Better Highway Consumption...

[Haysey]

Hey all....

with fuel prices etc etc i wanted to start a thread on how to LOWER consumption....

My car has a few mods and in the city it is ok with maybe 300-350km to a tank (half thrash half baby) but highway only gets me like 400-430km from a tank... now im hoping that his figure should be ALOT better.....

Now to drop consumption ive been staying off boost etc but its not enough.... im thinking for a long haul to change the chip back to stock as i think the one thats in it pumps alot of petrol in at about the 3000rpm mark to boost it quicker and therefore 100kmh=3000rpm isnt good!

also im thinking of winding boost down a bit but dunno if this will make a diference....

how many highway kms do you lot get and can you give me any pointers to make consumption lower......

btw ive only got a RB20

thanks

Ed

[neil_se]

Getting the AFRs tuned on a dyno if obviously going to make the biggest difference, even if its only a remap or SAFC, you're sure to get that money back in fuel savings before long.

[benm]

On Monday of this week I did:

400km highway driving (100-110km/h)

75km country driving (80-100km/h)

75km of very hard driving (showing my cousins the new toy)

I still had 1/4 tank left, so I could have easily got another 80-100km out of it totalling 650km all up.

I'm very happy with the economy of my gtr (but then you'd expect that with a $1200 tune).

[Fixxxer]

I was at 420km when I filled up (just under a 1/4 tank to go), so I don't have any reason to doubt I would have reached at least 480km. Probably 250km in highway, the rest city and around the 'burbs kind of driving. Couldn't get up mine too much cause my missfiring was really bad, but thats all sorted now R32 with all the add ons + r33 turbo.

To get better fuel economy u can do basic things like don't use aircon as much, keep car aerodynamic - windows up, (remove rear wing). Cruise at a lower speed lowers drag on the car (like 100km in a 110km/h zone), and just drive smoothly - i.e., don't race to the limit and pick the tallest gear possible when driving.

Fixxxer

[[[d a n n y]]]

did a full tank run to the snowys

lasted the whole way

[ghostflame]

i get about 550 to a tank. thats driving on the highway. plus with mods without computer yet in. thats a t70 turbo, 550cc injectors, bosch 044 pump, intercooler and all the other crap.

[Rossman]

will a full 3" exhaust system help at all or just use more fuel?

im running a stocko r33 gts-t and get bout 450 to a tank.

[RB30-POWER]

Should be getting around 8L/100km with an RB on the freeway regardless of mods.

[Josh]

I have forgotten what the word economy means... 270k's to a tank regardless of driving habit...

maybe I SHOULD fix that 02 sensor...

[bilbo117]

hmm. I get 600 to a tank on the highway..

R33 gtst with full exhaust, cai, boost controller (wound down for highway)

I find winding the boost down goes a long way....

[Cubes]

My Rb20DET running 1 bar making 164rwkw used to get 470km's around town not babying it, driving it hard or soft didn't appear to make much difference to fuel consumption. Average was 470km's.

On the open road I once saw 600km's, I was booting it quite a bit so it 'may' have got better if I drove it off boost.

The RB30DET which has its boost in by 2000rpm see's ~430km's to a tank using the stock pfc base map its making some where around 200rwkw.

Open road.. Unsure haven't taken it for an open road drive.

I am dropping a 3.9:1 diff ratio in to it so this will definitely see an improvement in fuel consumption. Especially on the open road.

The R32 @ 100km/h revs at 2782rpm. The tacho and speedo are slightly out. This is going by the pfc h/c.

A 3.9:1 will see 2487rpm @ 100km/h.

Edited December 29, 2005 by Cubes

[siksII]

what do people mean by tank? this always frustrates me.

when i say tank i mean 50L

this is when the light starts to flash, the gauge shows definetly empty and there is 15L left in an r33.

when i fill up i work out my consumption exactly by comparing kms and litres gone into the tank (i usually fill all the way)

anyway on the freeway i have done many 1000kms, and always got between 9.5-10L/100km.

[thommo]

My fuel economy can be pretty ordinary in stop & go driving around town (approx. 450km to a tank), but over christmas i did a bit of a road trip to NSW and after 421km filled up the tank with 42.6L.

Very close to 10L/100km, which I was pretty happy with. Car stayed at high boost (0.8 bar), runs PFC, full zaust, a/m fuel pump front mount etc.

Says a lot for having a good tune I reckon.

[discopotato03]

My opinions only .

Its been said that turbos sized to "spool" at just above highway cruise ie 100-110 generally give good open road consumption as boost , with extra fueling and retarded timing , is not needed . GTST's and GTS25T's were sized to boost in the lets get the thing rolling phase and when at highway cruise revs/load its difficult to keep them out of boost . I suspect the kind of use these cars had in Japan was crawling round the burbs with millions of other cars , average speeds were low and low speed torque was needed .

For Austalian conditions you could probably get away with the next size up turbine housing and maybe even the next taller final drive ratio . This should help to load the engine and turbo and be less fussy in the low mid range .

From what I read the Nissan ECU's are very quick to go rich/retard and hold off detonation . Now that we are getting better pump fuels and an easier say in the tune (ie PFC) you can retune for torque and crisp throttle response which means not filthy rich 10:1 mixtures and better timing numbers . My theory only but the next size up turbine housing will give less boost at low revs but the potential to advance the timing up a little should pull up the bottom end , and lets face it lowish CR engines need all the help they can get . Uncorking the turbo also benefits us more when on boost and helps reduce the thermal load on the engine which itself helps reduce the onset of detonation .

With my engine build I hope to keep the CR around 9:1 which makes for better part throttle torque (raised dynamic compression) a little more than std lift and the GTR head/inlet to have minimal inlet restriction (volumetric efficiency) . Turbo ? This will be the last part of the picture because technology is constantly updating , prices usually fall and there are some new things on the way next year .

My thoughts only , cheers A .

[benm]

I think that's the main reason why I get good economy in my GTR. The boost doesn't really kick in until over 4,000rpm and on the motorways im only doing 3000rpm so i'm driving on vacuum.

[mokompri]

will a full 3" exhaust system help at all or just use more fuel?

im running a stocko r33 gts-t and get bout 450 to a tank.

<{POST_SNAPBACK}>

exhaust upgrade = less back pressure = more efficiency

more efficiency = better fuel economy

same with freeing up the intake of restriction.

[ghostflame]

i have the same fuel economy as i did when it was stock standard with just a 3 inch exaust turbo back. and thats from a full tank to when it hits the last bar on the fuel gauge not under it.

[Downforce]

If you have a GT wing, take it off :lol: or adjust the angle of attack so it's more horizontally flat, giving less downforce but fuel economy will improve.

[RANDY]

Crikey... I get 350k's to a 50L fill in my stock R33GTST... highway or not. O2 replaced (as seen in the 02 thread).

I'm still hunting for a good reason why my economy is so poor... no smoke, new plugs, new O2 sensor... car runs smmoooooth.

[Cubes]

Get it on the dyno with some one who is willing to spend some time investigating cruise, light load and moderate afr's.