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M35 High Fuel Usage & Power Putput Issue?

luthepa1

By luthepa1,
in Four Door Family & Wagoneers

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luthepa1 Contributor

luthepa1

Posted
Posted

Ok I've been searching for some time on the forums and while I have found some slight insight into what I am trying to find in terms of answers, I still have not found info related to what I require.

Firstly I own a NM35 Axis Autech Stagea. My first question is my fuel consumption high? I mostly do short trips (~6km) to and from work, not always everyday of week. Other than that just local city driving around chatswood sydney. The longest drives on a more regular basis are from Chatswood to Sydney CBD (think its only ~12km) but this is just for Nov mostly. And on fewer occasions I have done distances from Chatswood to manly beach (~20km). Those figure can double as they are one way. So recently I have been getting 18L/100km. But lately that went up a little (yesterday I was getting 20L/100km of 47km range). However I admit I do love to push the car so maybe its just my driving style?

Also can anyone tell me in the fuel usage history screen what each bar of the bar graph represents? Is it between each start of car, or the recorded range, etc? And how does the range figure work? I am not quite putting 2 and 2 together here.

Secondly - My car is still stock at the moment. If I am just crusing around and give half throttle to make the gear box kick back I feel nice, quick acceleration. Always put a smile on my face. But the same cant quite be said for full throttle. Maybe its because it has stock intake and exhaust so it cant breath as nice. But sometimes it feels like the car is limiting output to protect the gear box perhaps? I read other posts and I think there is such a thing as a torque converter to protect gearbox and keep it cool. Is this what I am noticing on full throttle? Or do I have a downgraded trans fluid thats making my auto gearbox under perform? OR maybe I am just experiencing wheel spin and dont know it. Couple time I have had all windows down in back street and heard the wheel just breaking traction. But I feel the lack of power on full throttle in more car/ecu controlled.

Well that's it. If anyone has info on those points and suggestions to maybe changes needed (trans fluid change, torque converters, etc) would be greatly appreciated.

Old Gregg Enthusiast

Old Gregg

Posted
Posted

My undestanding is you will go through a lot of fuel on very short trips as it will run very rich in the first few minutes until gets to working temp.

Have read that while full stationary warm up at low revs before driving of is in fact bad for engine, a 30 to 60 sec warm up could reduce fuel consumption as has started to warm up before placed under load.

Have achieved under 10L/100km on straight Hyw work and 13 to 15 for mainly 22km each way commute - country driving.

(Cringe expecting to be corrected before pressing "Add Reply")

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

Intake shouldn't be a problem althouigh a highflow filter for the stock airbox would be a good idea. Bigger turbo back exhaust definitely a good idea. I don't have an M35 but I believe the fly by wire accelerator is not as sharp as it could be.

zoomzoom Mentor

zoomzoom

Posted
Posted

Not to be a smart ass, but for 6km trips Id be recommending a pushbike, or something like a sachs madass or postie bike if you have a bike license.

Thats a lot of heating and cooling cycles for a big car, and I doubt it really gives the car a full chance to warm up.

luthepa1 Contributor

luthepa1

Posted
  • Author
Posted

Cheers to all for the feedback so far. Appreciate it.

I was not aware my car had a fly-by wire accelerator. Never occurred to me.

Yes 6km to work (12km round trip) is not much. But there is a small twisty section of road on the way where I lock it down into manual mode and OMG!!!! This car fly's! It definitely loves the twisty, windy roads which is much to my liking. I grew up racing through the Adelaide hills. Eagle on the hill was always a bench mark road.

I guess to be clear the "gutless" sensation when applying full throttle is most noticeable taking off from stand still or rolling start. Kind of get the feeling that half throttle is just as good but maybe its just me. Actually its probably just turbo lag I am starting to notice more as the weather seems to be heating up in preparation for summer. I just cant help but think there is maybe something I can do to make the gearbox more obedient to my driving style.

Oh yeah... Stupid me. It dawn on me today that my comments about my fuel consumption being high (20L/100km) could be to do with me using manual mode a lot more in the last 1-2weeks as I try to understand this laggy acceleration feeling. Plus its more fun :-)

zoomzoom Mentor

zoomzoom

Posted
Posted (edited)

It may be worth taking off the intake piping and intercooler, and cleaning out the sludge that has built up if you havent so far. The throttle body would need a clean as well.

This ensures at low throttle openings that the intake is flowing the amount of air that the engine and gearbox expects from a stock vehicle, so the shift points and behaviour of the gearbox is optimal.

This may help fuel economy but dont expect too much. Then again with around town driving, it may just help. A new O2 sensor is probably needed.

As for the difference between half and full throttle, it sounds normal to me. On every turbo car I have owned, the power output wasnt a linear relationship with the throttle opening.

Edited by zoomzoom
andy65b Veteran

andy65b

Posted
Posted

Hi Paul

The M35 has some odd settings for the throttle to keep it in line with the Cruiser it is designed to be.

Throttle will not open more than 30% till after 3000rpm. this is controlled by the ECU. Only solution to this is buy a Nismo ECU from Japan.

from standing starts full throttle will give you a worse start than a gradual application. When you go full throttle the butterfly opens only 30% but it dumps lots of fuel and causes a slower take off.

Fuel Usage History, each bar represents the fuel usage for the last time you reset on the fuel usage screen.

It uses the overall fuel history to determine the 'distance to empty".

As it gets warmer your fuel economy will get worse as the computer will use more fuel to maintain engine temps.

Cheers

Andy

whitestag Community Regular

whitestag

Posted
Posted

Seems normal economy to me. I do short trips like u and I'm

About 20/100km and if i push it the trip computer can go as low as 3.7km to the liter.

Small trips means stop start normally. Eats fuel. When I do m5 runs out to other site I get better economy (6.5-7pm to the liter).

Daleo Grand Master

Daleo

Posted
Posted
I dont know how you guys tolerate fuel usage around 20L/100km. I would expect that from a luxury behemoth Mercedes SUV around town but not a family oriented vehicle.

20L/100km would be considered a "worst case scenario". My long term average is around 11-12L/100km. but you can't flog the pants off it and expect Prius fuel economy. The car weighs 1700-1800kg (depending on model/spec) what exactly do you expect? :thumbsup:

I own a GSXR1000, this can get 4.5L/100km on the street. On the track this goes to 20L/100km. It's all down to throttle usage. :)

If you want to play, you have to pay.

Daleo Grand Master

Daleo

Posted
Posted (edited)
You cant be riding that GSXR1000 like its meant to be at that fuel usage :)

I have a CBR1100xx and 6.5-7L/100km is my average street usage.

Lol, yeah, I know what you mean, I try to be good... I only said "can", not that it does vary often... :D My average is slightly less than yours, but my commute is mostly freeway.

Can't say I bought it to save on fuel... :thumbsup:

Edited by Daleo
iamhe77 Grand Master

iamhe77

Posted
Posted
Guys, Do you reckon he should reset the ECU so the transmission adapts changes, kick down characteristics to his driving?

Won't make a difference to the touchy kick down that the stock M35 has... no way of avoiding it if driving with a heavy foot, but if you have a controller right foot, a spacer kit will go a long way to giving the car an easier to control/predict kick down (don't have to walk on egg shells to avoid the kick down)

luthepa1 Contributor

luthepa1

Posted
  • Author
Posted

I find its not "touchy" enough (gearbox that is). well sometimes when not pushing it but if say i turn out a side street (rolling start) and i floor it its like, 1 sec.... 2 sec... oh! lets gear down a gear or two? not touchy enough. and in that instance i feel half throttle would have had me further down the road by then?

yeah think i should try some mods first. first id like to do the hdi fmic upgrade with thinner thermo fan. that should help at this time of yeah. i only got car nearly 3 months ago and maybe what i am noticing is summer arriving with increased turbo lag? after that exhuast. suggestions? 3 or 3.5 inch? not too loud either (thats a first).

so how do i reset ecu anyway? and recommended driving after reset before switching car off?

cheers!

iamhe77 Grand Master

iamhe77

Posted
Posted (edited)

ECU resetting is in the DIY section (in the stickies). Just drive it normally after a reset (it will learn)

Oh and squeezing the accelerator will give you more response rather than stomping on it :D

Edited by iamhe77
andy65b Veteran

andy65b

Posted
Posted
touchy on the stock ecu? try driving with a nismo ecu. if you even think about moving your foot it drops back a gear lol

lots of fun in the wet Iain especially at the roundabout just down the road from your place.

I just have to remember that I have a LSD and my car understeers in the wet when I lift off.

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