fuel efficiency with an aftermarket computer

[fresh]

hi guys

i'm looking into purchasing an aftermarket computer in an attempt to improve the fuel efficiency of my car

at the moment its a r33 gts-t. all i got is a full turbo back 3" exhaust and a boost controller runing 11-12 psi.

being as careful as possible not to use boost my car is going through 16L/100km, when boosting it this figure obviously just gets higher.

i've changed the oxy sensor, checked for leaks and all but the car is still using that much fuel its not funny, when i pull up at traffic lights u can begin to smell the petrol vapour from the exhaust, same happens when in the garage or parked etc....

just wondering if there is anything else that might be causing this, or if an aftermarket computer might fix it, i've been looking at wolf and PFC or maybe even autronic (for future plans) just wondering are any of them capable of handling an economy tune and well as a "power" tune. i do a lot of driving for work and uni and really can't afford this sort of economy

will a computer fix this ????

cheers

[Sydneykid]

The standard ECU is seeing excessive loadings, so it is adding fuel to protect the engine, that means higher fuel consumption. The ECU is also retarding the ignition timing to protect the engine from these unusual (for its programming) readings. This results in poor performance which you try to overcome by using more throttle and thus use more fuel. Generally this double whammy is called "rich and retard" protection.

The Apexi Power FC is the best I have found for the performance and economy as it has very good closed loop running and uses an AFM to accurately calculate the air flow and thus the fuel required. It also happens to be the cheapest of the superior solutions with zero installation costs, truly plug and play, just add tuning.

Hope that helps:cheers:

[meggala]

THAT ECONOMY SOUNDS TOO HIGH i WOULD BE LOOKING AT THE CAUSE B4 CHANGING ECU'S.

BTW SORRY FOR THE CAPS.

12-14 i would class as acceptble

[R31Nismoid]

im not even using my oxy sensor at the moment (turned it off in the PFC)

and im on 400km's... and ive given it a bit of stick here, and some freeway crusing.

and thats with my nice big turbo too

[Trust33]

My o2 sensor has had it.it rattles when i took it out and shook it.So the pfc has an option to ditch the o2 sensor.And R31Nismoid says it has netted him 400km to teh tank with his big turbo.Next retune i will ask the shop if they can do this option and what benifits negative benifits it has on the car.

But as with every performance upgrade the engine will chu more petrol.

[fresh]

cheers for the replys so far guys

sydkid, is there any advantage of choosing microtech / autronic / wolf over the PFC, i know the PFC is common as and is easy to find tuners etc... for, but would i be better off spending the money and going for one of the other, seems most people r doing well with the PFC.

the main featuyre i am after though is the ability to have 2 SEPERATE tunes on the computer, is there a computer that i can tune for bugger all boost but max. fuel economy, then switch over to lotsa boost and bugger fuel economy (eg, for drag/circuit).

just yeah i need the savings on fuel more then i need the power, but i do go to the ocasional drag day and wanna try some circuit stuff.

yeah is this possible ???

[Fazt_R33]

uhm... i got the same problem, get max 348km on a full tank... and at $1.35 pL ma wallet starting to become anorexic.

i also get fume smell... wen driving slow, reversing, or park and @ idle...

the car is stock as a rock.... nothing but an apexi bov and apexi intake....

any ideas?

[Sydneykid]

the main featuyre i am after though is the ability to have 2 SEPERATE tunes on the computer, is there a computer that i can tune for bugger all boost but max. fuel economy, then switch over to lotsa boost and bugger fuel economy (eg, for drag/circuit).

Sorry but this question makes no sense for a Power FC as it uses the AFM to measure engine load (plus the usual throttle position, map sensor for boost, water temp sensor etc). The AFM senses what airflow the engine is consuming and the PFC adds the necessary fuel for that amount of airflow. When cruising at constant throttle, the Power FC runs closed loop via the lambda sensor and leans out the mixture as much as possible to maximise the fuel economy.

Put simply, if you have "bugger all boost" then you have bugger all airflow and the PFC adds bugger all fuel. If you have "lotsa boost" then you have lotsa airflow and the PFC adds lotsa fuel and so "bugger the fuel economy".

This is not the case for other ECU's that use MAP sensors (instead of AFM's), they don't know the actual airflow into the engine, they guess it from the manifold pressure, rpm and throttle position. It can never be as accurate under all conditions like an AFM can.

There is a reason PFC's are so popular, they are all round the best in my opinion.

[Sydneykid]

uhm... i got the same problem, get max 348km on a full tank... and at $1.35 pL ma wallet starting to become anorexic.

i also get fume smell... wen driving slow, reversing, or park and @ idle...  

the car is stock as a rock.... nothing but an apexi bov and apexi intake....

any ideas?

Fumes as in partially burnt fuel or raw petrol smell? If it is raw petrol smell (like you get at the servo) then have your carbon canister and its plumbing checked:cheers:

[R31Nismoid]

My o2 sensor has had it.it rattles when i took it out and shook it.So the pfc has an option to ditch the o2 sensor.And R31Nismoid says it has netted him 400km to teh tank with his big turbo.Next retune i will ask the shop if they can do this option and what benifits negative benifits it has on the car.

But as with every performance upgrade the engine will chu more petrol.

you have mis-understood.

ive turned mine off so i'd expect to have poor economy (just like if it was stuffed)

turning it off wont make it better. Its just like having a busted one.

But i dont seem to. And i can only then put it down to my driving style. Even whilst ive booted it here/there this tank, im still around 400km's.

[Busky2k]

Theres definitely something wrong with your engine, and not the ECU which causing the fuel economy problems. If you smell petrol all the time, you might have a leak in the petrol lines, or tank. Or maybe even your petrol cap is stuffed.

[fresh]

i'ce checked around the fuel lines and petrol cap etc.... for leaks and wet-spots an there doesn't seem to be any

sydkid, rightio i see how that doesn't make sense at all, i thougth u could tune engines different ways so they react differently and such use different amounts of fuel.....but ur answer makes much more sense

so sounds like PFC is the go, any idea about what sort of economy skylines r capable of when well tuned ????

hoping to get down to 11L/100km when driving careful

[Sydneykid]

i'ce checked around the fuel lines and petrol cap etc.... for leaks and wet-spots an there doesn't seem to be any

sydkid, rightio i see how that doesn't make sense at all, i thougth u could tune engines different ways so they react differently and such use different amounts of fuel.....but ur answer makes much more sense

so sounds like PFC is the go, any idea about what sort of economy skylines r capable of when well tuned ????

hoping to get down to 11L/100km when driving careful

When running in the old RB30DET I got 8 litres per 100k's going to Bathurst and back.

[fresh]

thats more the economy i am looking for, 60L tank = 500+ kms around town

even more on freeways etc....

just can't afford to spend $50 to go to say homebush and back, thanks for alll the help but

[fresh]

other thing is, i heard there r 2 versions of the PFC, is there any difference, or is one better for a particular feature, or is it all minor trivial stuff ???

[Guilt-Toy]

i'ce checked around the fuel lines and petrol cap etc.... for leaks and wet-spots an there doesn't seem to be any

sydkid, rightio i see how that doesn't make sense at all, i thougth u could tune engines different ways so they react differently and such use different amounts of fuel.....but ur answer makes much more sense

so sounds like PFC is the go, any idea about what sort of economy skylines r capable of when well tuned ????

hoping to get down to 11L/100km when driving careful

This weekend i drove from paramatta to newcastle for $15. which is very good fuel economy. 150+ km (was $1.19c a litre BP ultimate)

PFC is the way to go.

[fresh]

well just for shits and giggles this weekend i am going to drive to the centre of parramatta, just driving normal, refill, see how much its costs.

then drives home trying to skimp as much as possible and see how much thats costs, and we'll see if we r getting anywhere

if u guys can do it on 12.6L i doubt i'll come close, prolly 20L or so

[lwells]

other thing is, i heard there r 2 versions of the PFC, is there any difference, or is one better for a particular feature, or is it all minor trivial stuff ???

There are numerous revisions of the PFC. This is standard practice for electronics. Basically they tinker with the design to make it cheaper to produce and correct any problems (if problems exist).

You have to be a little careful with PFC revisions if you want to use the hand controller, as only certain hand controllers are compatible with certain models/revisions of PFC.

As for actual models, there are three main ones: PowerFC (normal, standard version), PowerFC Pro (incorperates RPM ignition cut & RPM limiter) and PowerFC D-Jetro (a version of the PFC for use with MAP sensors). There is also a range of A.P. Engineering Power FC SPL's, but I know very little about them except that they are supposedly specially adapted PFCs for cars that aren't normally supported (inc RB20DET I believe).

LW.

[_Scotty_]

Has anyone had a noticable increase in fuel economy after tuning an aftermarket computer? A PowerFC is on my list of things to get down the track, but given the rising price of fuel if there was a decent increase in fuel economy it could be worth getting one sooner rather than later...

[Jack88]

uhm... i got the same problem, get max 348km on a full tank... and at $1.35 pL ma wallet starting to become anorexic.

i also get fume smell... wen driving slow, reversing, or park and @ idle...

the car is stock as a rock.... nothing but an apexi bov and apexi intake....

any ideas?

This weekend i drove from paramatta to newcastle for $15. which is very good fuel economy. 150+ km (was $1.19c a litre BP ultimate)

PFC is the way to go.

lol just look at what fuel is costing up a lt now!