Newbie with auto - what can I do about urban driving
 

I'm on my third tank since joining ecomodder.com. I have an '08 Nissan Versa 1.8L with auto transmission and bought an Ultra-Gauge. I've been experimenting with different driving techniques and can get about 41 MPG on the highway. I shift into neutral when exiting the highway and watch the MPG just soar. But conversely, once I start driving between traffic lights in an Urban setting, the MPG just tanks. I've tried all kinds of things to prevent this, but so far I can only manage about 22 MPG when driving around town. Things I've tried: 1) accelerate at 75% load, then shift to neutral and coast to the next light. 2) accelerate slowly to about 30 and then turn on CC until I can shift to neutral and coast to the next light. 3) Shifting to neutral at lights 4) turning off the engine if I'm 4th or more in line at a light 5) parking immediately when I enter a parking lot 6) braking early to give myself more time if I think a red is about to turn green. 7) inflate tires to 40 P.S.I. 8) replace oil with low-viscosity Mobil 1

But even with all that, every time I move away from a light I helplessly watch those hard earned 40+ numbers just ticking away. The Versa is such a light-weight little vehicle, why is it so hard to get it up to 30 MPH? Anyone else with an auto have any ideas?

Welcome to the site hellcats.

Does the Versa have a CVT or traditional automatic transmission? That'll effect how you should drive. But, generally its best not to load the engine up too much with an automatic type transmission. Moderate acceleration seems to work better. Neutral coasting is a good idea, especially up to red lights.

It is the cheaper traditional automatic. Maybe I'm just stuck with poor urban driving performance since I really have little control over shifting etc. I've really been trying to reduce my urban driving as much as possible (combining trips, riding my bike when possible etc.) But recently I tried to get across town during rush hour, and was forced off the highways due to multiple wrecks, a Mavs game, 99 deg. temps, and just generally snarled traffic. Had to watch my 40 MPG tank average drop down to 36. Ugh!

I have noticed that if I can coast a really long way to the next light then my average can get back up. But a small hill or having to hit the brakes just destroys those gains.

I feel your pain. My 3.8 Grand Prix just sucks fuel on acceleration. If you want to improve urban FE, air off, if your are not doing so. Also try not shifting in to neutral when coasting on some cars this may work better. Some discussion that on some cars the fuel injectors cut off under this condition saving more fuel than idling the engine. On my car I find very little difference between shifting to neutral and leavening it in drive, unless the air is on. Engine off works just worry about my old battery. Another biggie is if I can time the lights so I don't need to stop. For me about 3 well spaced light not stopped at yield about .1 MPG boost.

If you find anything that works please post it.
Good luck

With a normal automatic trans, you can try to fake the car into shifting early by letting off the gas a little. When it shifts, accelerate a bit harder, but not so hard that it downshifts. I'd definitely try to keep the rpms under 3000.

Not much to do with an automatic, I guess. I remember. But you still can reduce weight. If you can find 100lbs (!) or more you should see some significant change (maybe 1%) because of acceleration weight in stop/go traffic. Also, fully inflate tires. I even over-inflate by 9psi--like a lot of people here--but I am no expert and you should follow your judgement. If you could switch to LED lights, especially brake lights, there might be a benefit since they get used so much. I plan to do this one day, but I have not yet. Research it here on the site's search function. Good luck man. Report your gains, eh?

Probably the only tip I'll add is to turn off the AC while accelerating and turn it on when engine braking (DFCO). Remember that if you're decelerating rather than coasting, you're better off in gear and engine braking since it will cut off fuel flow (generally above 1800-2000 rpms to initiate, but continue down to 1000-1400 rpms during the decel). You'll still be turning the energy, so it will turn your alternator, water pump, and AC compressor for "free" by converting that forward momentum you already paid for into mechanical energy.

Whatever you do, avoid accelerating with the AC on. Your load will be about 5-7% lower on acceleration at the same rate without it.

Oh, one more suggestion, consider looking at other routes whenever possible that will provide fewer stop lights or at least synchronized stop lights. I have a number of ways to get out of my downtown, but it's always most efficient to cruise through green lights that are timed on the one way streets.

Thanks for all the suggestions! I have been mainly keeping the A/C off, but I sometimes cycle it on/off when its really oppressive outside. I've been trying to use DFCO when approaching a red light, but my car only seems to do it at high speeds (or at least Ultra-Gauge only detects it at higher speeds).

I'm going to try Daox's suggestion of faking the trans. to lower rpms.

I wish the Ultra-Gauge had something like "lap" mode on a stopwatch which would be a short-term "trip" so you could try a driving technique over a short distance and while already moving.

I agree. You can sorta do it right now if you get skilled at working the menu clicks. But maybe you have noticed that the first mile or mile and a half there is no average MPG calculation, just an instant reading while it gathers initial data. So you want your short ditances to be at least say 2 miles.

Is your gauge calibrated properly yet? If so, at about what speeds does your DFCO kick in when you coast?

That is important for me while driving around St Louis. My automatic Vibe tends to have fuel cutoff from about 38-65 mph (ScanGauge shows 9999 mpg). So, I try to drive on roads with speed limits of at least 40mph.
I don't put my car in neutral very much, except at long stop lights.
I also make sure to use MAX AC, which recirculates already cooler air. The cabin air cools faster, so I can turn the AC back off more often.
Good luck!

Timing the lights is important and route planning to eliminate lights can help a lot. Lighten your car as much as possible and run as high a tire pressure as possible. I give mine enough throttle so it shifts just above 2000 rpm. I can usually get around 30+mpg in pure city driving...but I've eliminated about 12 stoplights from my commute, so I don't do much city driving anymore :)

12@Tygen1: I've been trying your (and Daox's) idea of controlling the throttle to keep the transmission below 2000 rpm. I've tried to watch the instantaneous MPG, but with the speed changing at the same time it is hard to tell if the method helps or not. I have been reading about BSFC, and it looks like it is generally better at higher RPMs, but I'm sure there are many other factors at play. I guess I'll just have to conduct some tests. BTW, I'm very impressed with your 48.2 mpg with a 2L/auto. I would be very happy if I could just get to 40 with my combined city/highway driving around Dallas.

11@TheMarkOfPolo: I calibrated the MPG and tank fill level on the Ultra-gauge last week. The DFCO is detected at about 45 MPH or greater on my Versa, so it is not much use except when there's an obvious red light ahead when exiting the highway.

For best BSFC, it's high load and low rpm, which we can not do with the atx, so I just try to limit rpm based on the idea that the torque converter may be more effcient and have less slip with less rpm...it seems to work with my car. Keep in mind that you will be accelerating at a slower pace than 99% of everyone else. When I am going stop light to stop light, I will let it shift up to second gear then attempt to coast up to the next light, assuming it's red, this can drive the folks behind me crazy :) but we usually get to the light right when it turns and it causes no delays. The idea is to only build enough speed to get you to the next red light. If it's green, then you just want to go as slow as is reasonable.
Thanks for the nice comments, it has taken 2.5 years to get here, so don't think you will get that 40 number right away or without some failures along the way.
I commute into Philly everyday, so I get to fight plenty of traffic. I've been around Dallas as well, so you have a similar problem. Work on your route, there is often a lot of potential there that most folks ignore.