You cannot calculate gas mileage by looking at the fuel gauge. The gauge is not accurate. You can only check mileage when you fill the tank.

FWIW: FD fuel tank holds just over 20 gallons. See FSM.

 

I hope you are not seriously using the factory stock gas gauge to calculate mpg. Look at the pump next time and see how many gallons you used for the mileage driven/distance traveled. All this assuming you are also on correct size tires, then you will get an accurate fuel consumption number.

 

thanks guys, the next time i pump gas to full, i'll just make sure to check how much i dump then do the math. All this time, i thought the FD only has an 18 tank =[ , but 20 meant i have worse gas mileage

 

The size of the fuel tank has zero effect on gas mileage.

 

Exactly.

The difference between half tank to full, is not the same as half tank to empty as indicated on the gas level needle. I'm guessing because of the shape, and baffles of the tank

 

ON this note about calculating MPG...here's how I have done it, and it works with any size tank.

1. Fill up tank and zero out the miles.
2. At next fill up, record how many miles you drove divided by how many gallons you just put in.

So if I drove 180 miles, and I just put in 12 gallons, then I averaged 15mpg...

~CYD

 

^easiest and most correct way to do it.

 

Just did it the way CYD recommended, pump 11.177 gallon to full tank, distance travel 163.8mi

163.8mi/11.177 gal = 14.655 mpg

Still not where I want to be with stock non-seq setup, front mount Intercooler, blitz nur spec, apexi avcr, pfc, greddy intake, fluidyne rad. , aem uego,

How can I reach 18-20 mpg?
If I replace my cat with straight pipe, will it help improve mpg?

Cuz my car was tune with a straight pipe from Neptune speed, then put the cat back on since the straight pipe belong to Yoshi.

 

are you getting the 14.6 on the highway or around town, that's pretty common around town. Good luck getting 18-20 in town, they weren't rated that good when they were new.

 

You won't do much better than that unless you are on a road trip. Remember that a completely stock FD is rated at 15mpg city.

 

Replacing your cat with a straight pipe, will not improve mpg much however you will just be polluting the already polluted Los Angeles air and just asking to get pulled over. The best way to squeeze some mpg out of the car is to get a wideband, and tune the cruise tables yourself or go back to Yoshi and have him do some road tuning for better fuel mileage.

 

http://www.fuelly.com/

 

trainwreck, thanks.. but yeah, a note on the "got pulled over", i did 2 days ago for loud exhaust.

I will get the straight pipe anyway even thought it won't improve my mpg since every time I pulled on 2nd gear, around 5000-6000rpm, it make the choking "poof poof poof" sounds on the exhaust due to the cat. Not enough flow.