Fuel Economy or lack thereof....

[DRMAT]

:shock:

Hey guys,

Just wondering what sort of fuel economy you guys get out of your cars cos my TT Legacy gets about 15-16L/ 100km which i think seems a little high considering it isn't flogged ALL the time ;-)

Mat :shock:

[george|rst|]

With the standard ecu i could get 500k's to a tank around town...now with the Link approx 400 :shock: .. i havent ran it real low though..

[DRMAT]

Well my 15-16L gets me around 300kms.... if i'm nice... actually only if i run on Optimax... i tried some BP Ultimate and it only got 220kms!!!

Mat :shock:

[george|rst|]

WTF? :?

[DRMAT]

That's what i said!! Still chasing some bugs in the car tho so could be related to that. Does run rich cos exhasut pipe is black as.

Mat :shock:

[Karupt]

My v3 RA motor.. with RS ecu running rich as a pig.. used to get 280km's to a tank.. of semi thrash semi cruise.. nowadays it pulls over 400 JUST... however since getting the front mount.. I've done 60kms and used 1/4 tank already.. but I admit that its been thrashville since front mount went on :)

and loving it !

[[SPESHAL]]

45 litres or so gets me 300 km's.

Half a tank showing on the shit guage is usually 120 km's. Hrmm.

It could be a LOT better!

[RaZor]

With my North American Legacy Turbo(160hp stock), I'll run out of gas at around 375km with 55 L in winter conditions and 450-475km in summer conditions.

I Have Cat-less downpipe, cat-less exhaust. It runs 10psi instead of 8.5 with the stock exhaust line.

[RSSTi]

400 - 450 around town and about 550 on the highway.

[bosc0]

i get about 43ltrs to 400 kms.....
depending on how many cruises i go on and how many times i go up the hills it can vary. Some times i fill up every second day :shock:

[rs_wagon]

G'day Mat,

Have you ever ran the tank right down to empty? Coz every Subaru owner I know has the same problem whereby the fuel guage goes to below empty and they still have lots left in the tank. I think your fuel light should activate at around 9L remaining. Does your light come on at all?

I had the same problem when I got my RS where it goes to empty at 280km mark, but the fuel light comes on at about 420-430 most times. Then it will run dry around 480-500km.

I thought I had the worlds worst economy or was running really rich when I got it, but everyone tells me to just keep running it to over 400kms.

If thats not the problem, get the bugger checked!

BEN

[markmcrs]

Mine's the same as your's ben. Fuel guage goes just under empty at about 300km. My low fuel light starts to come on around 350kms. I've also been told(or did I read it in the manual) that when the low fuel light comes on, there is about 9lts of fuel left.

[DRMAT]

Hey Ben,

If i were purely going off what i get per tank that might explain it but i work it out so it doesn't matter how much is left in the tank, it goes by what i put in the tank. And i think the gauge is not too far off cos i normally put 30L or so in it and its only a 42L tank from memory. I never run it right down though... i don't know if the light works or not so i might get stuck! ;-)

Mat

[george|rst|]

Mine does the same, does any1 know a fix for this problem??

[bosc0]

Apparently the older Rexes have the same problem, i have a sheet somewhere explaining how to clean the fuel sender (or something), ill try and find it and post it up soon.

I think we may have discussed this in the yahoo board a while ago :roll:

[RSSTi]

This is from the MRT website on how to fix an inaccurate fuel gauge on a WRX, i'm pretty sure it applys to the RS as well.

The WRX has 2 sender units, the one on the RHS incorporates the fuel pump while a similar dome cover on the LHS of the luggage compartment also has a sender unit mounted on the tank, apparently the RHS one handles the lower half of the tank, while the other one on the LHS handles the upper half of the tank.

After lifting the carpet on the RHS of the rear luggage area you will find a dome cover held down by 4 Philip's head screws. Once the cover is removed you will find the top of the fuel pump and gauge sender unit. On this top cover are 3 fuel hoses and an electrical fitting. After removing those and the 8 * 8mm hex nuts the unit is removed with a bit of twisting and fiddling. The LHS unit can be accessed in the same way by removal of the dome cover disconnect the wiring plug and undo the 8mm hex nuts.

The RHS unit is far more bulky than the LHS comprising a fuel pump attached to a strainer bag system, the gauge sender unit is very basic being a plastic float on the end of a wire stem that actuated across a potentiometer. I found that after 4 years the potentiometer had a wear patch across it, so I wiped it down and polished the surface with 800 grit wet and dry, very gently!! After reassembly the gauge read 20% higher.

It seems that after a while the surface of the potentiometer gets a waxy build up or something on its surface from the fuel. The LHS handles the upper levels of the tank, I guess 1/2 to full, while the RHS handles the lower levels of the tank. Again by wiping the face of the potentiometer with a rag and very gently polishing it with super fine wet and dry and reinstalling the LHS unit the fuel gauge worked perfectly again. The tools required are a Philip's head screw driver for removing the baggage floor cover, a pair of pliers for releasing the hose clamps and a 8 mm socket for the hex nut holding the units to the tank. Overall all very easy job once you realise there are 2 of them. Should take less than 1 hr.

After talking to Subaru its a common problem for all Subaru models and is often done on 100,000km services if they suspect a problem. However if the problem returns quickly they end up replacing the LHS sender unit first as it is the cheapest, due to the wear on the potentiometers resistance surface, then worry if the RHS fails as it can get expensive.

In addition by bending the wire that attaches to the float you can fine tune how the gauge reads, ie dead empty can mean dead empty or 5 litres or what ever you require.

For those thinking of installing a fuel surge canister or plate in the tank you will need to fabricate 2 as both the LHS and RHS sender units have fuel pickups. The LHS fuel pickup connects to the RHS sender unit.

IMPORTANT: We must stress that there is a very fine margin between cleaning the potentiometer surface and destroying it! Use utmost care.

I havn't tried it yet, i'd be interested to see how people go.

Vic.

[bosc0]

yeah thats the one, thanks Vic.

hmmmm, how about you try it and let us know how it goes :D hehehe

[george|rst|]

Thanks Vic, im gunna give it ago, it pisses me off!! :x

[rs_wagon]

Wow, I thought the 2Gen Liberty/Legacy had a larger tank than the 1Gen. RS's have a 55 or 60 litre tank I think and I think the average is about 400-450km per tank - but then again, I think one of the main gripes with any Subaru throughout the ages is the fuel economy.

If it is a 42 litre tank like you say, your 300km per tank might not be that bad.

[DRMAT]

300 is a stretch as well though... like isaid it normally returns about 14-15L/ 100kms

I'll double check the tank size as well.

Mat

[Karupt]

I can safely say.. that since installing my front mount.. I've driven like a moron.. and have used more fuel than I have ever used before..

I am currently sitting on slightly above half tank.. and have done exactly 100km !

So best case scenario I'll get just over 200km's to a full tank.. gotta love that.. I should stop taking my friends for 'raps' in it to see how it goes :)

[Deaks]

Drmat,

Ive got the same car as you and i agree they have pretty shit economy but the tank is not 42 ltrs. Unless you've got a special tank you should have a 50 to 55 ltr tank standard. Your economy sounds a bit higher than mine. I'll explain what my car runs: K&N pod filter and a slightly bigger than standard exhust (soon to be 3") but other than that bog stock. I usally get 330kms out of 47ltrs which is about 13l/100kms. I think. I was speaking to Stephen(rs legacy sedan) on the 2nd cruise and he said that the gen11 legacys don't have as much fuel left when the light comes on . 4 ltrs or so. Not much to play with.

On the open road mine will get around 400ks to the tank and i have found that Optimax doesn't increase my milage(just decreases my bankbalance)
Stephen if your on this forum how much do you get out of your tank?

Deaks

[greasystick]

Howdy all,

Confession time - I've never seen the fuel light on my RS - where is it??

I generally fill up at 350-360kms on Optimax or BP 98, and put in about 42 litres, so about 12lts/100kms.

Do all Libby's have the same size tank?

Ta
Stu.

[DRMAT]

WHOA!! OK i got my car back form Subaru and just had a look in the manual... ok for your and my information Deaks the tank it actually 60L! WTF! I've never run it that low! Damn, i guess i'll have to try now to see how far i can go!
My car is running a K&N panel filter in original box but with 4" tubing feeding it from the front of the car and i have a 3" exhuast and high flow cat already on it.
Are you serious you don't get more milage out of Optimax?! Like i said i ran a tank of BP and got far less out of it than i normally would. What are you runnign in yours cos all the premium fuels are same price except the BP. optimax and Synergy are both 8c over unleaded price but BP is 8.5c over.

Mat

[rs_wagon]

I thought that Optimax was only 6c over unleaded? Anyway, I have found that my car runs life shite on BP, in particular it pulls and hesitates when off boost. I dont use any more or less fuel on BP, it just knocks my car around. Synergy has been OK but I dont have any Mobil servo's anywhere near me (they are all Shell luckily).

I have really used only Optimax on this and my last car and have always been happy, so I dont care about the price or mileage much (you cant with these cars really!).

[DRMAT]

Go Well Go Shell RS! hehehe
I won't be there much longer, i can promise it is 8c over though... that servo where i am was the last one to go up to the 8c over, we used to be 6c for months after everyone else went up.

Mat

[Deaks]

Drmat,

Is your maual in japanese because mine is and i can't read it. Now if our tanks are 60 ltrs (how cool) that means i should be able to run to about 430kms approx. I have seen the light once but only because i was facing down hill for a long time then when it went flat the light turned off. How much difference did your 3" exhust make? When i bought mine they said it had a 2.5" cat back but i don't think it is. It sounds like a mini F16 when goes past. :( How much did you pay for your exhust? I've been quoted $600 with high flow cat and my choice of muffler. Now i gotta scrimp and save between building the rally car! Let me know how far you get before you run out because i just filled up (on BP) and it will be a while till it goes empty, i hope.

Deaks

[rs_wagon]

8c - Harking Fell!!!! If I was old and cranky I'd write a letter to someone about that (like my dad does).

That seems like it has gone up about 3c since its inception. Last time I looked when I filled up at Shell Dingley I sware it was only like 5.8c over the unleaded price, unless I was so tired I ws looking at the LRP price instead....

Matt - Can individual servo's dicatate the price difference? I would have thought that Shell would use the iron fist for that.

[evade]

On the freeway I get 450km.
On the street, forget it. I wouldnt even care as the fun outweighs the cost :D .

[DRMAT]

Yeah Deaks it is all in Japanese with no pictures at all... luckily i can read Japanese and spent about 3 days translating it all.... nah not really. :lol:
I can get a fully translated one for you with all the pictures and everything from a contact i have.. it cost about $50and takes a week or two to get so let me know if you want one, you'll also have to send me your chassis number ie the BG or BH number whatever it is. It says the tanks are 60L... i guess there is only one way to find out though for sure! Seems like a big tank for a fairly small car if you ask me but we'll see. I don't mind sucking up all the crap outta the bottom of the tank and clogging my injectors for you guys :D I've never seen my light before either.

Hard to tell exactly how much diff the 3" zorst made (it is all the way from the turbo with large collector pipe) cos i was having problems with the car then that turned out to be FOUR, yes FOUR cracked ignition coils!!!! Sorry three cracked one almost gone!! And big cracks as well! It certainly revs out faster than before and the lag between turbos is less noticable. My exhaust was $1900 with my intake mods and is all stainless steel, mandrel bent, high flow cat and a hand made stainless muffler. Admittedly i didn't go to the cheapest guy in twon but he knows what he is doing and doesn't mess around. $600 sounds awfully cheap, especially when you consider that a cat converter is 200-300 by itself, an off the shelf muffler similar amount so it sounds as though it will be a cheap cat, cheap muffler and not stainless steel. Which is ok if you don't want the expense of stainless and normal steel will normally last longer than you have the car anyway. Is the $600 full exhaust or cat back? If it's full i woudl walk away personally, way too cheap. Consider that people like hiTech mufflers offer off the shelf kits for 200sx and wrx for 1500-1800. The other thing to consider, lots of considerations, is that there are a lot of exhaust system "professionals" who think and exhaust is just a piece of pipe and so you end up with a droning POS car that drives you insane. The good people can make the car sound sweet on cruise and full throttle without the droning.

RS Wagon... i'd love to write a letter, don't think they will change though considering they have something like 80% market share with Optimax! When first introduced it was only 5c above from memory but a year or three later it went up to 8c more. Shell Dingley you mean the big one on Boundary Rd? Shell Redwood Gardens, they are owned by the same mob that own all the other Shells this side of the city and god knows where else (Care i think they are) and they will be the same between all stations, the managers have no say at all on price difference betwene fuels, LRP is 4c more, Opti is 8c more. Unless some dick buggers it up when changing the price! They can dictate their overall price when coming down to match local competitors but when going up Shell calls the servo's and tells them what time to go up.

Shit thats along msg :P

Mat

[Deaks]

Drmat,

Yes it is just a cat back exhust but i was told by a reputable subaru tuner that i shouldn't put a full system on it because it would over boost the first turbo. The reason the exhust is so cheap is because my friends Dad owns the shop. So i get a big discount on most things like the cat and muffler. Would yours be about the same as a rex or louder? I think i'll stick with the cat back exhust for now. And its in mild steel.

My car had 57000km when i bought it, it now has almost 70000kms and ive only had it for 5 or so months. When you enjoy driving the car the destination is irrelevant.

I'll have to get back to you about the english manual.

Deaks

[DRMAT]

Yeah i've heard both sides of the overboosting story, some asy forget about it, it isn't a factor, some say it is....
As for volume i guess that would depend on which WRX you compared it to! It isn't as loud/ aggressive as the fully done up Wrxs but it is still reasonably loud, without being intrusive.

Mat

[rs_wagon]

Yeah Matt - I was only joking about the letter thing - But, what else should we expect from petrol companies, if it works and market 'needs' it, then jack the prices up to line their own pockets eh?

I cant see too many people with turbo and other hi-po cars turning away from Optimax if it keeps going up either - just dont tell your bosses, coz they might actually do it!

[lenm555]

Hi Guys,
While on the topic of fuel, I just replaced the oxygen sensor on my car over the weekend as its been throwing a check engine light (code 32) for a while when crusing on the highway sometimes, idle was a little inconsistant also. Anyway since replacing the sensor I have noticed an improvement in fuel economy of the car. I guess was running rich until now, and apparently a stuffed one does not always throw a check engine light as was the case on a mates car - just a thought for anyone suffering from poor fuel economy/rich running.

[Deaks]

Well there you have it, my tank is a lot bigger than i thought. The distance i got out of it isn't important because i was driving with a heavy right foot on the weekend but when i filled it up i put 54ltrs in it and the fuel light only just came on but didn't actually stay on all the time. If i drove sensibly (probaly not ever gonna happen) it would get around the 420km mark but with the heavy foot 360 was all i got.

Deaks

[RSTURBOWAGON]

I posted the same topic in another forum some time ago,and got much the same response. My `92 wagon has run out of fuel and the light didn`t come on at all,so I removed the r/h sender,unsoldered the probe and moved it up about 5mm,now it does light up at about 51 lts(out of 60)which is about 380Kms of steady 100K highway driving,so beats me. I`ve only changed the intake,nothing else!!!!!!!!!!! :cry: :cry: :cry:

[whitey]

I seem to get 9.07 L/100km (best yet) but this was just crusin on the highway hardley usin the Turbo. For normal highway drivin it gets about 10L/100km (which it pretty good I think)

I have a cut snorkus and a 2 1/2 " exhaust with a dump pipe and one muffler.

[greasystick]

Last fill (Optimax at $1.04/ltr - bastards!)

Exactly 50 ltrs (always to the second pop of the handle), 391 city kms, no fuel light.....12.8ltrs / 100kms all city driving, stock-as-a-rock 92 RS

[DRMAT]

DEAKS MY MAN!!! Way to go! I was driving around the last two days on and below empty just for you guys (not very far anyway) until i chickened out tonight and filled up and still only had to put 37L in it hahaha Stupid ferkin thing..... big mental challenge to see the car near empty and not fill it up! Maybe i just fix the bloody sender i think!

Mat :shock:

[Deaks]

so how many ks did you get out of 37ltrs? As i said i only got 360 out of 54ltrs with the heavy foot. I still think i'll be able to go another 30/40ks before filling up next time but i'll probably just fill it when i used to. Around 46ltrs.

Deaks

[Rod]

My fuel gauge is very consistent and reads correctly. Though i always use Caltex Vortex (it has better cleaning agents than the rest)
Even though it is only 95RON and not 98RON it works just as good in my car. The std RS ecu is tuned to 95RON anyway and I never felt any benefit using optimax etc... even when i was running with the chip.
Around town when the fuel light comes on, i fill it up and always put in around 50ltrs and usually have 400-430km on the trip odometer.
On the open road, doing the snowy mountain run, when i stop in Queanbean i usually put in about 48ltrs and have done 490km.
'92 RS 107,000km - usual mods
ps my previous N/A Liberty had a f*$# fuel gauge and i did pull it out and clean the 'pentometer' (spelling?) and it worked fine after that.
Rod

[DRMAT]

Was only about 200 Deaks but the car had been in getting work done at Subaru for two days and they had it running a lot so i lost a lot of fuel then :( Bastards, its ok i di't fill up their loan car either so we're even :D
I'm going to wait until i'm past empty from now on to fill up, that will leave me more than a quarter of a tank so i won't be picking up crap from the tank. Cheaper fillup as well :D


Mat :shock:

[Rod]

Mat,
'picking up crap from the btm of the tank'...... that one always gets me... how do you pick up crap from the btm when the pick-up on all fuel systems is on the bottom. You are always sucking from the btm of the tank... well near enough... Unless you have water in your tank, it makes no difference....suck the arse out of it !

[subarursliberty]

I only run 96 octane but when I come across the good stuff well you never give it a miss. Anyway approx 10-12 per 100 around town and I manage 8 per 100 on the highway.

I got under 6 per 100 on the highway oneday with my old front wheel drive GX. It was a big hit below the belt when I bought the RS home.

I used a quarter of a tank going to Sydney one day on the freway but coming home on the old pacific hwy used the rest of the tank. What a drive. I have found the putty road to be a but more fun but its a long drive.

[DRMAT]

Good point there, never thought of it that way. I guess cos when you have a lot of fuel left any crap in there is circulating and well dispersed, when you have bugger all int he tank the crap will be concentrated into a smaller volume of fuel and so you will be picking up a lot more. I would guess.
I used to work at a Shell Service Centre and know quite a lot myself and i have seen several cars that after running out of fuel or very low have had clogged injectors or carbies.

Mat :shock:

[whitey]

I agree with Rod suck the crap out of it, as long as you replace the fuel filter once and a while the injectors will never see the supossed muck in the tank :roll:

[Rod]

i think you would be hard pressed picking up shit as the subaru fuel pump filter screen in the tank is very fine and then you have the fuel filter itself also. You are correct though as the tank gets low any shit in there will be more concentrated in one area. When i pulled out the pump in my old N/A liberty to fix the fuel gauge, there was no crap at all in the btm of the tank- it had about 150,000km on it around then...
Water, etc is your real enemy. If you do pick up water you will know pretty well straight away.

[Leigh[RS STI]]

Petrol Prices are fucked at the moment, but i normally get about 4-500 kms out of a tank, b4 my exhaust mod i was only getting around 400. So yeh, best i have got was over 600 like near 650 but that was with majority freeway drving with cruise on!!

Leigh