Not sure what that is in mpg but I get about 350 miles to a tank in my si. or 27 mpg on average. If after doing the conversion you are much below that I would think that the sri and or a dirty maf sensor could be the issue.
I would clean the maf sensor and put the stock intake back on. If that doesn't improve the mpg then I would go to the dealer. 250 miles per tank is far too low. You are running way rich, what sri do you have? If the mpg goes up with the stock intake on then If I was you I would buy the x's intake as he has done many afr tests on it to prevent this problem.
Clean the maf sensor and use the stock filter. An oil film on a maf sensor will cause the car to run rich. It's worth a shot and the cleaner is only a couple bucks at the car parts store. If that doesn't work or you had the same mpg with the stock filter and stock header then something is wrong with the car hard parts or ecu I don't know? If the mpg changed at the time of the header install then you could have an issue there but I doubt that's it. Time for a little deduction, look at the time table for mods vs mpg to point you in the right direction. Additionally look at any other factors that could be compounding the issue. Larger rims? Lower air pressure in the tires? You and your buddies are sumo wrestlers?
... something maybe wrong with my fa5 si too
there was a nashville meet so i rolled out with 2 other 8th gen guys
i was 3 bars under full and the other fa5 was full and when we got there i have 3 bars left and he still have alittle over half tank or so
and from memphis to nasville is like 200 miles about...
is it just me??? or am i not getting the milage im suppose to?
Don't go by the bars. Fill the tank and reset your odometer/trip meter, drive to almost empty. Fill the tank again now divide the numer of miles on the trip meter by the number of gallons you just put in the tank. That's the best way to figure your mpg.
JMorris thanks for taking the time to help me out.
I only have the drop in filter and a Magnaflow exhaust for engine mods. My rims are 17" just like stock too, except that they're 225's and the rims are each 3lbs lighter than stock.
The mileage actually got a tiny bit better when I put the drop in filter in.
The only other factors are that there are always two people in the car and I do like to drive at about 3500rpm. Also if weather and traffic permits I Vtec in 2nd. Most of my drives are also only in the 10 to 15 km range.
jackolee - Listen to JMorris, don't go by the bars. I get about 70kms before I even lose one bar then when I get to about 200kms I have half the bars then at about the last four bars my total mileage would be 280kms.
Usually quite a bit of traffic. Vancouver has been bad lately. There is construction everywhere and the city has kind of been divided in half because of a mass transit system we need to have for the Olympics in 2010.
My milage is way low too. 07 Si FA5 w DCRH and intake. Good mix of city/highway miles. One tank averaged 22.8 miles per gallon. Our Suburban gets almost 18 mpg avg.
I tried a little experiment for about 200 miles after a fill up. I drove as slow as possible and never ventured into the 4500+ rpm range. I tried very hard to shift smoothly, not downshifting when coming to stops, doing everything I could to use as little fuel as possibe. (Very hard to do BTW). Even then, my MPG was under 28.
My overall MPG has been 25 to 27mpg. Pretty bad I must say. And nowhere near the 24/32 the car is rated at. I do vTEC from time to time, but I do drive on the conservative side. Especially since premium at my local station just hit $3.69/gal. $45.00 to fill my Honda??? WTF? :box: