Miles to TANK, S4 ONLY
06-05-13, 12:33 PM
#52
I hate when people use miles to tank as a measure of fuel economy... Seriously guys, it's simple division to find mpg.
As for tips for better gas mileage, it's mostly common sense. It is pointless to say that you shouldn't rev over 3000 rpm or something like that though, because what's the point of driving an rx7 if you don't take it above 3000?? And B ) It is a false generalization to say you will get better mpg by accelerating slow.
If you have to get up to speed, you have to get up to speed. There are marginal differences between working the engine at a low load for a longer period or time versus working it hard for a short amount of time. Generally, accelerating slower just allows you to more easily predict changes in traffic and lights sooner and be able to back off sooner and avoid needing to use the brakes which then means you wasted gas to heat up your brakes.
Another thing I see a lot of people do, whether rx7 or not, is leave the car in too high of gear when just cruising. I'm sick of hearing people's engine turn 3000 rpm to go down the road at 25-30 mph because they don't want to shift into 3rd or 4th. When maintaining speed at less than highway speeds, your engine shouldnt be turning more than 2000rpm. I can be in 4th at 28mph and 5th at 40mph with the engine turning 1500rpms.
Gas mileage is directly related to how much you use your brakes, because anytime you do that, it means you will need to accelerate again. Obviously you have to use your brakes some of the time, but it amazes me how many people tailgate people on the freeway and have to slam on their brakes anytime the person in front of them slows down at all, and then they wonder why their highway mileage is so shitty. I mean in light traffic, you really shouldnt ever have to touch the brakes on the freeway. Same thing applies in city, it's just much more difficult to predict lights and other drivers in the city. By giving a wide margin, you allow your self time to simply let off the gas when someone slows down for a turn instead of using your brakes and needing to accelerate again.
If you're accelerating onto a highway, or anytime you don't expect to slow down anytime soon, I think that is the best time to rev to the redline and open up the engine because that accelerating is going to good use.
Those are my opinions at least... I've never managed to keep my rpm under 4000 for an entire tank to see if that makes a big difference, however I do keep very good track of my mpg, and I notice very small difference between tanks when I redline a lot and when I drive conservatively. Rotaries love to be worked hard, it's when they are most efficient in terms of power per gallon (like all engines really).
As for tips for better gas mileage, it's mostly common sense. It is pointless to say that you shouldn't rev over 3000 rpm or something like that though, because what's the point of driving an rx7 if you don't take it above 3000?? And B ) It is a false generalization to say you will get better mpg by accelerating slow.
If you have to get up to speed, you have to get up to speed. There are marginal differences between working the engine at a low load for a longer period or time versus working it hard for a short amount of time. Generally, accelerating slower just allows you to more easily predict changes in traffic and lights sooner and be able to back off sooner and avoid needing to use the brakes which then means you wasted gas to heat up your brakes.
Another thing I see a lot of people do, whether rx7 or not, is leave the car in too high of gear when just cruising. I'm sick of hearing people's engine turn 3000 rpm to go down the road at 25-30 mph because they don't want to shift into 3rd or 4th. When maintaining speed at less than highway speeds, your engine shouldnt be turning more than 2000rpm. I can be in 4th at 28mph and 5th at 40mph with the engine turning 1500rpms.
Gas mileage is directly related to how much you use your brakes, because anytime you do that, it means you will need to accelerate again. Obviously you have to use your brakes some of the time, but it amazes me how many people tailgate people on the freeway and have to slam on their brakes anytime the person in front of them slows down at all, and then they wonder why their highway mileage is so shitty. I mean in light traffic, you really shouldnt ever have to touch the brakes on the freeway. Same thing applies in city, it's just much more difficult to predict lights and other drivers in the city. By giving a wide margin, you allow your self time to simply let off the gas when someone slows down for a turn instead of using your brakes and needing to accelerate again.
If you're accelerating onto a highway, or anytime you don't expect to slow down anytime soon, I think that is the best time to rev to the redline and open up the engine because that accelerating is going to good use.
Those are my opinions at least... I've never managed to keep my rpm under 4000 for an entire tank to see if that makes a big difference, however I do keep very good track of my mpg, and I notice very small difference between tanks when I redline a lot and when I drive conservatively. Rotaries love to be worked hard, it's when they are most efficient in terms of power per gallon (like all engines really).
06-05-13, 09:39 PM
#53
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What you are saying makes tons of sense. Except the last part, how does it not make a difference between tanks when you get on it and when you dont? I lose tons of mpgs if I drive the car a little harder... thats shifting at 3k or 4k every now and then. On average I'm getting around 16 to 18mpg 
06-06-13, 01:41 PM
#54
I really don't know, rotaries are weird. But when I get on it, I try to make sure I'm not just going to have to brake soon after - i.e. accelerating towards a red light. I think that makes a big difference. In town, I like to shift from 1st to 4th just to avoid wear on my transmission and clutch (and obviously, to have fun), it works hard for a couple seconds to get up to 30 or 35 but then gets to just cruise at 1500-2000 rpm with the throttle barely open.
16 to 18 around town isn't bad. I usually get 20+ or just under, but most of my driving is highway. I used to get 22-24 without much trouble, I don't know why it's less now.
https://dl.dropboxusercontent.com/u/...%20mileage.xls
I started keeping track during my trip to sevenstock 15, when I managed 27 on the freeway down there.
16 to 18 around town isn't bad. I usually get 20+ or just under, but most of my driving is highway. I used to get 22-24 without much trouble, I don't know why it's less now.
https://dl.dropboxusercontent.com/u/...%20mileage.xls
I started keeping track during my trip to sevenstock 15, when I managed 27 on the freeway down there.
06-06-13, 07:17 PM
#55
The reason why I posted KM per tank instead of MPG is because you can get 30mpg by driving 30 miles and filling up 1 gallon... It varies a lot, and your MPG over an entire tank is an average, you could have gotten 10mpg at one point and 20 another. So saying how many kms you got on a tank of gas is a perfectly reasonable way of explaining how good/bad your car is on fuel.
06-06-13, 07:35 PM
#56
You have a point but all it really proves is that you need more data.
MPG over the span of say, a thousand miles, is much more accurate than "x miles per tank".
Because of the large number of variables (speed, ambient temp, road condition, altitude, etc.) the more miles in the sample, the more accurate your figure will be.
MPG over the span of say, a thousand miles, is much more accurate than "x miles per tank".
Because of the large number of variables (speed, ambient temp, road condition, altitude, etc.) the more miles in the sample, the more accurate your figure will be.
06-06-13, 08:44 PM
#57
The reason why I posted KM per tank instead of MPG is because you can get 30mpg by driving 30 miles and filling up 1 gallon... It varies a lot, and your MPG over an entire tank is an average, you could have gotten 10mpg at one point and 20 another. So saying how many kms you got on a tank of gas is a perfectly reasonable way of explaining how good/bad your car is on fuel.
Step 1) fill up entire tank and reset trip odometer.
Step 2) Drive until tank is close to empty
Step 3) Fill up entire tank. Take note of gallons filled and miles traveled. Divide miles by gallons.
if you do a partial tank, just write down the gallons filled and don't reset OD. Then add those gallons to your total when you eventually fill up.
This is basically the only way of accurately measuring how much fuel was used.
Miles or km per tank is not at all a good way to measure how good your car is on fuel because people fill up their tank at different times and have different fuel tank capacities. Even when I fill up when the gauge reads well below empty, I still have more than 1 gallon of fuel left in the tank. Sure people generally fill up at about the same time, so it's not too terrible, but why use miles per tank when it is so easy to get miles per gallon?
06-06-13, 09:14 PM
#58
You have a point but all it really proves is that you need more data.
MPG over the span of say, a thousand miles, is much more accurate than "x miles per tank".
Because of the large number of variables (speed, ambient temp, road condition, altitude, etc.) the more miles in the sample, the more accurate your figure will be.
MPG over the span of say, a thousand miles, is much more accurate than "x miles per tank".
Because of the large number of variables (speed, ambient temp, road condition, altitude, etc.) the more miles in the sample, the more accurate your figure will be.
I don't have the diligence to drive my rx7 conservatively for a full tank... I guess I did when my engine was breaking in, but I didn't get very good gas mileage because it was a new engine.
06-06-13, 11:23 PM
#60
I drive my car from full tank to completely empty (needle is actually below E line) every time, so I don't mind using KM per tank because it always costs me $80-$83 to fill up at $1.25-$1.28 a litre.
But I also do what you guys are saying. Let me rephrase it, I used to get ~13mpg mixed and after changing only the air filter I am getting 17mpg mixed (two tanks of gas so far and both got the same exact MPG).
But I also do what you guys are saying. Let me rephrase it, I used to get ~13mpg mixed and after changing only the air filter I am getting 17mpg mixed (two tanks of gas so far and both got the same exact MPG).
06-08-13, 01:41 AM
#63
Senior Member
I average 265+ miles between fill-ups...more if its mostly highway. It seems my low fuel low don't work (no biggie), I'm usually putting in approx 14.5gal...the most I've ever put in was 15.9 and that was cutting it a lil too close for comfort, LOL.
06-08-13, 12:02 PM
#64
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Because of this thread, I decided to do conservative driving on a full tank just to compare numbers. TII though. Took an extremely depressing two weeks.
Two ~1h round trip highway stretch, and a few redline shifts just for engine's sake.
Other then that, all city driving with frequent lights. 1 through 4th gear shifting at 2.5k strictly. 4th gear cruising between 1.8-2.2k.
219 miles logged, 13.5 gallons used according to the pump. Math says 16.2mpg. I'll take it, especially considering all the stop and go on my commute.
If I ever travel 200mi +, I'll do a conservative highway cruise in 5th @ 2.5-3k. See what I get.
Two ~1h round trip highway stretch, and a few redline shifts just for engine's sake.
Other then that, all city driving with frequent lights. 1 through 4th gear shifting at 2.5k strictly. 4th gear cruising between 1.8-2.2k.
219 miles logged, 13.5 gallons used according to the pump. Math says 16.2mpg. I'll take it, especially considering all the stop and go on my commute.
If I ever travel 200mi +, I'll do a conservative highway cruise in 5th @ 2.5-3k. See what I get.
06-08-13, 01:58 PM
#65
06-08-13, 11:44 PM
#66
I shift at 3-3.5k every time when I'm in town. I only accelerate faster if I'm in the mood(which is a lot, I redline every time I drive the car) or when getting onto highways and there's cars coming up, etc. I still get ~16mph mixed driving like that. I see no difference in MPG by shifting at 3k and never redlining or accelerating. Unless I'm driving 75-100% city compared to more highway.
100% city MPG = 11-13mpg (never getting into 5th because highest speed limit was 60kph and there was lights every 50 feet)
Mixed = 16-17mph
100% highway = 28-32mpg. I've gotten 30mpg multiple times driving a 300kmph stretch of highway from Sault Ste Marie to Sudbury when I was in college. The speed limit is 90 the whole way until hitting towns and such, then it slows down to 80/70/60 or 50kph. I'm usually doing 20kph over the limit. It took me ~3.25-3.5 hours to do the 300km trip. Like I said, it's happened more than once driving that same stretch of road.
100% city MPG = 11-13mpg (never getting into 5th because highest speed limit was 60kph and there was lights every 50 feet)
Mixed = 16-17mph
100% highway = 28-32mpg. I've gotten 30mpg multiple times driving a 300kmph stretch of highway from Sault Ste Marie to Sudbury when I was in college. The speed limit is 90 the whole way until hitting towns and such, then it slows down to 80/70/60 or 50kph. I'm usually doing 20kph over the limit. It took me ~3.25-3.5 hours to do the 300km trip. Like I said, it's happened more than once driving that same stretch of road.
