The "How big is our gas tank" thread!!!

[a.blanco0905]

How big is my gas tank??

[mexillis]

Sounds about right for the speeds you're going. I dont remember how exactly I drove but I got 380 for a tank before which AVG is 22 when divided by 17 gallons. If you cruise at 60/65 you could get more out of these cars im sure but it's kinda hard to maintain that when you have UpRev/Mods.

[Ilya]

This thread should get shut down because Antz is going to come in and tell us young grass hoppers that we shouldn't have bought a luxury sport sedan if we expect good mileage and that he had to wait 4000 years before he was able to get his M and that we should all go to school and get our degrees and start our families and save money in a 401k.

lol.

I used to get 20mpg on the highway. That was before the ECU reset so the jury is still out on my car as of now.

[a.blanco0905]

Mex, I got about 350 miles on a full tank over the weekend and I put gas in it last night when I had **.* miles left, and I even drove for about 10 miles on **.* and when I put gas in the car it took 17.80 gallons so I think our gas tanks are 18 gallons... nonetheless thanks for the input... do you remember how fast were you driving? was that city/hwy combined for the 380 miles? or just highway? either way, I guess I should feel pretty good about the 19.9 MPG average on this beast... thanks.

Ilya, Wow, 20 on highway on an M35? but how fast were you driving? You dont seem to have a lead foot so I'm guessing something must definitely been off on your ECU, keep us posted... and Antz, I'm not complaining, I'm wondering, lol...

[The00Dustin]

Our tanks are 20 gallons. That fact has been discussed and debated over and over again, but it's in the manual and the FSM. Our cars are geared for performance, not mileage, I am driving 55 right now just to see, and I am getting 23.25, on a calculator, with winter gas. Normally I average 21 winter 22 summer, but that is driving 63 on 2 lane roads with 50-55 mph speed limits, passing a lot and stopping on average at least once every 10 miles. Driving to other states nets me similar mileage because interstate speeds are too fast for good mileage on our trannys. For the record, prior to my aformentioned experiment, I had gone over 400 miles on a tank at least twice. It always makes me nervous, though, there is no guarantee the tank is full and the computer lies inconsistently. Driving 55, I don't forsee any problem going 400 miles other than I have a 50 mile drive each way with nowhere to stop for gas, so I have to push it to whatever additional mileage over 400 is necessary due to little side trips. That said, my mileage is likely to be higher than most, grandma's get mad at me for accelerating so slow (because I want to train the thing for low RPMs and it is geared to low with a torque curve that either A) starts to get decent too high in the RPMs or B) isn't taken advantage of by the computer [stupid thing shifts down to maintain speed at 2000 RPM climbing baby hills]). Also, yes, this is an M45, 2006.

[Ilya]

Ilya, Wow, 20 on highway on an M35? but how fast were you driving? You dont seem to have a lead foot so I'm guessing something must definitely been off on your ECU, keep us posted... and Antz, I'm not complaining, I'm wondering, lol...

I also call BS on the 20 gallons, unless we have reserve that our computer does not see or needle does not see. I've been on E with *.* and I can only get like 17.5 gallons. I think it's a typo in all literature.

As for 20mpg...that was going to FL so 80-85 with a few runs of 130 in between (3 or 4). However, I reset the meter a couple of times throughout the 20hr trip so I don't think I'd count those 130 runs. I'm sure if I did 75 or 70 I'd be like 22 or 23mpg which is good for this car. After the ECU reset, I'll see how the highway MPG is (got a couple of trips coming up).

[a.blanco0905]

Dustin I have to agree with Ilya about our tanks not being 20 gallons and that's saying something as we dont agree on much That must be a great mistake on someone's part as just last night I pushed the limit on the **.* "miles remaining" with my fingers crossed, and when I filled up I got 17.80 gallons and even after the pump stopped I pumped in a little more gas in it. I'm sure driving at such speeds you could easily net 400 miles a gallon... since last night I'm "babying the car" around town without resetting the computer and I'm already down to 19.0 MPG... I also reset the actual trip odometer on the cluster to see my actual mileage at the end of this tank, so we'll see. Ilya, at those speeds I believe 20 is definitely a good number even if the ocassional 100+ didnt register... however, I'm surprised that the difference between M45s and M35s is not so drastic as I thought it would be like a 5 MPG difference easily, also maybe the Uprev is actually helping me achieve better MPGs at such a high speed.

[Ilya]

Just realized this thread was an M45 specific thread lol.

My bad. I'll keep out.

[a.blanco0905]

Nah you good, I just wanted to know if my car getting 19.9 MPG was good or bad to begin with... I even edited the thread title for you...

[mexillis]

i just read a few of these but anyone here can read through as many as they'd like.

http://townhall-talk.edmunds.com/direct/view/.f0d2b3a/0

[a.blanco0905]

Read some of it, it looks like Doc's on there... preaching to the choir...

[FNAWSM]

Hwy driving I get just over 22 mpg when I hand calculate and around 18 mpg city/hwy mix. I've never reset the ecu and I don't even know what that means but it scares me

[Ilya]

^^ lol

[The00Dustin]

Dustin I have to agree with Ilya about our tanks not being 20 gallons and that's saying something as we dont agree on much That must be a great mistake on someone's part as just last night I pushed the limit on the **.* "miles remaining" with my fingers crossed, and when I filled up I got 17.80 gallons and even after the pump stopped I pumped in a little more gas in it. <snip> however, I'm surprised that the difference between M45s and M35s is not so drastic as I thought it would be like a 5 MPG difference easily, also maybe the Uprev is actually helping me achieve better MPGs at such a high speed.

1) I've personally pumped 18.24 gallons into my tank, and the car wasn't spitting and sputtering or anything at that point. The 20 gallon figure could include some airspace, but since when does everyone believe on-board computers and think the E means the tank is empty? I've never driven a car where the needle didn't go well beyond E (usually at least as far as it goes beyond F when full). Also, how hard is it to imagine that maybe the computer calculates to a "reserve" E with 3 gallons left? I've had my computer say 0 miles to empty instead of going to **** and then proceeded to drive another 55 miles, and that wasn't even the time I pumped in 18.24 gallons, just saying. Much like the Y34 guys did when they had the bad gas gauges, you should try to be sure you fill your tank and pay attention to the miles on the tripometer so when the computer goes wonky you have an idea of how much further you can go. I wouldn't recommend pushing it to 19.5 gallons of gas used even if I knew you could, it's simply not worth it since running the tank dry could damage something and that could be why Nissan put so much nerve-racking emphasis on being out of gas well before you are (the manual actually says not to let the needle go past E).
2) Regarding the V6 vs V8 comment, as the window stickers on these cars when new indicated, the mileage difference is like 1 mpg for the V8. That said, I should imagine one could save more fuel by being conservative with the V6 than can be saved with the V8, but with "typical" driving, the difference isn't that drastic (of course don't forget the V6 didn't require premium fuel like the V8 back then).

[Ilya]

Why would you drive your gas tank that low anyway? Once the light goes on, I pull over. Period. No need to drive on the edge of the seat and pump 18 gallons+. lol.

[a.blanco0905]

^^I just wanted some good MPG numbers based on speed and this is what I get... a thread about how big our gas tanks are, lol... Dustin, if you drove 55 miles after your screen showed **.* your car's computer needs some attention... and about computers telling us/me how much fuel I had left, well... I went by the computer saying **.* drove give or take 10 miles (a couple of errands) at which point the fuel gauge was way below (outside the gauge range btw) and when I filled up it took 17.80 gallons...

[The00Dustin]

No no, my computer showed 0 miles til empty, not ****. It doesn't always show **** (and has never shown **.*), sometimes it goes right down to 0 (it has never gone negative, so that's a plus). Regardless, I complained to the dealer, it was under warranty, they said nothing was wrong. Anyway, at 80MPH in the Texas heat, 19.9 doesn't sound that low to me.

Ilya, I wasn't on the edge of my seat because I'm pretty sure it's a 20 gallon tank. My Park Ave Ultra light came on with 80 miles to go on the tank, the DTE went to "LOW" at 40 miles to go on the tank. I usually didn't even think about filling up until the DTE said low. It had an 18.5 gallon tank in it and I once pumped 18.1 gallons into it (you wanna talk about on the edge of your seat...). If the computer in our M's was halfway accurate in regards to the actual amount of fuel in the tank and not lying to us, I might well get 400 miles on every tank, and would certainly pump in at least 17.5 gallons every time. I wouldn't have to be on the edge of my seat because my drive is consistent. I don't do this in unknown territory on trips nor if I forget to reset my tripometer.

[mexillis]

i know someone with an M45 that ran out of gas and only filled up around 18 gallons. Sorry to add on about fuel tanks blanco but just wanted to throw that out there.

[The Bodyguard]

I'm getting about 18-19 mpg city and about 22 hwy, not much highway driving as this is my daily driver.....not complaining. My '07 M35 did very similar numbers?? I dont usually drive with my heavy foot, 60-70..65mph avg. or commuting 35-45...40avg. I try not to drive durring rush hour...BIG help!!

[a.blanco0905]

Mex... it's all good, it happens on every thread, lol. Dustin... everybody knows what I meant when I said **.* so why do u have to complicate things? Lmao... Also, a computer doesnt tell us how much gas there's in the tank, that's as analog as it gets (conventional fuel gauge) and finally...

this...

i know someone with an M45 that ran out of gas and only filled up around 18 gallons.

[The00Dustin]

Blanco, regarding asterisks and their layout, I only mentioned it in case someone else could later point out that it was somehow relevant. If I was trying to complicate things, I would have pointed out how awesome 400 miles per gallon would be, but I know you meant tank.
Anyway, the analog signal from the sending unit is converted to digital, and probably not really converted back to analog even for the analog dial, but the digital signal is used by the computer, which could easily be programmed to treat any given digital point as 0/E. Regarding the M45 that ran out of gas and only filled up around 18 gallons, you are aware of our tank filling issue, right? Infiniti would typically only cover it under warranty if you consistently had significant trouble filling up beyond half or three-quarters full, and often pointed out how it depended what pump you were using and wasn't necessarily the cars problem. I got that fix, and it's still difficult to actually get my car completely filled. The M45 Mexillis knows about may or may not have had that TSB performed, may or may not have pumped full blast without verifying the tank was full afterwards, may or may not have been parked on an incline that affected the amount of gas that could go into the tank, and may or may not have been affected by any other number of mitigating factors (for instance, did the car get towed, or did a service person provide 2 gallons that weren't counted to drive to the nearest station?). Regardless, suppose Nissan did screw up ALL of their documentation regarding the tank size on our car, do you really think they would just let it slide and not release any kind of statement or amended information regarding that?

[a.blanco0905]

[FNAWSM]

its 20 gallons, just accept it.

[bbs350z]

gas tank holds 20 gallons. the gas light comes on about 16-17 gallons so we dont run out of fuel on the side of the rode. its retard proof essentially. same case with the z, and when i removed my gas tank, it did indeed hold 20 gallons

[EniGmA1987]

I filled up my tank, drove it to where the gauge said I was just a tiny bit above halfway, and filled up again. The fill up from just a tiny bit above half was 9.3 gallons. So yes the tank is 20 gallons.


The needle on the gauge changes position depending on how hard you drive. SO if you drive at one speed for a while, and then switch it up and are doing some different stuff, the needle moves to show you how much gas you have left based on your current gas usage. That is probably why most people think the tank is much smaller. You are all driving it "a bit hard" and so when the gauge says it is on or very close to empty, you fill up and only need 15-16 gallons. This is just cause you are driving it where you use gas faster. If you drive exactly the same way all the time and take it easier, the gauge is quite accurate.

[The00Dustin]

Why do I feel like I just got Punk'd or something? Also, to all you new thread joiners (who agree with me, and may or may not have missed the initial point of the thread as I did even in my initial post before the tank discussion took over), does 19.9MPG @ mostly 80MPH sound normal / reasonable to you? I said it did earlier, but I'm thinking it's not THAT hot in TX this time of year and I may have driven 80 MPH for a tank and gotten better than that. Would have been with literally no stops, though, like 350-380 miles at 78MPH. Also, Blanco, there was a thread about an ECU reset making a difference regardless of how you drive recently. I haven't messed with trying that, have you?

[a.blanco0905]

I actually measured our gas tank volume today... it was 21.999 gallons. Case closed.

Moderator please delete or lock thread.

[StealYourFace]

I think this needs to be submitted to Mythbusters. Let Jamie and Adam have a go at it.

[a.blanco0905]

I think this needs to be submitted to Mythbusters. Let Jamie and Adam have a go at it.

Seriously...

lmao.

[WirelessAndy]

Sigh. I used to work literally down the block from them.