Took it easy on the car to see what kind of gas mileage I could get

[overst33r]

Our of curiousty I decided to see what I can manage in the new car to compare it to the old one...

Speed was between 65-70mph. The route was 90 miles. 12 of those miles were stop and go driving. I managed 37.3 mpg in the S. I figure 90 miles should be enough distance to eliminate the error in pump shut off and give me a decent estimate.

That's impressive to me considering the miata got 36mpg and has 400 less cc's and turns about the same rpm. So for all intents and purposes the two cars get about the same MPG, but the miata weighs 400lbs less. Now all I need is a 7th gear to get those RPM's down... it does 3400rpm at 65mph.

 

[JulesMaximus]

I find that damned near impossible to believe.

Edmunds.com has that car listed at 18 mpg / 25 mpg. Were you driving it downhill the entire time?

 

[LTC8K6]

The pump shutoff method is not reliable enough.

Get a scangauge2 or something that will read out your average FE.

 

[overst33r]

Originally posted by: JulesMaximus
I find that damned near impossible to believe.

Edmunds.com has that car listed at 18 mpg / 25 mpg. Were you driving it downhill the entire time?

I have gotten three tanks 25-26mpg while on my regular commute (70hwy/30city) and beating on it so the EPA estimate doesn't really apply, then again it didn't on my miata either for which I was getting 30mpg on the same route.

 

[thomsbrain]

Are these UK gallons?

90 miles isn't close to enough to reduce pump variance. That's less than 3 gallons, and I can tell you from experience that pumps can easily vary by 1/2 a gallon. So you're looking at +/- 20% error right off the bat. You really need to use up a full tank. The farther you drive, the smaller any differences in pumps will be in terms of percentage of overall fuel. And it really helps to average over a few tanks.

That said, the S2000 does pretty well on gas considering how tuned it is and the fairly short gearing.

 

[cheesehead]

Originally posted by: JulesMaximus
I find that damned near impossible to believe.

Edmunds.com has that car listed at 18 mpg / 25 mpg. Were you driving it downhill the entire time?

The S2000 only has a 2.4L engine (2L in the rest of the world), slippery aerodynamics, and a (relatively) low weight of about 2800 lbs. The massive fuel thirst is a combination of agressive tuning and the 8,000RPM redline. (Everywhere else it's 9,000.) While the car is quite fast if you put your foot down, the combination of low displacement and high-RPM tuning mean that there's very little power at low RPMs. As such, the S200 can't use the double-overdrive trick of the Corvette - put the gear ratio too low, and the car won't even move.

However, if you put the car on a highway, put it in 6th gear, and avoid accelerating or decelerating, the fuel economy should go up quite a lot. I'm guessing that the Honda VTEC system is far more economical in the lower-RPM cam setting, which most people will very rarely see.

Also, I'm a little fuzzy on this, but Consumer Reports reported close to 30MPG on the highway in an S2000 at some point or another. The EPA has a funny economy rating system - a "28mpg" Saab might barely do 22, while my dad's Mazda3 does 37 on the highway. (Yay, Ford!)

 

[AdamK47]

I'm able to get 99.9 MPG pretty regularly on the road.

 

[Throckmorton]

Originally posted by: Cheesehead

Originally posted by: JulesMaximus
I find that damned near impossible to believe.

Edmunds.com has that car listed at 18 mpg / 25 mpg. Were you driving it downhill the entire time?

The S2000 only has a 2.4L engine (2L in the rest of the world), slippery aerodynamics, and a (relatively) low weight of about 2800 lbs. The massive fuel thirst is a combination of agressive tuning and the 8,000RPM redline. (Everywhere else it's 9,000.) While the car is quite fast if you put your foot down, the combination of low displacement and high-RPM tuning mean that there's very little power at low RPMs. As such, the S200 can't use the double-overdrive trick of the Corvette - put the gear ratio too low, and the car won't even move.

However, if you put the car on a highway, put it in 6th gear, and avoid accelerating or decelerating, the fuel economy should go up quite a lot. I'm guessing that the Honda VTEC system is far more economical in the lower-RPM cam setting, which most people will very rarely see.

Also, I'm a little fuzzy on this, but Consumer Reports reported close to 30MPG on the highway in an S2000 at some point or another. The EPA has a funny economy rating system - a "28mpg" Saab might barely do 22, while my dad's Mazda3 does 37 on the highway. (Yay, Ford!)

Best gas mileage should be at whatever rpm the torque peaks at. I'd think that would be pretty high for an S2k

 

[cheesehead]

Originally posted by: Throckmorton


Best gas mileage should be at whatever rpm the torque peaks at. I'd think that would be pretty high for an S2k

Wouldn't two cam profiles give two torque peaks?

 

[Throckmorton]

Originally posted by: Cheesehead

Originally posted by: Throckmorton


Best gas mileage should be at whatever rpm the torque peaks at. I'd think that would be pretty high for an S2k

Wouldn't two cam profiles give two torque peaks?

I think I was just repeating a myth

http://www.airforums.com/forum...-gas-mileage-3283.html

 

[JulesMaximus]

Originally posted by: mariok2006

Originally posted by: JulesMaximus
I find that damned near impossible to believe.

Edmunds.com has that car listed at 18 mpg / 25 mpg. Were you driving it downhill the entire time?

I have gotten three tanks 25-26mpg while on my regular commute (70hwy/30city) and beating on it so the EPA estimate doesn't really apply, then again it didn't on my miata either for which I was getting 30mpg on the same route.

My car is rated 18/24 and I typically get 18mpg city and 23-24 on the freeway. Interestingly enough I tried babying the throttle for a tankful on a drive out to Palm Springs once. Filled up and drove there and back along with some driving while I was there. I reset my computer after filling up to see what the average mpg would be and after my trip I had driven almost 300 miles and it indicated 28mpg average. When I filled up though I calculated a true value of 25mpg.

Honestly, I don't think 90 miles is enough to give you a reliable number. Go through an entire tank and then let us know what you find. I'm betting it will be a lot lower than 37mpg.

 

[overst33r]

Originally posted by: JulesMaximus

Originally posted by: mariok2006

Originally posted by: JulesMaximus
I find that damned near impossible to believe.

Edmunds.com has that car listed at 18 mpg / 25 mpg. Were you driving it downhill the entire time?

I have gotten three tanks 25-26mpg while on my regular commute (70hwy/30city) and beating on it so the EPA estimate doesn't really apply, then again it didn't on my miata either for which I was getting 30mpg on the same route.

My car is rated 18/24 and I typically get 18mpg city and 23-24 on the freeway. Interestingly enough I tried babying the throttle for a tankful on a drive out to Palm Springs once. Filled up and drove there and back along with some driving while I was there. I reset my computer after filling up to see what the average mpg would be and after my trip I had driven almost 300 miles and it indicated 28mpg average. When I filled up though I calculated a true value of 25mpg.

Honestly, I don't think 90 miles is enough to give you a reliable number. Go through an entire tank and then let us know what you find. I'm betting it will be a lot lower than 37mpg.

Will do next time I get a chance.

 

[overst33r]

Originally posted by: Cheesehead

Originally posted by: JulesMaximus
I find that damned near impossible to believe.

Edmunds.com has that car listed at 18 mpg / 25 mpg. Were you driving it downhill the entire time?

The S2000 only has a 2.4L engine (2L in the rest of the world), slippery aerodynamics, and a (relatively) low weight of about 2800 lbs. The massive fuel thirst is a combination of agressive tuning and the 8,000RPM redline. (Everywhere else it's 9,000.) While the car is quite fast if you put your foot down, the combination of low displacement and high-RPM tuning mean that there's very little power at low RPMs. As such, the S200 can't use the double-overdrive trick of the Corvette - put the gear ratio too low, and the car won't even move.

However, if you put the car on a highway, put it in 6th gear, and avoid accelerating or decelerating, the fuel economy should go up quite a lot. I'm guessing that the Honda VTEC system is far more economical in the lower-RPM cam setting, which most people will very rarely see.

Also, I'm a little fuzzy on this, but Consumer Reports reported close to 30MPG on the highway in an S2000 at some point or another. The EPA has a funny economy rating system - a "28mpg" Saab might barely do 22, while my dad's Mazda3 does 37 on the highway. (Yay, Ford!)

It's a 2.2L in America since 2004. In Japan since 2006. I believe only Europe and Australia still have the 2.0L.

The aerodynamics aren't especially good at .32 Cd because of the relatively steep windshield.

Torque peak is at 6200rpm. There is no way I will get best gas mileage up there. The engine might be the most efficient, in terms of work in/out, but it will not get the best gas mileage.

You are right about two torque peaks. On the low cam, it happens about 4000rpm, and on the hot cam it happens right after it hits VTEC at 6200rpm. It helps that the "curve" is relatively flat on both cams.

 

[cheesehead]

Originally posted by: mariok2006


It's a 2.2L in America since 2004. In Japan since 2006. I believe only Europe and Australia still have the 2.0L.

Oops.

Originally posted by: mariok2006

The aerodynamics aren't especially good at .32 Cd because of the relatively steep windshield.

Remember, drag is a function of Cd * frontal area. And the S2000 has a lot less than, say, a CR-V.

Originally posted by: mariok2006

You are right about to torque peaks. On the low cam, it happens about 4000rpm, and on the hot cam it happens right after it hits VTEC at 6200rpm. It helps that the "curve" is relatively flat on both cams.

The extra 200cc in the US S2000 must make a big difference - every UK review of the S2000 complains that all the torque is up above 5,000RPM.

 

[overst33r]

Originally posted by: Cheesehead

Originally posted by: mariok2006


It's a 2.2L in America since 2004. In Japan since 2006. I believe only Europe and Australia still have the 2.0L.

Oops.

Originally posted by: mariok2006

The aerodynamics aren't especially good at .32 Cd because of the relatively steep windshield.

Remember, drag is a function of Cd * frontal area. And the S2000 has a lot less than, say, a CR-V.

Originally posted by: mariok2006

You are right about to torque peaks. On the low cam, it happens about 4000rpm, and on the hot cam it happens right after it hits VTEC at 6200rpm. It helps that the "curve" is relatively flat on both cams.

The extra 200cc in the US S2000 must make a big difference - every UK review of the S2000 complains that all the torque is up above 5,000RPM.

Yes. When driven back to back the difference is night and day. Dyno sheets show the same thing with the AP2 making 10+ lb-ft more across the rev range.

 

[dawheat]

Originally posted by: mariok2006

Originally posted by: Cheesehead

Originally posted by: mariok2006


It's a 2.2L in America since 2004. In Japan since 2006. I believe only Europe and Australia still have the 2.0L.

Oops.

Originally posted by: mariok2006

The aerodynamics aren't especially good at .32 Cd because of the relatively steep windshield.

Remember, drag is a function of Cd * frontal area. And the S2000 has a lot less than, say, a CR-V.

Originally posted by: mariok2006

You are right about to torque peaks. On the low cam, it happens about 4000rpm, and on the hot cam it happens right after it hits VTEC at 6200rpm. It helps that the "curve" is relatively flat on both cams.

The extra 200cc in the US S2000 must make a big difference - every UK review of the S2000 complains that all the torque is up above 5,000RPM.

Yes. When driven back to back the difference is night and day. Dyno sheets show the same thing with the AP2 making 10+ lb-ft more across the rev range.

Hehe night and day? From an ex-AP2 owner, let's not get carried away The S2k in any variant is a low torque car. It's more the difference between twilight and evening.

Best I got in my 2004 was 33mpg on 4 consecutive all highway tanks. Mixed driving got me about 24mpg.

Hard to believe you got 37mpg, especially if it was mixed driving - I'd imagine the short distance (90 miles is only around 3 gallons) is skewing your results.