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Car Forum / Nissan / Nissan Cars / November 20071997 Sentra Gas Mileage Boost Ideas...
Thinking about how to make my commuter car more gas efficient... I don't really use it for anything other than commuting so here are some ideas I had without going TOO extreme... 1. Remove unnecessary parts that are heavy and lower mileage... Trunk rugs, unneeded tools, electric window motors(?), floor mats, hub caps, etc. Anything that is extra weight... 2. Make sure my air filter is clean and free-flowing. Thought about a K&N high flow filter, but at almost $60.00, I don't think it will pay for itself in the long run... Especially with FI. 3. Clean the throttle body on my car. At 160,000 miles, it's all messy inside. 4. No jack rabbit starts or cruising overly fast. No heavy acceleration on the highway to pass, etc. Any other thoughts? This is NOT a creature comfort car... I'm even considering removing the seats and hardware I don't use throughout the rest of the car... Joe in Northern, NJ - V#8013-R Currently Riding The "Mother Ship" http://yunx.com/valk.htm Ride a motorcycle in or near NJ? http://tinyurl.com/5apkg Hillary Exposed: http://tinyurl.com/2v4avg > Thinking about how to make my commuter car more gas efficient... I don't > really use it for anything other than commuting so here are some ideas I had [quoted text clipped - 28 lines] > Hillary Exposed: > http://tinyurl.com/2v4avg Most of those things you're going to remove won't make much of a difference unless you get a couple hundred pounds out. Biggest bang will be a good front end alignment, tire pressure, engine in good tune, synthetic oil, slow starts, low speed, and highest gear as soon as possible. But if you do the math, it's probably not worth it. > Thinking about how to make my commuter car more gas efficient... I don't > really use it for anything other than commuting so here are some ideas I had [quoted text clipped - 25 lines] > > Hillary Exposed:http://tinyurl.com/2v4avg Like JimV said, you have to reduce weight significantly to see a mileage improvement. Here's my suggestions: Take out the spare tire if the occurence of flats in your commute is an extremely rare happening. Keep your tires well inflated, the higher the better. I have a same car, a 98 sentra. Tire pressure should be 33 psi front and 29 rear. Maybe make it 34 front and 31 rear. Rolling resistance goes down and mileage goes up. Don't go too high, though, because braking ability goes down a bit as well due to the tires contact patch getting smaller. Clean throttle body?? I seriously doubt that a dirty throttle body reducing mileage. It's not really blocking the incoming air. My beleif is that a dirty TB just reduces low rpm drivability; inconsistent idle, not so smooth down low, etc. It doesn't hurt, but doesn't really gain, either. Make sure your fuel filter is only about 15K miles old. If it's older, change it. Spark plugs, change them at 25K miles instead of 30K miles. Do you have bigger rims on your car? The smallest rims will get the best mileage, like the OEM 13s. Operate the AC as minimally as possible. In winter, I only run it to clear the windows in humid, rainy weather. Otherwise, vent to get cold air. CD >Do you have bigger rims on your car? The smallest rims will get the >best mileage, like the OEM 13s. Why do you think smaller rims will have any effect on mpg ? (aside from the fact that the costs of switching will easily outweigh any possible financial benefit from better mileage) >> Do you have bigger rims on your car? The smallest rims will get the >> best mileage, like the OEM 13s. > > Why do you think smaller rims will have any effect on mpg ? (aside > from the fact that the costs of switching will easily outweigh any > possible financial benefit from better mileage) It's all about the "contact patch". How much of the tire is actually on the road effect the rolling resistance. Small skinny tires will have a smaller contact patch than larger (and usually wider) ones. It's true that it wouldn't pay to switch though. >>> Do you have bigger rims on your car? The smallest rims will get the >>> best mileage, like the OEM 13s. [quoted text clipped - 8 lines] > > It's true that it wouldn't pay to switch though. It's more than that. Rotational mass. The heavy part of the wheel, the metal part, plays the most significant part in determining the rotational mass. Big 18" rims will have the metal part on the outer most part of the rim, with the lighter part, the rubber, being a very small part of the equation. Here's another way to look at it; take the same exact car, one with 13" rims, the other with 16" rims. Brakes are the same, engine the same, everything else is the same, except the rims (and tires of course) Total width of the wheel is the same, though. The 16s have lower profile tires whereas the 13s have the higher profile tires. The car with the bigger rims will be slower, and braking will be harder (longer) etc. All this is due to the bigger rims adding considerable rotational mass that weigh down on a car. This affects gas mieage, too. Considerably. CD >>>> Do you have bigger rims on your car? The smallest rims will get the >>>> best mileage, like the OEM 13s. [quoted text clipped - 7 lines] >> smaller contact patch than larger (and usually wider) ones. >> It's true that it wouldn't pay to switch though. FWIW, The same amount of tire is on the road, regardless of tire size. Simple physics. I will agree that a skinnier tire has a narrower contact patch, which might help. >It's more than that. Rotational mass. The heavy part of the wheel, the >metal part, plays the most significant part in determining the >rotational mass. Big 18" rims will have the metal part on the outer most >part of the rim, with the lighter part, the rubber, being a very small >part of the equation. I agree with the general premise, but I think you lose any gain when you make it practical in today's world. Within reasonable limits (same wheel model, same tire model, same OD) the difference in weight between two wheel and tire combos that reasonably fit on a typical vehicle, say a 15" vs 16" wheel, will be roughly the same rotational weight at the same physical point. If you start changing wheels, then maybe you can make a difference. We used to swap out larger wheel/tires for a pair of mini-lites at about 8 lbs each and that made a big difference. I don't think swapping one of today's ridiculously heavy 15" alloy wheels for a 14" of the same style will matter much - particularly when the additional rubber is factored in. > >>>> Do you have bigger rims on your car? The smallest rims will get the > >>>> best mileage, like the OEM 13s. [quoted text clipped - 32 lines] > style will matter much - particularly when the additional rubber is > factored in. Actually, the difference is significant because the extra 3 pounds of weight becomes more like 10 pounds due to the engine having to rotate the extra 2 pounds through a larger circumference. Mulitply that 10 pounds by 4 wheels and you get 40 pounds. These numbers are just approximations to give you a better idea of how it all adds up. My 98 Sentra had the stock steely 13s. I put on the alloy 14s from my previous 99. Despite the 14s being lighter, the 13s on the car were quicker. I took the sacrifice in performance with the 14s because they make the whole car look so much better. I probably lost 1 MPG on the highway due to the upgrade. There was an extensive experiement done on Maxima.org involving the Maxima SE from 1999, 2000, and 2001. The 99 had 16s, the 00 had 16s, and the 01 had 17s. Despite being more powerful, the 00 Max only very slightly beat the 99 Max due to the variable intake which enabled the 00 to make more power up top. The 00 also had a weight hit of being bigger and heavier than the 99. Now comes the 01 Maxima SE. Same as the 00 but now with very pretty 17s. That car was significantly slower than the 99 AND 00 Maxima SE. Those 17" rims were 8 lbs heavier, giving a total added weight of 32 pounds. Now, the 01 Max SE has to rotate that extra 32 pounds through a larger circumference. The original author who had a very good understanding of physics was able to calculate that those extra 32 pounds translated to same thing as putting an extra 256 pounds in the trunk. The 17s were killing the 2001 Max SE's performance. Ask anyone with a 2001 Max SE. They get blown away by the older Maximas. Remember, all these Maximas (99 thru 01) had the 3.0 liter V6 developing 190 to 227 HP, with TQ figures very similar from 205 to 217 ft-lbs. So given the added weight of the 00 and 01 car, they were all pretty much even in terms of power to weight. It is is no wonder that Nissan went to the 3.5 liter V6 in the 2002 Maxima SE. They could not go with smaller rims, and they had to get the Maxima performance advantage back. Look at all the other carmakers. As soon as 17" rims became standard on their models, they had to up their displacement to keep up. All this from a one inch rim size difference. CD >My 98 Sentra had the stock steely 13s. I put on the alloy 14s from my >previous 99. Despite the 14s being lighter, the 13s on the car were >quicker. I took the sacrifice in performance with the 14s because they >make the whole car look so much better. I probably lost 1 MPG on the >highway due to the upgrade. Did you maintain the same OD but using a "+1" concept? Or was the performance difference possibly due to a change in tire diameter, or a change in contact patch allowing more or less wheel spin? >There was an extensive experiement done on Maxima.org involving the >Maxima SE from 1999, 2000, and 2001. The 99 had 16s, the 00 had 16s, >and the 01 had 17s. <snip> Interesting, but are there any back to back tests of the same car with different sized wheels? comparing difference years with a variety of factors involved is not a very scientific test. >It is is no wonder that Nissan went to the 3.5 liter V6 in the 2002 >Maxima SE. They could not go with smaller rims, and they had to get >the Maxima performance advantage back. Well, they _could_ go with 16" wheels, but the marketing department tends to make these decisions rather than the engineering department. >Look at all the other carmakers. As soon as 17" rims became standard >on their models, they had to up their displacement to keep up. That's not why engines got larger. There's a marketing HP war going on. >All this from a one inch rim size difference. Show me some back to back tests and I'll be happier. I'm not doubting that there is a definite possible effect here. I've seen it. I'm just doubting that you'll see much of a difference with the very heavy alloy wheels in use today. >>My 98 Sentra had the stock steely 13s. I put on the alloy 14s from my >>previous 99. Despite the 14s being lighter, the 13s on the car were [quoted text clipped - 5 lines] > performance difference possibly due to a change in tire diameter, or a > change in contact patch allowing more or less wheel spin? I went from 175/70/13 to 175/65/14, so yes, the contact patch and overall diamater did not change. >>There was an extensive experiement done on Maxima.org involving the >>Maxima SE from 1999, 2000, and 2001. The 99 had 16s, the 00 had 16s, [quoted text clipped - 5 lines] > different sized wheels? comparing difference years with a variety of > factors involved is not a very scientific test. True, it was an experiment amongst Maxima enthusiasts. Still, it was very enlightening. >>It is is no wonder that Nissan went to the 3.5 liter V6 in the 2002 >>Maxima SE. They could not go with smaller rims, and they had to get >>the Maxima performance advantage back. > > Well, they _could_ go with 16" wheels, but the marketing department > tends to make these decisions rather than the engineering department. Look at the 2000 Maxima SE. It had 16s. but the larger body absolutely dwarfed them. Even the 99 Maxima looks a wee bit wanting with 16s. The engineering department would have been in agreement with marketing because they knew the Maxima was only going to get bigger and weigh more. Bigger rims were inevitable to suuport the growing Maxima. >>Look at all the other carmakers. As soon as 17" rims became standard >>on their models, they had to up their displacement to keep up. > > That's not why engines got larger. There's a marketing HP war going > on. And a speed war with 0-60 times. The anniversary edition 2001 Maxima SE was being dragged down by its beautiful 17s. >>All this from a one inch rim size difference. > > Show me some back to back tests and I'll be happier. I'm not doubting > that there is a definite possible effect here. I've seen it. I'm just > doubting that you'll see much of a difference with the very heavy > alloy wheels in use today. If the alloys are heavy, then the effect is even worse. Alloy wheels are supposed to be lighter than their steel counterparts. CD >I went from 175/70/13 to 175/65/14, so yes, the contact patch and >overall diamater did not change. Your contact patch did change shape. The size (sq in) of the contact patch doesn't change. >True, it was an experiment amongst Maxima enthusiasts. Still, it was >very enlightening. >Look at the 2000 Maxima SE. It had 16s. but the larger body absolutely >dwarfed them. Even the 99 Maxima looks a wee bit wanting with 16s. The >engineering department would have been in agreement with marketing >because they knew the Maxima was only going to get bigger and weigh >more. Bigger rims were inevitable to suuport the growing Maxima. Two tires of the same rough OD in 16 & 17" sizes will have a very similar load rating, give or take 50lbs. >And a speed war with 0-60 times. The anniversary edition 2001 Maxima SE >was being dragged down by its beautiful 17s. Again, I'd like to see some back to back numbers. >If the alloys are heavy, then the effect is even worse. Alloy wheels are >supposed to be lighter than their steel counterparts. Supposed to be. Remember the phrase "mag wheels"? That came from the original wheels which were magnesium alloy. They were very light. Most "alloy" wheels today are very heavy. Typical weights are 18-24 lbs for popular import sizes. My mag-alloy wheels weighed in at about 8lbs. Today's 17" wheels are more about appearance than performance on most cars (with an unacceptable loss in ride quality and ability to handle real world pot holes). > Thinking about how to make my commuter car more gas efficient... I don't > really use it for anything other than commuting so here are some ideas I had [quoted text clipped - 25 lines] > > Hillary Exposed:http://tinyurl.com/2v4avg All the already posted ideas are good especially keeping the tires inflated properly. Tire pressure goes down about one psi for every 10 degrees drop in temperature so as cold weather approaches it is necessary to re-check the tire pressure. A big factor in gas mileage is keeping the slides on the disc brakes well lubricated and sliding freely. The tire should rotate easily by hand when the wheel is jacked up and off the ground. Good luck. Al You can also go on a diet, ;) > Thinking about how to make my commuter car more gas efficient... I don't > really use it for anything other than commuting so here are some ideas I had [quoted text clipped - 28 lines] > Hillary Exposed: > http://tinyurl.com/2v4avg >> Hillary Exposed: >> http://tinyurl.com/2v4avg Hillary nude? I hope it's not Hillary Clinton, that's disgusting. >>> Hillary Exposed: >>> http://tinyurl.com/2v4avg > > Hillary nude? I hope it's not Hillary Clinton, that's disgusting. It is indeed Hillary Clinton.  SignatureJoe in Northern, NJ - V#8013-R Currently Riding The "Mother Ship" http://yunx.com/valk.htm Ride a motorcycle in or near NJ? http://tinyurl.com/5apkg Hillary Exposed: http://tinyurl.com/2v4avg >>>> Hillary Exposed: >>>> http://tinyurl.com/2v4avg >> >> Hillary nude? I hope it's not Hillary Clinton, that's disgusting. > >It is indeed Hillary Clinton. What's next, Dame Edna? If you want to go extreme, I think you should seriously consider selling the car and buying a motor cycle. Because of the age of the car, the motor must have some wear in it, and also the technology at the time the car was made is not as efficient as today. The cars today are more fuel efficient to start with. Stripping off the extra weight that you mentioned will not make much of a difference. Keeping the engine in good working order and well tuned up is a good starter. Make sure that the air cleaner and the fuel filter are always very clean. Using synthetic oil is a big help. Make sure that the wheel alignment, tire pressure, and the suspension are proper. Also, taking it very easy on the gas pedal is a big plus. Try timing your speed to have the green lights as much as possible. When driving on streets with many stop signs, drive easy to not accumulate too much speed. This saves wear on the breaks, and also saves some fuel from being more gentle in the acceleration and stopping for the stop signs. Stay away from fuel saving gadgets. Non of them work. The best fuel saver is common sense, and proper maintenance of the car. I have a 1998 Altima GXE. I am managing to have an average of 28 to 32 mpg in the city. SignatureJANA _____ Thinking about how to make my commuter car more gas efficient... I don't really use it for anything other than commuting so here are some ideas I had without going TOO extreme... 1. Remove unnecessary parts that are heavy and lower mileage... Trunk rugs, unneeded tools, electric window motors(?), floor mats, hub caps, etc. Anything that is extra weight... 2. Make sure my air filter is clean and free-flowing. Thought about a K&N high flow filter, but at almost $60.00, I don't think it will pay for itself in the long run... Especially with FI. 3. Clean the throttle body on my car. At 160,000 miles, it's all messy inside. 4. No jack rabbit starts or cruising overly fast. No heavy acceleration on the highway to pass, etc. Any other thoughts? This is NOT a creature comfort car... I'm even considering removing the seats and hardware I don't use throughout the rest of the car... Joe in Northern, NJ - V#8013-R Currently Riding The "Mother Ship" http://yunx.com/valk.htm Ride a motorcycle in or near NJ? http://tinyurl.com/5apkg Hillary Exposed: http://tinyurl.com/2v4avg |
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