Fuel Economy...WTF?

spearfish25 · 07-03-2009, 12:51 PM

Quote:

Originally Posted by TheWeatherman

Hey Spear... From what I've found with my '09 FX35 and this, the VQ motors don't start getting their best mileage until they are fully warmed up. When I just have my 15 minute trip to work, your mileage is close to what I'm getting. Once both of them are warmed all the way, the mileage goes way up. Just an observation for what it's worth.

Yeah, the car runs great so I'm with you guys on thinking it's engine temp related.

First it was oil coolers, now it's going to be engine block heaters...LOL

dad · 07-03-2009, 01:02 PM

Quote:

Originally Posted by spearfish25

Hmm, all good points. I'm going to top off the tank today and do the math. Will also fill up at a nearby BP instead of the usual Shell.

No, don't mix the gasolines, go to a different Shell station.

spearfish25 · 07-03-2009, 01:04 PM

Quote:

Originally Posted by dad

No, don't mix the gasolines, go to a different Shell station.

I have two shell stations within two blocks of each other. I gave up on one because it was disgusting and the pumps were always out of order. The other seems to be better run and is where I've been filling up. My guess is it's not the gas...or both stations get replenished by the same trucks.

jpit · 07-03-2009, 01:08 PM

The computer on the 370Z for gas mileage is by far the best I have had in a car. It has been accurate to within .1 of a mile for each fill-up I have calculated.

dad · 07-03-2009, 01:10 PM

Quote:

Originally Posted by spearfish25

I have two shell stations within two blocks of each other. I gave up on one because it was disgusting and the pumps were always out of order. The other seems to be better run and is where I've been filling up. My guess is it's not the gas...or both stations get replenished by the same trucks.

Try to fill up with Shell, different brands of gasolines could have different volitile levels. It's not bad to mix them, but your engine may run a little different.

OnCallZ · 07-03-2009, 02:10 PM

Had same problem as you, my commute to work is ~9 miles, half city half highway - my mpg is ~16. I have been trying different brands and I get the best mileage on chevron/shell, worst on 7/11 gas.

FricFrac · 07-03-2009, 05:37 PM

For me it completely depends on how I drive. I can get 28 MPG even on a hilly highway but I typically get 16 MPG with my foot on the throttle and its not the speeding - I really try to keep it within the limit as the cops are just crawling all over the place lately. Its the quick accelleration that gulps the gas.... which explains the 13 MPG I've gotten in the past

mrarroyo · 07-03-2009, 05:59 PM

Something else to remember is to at least allow 2,000 to 3,000 miles to allow all the parts to break in and seat before calculating the MPG. I change my oil and filter w/ Mobil 1 5W30 at 1,000 miles in all my cars to remove any flakes/dust/etc that comes off in the beginning of the break-in process. I then change the oil/filter at 5,000 miles and every 5,000 miles thereafter also with Mobil 1 5W30.

john370z · 07-03-2009, 09:18 PM

I am sorry to hear you mileage is less than many are getting. I have owned my z for 6000 miles and the worst MPG on an entire tank was 20.4 and the best is 22.9. Those numbers are all in town driving approx 50 miles a day. On the highway I've gotten about 26MPG but is has been a while since I have taken it on the highway.

john370z · 07-03-2009, 09:19 PM

P.S. I am a very sporty driver. rarely baby the car!

Forrest · 07-04-2009, 03:40 PM

Quote:

Originally Posted by Zcott

For what it's worth, I never trust the trip computers so I always to the math on my vehicles (just a habit).
My first two fill-ups the computer was dead on to the tenth.
22.5, and 23.3.

I've found that how I drive around town profoundly affects the mileage.
(I know, not a revelation)
Lord it's hard to stay off that pedal at lights!!!

i have tested the trip computer multiple times it is pretty darn acurate, infact its acurate enough i dont have to test it the old fashion way any more.

tvfreakazoid · 07-05-2009, 03:39 PM

WOW you change your oil every 5k and not 3k? do you use synthetic?

Quote:

Originally Posted by mrarroyo

Something else to remember is to at least allow 2,000 to 3,000 miles to allow all the parts to break in and seat before calculating the MPG. I change my oil and filter w/ Mobil 1 5W30 at 1,000 miles in all my cars to remove any flakes/dust/etc that comes off in the beginning of the break-in process. I then change the oil/filter at 5,000 miles and every 5,000 miles thereafter also with Mobil 1 5W30.

6SPD_FTW · 07-08-2009, 04:03 PM

I always change my oil at 5000mi with synthetic. Whatever you think, but 3K is overkill with synthetic, IMO.

I have averaged as low as 19mpg with some very aggressive driving. But the 370Z can be a very fuel economic car. I live in a somewhat rural area, so 80% of driving is technically highway driving. Not much stop and go around here and its only for brief periods of time when it is.

I just filled up today and averaged 28.1mpg (507mi on the tank and 18gal & tripmeter said 27.7mpg). On an 8-hr round trip, I averaged 29.2mpg c A/C blasting all the way. Of course, I had a little careless accident a week ago and have and will continue to drive like a little granny. I upshift @ 1500-2000rpms on every shift. Utilizing that low-end torque and keeping your R foot off the floor is a great way to save fuel!!

Short trips and frequent cold starts are about the worst thing for fuel economy, also. Doesn't matter how much you baby the car...fuel enrichment when the engine is under operating temp REALLY sucks the fuel down.

Late,
Trav

mrarroyo · 07-08-2009, 07:05 PM

Yes I use Mobil 1 synthetic and change my oil and filter every 5,000 miles. To me doing it every 3,000 miles is over kill unless I am using a regular dyno oil.

07-03-2009, 05:37 PM	#22 (permalink)
FricFrac A True Z Fanatic Join Date: Dec 2008 Location: Victoria, BC Posts: 1,481 Drives: 370Z 300ZX 280ZX 240 Rep Power: 228	For me it completely depends on how I drive. I can get 28 MPG even on a hilly highway but I typically get 16 MPG with my foot on the throttle and its not the speeding - I really try to keep it within the limit as the cops are just crawling all over the place lately. Its the quick accelleration that gulps the gas.... which explains the 13 MPG I've gotten in the past __________________ '09 370Z - '93 300ZX Vert - '83 280ZX - '83 280ZXT -'81 280ZXT stroker - '72 240Z - Stillen CBE, HFC, G3, Grounding Kit, Sways // Swift Spring // H&R 15mm // 5% Tint // Clear Bra //

07-03-2009, 09:18 PM	#24 (permalink)
john370z Base Member Join Date: Jan 2009 Location: new mexico Posts: 141 Drives: 2007 335i coupe Rep Power: 283	I am sorry to hear you mileage is less than many are getting. I have owned my z for 6000 miles and the worst MPG on an entire tank was 20.4 and the best is 22.9. Those numbers are all in town driving approx 50 miles a day. On the highway I've gotten about 26MPG but is has been a while since I have taken it on the highway. __________________ 2009 370Z, Had Berk HFC and un-installed them cuz too noisy!, Stillen CBE, 10mm rear wheel spacer, K&N drop in filters. Blower to come...

07-03-2009, 09:19 PM	#25 (permalink)
john370z Base Member Join Date: Jan 2009 Location: new mexico Posts: 141 Drives: 2007 335i coupe Rep Power: 283	P.S. I am a very sporty driver. rarely baby the car! __________________ 2009 370Z, Had Berk HFC and un-installed them cuz too noisy!, Stillen CBE, 10mm rear wheel spacer, K&N drop in filters. Blower to come...

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07-03-2009, 01:08 PM	#19 (permalink)
jpit Enthusiast Member Join Date: Feb 2009 Location: Washington State Posts: 440 Drives: 370Z Tour MT w/Spt Rep Power: 16	The computer on the 370Z for gas mileage is by far the best I have had in a car. It has been accurate to within .1 of a mile for each fill-up I have calculated.

07-03-2009, 02:10 PM	#21 (permalink)
OnCallZ Base Member Join Date: Jan 2009 Location: Florida Posts: 108 Drives: g37 Rep Power: 16	Had same problem as you, my commute to work is ~9 miles, half city half highway - my mpg is ~16. I have been trying different brands and I get the best mileage on chevron/shell, worst on 7/11 gas.

07-03-2009, 05:59 PM	#23 (permalink)
mrarroyo Base Member Join Date: Jun 2009 Location: Heaven on Earth Posts: 211 Drives: 09 Nissan 370Z M6 Rep Power: 16	Something else to remember is to at least allow 2,000 to 3,000 miles to allow all the parts to break in and seat before calculating the MPG. I change my oil and filter w/ Mobil 1 5W30 at 1,000 miles in all my cars to remove any flakes/dust/etc that comes off in the beginning of the break-in process. I then change the oil/filter at 5,000 miles and every 5,000 miles thereafter also with Mobil 1 5W30.

07-08-2009, 04:03 PM	#28 (permalink)
6SPD_FTW Base Member Join Date: May 2009 Location: Bristol, VA Posts: 59 Drives: 09 370Z Bl 6MT Rep Power: 16	I always change my oil at 5000mi with synthetic. Whatever you think, but 3K is overkill with synthetic, IMO. I have averaged as low as 19mpg with some very aggressive driving. But the 370Z can be a very fuel economic car. I live in a somewhat rural area, so 80% of driving is technically highway driving. Not much stop and go around here and its only for brief periods of time when it is. I just filled up today and averaged 28.1mpg (507mi on the tank and 18gal & tripmeter said 27.7mpg). On an 8-hr round trip, I averaged 29.2mpg c A/C blasting all the way. Of course, I had a little careless accident a week ago and have and will continue to drive like a little granny. I upshift @ 1500-2000rpms on every shift. Utilizing that low-end torque and keeping your R foot off the floor is a great way to save fuel!! Short trips and frequent cold starts are about the worst thing for fuel economy, also. Doesn't matter how much you baby the car...fuel enrichment when the engine is under operating temp REALLY sucks the fuel down. Late, Trav

07-08-2009, 07:05 PM	#29 (permalink)
mrarroyo Base Member Join Date: Jun 2009 Location: Heaven on Earth Posts: 211 Drives: 09 Nissan 370Z M6 Rep Power: 16	Yes I use Mobil 1 synthetic and change my oil and filter every 5,000 miles. To me doing it every 3,000 miles is over kill unless I am using a regular dyno oil.