Operating your TR for maximum mileage

[Monkeywrench]

Bob, these are great points. AFR = air-fuel-ratio, is that correct? How would this be done?

The soft top improvement is due to aerodynamics, I assume. Would a hardtop be even better?

Yep, that's what I meant.

This is where electronic fuel injection is really nice.

Unlike a carburetor, you can shut down the injectors on engine deceleration. A lot of the time, you save fuel engine braking instead of letting it coast in idle (the injectors are still operating).

On a SU, the piston should drop when the throttle is closed, so you'll do better dropping it into neutral and letting it idle. This is where an A/F gauge and an 02 sensor are nice.

Fuel atomization is a big deal. I suspect Webers are much better at this than SUs. The better the fuel is atomized, the greater % is ignited and the leaner you can usually get away with running it. I've heard of some newer Hondas getting away with 19.1 at cruise! The less load, the leaner it can run, usually. The newest designed motorcycle carbs would maybe be your best bet.

Personally, I would just get it tuned as best you can on the dyno, and find gains elsewhere. To run that lean all the time with a carburetor would be impossible, and if it did work, it would be tiresome to stay on top of. This is what you should do. I can't be held liable if an engine gets melted down.

If you want to take a look at what you can do with a carburetor, take a look at the "lean burn" Hondas of the 80s.

On a Miata, the hardtop is 2mpg better than the soft top up. It really depends on its design.

Making the Triumph flat bottom should be really easy, and should help quite a bit as well. Excessive air dams push air. If you can build a flat bottom, just extend the front valence down to meet it. Be careful with trans/rear end/ and exhaust cooling.

You can raise the rear of the hood up slightly to let air out of the engine bay as well.

The rear wheel covers will also be a help.

Depending on how big your mirrors are, they can be a help. Most states only require a one external mirror. Check with your particular state.

 

[glemon]

tall skinny tires, especially if you are running a 70 series tire or even lower profile, bigger diameter means taller gearing, narrower means less wind resistance and possible less rolling resistance too.

Space saver (weight saver) spare (older Saab fits I think), lower antenna if you have one, underdrive (smaller) water pump and alternator/generator pulleys, front wheel alignment for zero toe in when driving, narrow, cogged, v-belt on the narrow pulleys. Lower viscosity oils, make sure drum brakes aren't too tightly adjusted and dragging.

 

[tdskip]

Less weight = better gas mileage. That is my excuse for having the cars all without interiors and other superfluous luxuries

 

[angelfj1]

Saving a non-renewable resource doesn't strike me as left/right/center, just seems smart.

what makes you think anybody is smart?

 

[DougF]

Back in the mid '80's, I responded to a car related want ad. When the phone call came, the man began speaking to me for an extended period of time about the magnets that clamp on fuel lines and change the ionization of the fuel, blah, blah blah.
As soon as I asked him about the need to make any other adjustment to the engine or carbs, he explained that he had an important phone call and would call me right back. I'm still waiting.
We will be seeing a lot of these miracle gas saving items coming onto the market again with the higher fuel costs.
Buyer beware.