Posted: Mar 27 2007 at 8:08pm | IP Logged

I have a 2005 Nismo 4X4 crew cab (V6) and am looking for ways to improve my MPG. Has anyone converted their auto hubs to manual? If so, any gain in milage?

I am also looking for other options to gain on MPG so all imput is helpful. 

Thanks in advance.

Posted: Mar 27 2007 at 9:26pm | IP Logged

..

superstalker;

Welcome to the group..! 

Boosting Fuel Mileage updated 06.03.06

... It takes X amount of power to move gasoline engine vehicles from point to point. The engine converts gasoline to heat as the power source. Much more than fifty percent of the heat is wasted unused and is dissipated though the radiator and exhaust system. Large cubic displacement engines normally consume more fuel than smaller engines but this is not a ‘hard’ fact. One of the fuel saving technologies is reducing the of fuel using ‘cubic inches’ of the engine when full power is not required.

... Here is a list of a few of the mechanical things that can effect fuel mileage.

Cam and ignition timing, cam lift, duration and valve size. Leaky fuel delivery systems with vented vapor losses, restricted air induction systems i.e. dirty filters. Intake air can also be too hot or cold Restricted exhaust scavenging systems. Operating temperatures of fuel and engine. Carburetors with bad power valves, accelerator pumps and fouled choke systems. Carbon fouled injectors, sparkplugs, and piston rings. Type of transmission, automatics without lock-up converters and over-drives, gear ratios. The type of tires, tire size, the tire pressures and the wheel alignment. Example; Just think, is it possible that larger wider tires require less ‘toe in’ that could reduce drag and get better fuel mileage? The vehicle speed, the load, the wind speed and direction. The list can continue on including the type and additive mix of the gasoline. Gasoline blends are changed continually by area, altitude and season.

The driver knowledge and ability is the big factor for achieving the best fuel mileage if the vehicle is in proper condition.

Make sure the odometer in the vehicle is showing correct mileage. Increasing the diameter of the tires will reduce the amount of miles shown on the odometer. Keep a record of all fuel amounts, the mileage and the Miles Per Gallon between each gas-up. The record can be helpful in spotting problems with the engine when there is a sudden drop in mileage.

An example of the simple formula is 200 miles divided by 10 gallons = 20 MPG

Full tank amounts will vary due to air trapped in the tank but the MPG will average out in the long run.

Here are a few thoughts about saving fuel.

First thing a driver will notice when they start to conserve fuel is it will agitate other drivers around his vehicle. Please be considerate of other drivers who have no concept of your economy driving. The other drivers want to race to the next stoplight and remember, if they don’t get there quick enough they won’t get to stop!

1. Think about driving as an art while doing so. Stop rubber-necking, turn off the music, the cell and drive.

2. Install a dash-mounted vacuum gauge and use it. As the fuel mileage drops the vacuum needle drops. Try to prevent the needle from dropping below five inches. Readings will change with altitude changes.

3. Drive as if you had a fresh egg taped on the accelerator AND brake pedals.

4. Apply accelerator and brake petals smoothly.

5. Reduce speed as much and as soon as possible. Speeds above 50 MPH eat into the pocketbook!

6. Scan far ahead of your vehicle for traffic control signals and things that will allow you to ‘get off the gas’ sooner so you don’t have to ‘hit’ the brakes as hard – later. The over use of brakes means fuel has been wasted.

7. Drive as if your afraid your brakes are in poor condition and you are trying to save them.

8. Purchase your fuel in the morning when it’s cool and keep the tank full.

9. Air you tires up when they are cold and on the plus side of the recommended pressure and check them often especially on cold days.

10. Small amounts of high quality low ash synthetic Out Board 2cycle oil in the fuel (less than ¼ Oz per gallon) will clean and lubricate and reduce friction. The low ash oil will help the following items for better fuel mileage and life; electric gyrator fuel pumps, carburetor/injector parts, spark plugs, valve stems, compression rings and EGR systems. One sticky fuel injector can drop fuel mileage by one third.

11. Air dams can enhance cooling and reduce aerodynamic drag. Reduce the amount of air getting under the truck because the underside of vehicles create much air turbulence and drag at highway speeds. Bug shields, sun visors, wind deflectors and large outside mirrors can reduce fuel mileage.

12. The effect of heavy loads is detrimental to fuel mileage and brake life.

13. Modifying a vehicle with lifts and large wide tires is detrimental to fuel mileage and brake life.

14. Cruise control may save fuel in ‘flatlands’ but may not be economical in hilly country.

15. In hilly country do not allow the down hill run to cause engine ‘braking’ i.e. slowing down the vehicle unnecessarily. Run your fastest speed at the bottom of a hill and the slowest at the top. ... Only use engine braking when the vehicle is going to gain excessive and unsafe speed that would have required a fair amount of regular brakes. Excessive downhill braking can cause many heat related problems. Among these are warped rotors, brake fade, boiling brake fluid, wearing out pads, over heating seals, bearings and lubricants.

... Down hill engine braking and downshifting for increased engine braking is not going to consume very much fuel because the throttle will be closed. Long downhill runs of five or more percent grades are a good time for downshift engine braking. Two miles of seven-percent grades with curves should be mandatory.

So in hilly country it's a case of the having to use more throttle to regain the speed you lost by allowing short periods of unnecessary engine braking.

Posted: Mar 28 2007 at 7:09pm | IP Logged

Thanks Lakota.

Lots of good tips.