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achieving excellent gas mileage

6K views 48 replies 28 participants last post by  randyz  
#1 ·
Ive been trying different ways to increase gas mileage and this is what I came up with. I hardly ever slam the gas at take off but I occasionally get the rpms up there. So I started shifting about 2750rpms for about 3 tankfulls and achieved 25mpg with 50/50 city and highway. When I stayed on the gas shifting at 3500-4000rpms I achieved lconsiderably lower...avaraging about 22 mpg. Does this make sense???? Ive been talking to a few other people on other forums I visit and they are telling me that I must not be staying on the turbo, which I believe kicks in at 2500rpms. So is it true that the longer you are on the turbo the more your mileage will suffer?
 
#2 ·
I don't want to state the obvious here, but when the turbo kicks in you get boatloads of more air, right? Well in order for the car to stay functioning this increased airflow has to be matched with enough fuel to keep everything combusting properly and efficiently (maintaining a proper a/f ratio i.e. 14.7:1 in the case of staying under 3500rpm and no more than 80% throttle). Above 3500 rpms (or more than 80% throttle) the engine really starts to add fuel and change the ratio closer to 11:1 in the speed, hence why your mileage would suffer dramatically when shifting at that point.

I'm no expert at this like some of you guys are, but I think thats the right way to explain it. Please correct me if I'm wrong.
 
#7 ·
I don't want to sound like a prick, or state the obvious, but why didn't you get a regular Mazda6... the 4cyl or even the 6cyl would have a much better mileage than the MS6
 
#8 ·
I don't want to state the obvious here, but when the turbo kicks in you get boatloads of more air, right? Well in order for the car to stay functioning this increased airflow has to be matched with enough fuel to keep everything combusting properly and efficiently (maintaining a proper a/f ratio i.e. 14.7:1 in the case of staying under 3500rpm and no more than 80% throttle). Above 3500 rpms (or more than 80% throttle) the engine really starts to add fuel and change the ratio closer to 11:1 in the speed, hence why your mileage would suffer dramatically when shifting at that point.

I'm no expert at this like some of you guys are, but I think thats the right way to explain it. Please correct me if I'm wrong.
[/b]
Great explanation. I Granny-shift myself when I'm feeling like saving on gas. I usually get 24-25mpg 50/50. But oooooh when I put my foot down gas consumption is VERY noticable as I'm sure most can attest to on here. :D Sometimes you just gotta let the girl run buddy. :drive:
 
#9 ·
I don't want to sound like a prick, or state the obvious, but why didn't you get a regular Mazda6... the 4cyl or even the 6cyl would have a much better mileage than the MS6
[/b]
as i said in my first post...it was just a test. you are right...if i was that concered about gas mileage i would have got the 4 cyl mazda6. but what fun would that be. there are sometimes you just wannt hit that boost. i was just stating something that i didnt know if many people knew or not.
 
#10 ·
I don't want to sound like a prick, or state the obvious, but why didn't you get a regular Mazda6... the 4cyl or even the 6cyl would have a much better mileage than the MS6
[/b]
Well, just because some of us want good mileage most of the time does not mean we do not want excellent performance when needed. You do not have to drive insane all of the time just because you got a speed6. I drive 100 miles a day - if I were to push the MS6 the whole time, I would be in jail or dead.
 
#11 ·
Sorry to rain on your parade but, Gas milage and performance do not go hand in hand.

Something has to sacrifice.
 
#12 ·
Sorry to rain on your parade but, Gas milage and performance do not go hand in hand.

Something has to sacrifice.
[/b]
Of course, but if you are not driving like you are on crack, you can get excellent mileage from the MS6. If you are pushing things, your mileage will go to hell. I have gotten 29.5 mpg out of this car and considering all the comfort it has (and weight), that is excellent for this car. The fact that it has a powerful engine does not mean you have to force the max amount of gas through it 100% (or even 50%) of the time.
 
#13 ·
Of course, but if you are not driving like you are on crack, you can get excellent mileage from the MS6. If you are pushing things, your mileage will go to hell. I have gotten 29.5 mpg out of this car and considering all the comfort it has (and weight), that is excellent for this car. The fact that it has a powerful engine does not mean you have to force the max amount of gas through it 100% (or even 50%) of the time.
[/b]
Exactly. Well stated. Even when I see exotic cars they're mostly cruising. You know what you have on tap, just like they do. No need to go balls to the wall all the time. :drive:
 
#14 ·
Exactly. Well stated. Even when I see exotic cars they're mostly cruising. You know what you have on tap, just like they do. No need to go balls to the wall all the time. :drive:
[/b]
funny you mention that...i saw the bentley coupe yesterday on the road and him, me and a kia optima were all at the red light...i was on the far end away from the bentley. The kia launched on the bentley like nobodys business but the bentley just kept cruising...i would have loved to see him launch of the kia and make him feel stupid.
 
#15 ·
Of course, but if you are not driving like you are on crack, you can get excellent mileage from the MS6. If you are pushing things, your mileage will go to hell. I have gotten 29.5 mpg out of this car and considering all the comfort it has (and weight), that is excellent for this car. The fact that it has a powerful engine does not mean you have to force the max amount of gas through it 100% (or even 50%) of the time.
[/b]
What are you doing to get 29.5 mpg? How many miles does your MS6 have and are there any mods done to the car?
Curious, like you, I would like to get great mileage when cruising, and still know I have 274 hp on tap. As for performance and mileage, they can go hand in hand. My last car that I raced, ran 12.9s-13.1s and got 35 mpg on the highway. That was more than the factory rated it at.

Thanks,
Jason
 
#16 ·
What are you doing to get 29.5 mpg? How many miles does your MS6 have and are there any mods done to the car?
Curious, like you, I would like to get great mileage when cruising, and still know I have 274 hp on tap. As for performance and mileage, they can go hand in hand. My last car that I raced, ran 12.9s-13.1s and got 35 mpg on the highway. That was more than the factory rated it at.

Thanks,
Jason
[/b]
Yep, you can have both. You have to start with a 4cyl. powerplant though then add boost. Me and my friend are building a project right now and our projected numbers are 330hp/275tq, 0-60 under 5 seconds, 12 second 1/4's, and 28 city/35+highway mileage. Stay tuned for details. :drive:

On the MS6, you can easily get 28+mpg while cruising. Mine is a stock Sport. My car has just over 5,800 miles. On my last trip I put it on cruise control at 76mph and was running the A/C on auto at 77 degrees. I netted almost 29mpg. I said it before and I'll say it again. I LOVE my MS6. :D
 
#17 ·
What are you doing to get 29.5 mpg? How many miles does your MS6 have and are there any mods done to the car?
Curious, like you, I would like to get great mileage when cruising, and still know I have 274 hp on tap. As for performance and mileage, they can go hand in hand. My last car that I raced, ran 12.9s-13.1s and got 35 mpg on the highway. That was more than the factory rated it at.

Thanks,
Jason
[/b]
CAI is only mod. I do 98% highway driving (2 miles of my 100 mile commute is non-highway). I set the cruise control right around 2900 and have gotten that a number of times. almost 7000 miles on it now. 90% of the time I get 25+ mpg. If I feel like playing it will go down some. I have found that I am much better off driving 10 miles out of my way when they are doing construction on my normal route home. Stop and go KILLS the mileage (drops down to around 20mpg) - this is the worst thing I have found about this car. My 04 Focus SVT would often get 32 or so on a tank and stop and go might drop to 28ish. Amazing how much worse it is in this car (maybe the extra weight)?
 
#18 ·
CAI is only mod. I do 98% highway driving (2 miles of my 100 mile commute is non-highway). I set the cruise control right around 2900 and have gotten that a number of times. almost 7000 miles on it now. 90% of the time I get 25+ mpg. If I feel like playing it will go down some. I have found that I am much better off driving 10 miles out of my way when they are doing construction on my normal route home. Stop and go KILLS the mileage (drops down to around 20mpg) - this is the worst thing I have found about this car. My 04 Focus SVT would often get 32 or so on a tank and stop and go might drop to 28ish. Amazing how much worse it is in this car (maybe the extra weight)?
[/b]
Hahaha, it's funny how car enthusiasts run in the same circles. I also owned an SVT Focus. :D Yeah, the weight and the fact that boost comes on so soon lead to bad gas mileage I think. Since I've had it, the worst I've gotten is 21.5 mpg. And that was in traffic. I need to get that CAI. Need mo' powa'. :drive:
 
#19 ·
Sorry to rain on your parade but, Gas milage and performance do not go hand in hand.

Something has to sacrifice.
[/b]
I'd like to clarify that. They can in the same car, but with different driving techniques.

Example...An LS1 Vette or an F body can run low 13's high 12's and trap up to 110 MPH bone stock but they can still deliver 28+ MPG if you take it easy on the loud pedal.

So yes...you can have your cake and eat it too.
 
#20 ·
Personally, I've always been curious about putting in a boost controller and see how the computer would handle it if you set the boost to zero. The Talon I used to have had its wastegate actuator arm break off, and I ended up driving around for about a week till the replacement part came in. Had decent gas mileage, but then again, I had no turbo essentially, so why bother flooring it... it would just remind me it was broke... so maybe half driving habit half mechanics.

Controllable boost(with proper fuel mapping) and a taller 6th gear, then you'd have all the cake in the world and be sick for it. :D
 
#21 ·
Personally, I've always been curious about putting in a boost controller and see how the computer would handle it if you set the boost to zero. The Talon I used to have had its wastegate actuator arm break off, and I ended up driving around for about a week till the replacement part came in. Had decent gas mileage, but then again, I had no turbo essentially, so why bother flooring it... it would just remind me it was broke... so maybe half driving habit half mechanics.

Controllable boost(with proper fuel mapping) and a taller 6th gear, then you'd have all the cake in the world and be sick for it. :D
[/b]
It would actually hurt performance, as the compression ratio of a turboed engine is normally lower in order to allow some boost pressure in.

I imagine you could get tremendous gas mileage in this car:
-Add CAI and free-flow exhaust
-Install a boost controller and lower it to 5-6 psi max
-With a tuning solution, lean out the A/F
-Make the rev limiter kick in at 3000 rpms.
-Install narrower tires (aerodynamism)
-Remove Air Conditioning
 
#22 ·
Lets see????
Lousy 90 - 91 octane fuel with Ethenol. Plus 100 deg. temps across 2 states and a/c on 85deg. Cruise set at 80mph with 2 full size adults and LUGGAGE. This equaled 31mpg
I have the Short Ram and resonator tips in place of mufflers.
Our average fuel mileage for the trip from Below Sea level to over 7k feet and back was 26.8mpg
Not bad for sucking with low octane. OH, and the HIGH mileage tank was 91 octane with Berrymans B12 added to the tank.
 
#23 ·
I don't want to sound like a prick, or state the obvious, but why didn't you get a regular Mazda6... the 4cyl or even the 6cyl would have a much better mileage than the MS6
[/b]
I don't know what a i4 gets as far as mpg, but I get an average of 21 mpg with the v6. So the turbo may be using more gas than the i4 but not so much more or less than the v6.
 
#24 ·
CAI is only mod. I do 98% highway driving (2 miles of my 100 mile commute is non-highway). I set the cruise control right around 2900 and have gotten that a number of times. almost 7000 miles on it now. 90% of the time I get 25+ mpg. If I feel like playing it will go down some. I have found that I am much better off driving 10 miles out of my way when they are doing construction on my normal route home. Stop and go KILLS the mileage (drops down to around 20mpg) - this is the worst thing I have found about this car. My 04 Focus SVT would often get 32 or so on a tank and stop and go might drop to 28ish. Amazing how much worse it is in this car (maybe the extra weight)?
[/b]

LOL, I to owned an SVT Focus. I was actually one of the first people to boost mine, hence my screen name :D
 
#25 ·
I don't want to state the obvious here, but when the turbo kicks in you get boatloads of more air, right? Well in order for the car to stay functioning this increased airflow has to be matched with enough fuel to keep everything combusting properly and efficiently (maintaining a proper a/f ratio i.e. 14.7:1 in the case of staying under 3500rpm and no more than 80% throttle). Above 3500 rpms (or more than 80% throttle) the engine really starts to add fuel and change the ratio closer to 11:1 in the speed, hence why your mileage would suffer dramatically when shifting at that point.
[/b]

Dead on. Plus it goes without saying that if you don't rev it out, your mileage goes up. What fun is that, though? I try to shift under 4,500 on regular launches. Control the throttle, don't stab at it. Use the cruise control as much as possible! I consistantly get 23+mpg in mixed driving. And, trust me, I wail on it quite a bit!!!
 
#26 ·
I imagine you could get tremendous gas mileage in this car:
-Add CAI and free-flow exhaust
-Install a boost controller and lower it to 5-6 psi max
-With a tuning solution, lean out the A/F
-Make the rev limiter kick in at 3000 rpms.
-Install narrower tires (aerodynamism)
-Remove Air Conditioning
[/b]
While your at it,
-Remove the PS pump
-Remove rear seats
-Remove spare tire
-Tape up all the body gaps