Not Much You Can Do (to an engine to raise efficiency... o rly?)

[oldschool]

I guess we will all have to apply for experimental vehicle liscences for the cars we are working on, most places that exempts one from emmissions testing. Either way one has to be stealthy especially if you go for yrly or bi yrly emmisions tests. AS I understand even having a bottle under the hood that doesn't belong there can end the test right then and there, even if its not hooked up to anything.

Thats a good list Coyote, and I would like to add a few things. In the US vehicles 1967 or earlier are exempt from emmisions equipmwnt so you are pretty much free do play.

Singh grooves: shown to drop the exhaust gas temps at least 20 degrees so you are using more of the heat for power.

Edging the combustion chamber, smoothing the transition from the chamber to the squish area. This will increase the chambers tolerance to detonation.

If you port the heads or the intake and exhaust , make or leave the intake ports as rough as you can, this will help keep the turbulance in the port and the fuel in suspension.

Exhaust is exactly the opposite smooth is the answer. They used to sell antireversion header which helped to stop any exahust from reentering the chamber because of a lil cone just outside the header gasket. If you are into fabricating this same thing can be achieved to a diminished capacity stepping up the diameter of the exhaust pipe every so often, small next to the port to enhance flow speeds out of the port and larger as it goes out into the main system.

Opt for a cam that makes higher torque and less hp in the useable rpm range for your vehicle.

Anything that you can add that tends to increase the torque of the engine where you drive will tend to increas mileage as long as you drive for it.

[WaxyChicken]

The problem in my state isn't the tamper laws. the problem in my state is the emissions.
Granted, many engine mods will reduce emissions, but also if fuel emissions are TOO low then they will decline to approve your vehicle because such a dip in emissions would, of course, only be explained if the exhaust system was failing.

geez, what a joke.

[Who]

Originally Posted by roflwaffle

Peak efficiency varies little from engine to engine, and I've seen no laws against changing gearing.

Gearing is becoming a status symbol and a useful one at that. Oh how I'd love to have a 6 speed tranny mated to a 3 speed transaxle, especially if it could stay a low percent of the overall vehicle mass.

[DifferentPointofView]

They don't get you much for anything here unless they can HEAR that the exhaust is missing

I don't mess with the engine much, I do help the engine heat up by using grille blocks and stuff. It's not touching the engine, nor modding the engine, just the grille. Cops pull me over and I'll just say.

"like the custom grille men?"

[Ryland]

A gas engine is only turning 24% of the gasoline in to mecanical enengy, so there is alot that you can do.