eco modding an L series

spike · Post by **spike** » Mon May 21, 2012 8:43 pm

has anyone done any eco modding to an L series?
i found some people in america who had played with it and figured since Lisa will be either looking for a new home soon or joined by something else (probably a 2000 or so subaru non turbo sedan, turbo 98 wagon or a 1st gen forester)

anyway in the meantime im planning to try and save some money when using my wagon. I dont use it in the city at all so theres a basic given already, only places ive driven in the last month are the shops down the road (80KMH) and about 100 k north on 100k roads but fuel costs are killing me............

anyway...... plans so far are to give it a
quick tune
clean up the carb as i think this may have a problem (if i had the time and money id rebuild and put the FI engine in, anyone want to do it for me =P)
lose some weight, not really sure how yet rear seat isnt used but i want to have it if its needed
only thing i have left is to clean the aero up (i have a plan!!)

and the last thing thats been spoken about, not so much on this board but the america and on the eco sites ive read, is gear changes

And by this i dont mean diff ratios, it IS(!!) possible to change the gearbox to use the hi-lo on 2wd only, internal modification is required though giving you/me a 10 speed fwd car

purp · Post by **purp** » Mon May 21, 2012 11:16 pm

I'm not sure how having ten forward gears is going to help you with fuel economy (not noticeably anyhow). Surely any advantage gained from closer ratios is going to be minimal compared with all the other "driving style" changes you can make?

Gannon · Post by **Gannon** » Tue May 22, 2012 6:40 am

I once got knocked back on rego for not having my rear seat in.

Brumby Kid · Post by **Brumby Kid** » Tue May 22, 2012 8:04 am

10 speed would be good. You could do 100km/h at about 1,500 revs for example. You wouldn't need to Move it through the rev range as much, hence saving fuel.

steptoe · Post by **steptoe** » Tue May 22, 2012 9:13 am

See if you can get some leaner jets for the Hitachi

Copy the stop start technology - been hearing it in the traffic from a few cars - that don't normally have it

Freewheeling down inclines - at idle will draw less fuel than at normal road speed revs, or switch off and restart when engine required again. I have one stretch or two where I can get 1.6 to 2.4 km of no fuel used at all and if you neeed to keep braking - the hurried restart with foot on the brake is a great test for the booster

Walk ???

Have you been described as having two left hands ? think not with your noted achievements

spike · Post by **spike** » Tue May 22, 2012 10:25 am

purp wrote:I'm not sure how having ten forward gears is going to help you with fuel economy (not noticeably anyhow). Surely any advantage gained from closer ratios is going to be minimal compared with all the other "driving style" changes you can make?

Brumby Kid wrote:10 speed would be good. You could do 100km/h at about 1,500 revs for example. You wouldn't need to Move it through the rev range as much, hence saving fuel.

with the 10 speed mod you get 5 gears at the lower end of the field, so brumby kid is slightly wrong but also right. by using a lower diff ratio to get higher speeds from less revs you save the fuel HOWEVER take off and though the city can be a slight problem needing to lift the revs considerable to get the car to move off. With 5 lower gears (in effect probably 3 lower gears due to cross over in the gear ratios, 3rd low is probably close to 1st high etc) its like changing the diff ratio, no need for the revs)

Gannon wrote:I once got knocked back on rego for not having my rear seat in.

yes ive heard this apparently it comes out of businesses buying vans that have the rear seats and are thus people movers, removing the rear seats so you now effectively have a commercial vehicle without paying commercial rates. If you have it out for a day and get pulled over and have a reason for it to be out 'couldn't fit my fishing/camping gear in' you might get away with it

steptoe wrote:See if you can get some leaner jets for the Hitachi

Copy the stop start technology - been hearing it in the traffic from a few cars - that don't normally have it

Freewheeling down inclines - at idle will draw less fuel than at normal road speed revs, or switch off and restart when engine required again. I have one stretch or two where I can get 1.6 to 2.4 km of no fuel used at all and if you neeed to keep braking - the hurried restart with foot on the brake is a great test for the booster

Walk ???

Have you been described as having two left hands ? think not with your noted achievements

i will have to see about the jets, i do prefer the idea of FI but whatcha gonna do

yes once the cars up to temperature this is ok seems to be popular now

if i was very serious (and im not that serious about all this just trying to save some money) id get a vacuum reservoir and hook that in so i have brakes without engine.
With the fuel injection cars in the states they add switches with the ability turning the injectors off so there is no fuel at all.

Brumby Kid · Post by **Brumby Kid** » Tue May 22, 2012 11:14 am

Approx 6 seconds at idle is equal to the same fuel as turning the engine on.
Just something I heard, but what idle revs I don't know.

spike · Post by **spike** » Tue May 22, 2012 11:49 am

well i know that if your sitting for 7 seconds than yeah turn it off, how you know you will be sitting for 7 seconds i dont know.
and im not sure if this is the same as NA or FI, there are some other serious mods that i have in mind but probably wont get around too so wont bother talking about it just yet

purp · Post by **purp** » Tue May 22, 2012 2:34 pm

I wasn't completely disputing the idea of the gearbox mod (more gears = better is why more and more manuals are six speed), I just think for the trouble of doing it and getting the gears set-up right for your preferred cruise speed there are other things.

Tire pressure - higher pressure = lower rolling resistance. The trade off is in potential quicker tire ware and reduced braking ability.

Narrower tires = less rolling resistance. Narrower smaller profile tires = lighter = means less energy - but also means less grip on the road, and smaller diameter will change your engine RPM for given speed which could be good or bad.

Killing the engine when not used (lights and down hills) as people have said. I am very interested in the idea of a pressure reservoir for the brakes.

If you have a old diesel you can pad your fuel out very easily with various second hand sources of oils (think fish and chips) without difficult mods, but that isn't really an option with modern diesels.

Aero-dynamic improvements to the car...

Drafting in the slipstream of vehicles in front - not particularly safe and tends to piss people off....

spike · Post by **spike** » Tue May 22, 2012 4:46 pm

lots of stuff there purp and ill try and give my feedback on the things ive seen

its a hell of a mod and as i dont use it for city streets i probably wont do it, in the old mans Forrester i just throw it in low in the city for lights and stuff, the stop go sort of thing, its just something you cant do with the base model L.

tire pressure is a big thing, im not sure what to put mine at yet i will have to look that up too. Most people run at 32, serious eco modders go as high as 50 in special low resistance tires, im thinking about 40 but will see. Also i havent heard anything about faster ware but i know you get different wear patterns.

narrower tires are good for the fact it gives less rolling resistance as well as lower frontal area.

im more inclined on the down hill bit, i go up and down hills a lot but not the lights. Also its the same as push or bump starting the car, rather than using the starter motor which will kill it using it 17 times rather than once, as well as the battery and alternator.

you can still do it with modern diesels but it costs more, older are a lot easier and more rugged

aero will probably be the big thing, and im working on keeping the car cool while still aiming at being aero dynamic (im going to make a detailed thread about this soon)

as for some of the tips and techniques i simply wont be doing them, drafting etc. just because they are unsafe

Gannon · Post by **Gannon** » Tue May 22, 2012 5:40 pm

The engine off on downhill runs is dangerous and pointless. In an EFI engine, the injectors are turned off above 1500rpm when the foot is off the throttle anyway so you arent gonna be using fuel as it is. In other cases, if the throttle is closed, the engine will only be getting the amount of fuel it would at idle anyway, plus maybe a little bit more because of the higher manifold pressure, but negligible anyway

spike · Post by **spike** » Tue May 22, 2012 8:32 pm

please explain Gannon?
the only danger i see is the brakes and yes you have a point, hence the idea of the vacuum reservoir to fix this problem (sucked out when the engine is on and retains vacuum)
there is controversy over the rest of your statement gannon, i too would of figured it that way.

apparently (on modern cars) if going down hill in neutral the engine is at idle revs or slightly above (for some reason) if in gear with the clutch in the engine thinks its engine braking and stops fuel flow.

also for the serious people (im not serious yes) anything that is negligible is worth pursuing. some of the stuff that they go into is crazy

spike · Post by **spike** » Tue May 22, 2012 8:39 pm

heres a list of common modifications taken from the ECO modder website, ive taken some out cause they wouldn't work in this application

Vacuum gauge- pretty dam easy basically the higher the vacume the more efficent the engine is running (i think thats it)

Roof rack-dont run with it......i dont think ive ever had one hahah

Mud flaps- ill have the think about this one they seem useful but as-well they are using more fuel

Radio antenna- i will do this, less from the cleaning up the airflow but just to be different and i dont want it to get broken

Shave badges, door handles, rain gutters, etc. probably not gonna happen in my case but i will cover them up

Windshield wiper, hmmm i was thinking of removing one wiper but i think i will prefer to keep both but clean up where they sit out of the wind

Smooth wheel covers, basically hubcaps i will have a look but do like this idea but it will have to be pretty dam stylish

Swap/fabricate a more aerodynamic front bumper cover, gonna be a big job and i was thinking about somthing like a bull bar but that would through the weight right out carboard?

Grill block (partial/full), im going to try this one, first off i have to sort out some cooling issues first though

Boat-tailing behind tires this is not the strange thing that the serious boys do, this is a smaller bout tail behind each wheel

Belly pan / under tray, basically a bask guard wish many people have already

wheel skirts, like the 1930s cadilacs!!!

Soften / radius aft edge of front wheel arches, pretty dam hard on the subaru but i am going to look at it

Sealed panel gaps, big one it can ahve serious affects and can be done pretty easily (im using white electrical tape as my car is whit =P)

Partial Kammback, kinda hard to get your head around like a spoiler that goes all around the rear window

Rear corner airflow trip feature, so its a new rear bumper too, sort of the same as the boat tail design

Ride height reduction, hear that your lowered high school cheapo is an eco weapon! maybe ill do this maybe not considering what i use my car for

Use lowest viscosity engine oil recommended by OEM Synthetic oil, also keep the oil in the engine at the lower scale

Engine kill switch for easier Pulse & Glide / Engine off Coasting, as spoken about in this thread

Increased compression ratio, if i build a new engine yep ill do it

Advanced ignition timing, i wont go with this unless i can figure out how to change it with the flick of a switch (i don't think that's possible)

Alternator delete (or Externally Powered Electrical System) if your brave rip the alternator out of it, i wont do this but will be lookign at a smaller alternator as well as taking some of the load off it and yes it makes a difference

Power steering delete / manual steering rack swap not that hard an pretty good results

A/C delete i wont be doing this but it is an option, but i will be trying to use it less

Mechanical to electric radiator fan swap, pretty easy to do and iff the ducting is done right it will be as efficent as mechanical

Electric coolant / water pump, i wont be doing this but it is an option

Regear for lower cruising RPM, basically the same as the 10 speed box but an easier option is to change the diff ratios

Synthetic axle/wheel bearing lube, less resistance also keeps the bearings going longer

Synthetic transmission/differential oil, same as the other things to do with oils thinner the better to a point

Solar 12v assist, this one stumped me but then i realised with the removal of the alternator the solar would help charge the battery

Increase tire pressure to max sidewall, larger tire diameter but also lowers rolling resistance

Replace tires with low rolling resistance tires, pretty self explanatory

Lightweight wheels, were pretty hard up for wheels but i guess its possible to get the mags

Weight reduction, THE BIGGY!!! i will have to work out where i can lose some weight

Cruise control mod: fuel economy logic, the thing with cruise control is that it tries to maintain speed. what it should do is try and maintain engine load IE slowing down on hills and speeding up on the way down. its effectively a eco brain in computer form

purp · Post by **purp** » Tue May 22, 2012 9:16 pm

Several in that list (like delete alternator) seem aimed at reducing petrol use, but must presumably require charging the battery from an external source between drives.

Certainly an interesting approach.

spike · Post by **spike** » Tue May 22, 2012 9:59 pm

yes purp i jsut spent over an hour rewriting that list haha

MTB92 · Post by **MTB92** » Wed May 23, 2012 12:29 am

apart from driving down hill with little brakes, assuming you can fix that.

if you have to turn ignition off, there is a point where your steering has the potential to lock.

you loose power steering if you have it (driving a power steering system which isn't on is very different to driving a car designed for no power steering)

you dont have speed control thru throttle, rely completely on brakes.... which probably aren't working at this point (this is bad practice, you have less control)

you loose ability accelerate if you have to at any point.

basically you just have less control.

i dont see how low range driving makes any difference to fuel consumption. yeh you have more gears, but you have to change them more often to keep the engine in this sweet spot you talk of. if it was better, they would have been built that way to start off with.
have you heard of double shifting? i am a MTBer and it comes from this, where you reach the limit of the rear gears and then have to change the front AND the back to reach the next in sequence. this is exactly what you would have to do with the low range idea. it creates dead time where you are changing gears instead of putting the power down.

seriously, if you want to save money the things you have mentioned will be pretty insignificant compared to having a healthy running car. if you want to save a bit of coin, just dont buy lunch/a drink/chewing gum/etc once a week and you will save more.

2nd Hand Yank · Post by **2nd Hand Yank** » Wed May 23, 2012 6:00 am

- Skinny tyres at hard tyre pressures

- disconnect the driveshaft to the rear axle

I believe the driveshaft and rear axle always spin, causing some power loss.

spike · Post by **spike** » Wed May 23, 2012 7:22 am

@mtb, i didnt think about the steering lock but thats not to hard to fix, very easy fix on the power steering (remove it).
i dont think speed control though throttle is really a point of interest, with the engine off you cant acceleratre, engine braking will still work which youd want. When im going down hill ive never needed to accelerate

purp · Post by **purp** » Wed May 23, 2012 8:22 am

2nd Hand Yank wrote:- Skinny tyres at hard tyre pressures

- disconnect the driveshaft to the rear axle

I believe the driveshaft and rear axle always spin, causing some power loss.

This is a good point, especially of you were to mod the gearbox. Actually, if you just remove the tailshaft and rear axle shafts then you can just use low range anyway?

steptoe · Post by **steptoe** » Wed May 23, 2012 9:08 am

MTB92 wrote: you loose ability accelerate if you have to at any point.

Yes, take a drive with a driving instructor and do this, or even declutch and shift into neutral as you head towards a stop of any kind, lights, intersection etc and you will get raised eyebrow at least as you have lost sudden ability to escape an unforseen need using acceleration and a gear. What Gannon has said about efi switching of the injectors happens about 1500 rpm and above in all efi as far as I understand - watching trip computer fuel consumption real time will confirm. Trip computers derive their data from injector times etc , a challenge to find a trip computer in a carby car

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