Rb30det Fuel Consumption

[Cubes]

I've just redone my light/moderate load ign. and afr's...

Should be interesting next tank, the ignition has actually made quite a difference to how the car feels off idle, prior accelerating from a standing start in second would have it bog for a fraction of a second, now it simply accelerates without bogging.

I've got a real strange issue around 2000rpm as the turbo tries to make more than a few psi, it appears to bog, boost goes up, afr reading goes way lean then as soon as it gets over 2000rpm it clears its throat and acceleartion literally snaps on.

I'm assuming this may have some thing to do with the n/a cams running around 8degree's overlap and such a small turbo.

Nothing I do will get rid of it, super rich afr's, lots or little ignition timing or a mixture... Buggers me.

[jazza08]

Question... i have rb20 wit z32 afm/gtr injectors and im gettin 300ish kms to a tank, i had standard injectors and afm and got around the same, isn't that abit sh*t for an rb20?? I would like some fuel economy but if i cant have some decent hp and economy, well i did buy a car with a turbo n id understand lol Ive just seen some figures off rb20s and even rb25s that blow me away, even with i baby the motor!

Edited July 28, 2006 by jazza08

[Cubes]

Its all about maintaince, I'd also have to say (in my case) it doesn't have so much to do with tuning as on the base pfc maps with z32 and gtr injectors & the 3ltr I was pushing 440km's per tank.

The only time i've dropped to such fuel economy levels is when my injectors were shagged, the o2 sensor was still ok but definitely a tad slower than the new genuine o2 sensor I replaced it with.

So as I believe I've said before...

Check for vacuum leaks, ensure o2 sensor and injectors are in good condition and motor in good condition.

And drive sensibly, short shift around 2500rpm and use a little more throttle to get the car moving, driving like this its also critical your tuner doesn't have the afr's dropping to flat 12's as soon as any boost is made.

From factory my rb20det driving as such would hang in closed loop until roughly 2psi was being made, so it was running lean, possibly why it consistently returned just under 500km's to a tank.

But as with everything there are bad cars and good ones... Its just finding what is causing the problem. R33's suffer the poor fuel economy problems much more often than the R32's, its not displacement as I've noticed no real noticable difference and i'm 1ltr over a 2ltr.

[mr_rbman]

mmmm, i'm down to about 300 kms per tank, might have to get you to have a look at the values tonight joel if we get time!

[jazza08]

Hmm injectors are brand spankin and no leaks, may replace the o2 sensor when it gets another tune next week!

[Cubes]

If your running the stock ecu throw it in diag mode o2 sensor check, then drive it and ensure it meets the high/flow frequency as stated in the engine manual.

Check for vacuum leaks.

[jazza08]

Ahhh cheers

[FORZA-MOTORSPORT]

Im getting 440k's per tank at the moment when crusing, not sure when pushing her hard

[T04GTR]

cool.

26+t04z+crap throtle over map tune = 20-25L/100K

highway =10-13L/100k

[nicksamaniac]

Most of you guys are getting good economy! My 25/30 is running 19/100km no matter how I drive.

That's on a 25 tune @5psi. On the wideband it shows 14.5-15.8 in closed loop but gets right up to 11.1 at wot.

Will hopefully get better when I get my pfc and sard 800cc fitted and tuned.

[Piggaz]

8 year bump. Fark yeah!

[Blackkers]

lol 8 year old thread

[discopotato03]

I think the roads to good economy are CR injectors and gearing . An RB30 with at LEAST 9.5 static CR should make real good part throttle torque . I also think good injectors like EV14s help heaps because they have fine control (if tuned properly) at short pulse widths .

Most R series Skylines were geared to suit the std RB20/25/26 and Japanese roads , depending on the lump you removed the gearing can be pretty short for a 3 litre . I don't think any turbo R series was taller diff wise than 4.1 and a 3.9 would allow you to better use the extra part throttle torque . Note the difference in rear gearing between some JDM and some Aus spec S series cars , 4.1 to 3.7 in one case from memory .

Lastly and very importantly , turbine back pressure . If the turbine/housing combination is small this hurts consumption too .

A .

[KiwiRS4T]

I think the roads to good economy are CR injectors and gearing . An RB30 with at LEAST 9.5 static CR should make real good part throttle torque . I also think good injectors like EV14s help heaps because they have fine control (if tuned properly) at short pulse widths .

Most R series Skylines were geared to suit the std RB20/25/26 and Japanese roads , depending on the lump you removed the gearing can be pretty short for a 3 litre . I don't think any turbo R series was taller diff wise than 4.1 and a 3.9 would allow you to better use the extra part throttle torque . Note the difference in rear gearing between some JDM and some Aus spec S series cars , 4.1 to 3.7 in one case from memory .

Lastly and very importantly , turbine back pressure . If the turbine/housing combination is small this hurts consumption too .

A .

That's why I am still looking for an R34 GTR non v spec diff (3.545) not just for the fuel economy but more for more restful cruising at 110km/hr

[Ben C34]

Nick, isn't your in a patrol? The extra weight would make a huge difference.

I am getting just over 13 driving to and from work mostly (12ks each way) with my auto rwd Stagea. I have been meaning for ages to tweak all of the cruise section of my tune but still haven't.

[KiwiRS4T]

Why are you getting Sard 800 injectors? They won't help your economy. Are you going for 500KW?

[nicksamaniac]

800s because they come up cheap, New still sealed in box's for $200.

If something better Sized shows up for sale I'll get them, I really only wanted bigger than stock- like 400-500cc

Yeah it's in a patrol, on 35s and 6in lift so she's pretty aerodynamic!

And it has 4.94 diffs.

It does 2550rpm at 100km.

And it weighs 2200kg, probably bit more with a full tank.

Edited March 22, 2014 by nicksamaniac

[nicksamaniac]

My 4wd Stagea manual does exactly 13.5l per 100 regardless of hwy or city.

My old turbo single cam rb30 patrol did pretty much 14-15 per 100, with a vl turbo tune, on 33s with 4.11 diffs.

[nicksamaniac]

Why are you getting Sard 800 injectors? They won't help your economy. Are you going for 500KW?

500Kw at least!

I want to be able to lift a wheel whilst overtaking at 100km/hr!

But more seriously I was just gonna put it on the Dyno and lean on it (to a safe enough level) and see what it makes.