Dramatically improved RX-8 fuel economy
12-10-2003, 09:38 PM
#51
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Another thing to keep an eye on is tire pressure. Keep the tire pressures at the recommended (32psi) or a pound or two higher to get better gas mileage. Low tire pressures will cause a lower gas mileage because of the increased friction on the roadway. This will be particularly an issue in cold climates where the tires may not heat up properly in short commutes. Make SURE your tires are at 32psi minimum when cold.
A lot of things can affect overall mileage, including rear wings. While wings may look "cool" keep in mind why they're used in racing. It has nothing to do with looking cool. It's for generating downforce on the tires at high speeds to increase traction and grip. They DO slow down the car and they DO cost gas mileage as a result. This is a necessary trade-off in racing to get higher cornering speeds but it costs tire wear and gas to do it.
On the street you can't go fast enough safely to gain the benefit of those kind of racing body modifications. All those racing body attachments people put on their cars are costing them the same things it costs racers on the track; tire wear and fuel usage.
IF you have a rear wing on your car and if it's adjustable, set it to a neutral angle to minimize drag. You really can't go fast enough on the street to take advantage of the downforce in cornering; it's just for show. The front spoiler (which I bought for mine and it looks great) may have some benefit at freeway speeds because it helps reduce undercarriage drag by keeping air from getting under the car, but without hard testing data that's just a guess on my part. Reducing undercarriage drag is partly what they're for on race cars...that and providing downforce for the front tires to match the downforce on the rear tires.
Every add-on adds weight; weight means it takes more gas to move that body mass. Keep all this in mind before you load down your car with tons of add-ons and heavy speakers and such.
The RX8 DOES get the mileage they advertise IF you follow their standard testing procedures and configs for the car. I consistently get 19-20 mpg and I definitely enjoy the performance of this great machine. Anything you do that adds weight or increases drag and downforce will cost you mileage in return; nothing is free in this area.
A lot of things can affect overall mileage, including rear wings. While wings may look "cool" keep in mind why they're used in racing. It has nothing to do with looking cool. It's for generating downforce on the tires at high speeds to increase traction and grip. They DO slow down the car and they DO cost gas mileage as a result. This is a necessary trade-off in racing to get higher cornering speeds but it costs tire wear and gas to do it.
On the street you can't go fast enough safely to gain the benefit of those kind of racing body modifications. All those racing body attachments people put on their cars are costing them the same things it costs racers on the track; tire wear and fuel usage.
IF you have a rear wing on your car and if it's adjustable, set it to a neutral angle to minimize drag. You really can't go fast enough on the street to take advantage of the downforce in cornering; it's just for show. The front spoiler (which I bought for mine and it looks great) may have some benefit at freeway speeds because it helps reduce undercarriage drag by keeping air from getting under the car, but without hard testing data that's just a guess on my part. Reducing undercarriage drag is partly what they're for on race cars...that and providing downforce for the front tires to match the downforce on the rear tires.
Every add-on adds weight; weight means it takes more gas to move that body mass. Keep all this in mind before you load down your car with tons of add-ons and heavy speakers and such.
The RX8 DOES get the mileage they advertise IF you follow their standard testing procedures and configs for the car. I consistently get 19-20 mpg and I definitely enjoy the performance of this great machine. Anything you do that adds weight or increases drag and downforce will cost you mileage in return; nothing is free in this area.
12-10-2003, 09:53 PM
#52
It's not Mazda's fault. It's the US Govt (and other Govts) fault. They mandate a certain fleet average for MPG, then they separatly mandate emissions. The two can be unrelated. Then the Govt (US at least) mandates CAT lives. Now the three are unrelated, but are interrelated. So Mazda, complies with the fleet average (I have no idea how, but assume they do), then to comply with emission and cat life, they dump tons of unburnt fuel to the cats to cool the cats down to prolong life. Note this does not effect emissions because the cats do a great job of converting unburnt fuel into co2 and h2o, but this greatly lowers mpg. So what does Mazda do? They print a manual with ridiculous shift points. The epa has it's hands tied and tests the motor at those shift points and issues the city/hwy mpg estimates that are posted on the sticker. The problem is nobody will shift at those points! Mazda was smart, they designed a gret car with a lot of potential at high rpms and met federal standards by not making use of the high rpms. Any fault lies with the US govt's way of estimating mpgs.
12-10-2003, 10:15 PM
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Too many Italian cars in my past -- couldn't dream of regularly shifting a car anywhere shy of 1000K from redline unless I was starting off on ice.
I note that the engine makes some strange sounds when it's running < 3000 RPM. Unhealthy sounds.
The ride is jerky at low RPMs as well. Slight variations in throttle really jerk the car about. Bad news here with the rolling landscape. Could it be the carbon fiber driveshaft?
I note that the engine makes some strange sounds when it's running < 3000 RPM. Unhealthy sounds.
The ride is jerky at low RPMs as well. Slight variations in throttle really jerk the car about. Bad news here with the rolling landscape. Could it be the carbon fiber driveshaft?
12-11-2003, 12:33 AM
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For those of you who think you are doing your car a favor and shifting at low RPMs, you are hurting it more than helping. By shifting at low RPMs and never getting it to redline, the Rotary engine builds up a lot of carbon. Over time this leads to higher compression numbers, which can then lead to possible clogs or blown seals. Redlining the engine helps clear out this carbon buildup....but if you never redline it for 20,000 miles, don't expect to immediately start dislodging this carbon buildup by redlining...the damage has been done.
Be easy on it through the break in stage, but once complete, like someone else said "redline a day, keeps the mechanic away"...
If you have a rotary and are shifting at 3500 rpms, it is a shame. Go trade it in for a piston engine.
Happy Rotoring!
Kurt G.
Be easy on it through the break in stage, but once complete, like someone else said "redline a day, keeps the mechanic away"...
If you have a rotary and are shifting at 3500 rpms, it is a shame. Go trade it in for a piston engine.
Happy Rotoring!
Kurt G.
12-11-2003, 12:42 AM
#56
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Originally posted by cruzdreamer
I have the automatic too...dealer said don't worry about it until you at least have 5000 miles on it. Then a gentleman around 60 ish at the gas station noticed my car and started chatting with me about it.....I mentioned gas mileage was bad and he said I may not see it get better until I have anywhere from 12,000-24,000 miles on it. He seemed to know something about the rotary engine. So we shall see....that seems like a long wait but I bet we will get there in no time! I think weather has a lot to do with it...cold ,damp conditions and breaking it in....my theories from a person who knows squat about rotaries!:]
I have the automatic too...dealer said don't worry about it until you at least have 5000 miles on it. Then a gentleman around 60 ish at the gas station noticed my car and started chatting with me about it.....I mentioned gas mileage was bad and he said I may not see it get better until I have anywhere from 12,000-24,000 miles on it. He seemed to know something about the rotary engine. So we shall see....that seems like a long wait but I bet we will get there in no time! I think weather has a lot to do with it...cold ,damp conditions and breaking it in....my theories from a person who knows squat about rotaries!:]
12-11-2003, 01:24 AM
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Some of you suggested to reset the ECU to achieve better gas milage. How do you do that? I am assuming you disconnect the battery. How long do you need to keep it disconnected? Please advise...Thanks
Mark
Mark
12-11-2003, 01:37 PM
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You don't need to wait 12 hours. Disconnect one of the battery terminals and step on the brake pedal for a couple of seconds to discharge any charged capacitor in the electrical system.
12-11-2003, 01:38 PM
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Originally posted by Genshie
For those of you who think you are doing your car a favor and shifting at low RPMs, you are hurting it more than helping. By shifting at low RPMs and never getting it to redline, the Rotary engine builds up a lot of carbon.
For those of you who think you are doing your car a favor and shifting at low RPMs, you are hurting it more than helping. By shifting at low RPMs and never getting it to redline, the Rotary engine builds up a lot of carbon.
Is this something that you heard or something that you can actually show proof that this is the case?
12-11-2003, 07:37 PM
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Originally posted by O.R.A.
It's not about getting the fuel economy of a Prius or not. It is about all the hype of the Renesis being such an improvement in all areas, INCLUDING fuel economy, over the previous 13B.
It is about getting a fuel economy that goes along with the power and performance of the car. About meeting the expectations.
If the expectation, as presented by Mazda, is that the car is supposed to give an average mpg of 21 mpg, then it is reasonable for people to expect to get something close to that number if they want to.
You sound like the people that say that the RX-8 can't be a real sports car because it has 4 doors and more than 2 seats.
It's not about getting the fuel economy of a Prius or not. It is about all the hype of the Renesis being such an improvement in all areas, INCLUDING fuel economy, over the previous 13B.
It is about getting a fuel economy that goes along with the power and performance of the car. About meeting the expectations.
If the expectation, as presented by Mazda, is that the car is supposed to give an average mpg of 21 mpg, then it is reasonable for people to expect to get something close to that number if they want to.
You sound like the people that say that the RX-8 can't be a real sports car because it has 4 doors and more than 2 seats.
12-11-2003, 08:15 PM
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The Prius comment is weak.
18 mpg is no big deal if that's what was expected.
However, when Mazda engineers touted the Renesis as having much improved fuel economy... that's where the rub is. It doesn't sound like anyone is seeing it.
The rotary is just as thirsty (if not more so) as ever.
18 mpg is no big deal if that's what was expected.
However, when Mazda engineers touted the Renesis as having much improved fuel economy... that's where the rub is. It doesn't sound like anyone is seeing it.
The rotary is just as thirsty (if not more so) as ever.
12-11-2003, 09:00 PM
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Wow, people shifting at 2800-3000 RPMs?? Man, I wouldn't even consider shifting until 4500. I go by feel, but I looked today to see when I shift - and I shift around 5500. I mean the redline is 8500 and max torque at 5500. Mileage smileage....
12-12-2003, 07:17 AM
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You know, one thing I find funny is how there are a lot of people that post something like "I don't know why I get such bad mileage. I always shift at X rpms and all I get is Y mpg..."
Well, if shifting at X rpms is only getting you Y mpg, maybe you should try something else. You can't do the same thing over and over and expect a different result, even if it worked on some other car you had before.
Also, throttle position plays a big part in fuel consumption too. If you need to go at 60% throttle because of the low power available at 3000 rpms, this might not be better in terms of fuel economy than running at 30% throttle at 5000 rpms.
Well, if shifting at X rpms is only getting you Y mpg, maybe you should try something else. You can't do the same thing over and over and expect a different result, even if it worked on some other car you had before.
Also, throttle position plays a big part in fuel consumption too. If you need to go at 60% throttle because of the low power available at 3000 rpms, this might not be better in terms of fuel economy than running at 30% throttle at 5000 rpms.
12-12-2003, 07:36 AM
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Does anyone know what the official city and hwy mileage for the 3rd generation RX7 was supposed to be (what was on the manufacturer's sticker)? And what were the ranges people were actually getting on the RX7 city and hwy?
12-14-2003, 03:45 PM
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Originally posted by racerdave
The Prius comment is weak.
18 mpg is no big deal if that's what was expected.
However, when Mazda engineers touted the Renesis as having much improved fuel economy... that's where the rub is. It doesn't sound like anyone is seeing it.
The rotary is just as thirsty (if not more so) as ever.
The Prius comment is weak.
18 mpg is no big deal if that's what was expected.
However, when Mazda engineers touted the Renesis as having much improved fuel economy... that's where the rub is. It doesn't sound like anyone is seeing it.
The rotary is just as thirsty (if not more so) as ever.
12-16-2003, 03:00 AM
#70
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Originally posted by aussie77
Which means there has to be another explanation. I always knew that the stop and go driving in city would make the mileage worse, but I seriously believe that the weather has had a large effect too. Consider that over the exact same route a couple of months ago in warmer weather with a tank of 100% city, I got in the range of 16 mpg. That's a fairly large variation. The motto? Let your engine warm up, and avoid stop and go traffic!
Which means there has to be another explanation. I always knew that the stop and go driving in city would make the mileage worse, but I seriously believe that the weather has had a large effect too. Consider that over the exact same route a couple of months ago in warmer weather with a tank of 100% city, I got in the range of 16 mpg. That's a fairly large variation. The motto? Let your engine warm up, and avoid stop and go traffic!
Got my car in the summer ( I believe first private delivery in Canada.)
It is damned cold here in winter.
Tonight for example going down to 14F.
Have had some nights down to -5 already.
I get the sme mileage now as I got in the summer.
No, wait, I get BETTER mileage, as I learned that 1-3-5th gear shifting and keeping under 3500rpm really does help.
One thing else I know:
Sitting at idle, warming up, it uses exactly the same amount f fuel as driving on the highway at 60mph/100kmh.
So, only warm it up until the rpm drops to 1500, then drive it gently until it drops to the lower idle speed.
My $.02 worth on the subject.
12-16-2003, 05:07 AM
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if i read another post about gas mileage, i will have to drown myself in the stuff. Not that valid points haven't been made, but there are only so many times you can hear someone list their mpg and when they shift gears.
i haven't bought my 8 yet since i'm a law student for a few more months (buying it in May with my starting bonus), so i've been tooling around town in a corolla (exciting stuff, i know). i have a rather heavy foot and an a/t (unfortunately) so i don't get the best mileage, but the one thing that i have noticed that makes a difference no matter what the driving style is air pressure in the tires, like someone commented on earlier.
This is probably ridiculouly obvious, but the lower the pressure, the more friction and the worse the gas mileage. For every drop of 10 degrees F, your tires will lose about 1 psi in pressure. Thus, a drop in 40-50 degrees in the winter (depending on where you live) will drop your tire pressure by about 4-5 psi. (once your tires warm up somewhat, this variance will not be as extreme)
This may not seem like much, but it can have a big effect. Last year, during the winter, I noticed that my Corolla was only getting about 26 mpg (50/50 city/highway), which by 8 standards seems like a fantasy, but by corolla standards is pretty abismal. I added about 5 psi to my tires while filling up, and the next tank of gas gave me an immediate improvement to around 32 mpg.
Now, i'm sure that with the kind of attention that 8 owners give to their cars, this isn't that big of a factor, but i thought that i'd mention it since i'm sure it contributes somewhat to the worse winter mileage that people have been mentioning. i know i'm sure as heck not worried about my tire pressure, when it's 30 degrees out (or worse). From test driving the 8, I also know that when i get mine, I'll be putting that nice big tach to work, once i've broken it in.
i haven't bought my 8 yet since i'm a law student for a few more months (buying it in May with my starting bonus), so i've been tooling around town in a corolla (exciting stuff, i know). i have a rather heavy foot and an a/t (unfortunately) so i don't get the best mileage, but the one thing that i have noticed that makes a difference no matter what the driving style is air pressure in the tires, like someone commented on earlier.
This is probably ridiculouly obvious, but the lower the pressure, the more friction and the worse the gas mileage. For every drop of 10 degrees F, your tires will lose about 1 psi in pressure. Thus, a drop in 40-50 degrees in the winter (depending on where you live) will drop your tire pressure by about 4-5 psi. (once your tires warm up somewhat, this variance will not be as extreme)
This may not seem like much, but it can have a big effect. Last year, during the winter, I noticed that my Corolla was only getting about 26 mpg (50/50 city/highway), which by 8 standards seems like a fantasy, but by corolla standards is pretty abismal. I added about 5 psi to my tires while filling up, and the next tank of gas gave me an immediate improvement to around 32 mpg.
Now, i'm sure that with the kind of attention that 8 owners give to their cars, this isn't that big of a factor, but i thought that i'd mention it since i'm sure it contributes somewhat to the worse winter mileage that people have been mentioning. i know i'm sure as heck not worried about my tire pressure, when it's 30 degrees out (or worse). From test driving the 8, I also know that when i get mine, I'll be putting that nice big tach to work, once i've broken it in.
12-16-2003, 05:51 PM
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I was just at the dealership this afternoon and was told that I shouldn't expect to see my fuel economy go up to where the EPA reported until I get 5-7k on the odometer. They also informed me that it is oxygenated gas in WA. state that contributes to my poor fuel economy. I filled my tank in Idaho where they don't have this regulation and we will see how I do. So far so good. This oxygenation is supposed to help with emissions in the winter??? Anybody else heard of this? I don't want my dealer blowing smoke up my ***.
12-16-2003, 11:39 PM
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Re: cool
Originally posted by eclps0
i found out something 2. i unpluged my battery and reset the ecu, well i now have my results. I have increased my mpg by 3 instead of 16-17 i have receved 19-20 i reached 270 miles with 2 gallons left over OMG. I have always shifted at
1-2 2800rpms
2-3 3000rpms
3-4 3000rpms
4-5 2800rpms
5-6 3000rpms
and on highway i dont go over 82 tahst about 4100-4300rpms for about 45 miles a day.
i found out something 2. i unpluged my battery and reset the ecu, well i now have my results. I have increased my mpg by 3 instead of 16-17 i have receved 19-20 i reached 270 miles with 2 gallons left over OMG. I have always shifted at
1-2 2800rpms
2-3 3000rpms
3-4 3000rpms
4-5 2800rpms
5-6 3000rpms
and on highway i dont go over 82 tahst about 4100-4300rpms for about 45 miles a day.
you have way more self control then I do......I just got mine and it is killing me that I can't let this thing rip yet......this car just begs for more........Maybe after I get my gas bill I will have a little more self control............maybe?????
12-16-2003, 11:43 PM
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Originally posted by still w8ting
if i read another post about gas mileage, i will have to drown myself in the stuff. Not that valid points haven't been made, but there are only so many times you can hear someone list their mpg and when they shift gears.
i haven't bought my 8 yet since i'm a law student for a few more months (buying it in May with my starting bonus), so i've been tooling around town in a corolla (exciting stuff, i know). i have a rather heavy foot and an a/t (unfortunately) so i don't get the best mileage, but the one thing that i have noticed that makes a difference no matter what the driving style is air pressure in the tires, like someone commented on earlier.
This is probably ridiculouly obvious, but the lower the pressure, the more friction and the worse the gas mileage. For every drop of 10 degrees F, your tires will lose about 1 psi in pressure. Thus, a drop in 40-50 degrees in the winter (depending on where you live) will drop your tire pressure by about 4-5 psi. (once your tires warm up somewhat, this variance will not be as extreme)
This may not seem like much, but it can have a big effect. Last year, during the winter, I noticed that my Corolla was only getting about 26 mpg (50/50 city/highway), which by 8 standards seems like a fantasy, but by corolla standards is pretty abismal. I added about 5 psi to my tires while filling up, and the next tank of gas gave me an immediate improvement to around 32 mpg.
Now, i'm sure that with the kind of attention that 8 owners give to their cars, this isn't that big of a factor, but i thought that i'd mention it since i'm sure it contributes somewhat to the worse winter mileage that people have been mentioning. i know i'm sure as heck not worried about my tire pressure, when it's 30 degrees out (or worse). From test driving the 8, I also know that when i get mine, I'll be putting that nice big tach to work, once i've broken it in.
if i read another post about gas mileage, i will have to drown myself in the stuff. Not that valid points haven't been made, but there are only so many times you can hear someone list their mpg and when they shift gears.
i haven't bought my 8 yet since i'm a law student for a few more months (buying it in May with my starting bonus), so i've been tooling around town in a corolla (exciting stuff, i know). i have a rather heavy foot and an a/t (unfortunately) so i don't get the best mileage, but the one thing that i have noticed that makes a difference no matter what the driving style is air pressure in the tires, like someone commented on earlier.
This is probably ridiculouly obvious, but the lower the pressure, the more friction and the worse the gas mileage. For every drop of 10 degrees F, your tires will lose about 1 psi in pressure. Thus, a drop in 40-50 degrees in the winter (depending on where you live) will drop your tire pressure by about 4-5 psi. (once your tires warm up somewhat, this variance will not be as extreme)
This may not seem like much, but it can have a big effect. Last year, during the winter, I noticed that my Corolla was only getting about 26 mpg (50/50 city/highway), which by 8 standards seems like a fantasy, but by corolla standards is pretty abismal. I added about 5 psi to my tires while filling up, and the next tank of gas gave me an immediate improvement to around 32 mpg.
Now, i'm sure that with the kind of attention that 8 owners give to their cars, this isn't that big of a factor, but i thought that i'd mention it since i'm sure it contributes somewhat to the worse winter mileage that people have been mentioning. i know i'm sure as heck not worried about my tire pressure, when it's 30 degrees out (or worse). From test driving the 8, I also know that when i get mine, I'll be putting that nice big tach to work, once i've broken it in.
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