Catback exhaust lower mileage

[Onpoint101]

2011 Altima coupe and since I had my exhaust install my gas hasn't been the same. I use to get a week and 3 days on my tank and now it's just 5 or 6. Would I need to get it custom tune or get an intake or what does anyone recommend I do about this.

[xshinnyshinx]

It's probably because you're gunning it when you're driving now that you have an exhaust. I used to get like 9 or 10 days before and I still do because I don't rev it real hard as I used to.

[Onpoint101]

Yeah. I took it to Nissan and they said everything checked out right so I'm gonna reExamination and see how much I've been riding and etc. Also if gunning is nt the issue what will u suggest that I do?

[xshinnyshinx]

I'd do something about the actual catback and get it replaced or checked out thoroughly

[RicerX]

Welcome to NICO!

1) What kind of catback is it? What engine do you have and what transmission?

2) What RPM are you revving to typically? I find that when I add catback exhausts to my cars my foot gains a couple pounds

Be sure your driving habits have not changed. Catbacks typically change airflow which can adversely affect fuel economy depending on setup (that's kind of the point)

Anyway- get back to us with some specifics so we can better narrow down what the true problem is. I doubt it is the catback that's the problem.

[downedzephyr]

It's the lead-foot syndrome!

[CoupeVQ35CVT]

I've had 2 cars with 3 different exhaust setups, and I can tell you that none of it made any kind of drastic difference whatsoever to the MPG of my cars.

It is most probably a bad install, a defective exhaust piping setup, or lead-foot, as already mentioned.

Just FYI, what was your MPG gauge at before, and what is it reading now? Mine had been rock solid at 23.7 to 23.9 for about 3 years then due to a change in driving route and habits, it's up to 24.4 MPG. I drive the 3.5 CVT coupe.

[RicerX]

I have done the following setups with my car, and I'll rank them from best to worst with fuel economy with my driving habits:

1) Racingline Y-Pipe + Greddy Spectrum Elite Catback
2) Tanabe Axle-back only
3) Stock
4) Racingline Y-Pipe + Tanabe Axle-back (I attribute this to wildly changing airflow dynamics that disrupt efficiency)

Unless your catback is some eBay botch job, I find it very hard to believe that, with a proper installation, you have drastic fuel economy decreases from a catback. It's either the lead foot syndrome (trust me, I got the lead foot syndrome BAD when I added my Ark Performance catback to my 370 - went from 24 MPG on my work commute to 20-21 LOL) or there may be a leak somewhere or the exhaust's airflow dynamics are so terrible they're causing resistance.

[downedzephyr]

I have done the following setups with my car, and I'll rank them from best to worst with fuel economy with my driving habits:

1) Racingline Y-Pipe + Greddy Spectrum Elite Catback
2) Tanabe Axle-back only
3) Stock
4) Racingline Y-Pipe + Tanabe Axle-back (I attribute this to wildly changing airflow dynamics that disrupt efficiency)

Unless your catback is some eBay botch job, I find it very hard to believe that, with a proper installation, you have drastic fuel economy decreases from a catback. It's either the lead foot syndrome (trust me, I got the lead foot syndrome BAD when I added my Ark Performance catback to my 370 - went from 24 MPG on my work commute to 20-21 LOL) or there may be a leak somewhere or the exhaust's airflow dynamics are so terrible they're causing resistance.

Interesting, we've done basically the same thing! In order from oldest to newest for me:
1) Stock + Injen Intake
2) Tanabe Axelback + Injen Intake
3) Racingline Y-Pipe + Tanabe Axelback + Injen Intake
4) Racingline Y-Pipe + Greddy Spectrum Elite Catback + Injen Intake

Over the course of my various changes I can't say I've seen any significant changes in my gas milage other than when I purposely put my foot to the floor. I also agree that there may be a leak; did you use the proper size gaskets for your exhaust?