Poor MPG Commom After Boost

**kobe 8** · December 26th, 2003, 07:05 AM

My gas mileage went down from 27-28 mpg (before JRSC) to 22mpg. Is this common since I have a higher flow fuel pump along with the JRSC. I read somewhere that after the install, someone got better gas mileage?

**Ray000** · December 26th, 2003, 12:57 PM

I think typically a FI car should get the same if not possibly better gas mileage than your stock NA motor. BUT, if you have just gone FI than its likely you are driving around everywhere with the pedal to the metal and with any car the MPG will go down.

**CROM** · December 26th, 2003, 12:58 PM

Do you have a timing controller?

With severely retarded timing your gas mileage is going to suffer when you aren't on boost and trying to make a little extra power (like going up a slight hill or accelerating past a slow driver,that does not rquire the pedal to meet the floor). Cause you're going to have to give it more gas than you normally would.

I noticed this occuring when I initially installed my supercharger and had no means of controlling my off boost/on boost timing. I purchased a BTC and noticed a significant gain in gas mileage. I run 10psi and 290cc injectors w/larger fuel pump and I get around 32mpg daily and on the highway I have gotten up to 40!! [img]eek.gif[/img]

**kobe 8** · December 26th, 2003, 05:03 PM

I don't have bigger injectors but I do have a BTC & my MPG is still low. I just thought that if you have FI, naturally your gas mileage will tend to be lower than normal. Just wondering what others are getting....

**217gsr** · December 26th, 2003, 05:12 PM

Kobe, you are describing EXACTLY what happened to me when I first installed my blower. I went from roughly 28 mpg to 22. After a couple months, I learned to not always drive in boost. If you have a boost gauge, take note of whether or not you are driving in boost often. Once you get used to the new blower, your mileage will go back up. Mine is up to 30-31 again.

**kobe 8** · December 26th, 2003, 05:51 PM

Thanks 217gsr, I'll try that method....

**Max Psi GSR** · December 27th, 2003, 03:17 AM

Just for refrence on the MPG issue and "foot to the floor" syndrome......

I did this open-track(road racing)event in Virginia where I filled up with 110octane and got appx. 9mpg. Its somewhere around there because I filled up TWICE and got a total of 180 track miles on the car.

Now keep in mind, when I got it back home....it proceeded to get 25-30 all day long. Im really a grandma on the streets, and usually cruise at 75-80 on the interstates.