Forced Induction: Does it increase fuel economy?

[Aaron 02 Si]

With today's increasing prices on fuel, I am looking to cut corners wherever possible.
Does a supercharger or a turbo greatly increase the fuel economy of the EP?
Does adding a cold air intake increase fuel economy?
Also, what are some other things that could be modified to increase the fuel economy?

Thanks

[EtherGhost]

The cold air intake will probably increase your fuel economy. A supercharger will probably decrease your fuel economy because of the parasitic drag on the engine. Not sure what the turbocharger would do. It could conceivably make your car more efficient, but if you install a turbocharger you'd probably be driving it harder...

[SiR Medic]

Turbocharging will DECREASE fuel mileage.

Turbocharging works by using compression to increase the amount of air going into the cylinders. In order to take advantage of this, more fuel must be pumped in as well. This is why turbo cars always require upgraded fuel injectors.

Results vary of course, depending of driving style, etc.

There is very little you can do to increase mileage AND improve power, Honda does much of that on its own.

[2.0L Monster]

If you really want more miles per gallon, swap in a D17 from the HX. You can get close to 40 mpg. I think its the HX, its the engine with the same vtec as ours.

[Tenacious G]

think of it this way ... in order to make more power, you need to use more fuel. any FI will take a toll on your fuel economy.

[smilla0]

Use thinner head gaskets, have your cylinder head milled, and/or use higher compression pistons (like from a K20A2/K20A). This will increase your compression ratio which will increase both power and fuel economy. But you'll also need to run higher octane fuel, which will probably cost you more, but you might break even. Using the Type-S 6 speed and final drive gear will also improve your 1/4 mile times while increasing highway miles. Hell, you might as well just do a complete Type-S engine/tranny swap. The Type-S is supposed to get 2-3 more mpg than our cars. Using a DC5R tranny and diff will significantly improve your 1/4 mile while keeping your highway mileage the same. Not sure about the DC5R motor. Lightweight forged rims will help both, too. Stripping out the interior of your car and other non-essential parts will help alot.

Perhaps, the best mod is to sell your car and buy a motorcycle. Besides the major fuel savings, you'll save yourself a lot of cash on the car (and probably insurance too) but still be fast. And buy an old cx hatch for the cold/rain. Honestly, if you can't afford to pay for gas with a new Civic Si, you might want to reconsider your decision to own a new car. The money you pay for mods could pay for many years of gas.

[Aaron 02 Si]

thank you for your comments.