# RB26 mpg?



## bigal23 (Apr 22, 2015)

Not a terribly exciting subject and I know I didn't buy a Skyline for its fuel efficiency but I just wanted to know what people are getting out of theirs.
As this is my first gtr I have nothing to compare it to but she does seem rather thirsty especially since I've had her mapped and new coil packs fitted due to a misfire on boost.

She's a 1994 32 gtr, stock fuel pump, stock fuel rail, stock injectors, stock turbos with N1 steel internals running 0.9 low and 1.2 high.
Mapped to produce 405 bhp on high boost.

Anyway, I'm getting around 120 maybe 130 miles out of every £40 of super (either Shell v power or Tesco 99ron if I have to)

I know that obviously I'll see the fuel needle drop nearly as fast as the rev needle climbs if you open her up but yesterday drove to the coast with the wife and kids so was a fairly sensible cruise (on low boost) and I still only averaged about 17mpg.

Does that sound about right?
I mean I'd expect those kind of numbers if I was running mahoosive turbos or high flow injectors but on a pretty stock set up to me that seems a bit low.

Maybe just my lack of gtr experience or that and the fact my daily driver is an Octavia vrs diesel which only needs filling up twice a year :chuckle:


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## Cris (Sep 17, 2007)

For normal road driving I'd expect around 20mpg.


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## CT17 (Mar 25, 2011)

18-20 mpg driving normally, less with some traffic.

I don''t think you are far out.
So probably right for your driving style/local conditions.

I get 17mpg driving sensibly with 600bhp.


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## FRRACER (Jun 23, 2013)

Getting about 15mpg at the moment on a Mines stage II ecu.


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## Nappyboy28 (Jan 11, 2014)

I'm coming from an MK7 GTI and I was getting 36mpg even with 380hp 380tq. lol I still love my 19mpg though.


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## RSVFOUR (May 1, 2006)

mine is completely stock and i get around 22-23mpg with more on a run as long as i drive sensibly.


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## philo (Sep 4, 2013)

i got 25mpg to and from the ring last week
but 2 gallons a lap !!


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## StreetRunner (Feb 14, 2015)

Stage 1 here, got 26mpg all the way to Nurburg and back averaging 90mph last weekend.

£30 gets me about 130miles if sensible 100miles if not. 

My RS4 was bad £30 70miles sensible.


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## StreetRunner (Feb 14, 2015)

philo said:


> i got 25mpg to and from the ring last week
> but 2 gallons a lap !!


Were you in a grey 32? Going around with an evo?


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## philo (Sep 4, 2013)

yeah, I had to remove the rad on Saturday and repair it with metal putty !


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## moleman (Jun 3, 2002)

philo said:


> 2 gallons a lap !!


So 7 laps per tank?

Bit gay. I'm lucky if I get 4. :chuckle:


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## StreetRunner (Feb 14, 2015)

philo said:


> yeah, I had to remove the rad on Saturday and repair it with metal putty !


Yer spotted it a few times going around, looked nice.


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## philo (Sep 4, 2013)

haha
got a 72 litre tank in a r32 though !


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## moleman (Jun 3, 2002)

An extra 7 litres does not buy you 3 laps. lol

It's way cheaper in my 106. 17 laps to 41 litres!!!


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## philo (Sep 4, 2013)

seemed a lot cheaper this year with a good exchange rate
£1 a litre for super and 9 laps for £152


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## Jags (May 20, 2007)

They're pretty thirsty cars even as stock but they're also pretty old now so changing lambda sensors may also help


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## Dan ep3 turbo (Sep 29, 2013)

I'm getting around 25mpg from my 800bhp r33 gtr on a run


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## rob wild (Jul 30, 2007)

Driving normally with some town work mine does 27mpg. On boost its sub 10mpg. It's one of the most fuel efficient performance cars I've had tbh, think it's all in the tune! 

I'm hoping it might be even better with my Link G4+ that's going on. Only from the point of view that it's really handy to be able to go and do a driving day with the other chaps (with some spirited driving) and not having to worry about constantly having to find a fuel station.


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## bigal23 (Apr 22, 2015)

Well this has proved to be a lot more entertaining than i expected!:chuckle:

So generally speaking she's not bad compared to some but it's safe to say i've never got anywhere near 25mpg on a run 

What things should i be checking to make sure she's not just spunking fuel with my current setup?


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## LongRat (Apr 9, 2012)

Just looking at this thread it's immediately obvious that the fuel economy people get is as variable as the setups of everyones' cars. What I would say though is that an efficient setup is most likely to be able to be a fast setup. When cruising, I see absolutely no reason why a well mapped good engine shouldn't get 25 MPG. I was at MGT and they had a customer car in running 800 BHP at the wheels and it was getting 25 MPG on a cruise. In my R32 I get about 18 while driving sensibly. In my opinion that is poor. Mapped by MGT to 413 at the wheels but that's largely irrelevant. I think going to a modern ECU and getting rid of the airflow meters etc might make a good difference and I would like to hear from people who have done this whether it was the case.
As a matter of interest, my previous car was a 1994 MR2 turbo. This car could get over 40 MPG on the motorway (once managed 43 over 200 miles) but produced about 300 at the crank. Very few modern engines could get near that ratio of economy to power. The Toyota 3SGTE is an underrated unit on many levels.


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## Dan ep3 turbo (Sep 29, 2013)

Lower power cars with smaller turbos will be worse on petrol on a run because of manifold pressure were as big turbos will more vacuum. Also how lean the car runs on partial throttle will play a massive mart so will size of cams as big duration cams waste fuel. I have 280 degree cams tho and I think I could prob get close to 30pg if I drove at 70 and didn't put my foot down at all


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## r32Rich (Apr 5, 2014)

So getting about 60 miles of fun for £30 in a 500bhp gtr sounds about right then, did wonder if that was a bit poor.


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## R32 Combat (Jan 29, 2004)

I have a standard car returning 20mpg on my route to work.


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## EF Ian (Jan 11, 2013)

I get 30mpg on the motorway, but thats in a lightweight RWD, drops to well under 20mpg during normal driving, but then i don't really take it that easy normally.


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## UKPAISLEY (Jan 17, 2003)

Just had my new map and managed a good 25 on a run. I have larger turbo s and at motorway speeds I am just on a positive pressure of about 3 or 4 PSI.


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## endo (Jul 11, 2007)

1000 mile round trip to Silverstone from Scotland..
£180ish spent on v-power

around 37-40 MPG off boost motorway cruising 
(on boost overtakes @ 1.47bar... lol maybe 4-5 MPG?)

Needless to say some black magic was involved in the engine building & mapping.
(and deep pockets)


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## tarmac terror (Jul 16, 2003)

endo said:


> around 37-40 MPG off boost motorway cruising
> (on boost overtakes @ 1.47bar... lol maybe 4-5 MPG?)


 37-40MPG!!!!!!

That's insane!! Are your injectors firing once every 10 crank revolutions??? :chuckle:


That is indeed some serious economy from an RB......is that one map or do you have a 'motorway' super-econ map and a 'sport' map??



TT


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## bigal23 (Apr 22, 2015)

endo said:


> 1000 mile round trip to Silverstone from Scotland..
> £180ish spent on v-power
> 
> around 37-40 MPG off boost motorway cruising
> ...



Wow really? Maybe I need to borrow your calculator :chuckle:

Quite a few people commenting on a decent map making the difference, are some maps done to chuck a lot of fuel in to get more power then?
Guess as a few have said it depends on the set ups and variables of the car.

On another thread I did see someone mention new injectors being more efficient, would that be a reference to the efficiency of it's fuel injecting capabilities or in terms of fuel consumption?


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## CT17 (Mar 25, 2011)

bigal23 said:


> Wow really? Maybe I need to borrow your calculator :chuckle:
> 
> Quite a few people commenting on a decent map making the difference, are some maps done to chuck a lot of fuel in to get more power then?
> Guess as a few have said it depends on the set ups and variables of the car.
> ...


Some cars are mapped for POWER.
Which means the mapper spends less time/effort on the partial throttle settings.
Which means poorer economy.

Obviously mods and good injectors etc.. also plays a part.


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## bigal23 (Apr 22, 2015)

CT17 said:


> Some cars are mapped for POWER.
> Which means the mapper spends less time/effort on the partial throttle settings.
> Which means poorer economy.
> 
> Obviously mods and good injectors etc.. also plays a part.


Funny you should say that, couple of times on part throttle she has been a bit hesitant and I was told by another tuner it was due to running map sensors on stock throttle bodies as opposed to a single??


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## endo (Jul 11, 2007)

tarmac terror said:


> 37-40MPG!!!!!!
> 
> That's insane!! Are your injectors firing once every 10 crank revolutions??? :chuckle:
> 
> ...


Just the one map (Nistune),
Mapped so it runs towards lean off boost purely for cruising, and then guzzles fuel once you put the foot down.

Kind of pointless to have it mapped for power (all the time) when the engine is barely working, and what response you might loose from this is made up by porting/balancing/plenum/cams etc.

It did shock me the first time I drove home after the rebuild, when i used between 1/4-1/3 of a tank to drive back from Durham... (that drive used to be well over 1/2 a tank)


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## blue34 (Jul 28, 2005)

It's always a good idea to have a wideband AFR gauge fitted... it tells you a lot about your fuelling and can give a warning if an engine is likely to destroy itself if it runs lean under boost. 

In the cruise at light constant throttle, say 75mph the fuelling should be spot on. If the ecu is in closed loop then the lambda sensors will feed back to the ecu and the ecu will do it's best to adjust + or - 5% get to an ideal mixture, and the gauge should read an ideal 14.5. 

Obviously there's a lot more to it and it will richen up under load but in the cruise, If it's set correctly I think it ought to be possible to get 28-30mpg from an RB irrespective of the state of tune.


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## jps (Aug 1, 2007)

*R34 mpg*

just for info.


2005 R34 V Spec II NUR R Tune.

288.8 miles yesterday from Nottingham to Ace Cafe.

46.62 litres = 10.255 gallons

gives 28.16 mpg.

very surprised


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## bigal23 (Apr 22, 2015)

jps said:


> just for info.
> 
> 
> 2005 R34 V Spec II NUR R Tune.
> ...


Now that's just depressing, am I allowed to swear at you on here? :chuckle:

Guess the fact that even as stock your car is 11 years younger than mine will have something to do with it!


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## jps (Aug 1, 2007)

bigal23 said:


> Now that's just depressing, am I allowed to swear at you on here? :chuckle:
> 
> Guess the fact that even as stock your car is 11 years younger than mine will have something to do with it!


sorry.


yes, it is standard as far as we can tell, 450bhp, R1 engine & R1 ECU as from Omari in May 2005 - no mods or new maps.

running on Shell V power.


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## bigal23 (Apr 22, 2015)

jps said:


> sorry.
> 
> 
> yes, it is standard as far as we can tell, 450bhp, R1 engine & R1 ECU as from Omari in May 2005 - no mods or new maps.
> ...


Only just realised I've been drooling over your Shrek thread today!!

Proper nice car you've got there mate, not bad for your first Skyline hey :chuckle:

And maybe the R1 was a super efficient setup, I had heard they were only 4 cylinders though :chuckle:


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## jps (Aug 1, 2007)

bigal23 said:


> Only just realised I've been drooling over your Shrek thread today!!
> 
> Proper nice car you've got there mate, not bad for your first Skyline hey :chuckle:
> 
> And maybe the R1 was a super efficient setup, I had heard they were only 4 cylinders though :chuckle:


thanks,


also, noticed this VW Passat 2.5 TDi yesterday.


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## ab20000 (Jun 30, 2012)

Not really measured mine but I know I don't get much. Certainly nowhere near the 37-40 quoted. Are you sure the calcs are right - sounds too good to be true. (great if it is right!)


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