How To Improve Fuel Economy?

[dd4321]

Just wondering if anyone can offer a suggestion.

I have R33 GTST series 1 (95 model) with light modifications, ie: HKS cat back, HKS SSQV BOV, Apexi air filter. Fuel economy is really shitty.. getting around 18-20L/100Kms. I normally drive me car to work which is 10 mins away, all city driving, no highway.

I've done the following in order to search for better fuel economy:

- Major service, change belts, water pump, replace plugs with iridium

- Clean air filter, clean AFM

- Change O2 sensor

- Clean fuel injector with Nulon injector cleaner

- Reset ECU.

Fuel economy has not improved. The car has characteristic of running rich, soot all over rear bar, popping sound when changing gear. Popping sound is fixed after changing spark plugs. A/F gauge indicates mixture of around 14.5 during cruising, which I believe is close to ideal.

Can anyone offer any suggestion on what other things I should look at to improve fuel economy?

Thanks

DD

[chalon]

I reckon the HKS SSQV would play a part in it. I'm guessing you have it set up to vent to atmosphere?

You can try get a plumb back - that will make a difference.

If you're keen on the sound, then look at getting an aftermarket ECU and getting it tuned to suit.

[dd4321]

I reckon the HKS SSQV would play a part in it.  I'm guessing you have it set up to vent to atmosphere?

You can try get a plumb back - that will make a difference.

If you're keen on the sound, then look at getting an aftermarket ECU and getting it tuned to suit.

<{POST_SNAPBACK}>

Spot on, yes it is vented to atmo. Can it be converted to plumb back system? Or anyone know any plumb back system that making resonance sound?

Also, can anyone else with HKS SSQV BOV confirm bad fuel economy / engine running rich?

Thanks

DD

[RyanN]

have an atmospheric style bov i read some where makes it run rich since the ecu expects more air when it vents, doesn't get it so i runs rich when reving hard. I tested this by reving the crap out of my car which resulted in a small backfire every time the bov vented, i replaced it with the stock one and didn't backfire however i lost the flutter noise coming back through the pod filter so put it back on, screw fuel economy the flutter sound was awesome

But a few weeks ago i replaced the o2 sensor which as improved fuel economy slightly as i used to get a maximum of 310km out of tank before the light came on, at the moment ive got a quarter left at 350km on the trip. im guessing i might get around 490-410km out of the tank now since the replacement. (and thats not driving like a sunday driver, i gunned it a few times and accelerated at a normal speed)

Edited October 19, 2005 by RyanN

[dd4321]

have an atmospheric style bov i read some where makes it run rich since the ecu expects more air when it vents, doesn't get it so i runs rich when reving hard. I tested this by reving the crap out of my car which resulted in a small backfire every time the bov vented, i replaced it with the stock one and didn't backfire however i lost the flutter noise coming back through the pod filter so put it back on, screw fuel economy the flutter sound was awesome

But a few weeks ago i replaced the o2 sensor which as improved fuel economy slightly as i used to get a maximum of 310km out of tank before the light came on, at the moment ive got a quarter left at 350km on the trip. im guessing i might get around 490-410km out of the tank now since the replacement. (and thats not driving like a sunday driver, i gunned it a few times and accelerated at a normal speed)

<{POST_SNAPBACK}>

Thanks for the reply mate...

BTW, did you replace the O2 sensor with original Nissan or EL Falcon one? Where did you get your O2 sensor and how much if you don't mind me asking?

Thanks again

DD

Edited October 19, 2005 by dd4321

[satanic]

Yeah Ryann... interested to know what you did with the o2 sensor... very interested!

[LANFOH]

The best way to get better fuel economy for you would be to get an electronic fuel controller eg safc2 or PFC and get it tuned accordingly on a dyno. Your atmospheric BOV will only make you run rich for a split second when your AFM is tricked. The standard ecu is known to run rich in standard trim. I fitted a fuel controller a few weeks a go and im making more power and using less fuel than before.

[satanic]

WORD on that one... I totally agree, after my SAFCII was installed; not only did I get more power but I also noticed a major increase in fuel economy.

I want to get my AFM cleaned, and replace the o2 sensor... I just need to know how to do both And with what?

[RyanN]

i used the ford el one which i picked up at repro for $78 bucks.

I totally agree, after my SAFCII was installed; not only did I get more power but I also noticed a major increase in fuel economy.

did/can you tune it yourself? as i dont have any performance shops/dynos in close proximity.

Edited October 19, 2005 by RyanN

[LANFOH]

i used the ford el one which i picked up at repro for $78 bucks.

did/can you tune it yourself? as i dont have any performance shops/dynos in close proximity.

<{POST_SNAPBACK}>

You can install the SAFCII by yourself if you feel game in cutting into your standard ecus loom and connecting it up to the approrpiate wires, but it would be very wise to get it tuned on a dyno by spmeone that has done it before using all the correct a/f ratio reading equipment. The last thing you want is your car leaning out at high revs. Doesnt cost much either to tune a fuel controller.

[satanic]

I installed mine with a mate - 2 hour job, not that hard provided you have good eyes and small hands

I also got mine tuned for $160 flat which was a superb job - read my thread or my blog or my site about the tune

Ryann - can you go into a bit more detail regarding the o2 sensor, like what you have to do

[dd4321]

The best way to get better fuel economy for you would be to get an electronic fuel controller eg safc2 or PFC and get it tuned accordingly on a dyno. Your atmospheric BOV will only make you run rich for a split second when your AFM is tricked. The standard ecu is known to run rich in standard trim. I fitted a  fuel controller a few weeks a go and im making more power and using less fuel than before.

<{POST_SNAPBACK}>

Which one you reckon is better, SAFC2, PFC, or change the ECU altogether to PowerFC or GReedy E Manage? Obviously aftermarket ECU will produce better result, but in terms of 'bang for your bucks', which one is better?

BTW, anyone using GReedy E Manage? Any good?

[hbs2jh]

my fuel eco is really shit as well. 20L for 100km...

i fink it's from HKS SSQV.. vent to atmos..

[RyanN]

well, the biggest part of job is getting the old one out, half a can of wd40 later, it was out. the nissan and new o2 sensor has 3 wires, snip the new o2 sensor connector off as it wont fit, buy some crimp connecters from autobarn or where ever; crimp them on to sensor and the nissan wires (cut the nissan connecter off) then plug it up and you shall have better fuel economy. You will notice that the nissan plug has two wires the same and one odd, this will be the same as the new one just that the colours wont be the same. took about 5min to rewire but close to 4hrs to remove the old sensor.

[satanic]

Cheers Ryann