Originally Posted by chito
I found a stock exhaust and put it on. Then I heard the exhaust leak I had missed. So on monday as I drove around the car actually felt really weak. It struggles to get up hills and no improvement on mpg's, maybe a little less if anything. I'm guessing it because of the leak. On tuesday I put the 2.25" exhaust back on and the car is back to running normal. I did notice that if I use 89 octane instead of 87 the fuel economy goes up from 31mpg to 33mpg. I know the EX motors have a slight increase in compression. So has anybody else experienced this or any ideas on whats going on
Not sure I agree with Old Mech about taller tires necessarily costing in FE, since Sentra-SER seemed to find somewhat different in this pretty thorough test: Tall tire test (taller gearing advantage offset by wider, heavier wheels/tires?)
As for the differences in mileage you describe driving around, I think you have to consider something else Old Mech said: that driving style (and conditions) will affect FE significantly. I would keep the stock exhaust on the car... that's "normal." The EX is only rated for like 127 HP, so it's not surprising it feels slower than what you might be used to. My DX in 106 HP, and it does scale hills a little slowly. But it does all it needs to do and then some.