kiryu

Hi folks when my car was bone stock, I am getting average 20 mpg, 28 on the highway and 18 local. I dont drive a lot of freeways, but when I do the mpg increases dramatically.

So I got borla for a few months now and I noticed I am losing a lot of MPG on the average. I didnt count the first month after I got the borla because I want to take into account the fun factor of hearing the exhaust, stepping hard on the gas etc. But it's been several months and I found my MPG hardly go above 16. I do get to 17-18 with some highway driving, but it never gets above 20 anymore. I thought a more free flowing exhaust (catback) with no secondary cats would actually increase mpg? I did not drive aggressively in the past month just to see how things go, and the mpg did not improve. I can understand the intake would affect the mpg since that has to do with air/fuel mixture etc., and maybe the upgraded headers with no cat, but a catback?

Do you think the trip computer might give wrong readings with the new catback? in that case I should really check the gas receipts and actual miles driven.

Thanks for any input

Zelfiris

My friend with catback gets better mpg than my ISF with headers + catback.

On my previous car I went with an aftermarket catback and also noticed loss of mpg compared to when i had the factory catback installed

Lets Drive

iTrader: (3)

The borla didn't change my mileage, and for that matter, neither did headers (sorta). I experienced a drop directly after installing the latter, but once I adjusted my driving, MPG went back up. My right foot still dictates MPG, by far (around 19 during winter months, 20-21 summer).

j3ff

If it makes you feel better, I average about 12 mpg. But I am definitely not driving in an economic manner.

BS ISF

after installing full exhaust the ecu makes it run very rich so mpg's will suffer a tad with both. not sure if my borla changed much at all.

zebani

iTrader: (5)

If you think that the trip computer might be wrong, just reset your trip meter at each filling. Keep your gas receipts, or use an app for that, to see how many miles you get between each filling and how much gas you put in your car. After 3-4 fillings, you should start getting pretty accurate information about your mpg.

Although I say 3-4 but that might be different in your case. For some reason if you have to drive mostly on the highway on your first tank and mostly city on the second one, you might get hwy and city mixed on your 3rd tank.

I8ABMR

I went through this before and its probably you just staying on it to hear it