What engine only mods for better efficiency?

[Floordford]

Im not really even talking about my car. My car will only get 35mpg highway with a hurricane force tail wind. I was thinking of a 2 door hatch Ford Aspire with a 1.3 manual. Ive been trying to find a good fuel sipper but the popular ones are getting more attention as fuel savers as gas is going up. So I wanted to get a fuel sipper that is kind of under the high fuel mileage radar.

Yes id be doing this work myself. And to me its not that daunting of a task to tear an engine to bits and put it back together. I just have to have a plan of attack. I have been porting, polishing, smoothing and doing fab work for close to ten years. To me its fun to think of out of the box solutions to fix things other people ignore. I guess im a shade tree tinkerer but I suppose 80% of the people here are too.

[cleanspeed1]

OK, then balance and blueprint the engine to death, barrier coat the pistons, Total Seal Gapless piston rings, degreed stock cam or find a core to regrind for more torque, valve job to boost the low to mid lift flow, mild cleanup on the head, match everything.

Find a gearset that will slow the engine down.

[Arragonis]

IMHO and I am not an engineer, you have 3 choices.

1. Replace the engine with a smaller one, or replace an autobox with a manual or replace the final drive with a longer one.

2. See if someone has done a Diesel conversion and look at that. Diesel engine choices in the US are limited but there is a conversion of a Honda Insight to a 1.2 3cyl TDI somewhere - but that is expensive.

3. And this is one off the wall - back in the day I was a Mini (as in old style Mini not the BMW, er, 'thing') tuner. The bible for this car was David Vizard's Tuning BL's A-Series Engine. This book (>1000 pages) was a masterpiece on how to improve the 1952 OHV, 3 main bearing engine to something that would touch 1.5 litres and make 100hp/litre.



He did include a chapter on building an FE based engine though. I didn't follow it (I was after POWAH) but it did include a lot of stuff about efficient breathing, longer stroke, combustion chamber design and so on.

He took it on a tour of the US too.

[bwilson4web]

I remain a little confused by 'thinking outside the box' and 'not my car.' Is this a real, 'I have the title' car or a day-dream car?

If a real car, how about some specs:

• make/model
• in-service miles
• engine
• transmission
• wheels and tires
• instrumentation
• MPG at xx mph over a 10 mile flat route, no stops, both directions

Now thinking 'outside the box' is often helped by understanding the box:

• rolling drag - a function of tires, bearings, and transmission friction
• stirring drag - a function of transaxle lubricant
• aerodynamic drag - a function of shape and cooling air flow
• thrust - what the engine power provides
• brake secific horse power - a measure of how much power (for thrust) as a function of fuel burned ... often badly measured on a test stand without accessories including the water pump.
• accessory load - the amount of power sucked from the engine to provide 12V power, power steering, power brakes, air conditioning, and any other parasitic energy drains

Before leaving 'the box,' consider the basics:

• tires - low rolling resistance and 4-wheel alignment. Sumitomo T4s are low rolling resistance and have a maximum sidewall rating of 51 psi, excellent for lower rolling resistance. Oversized, they can provide 2-6% overdrive without making a single mod to the drive train. But at least pump up the tires to the maximum sidewall.
• lubricants - not just engine but also include the transmission and if it has one, differential. Try to drop any pans and access holes and clean out the gunk. Then drive 1,000 miles and do a second chance to get rid of the 15-25% carry forward from the previous change.
• spark plugs, air filter, and PVC valve
• throttle body cleaning and injector cleaner
• disk brakes - make sure they only lightly brush the surface

Now baseline your car performance by using any of the web-based, mileage recording systems: Fuelly, Ecomodder (of course), fueleconomy.gov. If you do not have these, get quality instrumentation:

• ScanGauge or equivalent mileage instrument - I prefer recording systems so I don't have to memorize the data.
• GPS with recording capability - Garmin nuvi is good but there may be others. This is needed to get true mph as well as terrain emphermis and actual driving routes and patterns.

Benchmark your perfectly tuned car against your real world driving. Use this data, analyzed at home on your computer as if you are analyzing a stranger's data. Select a series of hypothesis and test each one, one week at a time. Folks have already offered various hypothesis to which I would add these specific to the engine:

• replace mechanical water pump with electric - with a good controller, it will only draw power as needed to cool the engine allowing faster warm-up and lower overall power drain.
• hill billy plug-in - use 24V, deep-discharge batteries charged up at night that feed a 12V (actually 13+V) power supply to offload the alternator.
• body, air inlet block - some form of inlet air block so the minimum amount of air enters for the conditions. More blocking in the winter and high speeds. Less blocking in hot weather and low speeds.
• tire overdrive - largest, low rolling resistance, maximum sidewall pressure tires that will fit.
• air dam and side skirts - to reduce under body drag.

There is a lot of space 'inside the box' and once you've gotten the car to walls, then it is time to go outside the box ... with a high efficiency, hybrid. This is called shreding the old box and getting a better box.

Bob Wilson