Hi
As title indicates, what performance mods have you done to your car and did you notice a gain or reduction in mpg?

Some of you will probably say this is a stupid question and I should buy a prius or something. Well, dont bother.

So I thought why not try to improve both hp and mpg.
* Tune?
* Headers? Makes sense to increase mpg in daily driving due to less resistance?
* SC pulley or crank pulley?

Or any other performance mod you noticed an mpg gain from?
thanks

and yes, I live in a country with ridiculously high gas prices.

Done SCP, TB, HE, IC Pump, LTH no cats, 550 injectors, & tune. Saw MPG gain on Freeway driving 18-23 mpg pending on trip miles cruising at 80-85 mph. 10 miles trips I see 18, 100 miles I see 21-23 mpg. City sucks unless you baby the pedal 10-15 mpg.

Before mods, mpg was 17 if I’m lucky

ok so did you do everyting at once or did you notice any specific component which made most of the gain?

October I did cooling, 76 SCP & tune saw no mpg gain until November did 82 TB and 550 injectors with retuned and saw a decent mpg gain. But after installing LTH with retuned in December, I confirmed my mpg raised significantly during freeway driving. Very satisfied with that... and POWER! Honestly, I think you can get away with NOT installing LTH and have decent mpg gains. But exhaust companies advertise that you’ll get better mpg with LTH.

Just finished a 70 mile trip on fast trak sometimes going over 100, cruising 85 and still got 19 plus overall for the trip. Above photo was from a trip to San Diego.

Thanks for reply. I was thinking maybe to do long tube headers and a tune and keep the rest stock for now if that makes sense. To get a little more power, and better engine sound and hopefully a little better mpg. Maybe also sc pulley, but after reading a few horror stories about failures I am a bit sceptical as I dont want to risk big $$$ to repair after failure. However, I would assume the sc pulley quality has gotten better after failure reports? 🤔

if I can redo, I would do SCP, cooling, injectors and LTH with tune. TB I didn’t really notice power gain much. Definitely noticed night n day when LTH installed. However, after LTH installed, I’m getting primary O2 sensors code after installating new sensors as well...a bit frustrating but I cleared em and monitor. Maybe my sensor is getting dripped with rear main seal leaks. 🤬

FWIW.... My 2004 E-500 with the naturally aspirated five liter got 26 on the freeway every tank... Average speeds from starting cold to turning it off 104 miles later of 70-80. That car had the seven speed... Wonder how different ratios are? Wonder how impossible it is to get one to live behind the force fed bent eight in an E-55? Electronics for that automagique? I really liked that box. Closer ratios then the five speed. If failing memory serves 2000 at 70mph in seventh.

ok but no issues related to sc pulley?

Ok i believe engine rpm is approx. 1500 in 70 mph but not sure. Anyway seems to be a bit more thirsty than your 500... dont think 7 speed could handle the torque.

Seven speed lives happily behind 5.5 liter twin turbo bent eight and 6.0 liter bent 12 in S-65.

Hmmmm.....

None so far.