Increased mileage- electronic fuel injection

I know I can increase mileage by putting a smaller carburetor and smaller diameter exhaust on an older engine. It will decrease the horsepower, but what if I already have too much horsepower. What can I do to a fuel injected engine if I want to reduce horsepower?

Your premise is over-simplified.

Forget about “reducing horsepower” to improve fuel economy in your FI vehicle. Your best bets are a properly maintained vehicle and a disciplined right foot.

What if I would prefer my daughter NOT drive a 300hp vehicle?

Depends on the vehicle. What type of car is it? I’ll tell you whether you can de-tune it easily.

Buy her a 150 hp vehicle.

A Ford Mustang

Sorry, that’s not a car that you can detune by computer. However you can restrict the intake of the car by 1/2 which will cut down on the power significantly. Take a piece of sheet metal and design a restrictor plate to place BEFORE the mass airflow sensor.

I don’t think any of this is really necessary however. Girls don’t get into the same “push-the-limits” antics that guys get into. Girls aren’t out to prove their masculinity if you know what I mean. Besides, there is a certain level of trust you need to have between you and your daughter that should be left intact until it’s violated. Finally a modern mustang has traction control and will keep her out of trouble if she gets a little too agressive. Once again though, I doubt she’ll get into much trouble.

Oh and nothing you do will affect the fuel mileage-the computer already optimizes fuel mileage based on the position of the throttle plate.

One stone age method - put something under the gas pedal (brick?) that limits gas pedal travel.

I believe you are right on the sociological aspects…

A technical question then. What if I clogged two injectors on a 6 cylinder engine and installed a 4 cylinder distributor and custom cam?

Unless you’re a closet car computer guru there’s no good way of doing this. You’ll have all kinds of problems with how the engine reacts.

Install a throttle stop that will only allow the throttle plate to open halfway.

If you want to remove something to make the car safer, remove the back seat. Multiple passengers is the quickest path to teenager reckless driving and an accident. Easy to do, no engine mods required, and increases cargo space!

just make sure to drill it into the floor, otherwise that could slide around to underneath the brake pedal, which would certainly reduce gas consumption, because it would be wrecked.

A smaller carb might help, but just putting a stop on the accelerator might work, but it also could slow the car down in an emergency situation where a little more power might prevent an accident. Driver training is free and lacks all the down sides, it also is 100% transferable from car to car.

Reducing the exhaust size is likely to decrease performance, mileage and life of the engine.

“A smaller carb might help”

On a FUEL-INJECTED engine? Hmmmm…

Whatever you do to the car, to detune it, someone may “repair” the car for her.

If you want to really know how someone is actually driving a vehicle, you can plug a chip, called Drive Right, into the scan tool test plug. You later connect the Drive Right chip into your pc (personal computer) via a usb cable, and download the vehicle’s driven history and view the data. Cost: about $150.

What if I would prefer my daughter NOT drive a 300hp vehicle?

I would give her a Focus instead of a Mustang. It would be better than castrating the Mustang.

Didn’t bannanas up the tailpipe work for Axel Foley?

That was a Fairmont, not a Mustang! ;o)

Almost any detuning will violate federal emissions laws.