Making Your Stagea A Fuel Miser

[ssshonky]

do you know what your getting L / 100km time wise?

A six speed box might help...

I got a huge shock (ok, I drive a GTT, but that isn't the point). Driving from my farm (400km trip) to Perth, I found I was doing 3,000 rpm in 5th at 120kph, considering I drove my mate's ED Falcoon the trip before at was doing a cosy 1,700rpm at the same speed.... So there I think may lie an important factor for an inherent lack of fuel economy, because of the high 'cruise' revs. These things desperately need a sixth cog...

[Marco-R34GTT]

Well I'm getting about 400km per tank...

I'm guessing an R34 GTT's fuel tank is 60ltrs??

I should check in teh manual..

[Raysboostin]

A six speed box might help...

I got a huge shock (ok, I drive a GTT, but that isn't the point). Driving from my farm (400km trip) to Perth, I found I was doing 3,000 rpm in 5th at 120kph, considering I drove my mate's ED Falcoon the trip before at was doing a cosy 1,700rpm at the same speed.... So there I think may lie an important factor for an inherent lack of fuel economy, because of the high 'cruise' revs. These things desperately need a sixth cog...

its a good idea in theory, but as far as im aware 6th gear (.793:1) in an r34 gtr box is roughly the same ratio as 5th gear (.752:1) in a r33 gtr 5spd and the aftermarket ones are geared even more aggressively and will chew more fuel. i have a formula for working out cruising rpm some where, i'll work it out and tell u what the difference is. i dont think it would be any more 200rpm or so.

imo the fuel economy might be hiding in the final drive (diff) ratio. diff ratio change has a massive effect on cruising rpm, but it'll cost ya some acceleration.

also just went through my first full tank of fuel (95ron premo) in my rs4s and got about 550kms. it was a good mix of casual and hard driving, about 70/30.

[ssshonky]

but you see thats pretty bloody good.. most people are struggling to get 400k till the light comes on. so what about yours is different? to be honest if we ever get to the bottom of it I think we will find one common link between the cars and sh1t fuel econ

( other than the fact they are a lard-arse wagon with a slush box )

also just went through my first full tank of fuel (95ron premo) in my rs4s and got about 550kms. it was a good mix of casual and hard driving, about 70/30.

[pixel8r]

but you see thats pretty bloody good.. most people are struggling to get 400k till the light comes on. so what about yours is different? to be honest if we ever get to the bottom of it I think we will find one common link between the cars and sh1t fuel econ

( other than the fact they are a lard-arse wagon with a slush box )

I've managed to get mine down to 11-12L/100km these days. I live in Adelaide and drive to work and back every day, and the shops etc. so nothing out of the ordinary. A lot of it comes down to tuning/ignition timing, driving style, and how much boost you're running.

I recently dropped my boost back a little just to be sure all was safe, and I noticed an improvement in fuel economy just with a ~3psi drop. I think thats telling me I hit full boost too often??

It depends what sort of traffic you're in too, and the weather. Obviously more stops and starts will use more fuel, and if you use air/con a lot that will use a fair bit more fuel too.

I think there's only so many things you can do to improve fuel economy - and these are: change O2 sensor, lower the boost, get some kind of engine management and a good tune, and lift your right foot off the floor on the odd occasion

Edited October 5, 2007 by pixel8r

[ssshonky]

can you tell us what boost you were running before you dropped it? and what is the timing currently set to ?

I've managed to get mine down to 11-12L/100km these days. I live in Adelaide and drive to work and back every day, and the shops etc. so nothing out of the ordinary. A lot of it comes down to tuning/ignition timing, driving style, and how much boost you're running.

I recently dropped my boost back a little just to be sure all was safe, and I noticed an improvement in fuel economy just with a ~3psi drop. I think thats telling me I hit full boost too often??

It depends what sort of traffic you're in too, and the weather. Obviously more stops and starts will use more fuel, and if you use air/con a lot that will use a fair bit more fuel too.

I think there's only so many things you can do to improve fuel economy - and these are: change O2 sensor, lower the boost, get some kind of engine management and a good tune, and lift your right foot off the floor on the odd occasion

[Raysboostin]

but you see thats pretty bloody good.. most people are struggling to get 400k till the light comes on. so what about yours is different? to be honest if we ever get to the bottom of it I think we will find one common link between the cars and sh1t fuel econ

( other than the fact they are a lard-arse wagon with a slush box )

there's ur problem mines a manual. (like i said earlier its an RS4S) totally stock until i got a 3inch cat back 2 days ago

Edited October 5, 2007 by Raysboostin

[webng]

there's ur problem mines a manual. (like i said earlier its an RS4S) totally stock until i got a 3inch cat back 2 days ago

Yeah but Pixel's is an auto too and he's getting pretty much factory figures. I live in Adelaide too but getting more towards 15-16L/100kms with no mods bar the same mbc @ 9-10psi. As mentioned before, if anything, the car gets driven by the minister of finance quite sedately.

[Duncan]

mine is still 14-16l/100, same when it was auto or manual - shame because I was expecting (hoping for) an improvement

[Mr_RS4]

See I don't even know if it comes down to the tune all the time either (crazy as it sounds). But I installed the SAFC / SITC combo (I know its not going to give the same result as a stand alone ecu but still....) and had the car tuned. Timming was advanced in the lower rpm and then slightly retarded up top, and going by the print out I was getting a fairly nice A/F ratio, sitting around 13.5 around 2000rpm then dropping a little to 13.0 around 3000rpm then steadily drops to 12.0 to 4000rpm then stays around high 11's to redline, its a bit up and down and could be better but its just an safc and still a damn sight better than the factory one.

Since a lot of people here are using the safc it would be good to compare A/F ratios alone just for safc tunes. I think a bit more time spent could of gotten better results but my point is I'm still lucky to get 400kms a tank. Its a S1 but I personally didn't notice much improvment and was pretty dissapointed. A note also I was also suffering an ignition breakdown (and the dyno sheet shows it) but haven't gotten around to getting new coil packs, but have a pretty new O2 sensor, new plugs and its a nice fresh engine. However I only ever notice the ignition breakdown at higher rpm when my foot is flat so its hardly bad. I'm running 10psi boost but was running stock before the tune and didn't make any difference.

I've tried many different ways of driving it but the best I've found so far is leave it in POWER so it drags the gear changes out but I use a little less throttle just to keep it off boost as much as possible and if I'm in slow traffic I leave it in 2nd. The times I hit 400kms (best yet is 430kms) is mostly highway. But sadly I'm just about to give up. I have been seriously considering a manual conversion. But people seem to be giving mixed responses with better fuel ecomony there too.....as much as I would love a manual again I think I'll try a MV valve body first as a lot of people I've spoken to say the get better fuel economy. As I think thats where a lot of my power seems to be going. I don't know if we'll ever nail it down to one thing as I think its a lot of different things that are effecting the economy and all cars are going to be affected by different things or different combo's of problems.

As a last note a friend of mine has an '06 WRX and on around 55 odd ltrs of fuel he is only getting 500ish kms to a tank driving down from gympie area to brisbane. Thats on a much newer 4cyl turbo stock standard. So I think I'm doing too bad afterall. All in all if I could get a consistand 400kms normal driving and around 500kms highway I would be more than happy and I don't think thats too much to ask...or is it???

P.S you can all grab a coffee and a snack now

[ssshonky]

thanks for writing all that.. was interesting to read that your tune did little to increase your fuel econ .. and yes.. we dont seem to be getting consistant answers as to if people converted to manual from auto the fuel economy got better. Hey you mentioned the MV Valve body kit? what is that? does it fit into the auto box? I too am curious about the comment that was made that the torque converter seems to loose a fair bit of power? or something like that!

I think I'll try a MV valve body first as a lot of people I've spoken to say the get better fuel economy.

[pixel8r]

I was running 12psi with my last boost controller but it dropped off to about 9psi at the top end. the turbotech one holds boost pretty well constant so it meant I was running 3psi extra up top which proved too much for it (pinging a bit under full boost). So I put it down a little, and its now somewhere around 9psi. So I could also be running less power than what my sig says (i'm not gonna edit that tho ).

But some other things that affect my fuel economy (that I forgot to mention) are:

* bigger turbo (GT30 but with same RB25neo housing - from Adelaide Turbo Services).

* MV auto shift kit.

The bigger turbo means I have more lag which means I'm off boost when just cruising around. I think this made the biggest difference to fuel usage but getting one will be more expensive than any fuel you'd save in the next 5+ years, so not really worth it for a fuel economy mod. Its just a nice side-effect.

But I had the turbo before my last tune and was still getting around 12.5-13L/100km and after the last tune and now with less boost its now more like 11-11.5L/100km.

Cant really say if the shift kit affected fuel economy. I got it installed only a month or so after I got the car so wasn't paying that much attention to fuel economy before vs after. It does improve the gear shifts hugely so I've always recommended one just for that. And the fact that it only costs $300 or so more than a normal gearbox service which you have to do every year anyway.

When my car was stock, I was getting 13-14L/100km so I do think the turbo had a lot to do with it. My reason for not mentioning it before was that I didn't realise it was that that made all the difference (i do now).

At the end of the day though, stageas cost a bit more to run (98octane fuel etc) and cost more to insure - its just part of the cost of owning an awesome car.

[pixel8r]

opps - sorry - double post.

Edited October 8, 2007 by pixel8r

[Stinky Rooster]

Making Your Stagea A Fuel Miser

Can it be done?

so, basically, no.

[Mr_RS4]

Well atm there doesn't seem to be any clear path to saving on fuel put it that way. Some just seem to be lucky I think, I think I could be doing better but I also know there are some doing much worse than me too. I know that they are a heavy car with a slush box like every one has said and I'm not expecting n/a 4 cyl fuel figures but I don't think that at somewhere around 400kms or more per tank of normal town driving and around 500kms of highway driving would be too much to ask.

Myself and a couple of mates actually want to drive down to bathurst for next year and the stagea is going to be the best car to take but if I cant do something to improve the fuel economy then we may be squeezing into something smaller....

Basically I'm going to try the M.V valve body upgrade, a new set of coil packs, another O2 sensor, clean the AFM, and then get another tune. See how I go from there as thats all I can think of atm that may actually have some effect.

Does anyone know if its possible to change the lockup of the torque converter. Because at lower to medium speeds say 60 to 80 or so kms the converter will flare really easially. But at say 100 - 110 and above you can have 5psi or so of boost and it will stay locked. So if there were a way to manually (with a switch or something) activitate the lockup as there may be some advantage espically as it flares so easially.

[pixel8r]

I think one of the main reasons the stagea is not the best on fuel is to do with gearing.

The diff ratio is something like 4.3 which is basically geared for quicker acceleration and revs (very few cars have a diff ratio this high). I think the whole idea is to get the RB25 revving quickly to get it on boost fast in order to get the heavy wagon up and going. It certainly works as far as performance is concerned - Nissan have produced an awesome "sports wagon" (or "super touring wagon", but to me the concept is practically the same).

But all this is at the cost of higher fuel usage, compared to our local relatively-fuel-economy-friendly wagons and sedans.

Actually, with my current setup, my fuel economy is in the range of your average family wagon (falcon/commodore wagon), although its a bit more thirsty on the highway, but not by much. Add to this the fact that it has a great deal more power and performance to rival some V8's, and the stagea doesn't look so bad after all.

But I must admit, in stock form, I was a little disappointed with the fuel economy I was getting. On the other hand, I have about 500-600rpm worth of extra lag now with the bigger turbo so I've sacrificed a touch of responsiveness at low revs for more mid-top end performance. I wouldn't describe my car as laggy however

Edited October 8, 2007 by pixel8r

[webng]

16.5L/100km at last fill, BP Ultimate.

Before that i got 13.5L/100km after dumping in a whole bottle of Nulon Injector Cleaner.

[ssshonky]

far out man .. thats a pretty massive discrepancy!

and to be honest.. you dont know if the injector cleaner really did a whole lot or not?

I wonder if you ran a tank full of super high octane I wonder if you would get a fantastic fuel economy reading. I wonder if the motors are just unhappy at running 98 ron

16.5L/100km at last fill, BP Ultimate.

Before that i got 13.5L/100km after dumping in a whole bottle of Nulon Injector Cleaner.

[Mr_RS4]

Well I don't really see the injector cleaner doing anything in regards to fuel economy. I mean how is a dirty injector / injectors going to make fuel economy worse if fuel is already having trouble being squirted through?

Sure it can be dangerous as far as your engine running lean goes and it will probably sound or run a bit rough but we'd have to be talking about some pretty clogged injectors. Needless to say I still run a bottle through from time to time but I don't do it for fuel economy and haven't noticed any improvements from doing so either. Also "IMO only" I haven't noticed much difference from using different fuels either. Have tried all the 98oct blends out there (optimax, ultimate, vortex, mobil 8000, and the new shell one....forget whats its called atm). I tend to stick to BP where ever possible as thats what I've used for years but now my nearest station is a mobil I mainly use 8000. I've even had to resort to normal premium before when on a trip and it did great on that so go figure.

Lets face it most of us aren't running a level of tune thats going to be affected by what fuel we use, unless of couse you try regular unleaded or something like that. Considering the Stageas stock ECU is detuned compared to the R33 (from what I've read) and most would be running around the 10 psi mark on stock turbos then I don't see different premium fuels making much difference, unless you had some sort of programable ECU or piggy back and actually filled up with each different fuel and then put it on the dyno and tuned it for each one. Then you might see different results.

[Mr_RS4]

I've been giving this fuel economy issue a lot of thought since I bought the car....

I'm starting to think that the poor 2.5ltr RB25 just isn't enough motor to pull the S1+2 Stagea's around. Sure when the foots down they go quite well considering its a 2.5 6cyl pulling around that much weight but in normal light to medium throttle it just feels almost laggy until it builds up pace almost forcing you to use more throttle to get it going then easing off which is why the economy is so shit. The thing is I still love Stageas and I still think they are a really great package for a wagon. I mean with the right kit, wheels and suspension setup they look sexy and handle very well too but IMO as far as the powerplant goes it might just be an old school case of more cubes is better.....

Why didn't Nissan come up with the VQ series motors 10 years ago

Speaking in theory I wonder about the difficulties of fitting a 2JZ or even a VH45DE (if I got it right) or the soarer's V8 would go. Forgetting straight away about keeping the AWD or about being a patriot to Nissan just find a cost effective way to get more cubes (and still preferably being turbocharged) into the stagea and maybe ditching some weight along the way. May end up with a lighter car, with more power and HOPEFULLY more economy. And maybe an easier manual conversion too! This is just one of many ideas i've had floating around in my head and is a bit on the extreem side but I haven't ruled it out!