pdexta

I've always been quick to call people crazy when they claim to get 30 mpg in their S2000. Since getting the car about 14,000 miles ago I've only reached 25 mpg on 2 tanks of gas and both were all interstate with the top up and air conditioner off. I'm quite consistent in recording 20 and 21 mpg around town, with a cumulative average of 21.97 mpg.

I recently had 4.44 gears installed and have done my very best to take it easy breaking them in. I've been interested to see how the gears would affect my gas mileage, I'm assuming I'll lose a little bit. Well, I finally made it through my first tank with the gears. I noticed that I was getting good mileage but certainly wasn't expecting my 2nd highest EVER! 25.73 mpg with gears, around town, top down!

This really makes me wonder what I could get on the highway, with stock gearing, taking it easy, with the top up. Unfortunately, I was never able to do it I shall doubt no more! 30 mpg definately seems attainable under the right conditions.

MacGyver

When you say "interstate with the top up and air conditioner off", do you mean your windows were down? If they were, you'll actually get better mileage with the windows up and the A/C on while running on the interstate. I managed around 27-29 mpg with mixed highway/city driving back in my stocker days, but I'm sure that has dropped since I put the test pipe on and didn't install the O[sub]2[/sub] defeater.

Sub-Zero

You may be getting better acceration with less pedal due to the gears. Thus you don't need as much gas to get you up to speed. Your highway mileage should be less at the same speed because you will be turning a little higher RPM, unless you polished your gears before installing them. I have seen dynos of 5hp gain from polishing the gears due to reduction in friction. I don't believe the 5hp but it makes sense about the friction reduction.

captainbk

On my recent trip to the mountains, I consistantly got 28-30 running at a steady 80mph. I am sure it would have been better at 65-70and if I used the cruise control all the time. My only mods are the exhaust, FIPK and the Hondata gasket. Just my 2 cents worth....

Sub-Zero

On the highway at 70-80 I get about 24. City is around 20-21 if I can keep my foot out of it. About 16 if I play.

It is not the turbos fault I understand.

SiCK HONDA

Am I stupid, it's early... but doesn't your speedo have to be calibrated with new gears??

Could this be a false mileage reading due to the new gearing?

Sub-Zero

Excellent point!

MDMAS2k

Explain to me how you can get better mileage when you have the A/C on. This puts more force on the crank which would make it work harder to maintain the same rev per min.

Just a ?

MacGyver

At low speeds this is true and your mpg will go down with the A/C on. However, at high speeds (i.e., highway) the increased drag from having your windows open exceeds the drain on your engine from the A/C compressor.

jvrabel

I'm pretty sure Mythbusters did a show on this and they said the break even point is 55 mph. Over that use the a/c, under use the windows. I've been using that as a rule lately.