I'm wondering if anyone has used these and know if they increased gas mileage. I'm just trying to justify the $70 for them because it would've been gas anyway if they do help

If they do, how much did you see the increase by?

They will certainly make the Z more aerodynamic, but I doubt that you'll recoup your $70 investment from increased mileage any time soon. If you like the covers, buy them. Adjusting the carbs and gapping the spark plugs will probably be as effective for increasing MPG - and those only require time, not money. 2¢

Dennis

To adjust the carbs would actually require a lot of time. He'd have to remove the EFI and install them first......

I'd have to agree with Dennis (aside from tuning carbs on a FI engine ). Tune the engine properly first. Read the FSM on the proper techniques to tune your engine. Change your driving style to shift sooner. Easy on and easy off the gas & brakes. Those will make much more of a difference to your gas mileage than headlight covers, especially since the headlight covers do nothing to address the fact that the rest of the front of the car isn't very aerodynamic.

At $3.50 per gallon, assuming that you get 25mpg, a 1% improvement it would take 7,000 miles of driving to recoup the $70 "investment". However, I would guess that the improvement would be closer to 0.1%. At that rate, it would take 70,000 miles of driving to break even.

A more valid justification for the purchase is this; if you like the way they look, you should purchase them.

I love math problems . Justifying $70 / $3.50 means you need to save 20 gallons of gas. At 25 mpg that means you would need to save 500 miles worth of gas. So at 1% improvement you would need to drive 50,000 miles. At .1% improvement which is more likely, that would be 500,000 miles.

The way I would self justify it is you would improve resale value by at least that amount. Go for it and post some pics!

This is really a memory test for me but I remember reading someone tested the improvement in mileage/or coefficient of drag when headlight covers were installed on a 240Z and the improvement was .3, whether that was mileage improvement or coefficient of drag improvement I can't remember.

Edited January 2, 201213 yr by Mikes Z car
better memory

To adjust the carbs would actually require a lot of time. He'd have to remove the EFI and install them first......

Someday, I will learn to do a background check on a poster's Z before responding. Thanks for keping me honest. I keep forgetting that all Zs don't have carbs........:stupid:

Dennis

thanks for the information

i do like the covers, but I dont have money to spend on things that wont help mpg. right now I believe Im getting around 18mpg. I havent adjusted my valves or gapped the spark plugs yet though.