1jz fuel economy

[J0RD0]

hi everyone, I have me a 1jzgte vvti engine + auto running a motec and 660cc injectors. At the moment everything else is stock (turbo/cams etc) and its also running what i think is stock boost 9psi. My problem is its getting on average about 230 - 280ks to a 45ltr tank which is pretty piss poor if you ask me, i did a run just putting it around which was very hard to do with an almost no lag and got around 320ks to a tank. I still have the standard 1jz injectors and im wondering if i re-fit the stockers and re-tune the engine will this give me a bit better fuel economy? Or will it just be a waste of time and money?

Im also wondering what a standard 1jz soarer or supra gets to a tank on average just for comparison?

[Dieseltrain]

Who tuned the Motec ? Sounds to me like they didnt spend anytime tuning part/light throttle applications very well . Did you retain the AFM or go MAP tuning only ?

[J0RD0]

brisbane turbo and tuning, forgot to mention the tuned it without a tps and it is map sensored. The tuner also complained it was hard to tune with the auto/torque convertor at low revs. Sometimes on really light throttle its hesitates and drops revs, on the otherhand it is super fucking responsive and makes decent power. Eg i can be doing 60kph and in overdrive and give it slight throttle and it is on boost instantly

[J0RD0]

Also ive changed the plugs about 5 times since ive had the car back and they dont seemed to be fouled up or anything.

[EldarO]

i was getting 400 odd k's out of 60 litres, so yours aint too shab i guess, with the smaller tank.
mines 100% standard bar exhaust.

[mullett]

Changing the injectors will make bugger all difference if it's been tuned right. Does your Motec have wide-band 02 capabilities? You need an ecu that can 'self tune' in light load situations (like a factory ECU does in closed loop mode) to get around the problem of the auto on the dyno. The other option is a 'lock up' torque converter, although I'm not sure that it would help enough, or to get the engine tuned on an engine (rather than chassis) dyno.

Are you planning more mods? It seems to me that if you're going to leave the car at the level it's at now, you might as well go back to a standard ECU, it'll probably be much better on fuel.

-RM.

[Hash_ra23]

easy fix:
look under your rear guards...see all that rubber?
stop causing that.

done.

[J0RD0]

you might as well go back to a standard ECU, it'll probably be much better on fuel.

-RM.

HA HA you reckon i should spend a couple of grand wiring up a standard computer just to get a few extra ks?

[J0RD0]

easy fix:
look under your rear guards...see all that rubber?
stop causing that.

done.

pphhhhhht good one hash i didnt build this car to go to the shops in and do my shopping, i built it for other purposes .

[mullett]

HA HA you reckon i should spend a couple of grand wiring up a standard computer just to get a few extra ks?

It was just an option, depends on how much you changed the standard loom (if you started with it). When I did my EMS on the MR2 I left the standard plug pretty much intact, so it would have been a fairly easy job to go back to the stock ECU.

-RM.

[Aust162]

i got 325kms off my jza70 (manual). not sure how big the tank is though.. 60litres+ i'd say.I was babying it most of the time too, so your fuel economy is pretty decent compared to mine!

[J0RD0]

It was just an option, depends on how much you changed the standard loom (if you started with it). When I did my EMS on the MR2 I left the standard plug pretty much intact, so it would have been a fairly easy job to go back to the stock ECU.

-RM.

nah its motec loom and computer, i only used the plugs off the stock loom

[mullett]

325km out of 60L? The hell with that man, my evo does 300 to 40L if I'm nasty to it...I'm curious about these cars with terrifying fuel consumption, are you guys doing a lot of really short (5-10km) trips, or in heavy traffic a lot?

Also, if your car has a 60L tank, you probably put 55L in...

-RM.

["Z" UTE]

VVTi 1JZ stock ECU in an RA23 got about 9-10litres per 100k on a trip,(Canberra to Dubbo) and anywhere from there to 15 litres per 100k when having some fun.

The low down pulling power is a characteristic of the VVTi.

cheers Chuck.

[EldarO]

325km out of 60L? The hell with that man, my evo does 300 to 40L if I'm nasty to it...I'm curious about these cars with terrifying fuel consumption, are you guys doing a lot of really short (5-10km) trips, or in heavy traffic a lot?

Also, if your car has a 60L tank, you probably put 55L in...

-RM.

they're about 63L, so you whack pretty close to 60L into em.

they do chew fuel,might have something to do with the 1J (standard) never actually being off boost.