N/a Fuel Economy Thread

[TokyoTaxi]

mythbusters ahoy!

this thread is full of myths and assumptions with no facts

there is no logical way that upgrading the coils to splitfires would affect fuel econonmy that drastically

i suggest there is something fundamentally wrong, for it to go from 500kms a tank to 100kms a tank

go see a mechanic - it doesnt add up

You're correct that there's no "logical way" that putting NEW Splitfire coilpacks in could increase my fuel consumption but that's exactly what happened.

As for seeing a mechanic, I am one and have been since 1988 so I'm not quite a newby.

Happy to hear some suggestions tho

At the time I put the coilpacks in, I installed a set of Irridium plugs at 1.1mm gap. I then removed the ECU fault code ( 21 ).

I'm almost certain I re-set the ECU but I was working on 3 cars at once so I'm a bit fuzzy on that detail.

Anyway, when the fuel economy issue arose, I started searching this forum and stubled across a thread ( can't find it again ) in which a few people discussed issues with new Splitfire coilpacks which were rectified by fittng new OEM coilpacks. I started searching further ( google ) and found that many japanese tuners favour OEM coilpacks over Splitfires and so on. Anyway, Splitfires are great for th price and maybe I got a "not great" set ? Anyway, when I get some spare time I'll start looking into it more.

[cosmic starz]

he said it dropped a 100 i.e. to about 400 from 500

but the thread is full of guesswork alright!

as I said in my earlier post I have had both std coils and Splitfires (each for about same time, 1 1/2 yrs) and have tracked fuel consumption closely for past 3 years + and there is no discernible difference - steady 9.5-9.7 l/100 km average whichever type in motor - both ran very well, good start-up and very clean burning (no soot at all on tailpipe) - but some of the oem coilpacks did breakdown necessitating the change-over and Splitfires were definitely the best buy on cost basis

anyone getting very bad mileage definitely should look at problems with driving style and/or mechanical/electrical issues beyond just the coilpacks

[MissR34]

PMS ?? did I emphasise that enough????? lol again and more lol

But seriously, I'm glad you've had no ill effects from "your" Splitfire coilpacks, but others have ( including myself ), and have documented it. Some big HP applications have replaced their Splitfires with new OEM coilpacks and have "gained" power.

Anyway, I can live with the fuel economy I have so long as petrol doesn't get too much more expensive.

i gained 7kw when i put my splitfires in

[TokyoTaxi]

i gained 7kw when i put my splitfires in

So you removed a set of NEW OEM coilpacks and installed a set of NEW Splitfires and gained 7kw ?

Or, did you replace your 8ish year old OEM coilpacks with new Splitfires and gained 7wk ?

[MissR34]

i had 3 new oem coilpacks b4 the spiltfires went in

[Silver_GT]

Lucky people getting under 10L/100, im only getting 12.5 as a Personal best!

[THR34T]

best ive gotten is just over 450k's, on average it normally just clocks over 400. ive run it down to near empty when the light comes on around 3-4 times to see how many K's i can get out of the whole tank. ive got all the basic mods - pod, cai, 2.5 exhaust system, extractors and a hi flow cat.

[natho33]

i just finished a full tank of bp ultimate 510ks all city driving

stock r34 coupe auto except kakimoto catback

[FULOCK]

i just finished a full tank of bp ultimate 510ks all city driving

stock r34 coupe auto except kakimoto catback

Im seriously confused..... the pattern I've seen so far is most people either say they just clock over 400k's on a tank.... and other's claim they get easy 480-500k's in city traffic.

I've had a R34 4Door GT-T - and I struggled to get 400k's on a tank on average and that's driving while the light was on for a bit before filling up again (and I drove it like an absolute grandma!!!)

I did not go over 3000rpm's the whole tank!!!!! and that's very light foot accellerating, it did not hit boost the whole tank!!!

I put my R34 on the dyno and they told me everything was fine with it, air/fuel mixtures were like they should be........

With spirited driving the whole tank, every day to work and back i'd get as low as 340k's a tank!!!

Now I have a Stagea RS Turbo (RWD) - so same running gear - and I get exactly the same figures to a tank!!

So how are people getting 500k's to a tank!! I really want to know!!!

Have i just been unlucky and the two RB25DET's i've owned been thirsty ones??

Is there a secret that some know and other's dont about these engines??

I always make sure I look after my cars well too, new oil (good oil) and oil filter every 5000k's, do sparkies approx every 10-15,000k's, always use good fuel... so I dont see anything that im doin wrong......

someone please enlighten me!!!

[666DAN]

Nah they're not thirsty at all, my R34 gets ~420km/50L at best with 75% highway driving, that's down to about 320km/50L for city. Mainly as I'm a lot heavier on the throttle being such an impatient driver.

My R34 25GT used to get consistant >500km/50L though which I thought was great considering my GTi Corolla used to get ~550km/45L

[FULOCK]

Nah they're not thirsty at all, my R34 gets ~420km/50L at best with 75% highway driving, that's down to about 320km/50L for city. Mainly as I'm a lot heavier on the throttle being such an impatient driver.

My R34 25GT used to get consistant >500km/50L though which I thought was great considering my GTi Corolla used to get ~550km/45L

So are you saying your current R34 is a GT-T and drinks more petrol than your R34 25GT which was non-turbo??

NA R34 more fuel efficient than R34 GT-T??

I really want to get to the bottom of this as I am in the market for another R34 4Door NA or Turbo depending on these factors and price I can find one for....

[Turk1]

My car will always be empty at around the 320km mark. I've got the car hooked up to computers and everything and every mechanic says that there is nothing wrong with the car. I just get confused becuase people here say there getting 400+ no worries.

[FULOCK]

My car will always be empty at around the 320km mark. I've got the car hooked up to computers and everything and every mechanic says that there is nothing wrong with the car. I just get confused becuase people here say there getting 400+ no worries.

Im glad im not the only one.....!!

Im starting to think that people who claim they get over 450km's and upto 500+km's in city driving are either pulling our leg, adding an extra 40k's or so to their figure for good luck, or their car is running very very lean!!

I dont want to lean out my engine coz that means a hotter running engine and dangerouse on high rpm's (dunno if you can even do that a factory ecu).....

***** if someone has first hand experience getting their economy to improve from barely making 400k's a tank to making the claimed 500+ k's to a tank, on a RB25DE or DET, NEO or not, myself and im sure many other members would love to know what or how you did this??*********

Is it as simple as a faulty oxy sensor that could make such a difference, or airflow metre...... or something not so obviouse as maybe faulty injectors, coilpacks leaking... etc....

[Turk1]

I even got my o2 sensor changed along with coilpacks but still seem to just crack over 300 to the tank.

[666DAN]

So are you saying your current R34 is a GT-T and drinks more petrol than your R34 25GT which was non-turbo??

NA R34 more fuel efficient than R34 GT-T??

I really want to get to the bottom of this as I am in the market for another R34 4Door NA or Turbo depending on these factors and price I can find one for....

Yeah my 25GT was great when it was in N/A trim, I was impressed as it was an auto as well which you'd expect poor economy from. My best ever average was 9.1L/100km...9.3L/100km was normal. This was a 3 year old car with only an aftermarket exhaust.

After the turbo went on and other stuff followed that number went out of the window though

[AYW550]

a couple of years ago, when my r34 gt4, with manual and four doors was completely stock the best i ever got on a tank of gas was

580ish km

that was on BP 91 and i filled it up to the point where it almost poured out onto the ground! and i drove a good 25 km after the fuel light came on, prolly 90 percent of those km's was on mostly flat highway and i drove very conservatively, but even if id been driving in town with alot of stop and go id always get somewhere btw 450-500km

also i think there is alot to be said for driving at 90kmh an hour versus 100-110kmh, but its awful hard to bare being passed on the highway!

now ive done quite a few mods while keeping it N/A and need a good tune-up so im not sure what my milage is like now

[FULOCK]

a couple of years ago, when my r34 gt4, with manual and four doors was completely stock the best i ever got on a tank of gas was

580ish km

that was on BP 91 and i filled it up to the point where it almost poured out onto the ground! and i drove a good 25 km after the fuel light came on, prolly 90 percent of those km's was on mostly flat highway and i drove very conservatively, but even if id been driving in town with alot of stop and go id always get somewhere btw 450-500km

also i think there is alot to be said for driving at 90kmh an hour versus 100-110kmh, but its awful hard to bare being passed on the highway!

now ive done quite a few mods while keeping it N/A and need a good tune-up so im not sure what my milage is like now

ok, 580k's on 90% flat hwy I can maybe beleive..... but 450-500km in town still to me sounds like a lot of km's..... was that peak hour traffic and no highway driving what so ever? and on Standard unleaded also!!!! WHAT THE!! HOW????

[Silver_GT]

Just a note to all;

Had the standard exhaust on my r34 for the past 2 weeks due to driving long distances to work. Fuel economy has improved quite a bit

so far ive managed around 540km before filling up, and it worked out to be 10.1L/100km

thats pretty good for an rb25 i rekon!

With the 2.5" Catback i managed around 11L/100km.

Edited August 24, 2009 by Silver_GT

[Turk1]

Well my average is like 15L/100km.....

[meadan]

best ive had in my rb25 powered r32 is 540km/tank. Majority was highway driving though