improving fuel efficiency

[Giselle]

Thanks very much nitrodann! that's a great list of things to do

the real nature of my question wasn't "what boring driving can I do to save fuel", but rather "what things can I do to my car to improve fuel economy". My thoughts there was a combo of the very useful maintenance tips given, and also wondering if the old engine can be brought into 2013 by replacing some old outdated designed parts with new ones. I suppose the 1.6 got replaced fairly early so there won't be any newer parts

[sailaholic]

Thanks very much nitrodann! that's a great list of things to do

the real nature of my question wasn't "what boring driving can I do to save fuel", but rather "what things can I do to my car to improve fuel economy". My thoughts there was a combo of the very useful maintenance tips given, and also wondering if the old engine can be brought into 2013 by replacing some old outdated designed parts with new ones. I suppose the 1.6 got replaced fairly early so there won't be any newer parts

The problem is the engine computer only knows old parts. So while newer design injectors might (should) help with better efficiency they would have to be very close to the same size as the computer won't be able to compensate.

Going down the road of a newer (aftermarket) computer is something I would heavily recommend AGAINST given your goals. Too much time and cost.

A great fuel saver is just as likely to be a manual gearbox and manual engine (engines made for autos were slightly different internally) and had a different computer to suit. But again, costs of the swap are unlikely to pay off in fuel alone.

If you did end up doing an engine swap it would be worth looking at the nb engines and using the nb computer but this is a lot of work and only economical if you did the job yourself / with friends.


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[Guran]

Giselle, it sounds like you're mainly concerned about operating costs, rather than fuel consumption alone. In this case, you can forget about modifying your car to save fuel, because those costs will dramatically outweigh any benefits. Some ways to save money with your NA6 are to:
1) minimize your usage by avoiding unnecessary driving,
2) avoid peak hour traffic if possible,
3) shift to neutral when stopped in traffic,
4) treat the accelerator like it has a sharp spike on it,
5) good maintenance (see Dann's advice).
Boring, but that's what it takes.

[Blade_Hunter]

3) shift to neutral when stopped in traffic

Why? idle is idle weather spinning on the torque converter or disengaged from it.

[sailaholic]

3) shift to neutral when stopped in traffic

Why? idle is idle weather spinning on the torque converter or disengaged from it.

Not in an auto. It takes more idle effort to spin the torque converter. If you doubt it put your foot on the brake and shift between n and d and see if the revs change / or if load comes onto the box.


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[Okibi]

3) shift to neutral when stopped in traffic,

Do NOT do this! It's a pet hate of mine.

Being a safe and courteous driver is far far farrrrrrrr more important than saving fuel.

[Blade_Hunter]

Not in an auto. It takes more idle effort to spin the torque converter. If you doubt it put your foot on the brake and shift between n and d and see if the revs change / or if load comes onto the box.

The revs rise when you shift to neutral because there is no resistance but it doesn't change the amount of fuel being used, it's still idling the same just with a slight resistance from the torque converter when in drive.

Edit: Just did a bit of google searching and whilst I still remain somewhat scepticle, I will concede my point, it looks from all links I found that you are in fact correct:

Example: http://money.howstuffworks.com/personal ... cally8.htm

Even knowing this though it makes no sense in my head, the resistance from the torque converter is not massive, it's only fluid being pushed through a bunch of fins so why would the engine need to throw in more fuel to counter it? Anyway, Uncle google proved me wrong

OP: Read that link for some tips. If you really want to save fuel turn your engine off at every stop light, I think the fuel saving would be negated by the wear on your starter motor and other components but I may be wrong

[Blade_Hunter]

[22Silver]

I get anything from 8L/100 up to like 15L/100 depending on how I drive, and whether or not I'm going up a mountain.

It makes a huge difference, slowly coasting up to traffic lights that are red, rather than driving up fast and braking hard. If you drive up a tiny bit slower, you might even catch up to the stopped traffic as they start moving, and avoid dumping ALL your kinetic energy into the brakes.
Getting to speed limit over the course of a few extra seconds, instead of flooring it every time something causes you to fall below the limit.

[93_Clubman]

As Dann says, good maintenance is really important, particularly given the age of most of our MX5s - many of the issues forumites have with NAs & NBs is due to poor maintenance at some stage of the car's life.

The list I use for my NA8:
check/ replace engine oil, oil filter, & sump plug crush washer (every 6 months)
check/ replace gearbox oil, including turret (every 2 years)
check/ replace differential oil 75W-90 (every 2 years)
check/ flush/ replace brake fluid (every 2 years)
check/ flush/ replace clutch fluid (every 2 years)
check/ flush/ replace coolant in radiator & expansion tank (every 2 years)
clean/ replace air filter (every year)
replace fuel filter (every 2.5 years/50k kms)
check/ clean/ replace 4 sparkplugs NGK BKR5E-11 (every year)gap=1.1mm
check/ replace spark plug leads
check & clear ECU codes by disconecting battery
check/ clean/ adjust idle screw 850RPM +/- 50RPM
check/ adjust timing - 10 degrees BTDC
check/ adjust throttle cable freeplay 1-3mm
check/ clean throttle body & fuel injectors
check/ clean MAF element
check/ clean PCV valve
check/ clean restrictor operation
check throttle position sensor
check/ replace O2 sensor
check evaporative system
check/ clean cold start pipe fittng & connections
check fuel lines & hoses
check/ adjust/ replace alternator belt 4PK885 - new / used belt: 8-9mm / 9-10mm deflection with moderate pressure
check/ adjust handbrake
check/ adjust clutch pedal freeplay
check/ adjust brake pedal freeplay
check/ adjust front & rear wheel alignment
check/ adjust wheel balance
check/ adjust wheel nut tightness
check/ fill washer bottle level
check/ adjust/ replace tyres & pressures
check/ replace wiper inserts (annually just prior to Winter)
check/ replace front & rear brake pads, grease caliper slider pins & machine discs as necessary
check/ replace timing belt (every 100k kms)
check/ replace waterpump (best replaced in conjunction with timing belt)
check/ clean power window switch contacts
check/ tighten hardtop latches securing screws
check/ clean inside front lower quarter panels
check/ clean windscreen cowl drains & ventilation intake
check/ clean soft-top drains & drain pipes, as well as sill drains & front windscreen frame rubber side drains
check/ clean battery terminals & under battery tray for rust
check/ clean underbody
check/ clean boot, especially boot floor & arms for water or rust
check/ clean engine bay
check/ clean interior, especially parcelshelf & floorpan for water or rust
check/ clean/ polish exterior
check cooling system
check/ replace inner & outer gearshift boots & gearshift base collar/ cap
check brake lines, hoses & connections
check clutch line, hose & connections, including slave cylinder
check/ adjust/ replace front wheel bearing freeplay
check engine mounts
check steering operation & gear housing
check steering linkages, rack guide & tie rod ends
check front & rear suspension ball joints
check/ tighten bolts & nuts on chassis & body
check/ replace driveshaft dust boots
check tighten exhaust system heat shields
check/ tighten exhaust manifold bolts & nuts
check/ replace damper dust boots
check/ replace fuel pump wiring harness top tank connection
When present:
check/ adjust/ replace AC & PS belt - new/used AC belt 8-9mm / 9-10mm deflection with moderate pressure
check/ adjust/ replace powersteering fluid & lines
check adjust/ replace automatic transmission fluid

[meanmx]

3) shift to neutral when stopped in traffic,

Do NOT do this! It's a pet hate of mine.

Being a safe and courteous driver is far far farrrrrrrr more important than saving fuel.

Couldn't agree more

[hks_kansei]

How does neutral cause any issues?

[Mr nanotech]

I think this is to avoid roll backs? BUt then you are on the brake with the clutch engaged anyway if it's in gear... so I don't see the point.

[StuwieP]

don't want to spend time looking around for 'D' if you suddenly need to get going / out of the way.

yes - arguably this is true for a manual, but N-1st is going to be much more of a habit/instinct than for an auto 'box.

I suspect the fuel savings would be minimal anyway, especially taken in comparison with the other (excellent) suggestons.

[Mr nanotech]

Oooooooooh I completely forgot it was auto hahaha