Suggestions to improve my poor fuel economy

LIFTED · Post by **LIFTED** » Tue Sep 20, 2011 11:58 pm

Wow interesting reading guys.
Littlewhiteute: I was going to try testing higher octane fuel later on.
I'm also going to get some flashlube.
Is UEC like that carbi clean stuff that come in a spray can?
So I could run my tyres at 44psi !!
Maybe driving it like a Granny I haven't been reaching it's economical power band revs
I was going to change the plugs at the next oil change due in another 2000km hmm might do it earlier, I used to use that castrol magnatec in my "other" car.
I have read that the K&N air filters are good but others have said the oil in them can block some sensors, the O2 one I think, I might do as niterida said and change the O2 sensor, to reset the ECU I think I just have to disconnect the battery for a while.
My challenge now is too improve my economy!

mud_king91 · Post by **mud_king91** » Wed Sep 21, 2011 9:38 am

niterida wrote:That only applies to newer EFI cars that have ECU's that 'learn' and can change the tune to suit the fuel. Something as old as Gen1/Gen2 Liberty probably doesn't apply. Certainly didn't make any difference to my Gen 3 Outback - which by the way I get just over 10l/100km around town but town is Geraldton so its a lot more free flowing than city traffic

E10 is just a no no i destroyed my rodeo with that s@#t

NachaLuva · Post by **NachaLuva** » Thu Sep 22, 2011 12:31 am

mud_king91 wrote:E10 is just a no no i destroyed my rodeo with that s@#t

Are you sure it wasnt just a bad batch?

A while ago there was a string of people with destroyed engines from bad fuel. 1 sample i saw on the news was actually cloudy!!!

Then there have been examples of dodgy stations who have filthy underground tanks.

I always try to avoid small stations with a low turnover, i look for a large well kept servo where there is less likelihood of bad fuel. I know that sounds very anal but....

taza wrote:nachaluva what fuel economy do you get out of your 98 manual Forester? I get about 450km to a tank around town in my 2001 but I am very heavy footed. and 52ish L fuel up.

I've only had 3 tanks but so far:
405km from 43L (10.8L/100km)
101km from 13L (12.7 " )
428km from 45L (10.5 " )

All with E10.
This last tank was a 4WD trip (should that be AWD trip?

) with lots of crawling in low range, twisty roads & steep assents, but also freeway getting there & back.

2nd Hand Yank · Post by **2nd Hand Yank** » Thu Sep 22, 2011 1:51 am

^^
Don't fill up while the tanker trucks are refilling the servo.

It can stir up sediment at the bottom of their tanks.
I avoid it unless I have no other options.

Nice economy btw, considering you did some offroad with that.

LIFTED · Post by **LIFTED** » Fri Sep 23, 2011 7:20 pm

I couldn't find any flash lube so I bought some Nulon injection cleaner and put this in my tank for the first 100km distance no change then today after about 130km distance of driving I noticed while on the freeway my revs are lower! Unbelievable !
At a constant 100km/h the revs used to sit at 3000 now they sit at 2750
and for 90km/h the revs sat at 2750 now they sit at 2500
and for 80km/h the revs sat at 2500 now they sit at 2250
I've finally found and bought some flash lube and will use that after this Nulon stuff runs out.

mud_king91 · Post by **mud_king91** » Fri Sep 23, 2011 7:42 pm

nachaluva wrote:Are you sure it wasnt just a bad batch?

A while ago there was a string of people with destroyed engines from bad fuel. 1 sample i saw on the news was actually cloudy!!!

Then there have been examples of dodgy stations who have filthy underground tanks.

I always try to avoid small stations with a low turnover, i look for a large well kept servo where there is less likelihood of bad fuel. I know that sounds very anal but....

I've only had 3 tanks but so far:
405km from 43L (10.8L/100km)
101km from 13L (12.7 " )
428km from 45L (10.5 " )

All with E10.
This last tank was a 4WD trip (should that be AWD trip? ) with lots of crawling in low range, twisty roads & steep assents, but also freeway getting there & back.

not sure all i know is i got nowhere with even legal ways and learnt to never take your workplace to court... im guessing it was something bad tho because the servo shut down now... doesnt fix the engine i spent half a year putting together

2nd Hand Yank · Post by **2nd Hand Yank** » Fri Sep 23, 2011 9:53 pm

mainbreak wrote:I couldn't find any flash lube so I bought some Nulon injection cleaner and put this in my tank for the first 100km distance no change then today after about 130km distance of driving I noticed while on the freeway my revs are lower! Unbelievable !
At a constant 100km/h the revs used to sit at 3000 now they sit at 2750
and for 90km/h the revs sat at 2750 now they sit at 2500
and for 80km/h the revs sat at 2500 now they sit at 2250
I've finally found and bought some flash lube and will use that after this Nulon stuff runs out.

That's remarkable.

I wonder if my L Series has any spots that need de-gunking.

NachaLuva · Post by **NachaLuva** » Sat Sep 24, 2011 12:50 am

mud_king91 wrote:not sure all i know is i got nowhere with even legal ways and learnt to never take your workplace to court... im guessing it was something bad tho because the servo shut down now... doesnt fix the engine i spent half a year putting together

Dude very sorry to hear that. Sounds messed up in a few ways

mainbreak wrote:I couldn't find any flash lube so I bought some Nulon injection cleaner and put this in my tank for the first 100km distance no change then today after about 130km distance of driving I noticed while on the freeway my revs are lower! Unbelievable !
At a constant 100km/h the revs used to sit at 3000 now they sit at 2750
and for 90km/h the revs sat at 2750 now they sit at 2500
and for 80km/h the revs sat at 2500 now they sit at 2250
I've finally found and bought some flash lube and will use that after this Nulon stuff runs out.

Is it an auto? Glad it worked, sounds like your injectors had some good deposits lol

pitrack_1 · Post by **pitrack_1** » Sat Sep 24, 2011 1:25 am

Some experience based suggestions:

1) Thermostat operation. If your engine is running cold because your thermostat is stuck open, the choke will be on more-or-less permanently. Thermostat sticking is common in older vehicles (say over 5 yrs of age)- I've noted it in at least 3 cars my family/I have owned. Furthermore the engine tends not to run at its most efficient. Losses can be quite substantial. Symptoms include a low-reading temp gauge, engine takes a long time to heat up, the heater don't work properly in winter and reduced range on a tank.

2) Good quality oil can improve fuel economy. Check the specs and use as low a viscosity as your engine will tolerate and high a quality as your wallet will.

3) Fuel. Modern EFI engines with knock sensors benefit from the Optimax/V-power/whatever type stuff. You get improvements in drivability, power and fuel economy. It should be noted E10 loses you more in economy over what you save in the pump price - it's false economy.

4) Tyres at ~35psi for standard passenger vehicles. Not too sharp/wandery but better than the generally lower placarded pressures. Improves fuel economy, tyre life handling and safety. 34/32 psi front/rear for front-wheel-drive vehicles was also recommended by an advanced driving course I did- they wouldn't let you on with lower due to the risk of a tyre rolling off the rim which would dig in and flip the vehicle.

My experiences:

a) 1990 N13 Nissan Plusar (no knock sensor). NOT E10 compatible. After replacing the thermostat (cold temp gauge, weak heater in winter) the fuel economy improved from 10l/100km to ~8l/100km. I went from 400km/tank to 500km/tank between refills. I have the fuel log to prove this, too! Optimax/V-Power seemed to provide somewhat better driveability.

b) 2004 BK Mazda 3 SP23. E10 compatible. The fuel economy blew out from ~8-8.5l/100km to 10l/100km, I noticed the temp gauge was no longer stable, tended cold and the heater wasn't as efficient. I changed the spark plugs (no effect), finally at the next service I had the thermostat changed and reverted to the original oil spec (10W-30, they had moved to 20W-50 - still in spec- due to the engine being >150k kms). Result: immediate improvement back to 8-8.5l/100km. It had degraded 25% or that's 20% better afterwards, depending on how you look at it. I also use Shell V-Power, and at ~150c/litre I calculate that the cost of the thermostat replacement- ~$250 - will be recouped within 10,000km- 6 months' normal driving (10,000km/100km*1.5l*$1.50). I attribute most of it to the thermostat replacement. Don't you wish all your investments returned that?!! The V-Power gives better driveability, more responsiveness and some improvement in fuel economy.

LIFTED · Post by **LIFTED** » Sat Sep 24, 2011 7:37 pm

nachaluva Yes it's an auto and I'm stocked that stuff in a bottle could have that effect.
Thanks for all those suggestions Pitrack 1 My temp gauge sits on half and the heater is fine. Someone earlier said they put a lower thermostat in their car I'm not sure why or what this would achieve?
I'm not sure what oil spec I can get away with on a 1992 2.2l with 175K on the clock any oil spec and brand recommendations?
Would it be worth changing the diff oil?

NachaLuva · Post by **NachaLuva** » Sat Sep 24, 2011 8:54 pm

Yeah thx Pitrack, some good suggestions. My previous Falcon (currently on my 4th falcon & 7th Ford overall lol) had poor heating, low temp reading but economy wasnt too bad till auto decided it wanted to be in a forward gear AND reverse at the SAME time! Not so good lol.

I think current thermostat in my Forester is fine, everything seems to as it should be. But i want to change the plugs & leads, it still misses a little & as the leads look original (so 13 years old) i think its time to renew.

Mainbreak i'm surprised it had such a big effect...bet you're happy lol
You should find better power & driveability, & better economy

pitrack_1 · Post by **pitrack_1** » Sun Sep 25, 2011 1:17 am

mainbreak wrote: I'm not sure what oil spec I can get away with on a 1992 2.2l with 175K on the clock any oil spec and brand recommendations?
Would it be worth changing the diff oil?

Hi Mainbreak,

1) I'm unfamiliar with your engine so can't recommend an oil per se, just general recommendations:
- 175,000kms isn't much on modern engines. But Jap engines have fine tolerances and don't take kindly to missed oil changes or cheap oil. If you're suspicious of the history, a desludge (oil flush) and oil + filter change are the go.
- The oil specs for viscosity and grade will be in the owner's handbook. Use a good quality oil, in my opinion semi-synthetic or better.
- Good quality oil can improve fuel economy cover the difference- or even the whole cost- over the course of 6mths/10000km. Figure: if it saves you 0.25l/100km over 10,000km, the saving @$1.50/litre is: 10000/100*0.25*1.5 = $37.50 = 5l reasonably good oil.

2) Suggest doing the coolant too- corrosion/scale in alloy engines isn't a good thing so if suspicious a flush, change with good quality brand-name that matches what your car requires and mix it yourself from concentrate. Use deionised water if you have 'hard' water in your area. On the other hand, this can dislodge scale/rust in badly corroded systems and cause problems!

mainbreak wrote:I couldn't find any flash lube so I bought some Nulon injection cleaner and put this in my tank for the first 100km distance no change then today after about 130km distance of driving I noticed while on the freeway my revs are lower! Unbelievable !
At a constant 100km/h the revs used to sit at 3000 now they sit at 2750
and for 90km/h the revs sat at 2750 now they sit at 2500
and for 80km/h the revs sat at 2500 now they sit at 2250
I've finally found and bought some flash lube and will use that after this Nulon stuff runs out.

3) Hmmm, you said later you have an auto...3000rpm sunds highish for 100km/h. It's possible that the auto didn't change up from 3rd to 4th, or the torque-converter lock-up didn't engage in 4th. This could be a misselection, a trannie problem, or indeed related to an underperforming engine as throttle position will influence the gear selection and torque-converter lock-up. Perhaps a trannie fluid change?

4) Tyre choice can make a difference to fuel economy too. Some tyres roll better than others, and it's hard to tell as there's no hard numbers on any as far as I know.

5) And AWD uses more fuel than F(ront)WD. Rumoured/roughly about 5-10%? So 10l/100km FWD becomes ~10.5-11l/100km AWD.

pitrack_1 · Post by **pitrack_1** » Sun Sep 25, 2011 1:45 am

nachaluva wrote:But i want to change the plugs & leads, it still misses a little & as the leads look original (so 13 years old) i think its time to renew.

Nachaluva,

Are you sure it's missing? Soobie boxers tend to be throbby engines and can (at least to me) sound like they're missing regularly when they're actually running fine.

LIFTED · Post by **LIFTED** » Tue Sep 27, 2011 12:22 am

mainbreak wrote:I couldn't find any flash lube so I bought some Nulon injection cleaner and put this in my tank for the first 100km distance no change then today after about 130km distance of driving I noticed while on the freeway my revs are lower! Unbelievable !
At a constant 100km/h the revs used to sit at 3000 now they sit at 2750
and for 90km/h the revs sat at 2750 now they sit at 2500
and for 80km/h the revs sat at 2500 now they sit at 2250
I've finally found and bought some flash lube and will use that after this Nulon stuff runs out.

Bugga, just topped up after 300km and economy despite a drop in revs after using nulon injection cleaner 12.3l/100km I've still got more nulon left which I've put in the full tank. Ill use this stuff up, then try the flash lube.
I'm thinking of gradually working through all the suggestions one at a time and boring you all with my fuel consumption results as time goes on.

Hmm I did find this website they do some pretty radical things http://ecomodder.com/

LIFTED · Post by **LIFTED** » Tue Sep 27, 2011 11:56 pm

I was looking for where to get Subaru UEC when I came across this product and how to use it http://www.nulon.com.au/products/Aeroso ... e_Cleaner/
Is it the same stuff as subaru, can you apply Subaru UEC the same way?

niterida · Post by **niterida** » Wed Sep 28, 2011 7:05 am

mainbreak wrote:I couldn't find any flash lube so I bought some Nulon injection cleaner and put this in my tank for the first 100km distance no change then today after about 130km distance of driving I noticed while on the freeway my revs are lower! Unbelievable !
At a constant 100km/h the revs used to sit at 3000 now they sit at 2750
and for 90km/h the revs sat at 2750 now they sit at 2500
and for 80km/h the revs sat at 2500 now they sit at 2250
I've finally found and bought some flash lube and will use that after this Nulon stuff runs out.

This sounds more like the torque converter locking up. Cleaning injectors etc etc shouldn't have any effect on the revs/kmh - this is solely dictated by your tyre size, diff ratio and gearbox.

As Pitrack stated - cleaner injectors or a change in driving style probably means you were easingup on the throttle slightly which will allow the electronics to lock the converter up.

On a side note - I have just put run-flat tyres on my Outback and the fuel economy seems to have improved markedly. Used a tank to do less than 400kms with empty trailer on the way to Perth and then over 400kms with a fullish trailer and going faster on the way home with the run flats fitted.
They are a much firmer sidewall tyre so don't flex as much which would be the reason why - but it also makes them very noisy and a bit harsh......

2nd Hand Yank · Post by **2nd Hand Yank** » Wed Sep 28, 2011 8:36 am

44 psi vs. 32 psi helps a lot.

I tried that leaving Perth, heading to Geraldton.
It's not as harsh as I'd thought.
Tyres are rated for a max pressure of 51 psi, so it should be safe.

I think I can get about 40-50 km more per tank.

pitrack_1 · Post by **pitrack_1** » Thu Sep 29, 2011 12:22 am

niterida wrote: On a side note - I have just put run-flat tyres on my Outback...

Did you remove the spare? Less weight, better economy + more storage space...

pitrack_1 · Post by **pitrack_1** » Thu Sep 29, 2011 12:28 am

2nd Hand Yank wrote:44 psi vs. 32 psi helps a lot.
...I think I can get about 40-50 km more per tank.

10% would be well worth the gain- not just $$$ but less time at the bowser and longer range. No adverse handling (wandery)? You may also prematurely wear the tyre centre tread area.

I found >36psi too harsh + wandery on my cars and I did start wearing out the centres.

2nd Hand Yank · Post by **2nd Hand Yank** » Thu Sep 29, 2011 12:52 am

pitrack_1 wrote:10% would be well worth the gain- not just $$$ but less time at the bowser and longer range. No adverse handling (wandery)? You may also prematurely wear the tyre centre tread area.

I found >36psi too harsh + wandery on my cars and I did start wearing out the centres.

the edges of these tyres are already pretty worn.
Centres are good on these tyres that are barely still road-worthy.

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Suggestions to improve my poor fuel economy

Fuel economy improvement suggestions