on an 05 or newer Frontier yet, I can tell you from first hand experience that the only mileage increase ever noted was on the highway.

I had a '94 chevy s-10 with 4.3 v-6 auto and after installing a 2.5" flowmaster cat-back system, I lost 4 MPG!!!   Yep, you read that right, 4MPG (from 17/21 to 14/16).  I also lost power.  I used to race motocross and had to drive ALOT, so I would drive to the same tracks over and over.  And there is one track in the high desert out here (southern calif.) that you have to drive up a long steep grade to get there. I used to go up that grade in overdrive at 75mph with my stock exhaust.  After installing the flowmaster system, I could barely go up in drive and maintain the speed limit.  And this was  with only a 2.5" single exhaust.

You have to remember that the manufacturers spend MILLION$ in research and developement, so if there was a way to get better power and mileage out of just installing a free flowing exhaust, they would have done it. 

The only exhaust system I've ever seen that seems to give the best of both worlds is the Walker Dynomax system.  The problem is that it doesn't sound as loud as everything else which is what people want.

This is just my .02   I try not to learn the hard way and if I can help someone with limited funds avoid a $$$$$$ mistake, then it's woth it.

Take care!