fuel economy

[jake32]

replaced leaking inlet manifold gasket on 260rs..fuel econ has gone from 17ltr per100k to a liveable 14ltr ..little happier with that..also fixed the rough idle problem.

:headspin:

[Sydneykid]

Good thread.  

I've been at this question for a while, as the one thing I like more than performance is  cheaper performance.  My stagea is stock except for a bleed set at 8 psi and a K&N panel filter. I have established that besides the weight of the car the auto is the main thing holding fuel economy back.  To get decent mileage you need to lock up the torque converter in 4th gear (ie: use the overdrive).  It will not do this until fully warmed up and seldom does it around town, contributing to the abysmally poor fuel economy you get under these conditions (hot weather, a/c on -18-20 l/100 km is not uncommon).  On the highway you can drive for miles without the converter locked up unless you do the following:  establish the cruise speed - say 100 - 110 km/h, then throttle back until you get 12-14 inches of vacuum , then gently press on the accelerator until your boost gauge reads 5-8 inches of vaccum, and then you should feel the converter lock up, after which if you modulate the throttle smoothly, you can drive it like a manual unless you go into boost, whereby the converter drops back off the lock up and your fuel economy suffers again.  I have obtained 500 km out of 60 L, which is 12L/100 km on the stock set up driving it in this manner, and well justified the purchase of the boost gauge to my wife in doing so.

However I noted that in very hot weather (towing a small tinny near gladstone), the auto goes away badly, indicating to me that a trans cooler is a must.  Upon fitting one (I used one out of an EVO 4 ($30 NZD !) and tucked it where the stock intercooler lives, but on the drivers side, keeping the stock trans cooler in its original position for a double whammy effect), fuel economy improved all over, and now the weather is cooling again, economy is better still (slightly leaner air/fuel ratio and cool trans fluid).  

I really want to do a  3" turbo back exhaust and intercooler now because anything that improves system efficiency must improve economy off boost.   Has anyone got "before and after figures" for fuel economy after these mods ?  Obviously a fuel computer would be the next best thing too...  I need the data to sell these things to my wife...

Thanks fellahs

Ben

Hi Ben, try this one....

It has been 2 months since I fitted and tuned the Jaycar IEBC and DFA at a cost of $150 in parts and $160 in dyno time. The around town fuel economy has improved from 16.5 L/100k to 13.3 L/100k, the cruise fuel economy has improved from 14.7 L/100K to 12.3 L/100K therebye saving me ~20% off my fuel bill. Average Optimax cost has been $1.12 per litre and I have used 585 litres in that period.

That means I have saved ~$130 in 2 months, and in 4.5 months I will have paid for the DFA and the IEBC and the dyno tune.

And that's with a STANDARD exhaust, wait until I put the 3.25" one on that is coming off the R32GTST next week.

Hope that helps remove the thumb screws:cheers:

[Ben D]

Thanks guys.

She's now sold on the idea . Thanks sydneykid I'll look up the jaycar equipment and Jay95R33, can you let me know what colour wire I should be looking for re: the lockup converter ? I have been interested in having a switch on the dash which manually locks up the converter when I'm on the highway, if I can locate the wire, I can always put a switch on it and test to see what it does. My guess is it would energise a solenoid in the gearbox.

Hey, has anyone had experience with the 3" downpipes sold by RZone performance ? http://www.rzoneperformance.com.au/

Their mild steel unit front and dump pipe for R33 is a bolt on and only $165, stainless $285. I like their 3" cats too for $165. Will these fit the stagea ?

Hi Ben, try this one....

It has been 2 months since I fitted and tuned the Jaycar IEBC and DFA at a cost of $150 in parts and $160 in dyno time.   The around town fuel economy has improved from 16.5 L/100k to 13.3 L/100k, the cruise fuel economy has improved from 14.7 L/100K to 12.3 L/100K therebye saving me ~20% off my fuel bill.  Average Optimax cost has been $1.12 per litre and I have used 585 litres in that period.

That means I have saved ~$130 in 2 months, and in 4.5 months I will have paid for the DFA and the IEBC and the dyno tune.

And that's with a STANDARD exhaust, wait until I put the 3.25" one on that is coming off the R32GTST next week.

Hope that helps remove the thumb screws:cheers:

[Ben D]

Hey Sydney kid, that Jaycar thread you've done with the details on how you tuned the DIY boost controller and air flow meter intercept is the best thread I have read on the web. Well done mate.

I have those bits on order now as from reading that you should be able to pull approx 15% fuel out of these things across the entire rev and load zones, which should translate into an immediate 15% improvement in fuel economy. I won't bother with a dyno, I'll road test and data log with a WBO2 wide band lambda plumbed into the downpipe once I get a 3" bolt on job. I'll post a separate thread asking about that R Zone performance piece, at it would be easy to buy one and add another O2 sensor boss to accomodate the wide band before installing it and voila, we're away.

Now my calcs , 15% improvement on 500 km/tank on the highway = 10.6 L/100 km, around 580 km/tank - hey I can live with that.

he he bought the boost controller too, will tell the wife that's part of the fuel controller..................

Will keep you informed.

Ben D

Thanks guys.  

She's now sold on the idea .  Thanks sydneykid I'll look up the jaycar equipment and Jay95R33, can you let me know what colour wire I should be looking for re: the lockup converter ?  I have been interested in having a switch on the dash which manually locks up the converter when I'm on the highway, if I can locate the wire, I can always put a switch on it and test to see what it does.  My guess is it would energise a solenoid in the gearbox.  

Hey, has anyone had experience with the 3" downpipes sold by RZone performance ?   http://www.rzoneperformance.com.au/

Their mild steel unit front and dump pipe for R33 is a bolt on and only $165, stainless $285.  I like their 3" cats too for $165.  Will these fit the stagea ?

[Lone]

Damn ill be interested on those dump pipes...

[Sydneykid]

I have yet to find a 3" cat that is truly "hi flow", there is "low flow", "piss poor flow" and "hardly any flow at all". I am now using the Magic 4" cat, it flows almost as good a straight through 3" pipe. Nothing good is ever cheap.

[r33fred]

in light of a recent trip in my staj, i thought i would see if anyone else has experienced crazy fuel economy figures at times.

normally i get 12 liters per hundred k's on average. this is ok, consisting of a mixture of city and country driving.

driving at 130 ish in the middle of a hot day with the ac on (for about 300 k's out of my 650k total trip), i took my average! economy for my trip up to 20 liters per hundred!!!

that seems a little excesive... anybody care to comment? perhaps the ac + 130 = bad fuel economy?? well... obviously, but that bad?  

(12 psi boost, exaust & pod)

Check your o2 sensor... There only good for about 60,000k... replacement is about $80... Shake the sensor, if it rattles inside then its stuffed. A non working o2 sensor can cost you about 100km per tank.

Should the ECU not register readings from the sensor then its goes into a bit oif a failsafe situation where it enriches the mixture and I think also maybe even retards the ignition timing slightly. .

[ICE12]

Is this O2 sensor a genuine item or who can we get them from.

Cheers ICE

[Lone]

You can use an aftermarket one witht he same amount of wires with no problems, just retain the connector from the old one and join it onto the new one..

r33fred: Ive never heard of the 'rattle' trick before? Who said this one to you because as far as I know theres no real way to test an o2 sensor other then on the car running..

[r33fred]

Remove it from the dump pipe and then shake it, if it rattles inside then its obviously stuffed. The O2 sensor on my mates stagea 4cefed @ 64,000k rattled inside and I replaced it.. I replaced one before and economy improved by about 100k per tank.

I got the 02 sensor from Automotive Service Solutions in Brisbane.. ph 07 3857 9500.... part number 23009 3 wire uni fit. @ $130 total includes freight. Has two whites and a black wire which u connect to the original 2 browns and 1 white... so two white wires connect to two brown wires and the black wire to the singular white wire.

Use a 22mm ring or open ender... short open ender is easier. Not hard to remove..

[Lone]

I dont know exactly why you would have a rattle in the o2 sensor unless some of the tip has broken inside, but as I said the only true way is to actually test the voltages on the car whilst running.

And I can supply these universal O2 sensors (NTK Brand [Japanese]) for around the $85 mark inc. GST

[jess]

Hi guys, before Jaycar IBC, DFA and a quick tune, 14.5 litres per hundred kilometres, after = 12.0 litres per hundred kilometres.  Hoping the exhaust will help some more.  

Hi there sydneykid

I have owned my stagea for about a year and have finally decided to boost it up but can only get around 8 psi. I was interested in how you boosted your stagea and what parts you used. Also on the fuel, I am getting around 440 per tank (long distance) two passengers, hot day with the air on just by fitting a fuel catylist. Hope to hear back from you soon. Thanks Jess Sydney

[Sydneykid]

Hi there sydneykid

I have owned my stagea for about a year and have finally decided to boost it up but can only get around 8 psi. I was interested in how you boosted your stagea and what parts you used. Also on the fuel, I am getting around 440 per tank (long distance)  two passengers, hot day with the air on just by fitting a fuel catylist. Hope to hear back from you soon. Thanks Jess Sydney

Hi Jess, have a read of the Jaycar IEBC and DFA thread, it explains everything.

[ian]

While I drive a slightly different car :-) - a R34 4 door GTX turbo - the fuel use figures should be within 13% or so (the weight difference) of a series 2 stagea..

- on that point, in the conversations above you should say always say which engine you have, as the neo version stagea could be a lot different to the non neo one!

On very long trips that I do (ie I drive 2000K in two days) I will get 10L/100km if I stay on 100km/h, 13L/100km if I sit on 125 to 135km/h, and 14L/100km if I'm also pulling another 400kg in a trailer (which would make the total weight 200kg heavier than a stagea).

In addition, does anyone know why the people with the auto gearbox are having the problems above? If it has (??) the same MAT gearbox that the R34 has, it is VERY efficient in getting into 4th gear - which is actually a HIGHER ratio than 5th gear is in the manual!

So some of the fuel usage figures above appear to be a little high!

[Sydneykid]

While I drive a slightly different car :-) - a R34 4 door GTX turbo - the fuel use figures should be within 13% or so (the weight difference) of a series 2 stagea..

- on that point, in the conversations above you should say always say which engine you have, as the neo version stagea could be a lot different to the non neo one!

On very long trips that I do (ie I drive 2000K in two days) I will get 10L/100km if I stay on 100km/h, 13L/100km if I sit on 125 to 135km/h, and 14L/100km if I'm also pulling another 400kg in a trailer (which would make the total weight 200kg heavier than a stagea).  

In addition, does anyone know why the people with the auto gearbox are having the problems above? If it has (??) the same MAT gearbox that the R34 has, it is VERY efficient in getting into 4th gear - which is actually a HIGHER ratio than 5th gear is in the manual!

So some of the fuel usage figures above appear to be a little high!

Our Stagea S1 (1997) RSFour (4wd) Auto RB25DET (non Neo) weighs 1694 kgs with a full tank of petrol and no one in it. It is a waggon, so it is about as aerodynamic as a house brick.

[r33fred]

I dont know exactly why you would have a rattle in the o2 sensor unless some of the tip has broken inside, but as I said the only true way is to actually test the voltages on the car whilst running.

And I can supply these universal O2 sensors (NTK Brand [Japanese]) for around the $85 mark inc. GST

Naturally you test for resistance or voltage, or carry out the self diagnostic just saying that if it rattles then its obviously U.S

[benl1981]

So there is fuel savings to be had with the DFA...

I get about the 11-13L/100 in my R33gtst manual. Hopefully maybe get it down to 10-11 with some tuning. With the prices of fuel these days it may pay for itself, plus some more power and less emissions

Say 15k per year. A saving of 1.5L/100kms is 225L which is Approx $250 or more on fuel.

Due you think a 1L/100km saving is achievable quite easy even on a manual R33? I guess you have to have a fairly decent tuner.

[m0dular]

Hey, top thread guys!

- on that point, in the conversations above you should say always say which engine you have, as the neo version stagea could be a lot different to the non neo one!

Are there different fuel economy figures between the neo and non-neo stageas?

Likewise, have the blokes who have done the manual conversion achieved better results?

I'm still researching which stagea is the best to buy & the threads at SAU are the best advice on the net for sure

[Sydneykid]

Wooohoo, got the Stagea into the 11's...........that's 11 litres per hundred k's. Combined city and highway driving.

[Jay95R33]

Well done SK, 11lt per 100km is pretty respectable. I'm still hovering around the 13lt per 100km with about 60% city driving, 40% highway.