Tuning Rb25S For Eflex And E85 .

[flying saucer]

did you have to change any fuel hoses on the car?

i recently changed all mine to these http://mrparts.com.a...product_id=1434 they are rated for E85 specifically

i got my e85 test tube just from ebay in the USA. none of the australian resellers of quickfuels bothered keeping them in stock

[discopotato03]

Round tripped Canberra yesterday to get TechEdge to mod my box cable and supply and calibrate the 4.9 sensor .

I had it in today and it does heat faster and the readings are slightly leaner than the original sensor showed . I got out on the M5 to check the higher (legal) cruise mixtures and they float around 0.98 - 1.00 lambda.

Something I've noticed with Eflex E70 is that lean mixtures under load cost power/torque but my engine doesn't detonate . It doesn't make good poer on boost much above 0.95 lambda , it likes 0.9 much better and on full load the settings I use ramp down to 0.85L and even 0.82 at times .

I was having a few off idle and very low rev drivability problems and the answer seems to be having idle mixtures in the 0.99 to 1,02 area and accel enrichment on the PFC in the 1000 rev area set to I think 3.4 amd sustain at around 0.7 to 0.8 . Sometimes it still gets a bit twitchy if I back off at 15-1600 and slightly open the throttle again , mixture shows slightly lean with this .

Its probably now almost as good as I can get it with my limited tuning skills and a little more experimenting may improve drivability and consumption a little .

A .

[discopotato03]

No it seems I keep advancing timing in areas and it continues to get better . I know this Eflex is slow burning but how much idle and very low rev timing can an RB take ? Its idling on 22 degrees atm and the whole left ignition timing column (400 revs) is 18 degrees .

I'm getting a bit braver with timing and advancing in increments the 2-5000 rev sections which are 40 degrees at the top ranging down to 25 .

I don't have the wide band in all the time because the cable has to go out the window to get to the oxygen sensor . It would be better if it went through the firewall and was permanently installed .

The thing I don't like doing is starting up until the probe is up to temp though its probably not such an issue with high ethanol content fuels .

Anyway most of my interest currently is getting smooth running and acceptable round town consumption .

I'm interested to hear what others are getting around town on a really good tune . Driven sensibly is 400 km/60L achievable ?

One question and I haven't looked yet . Can you select at what revs the decel fuel cut ends because I'm having a few drivability issues when it starts fueling again at ~ 1300 revs . Lower would be better .

A .

Edited September 5, 2012 by discopotato03

[GTSBoy]

There's little point in running extra advance at idle.

[discopotato03]

I think its a case of starting the fire earlier with a slower burning fuel so the pressure rise happens when it does the most good . I reckon theres more to alcohol fuels than meets the eye and it goes away from petrol tuning practices . I'm not saying that extra advance at idle is necessarily the go but a stable ide is a good thing .

I'll see if I can cut and paste part of my timing map , just don't laugh because I'm a beginner .

A .

20 22 27 30 38 40 40 40 40 40 40 40 40 40 40 40 40 40 30 30

20 22 27 29 38 40 40 40 40 40 40 40 40 40 40 40 40 40 30 30

20 22 27 32 38 40 40 40 40 40 40 40 39 38 37 34 34 34 30 30

20 22 27 33 38 40 40 40 40 40 40 40 38 34 33 30 30 30 30 30

20 22 28 34 38 39 40 40 39 40 39 39 38 34 33 30 30 30 30 30

20 22 26 33 36 38 39 40 38 39 36 39 34 33 33 30 30 30 30 30

20 22 25 32 34 36 37 38 37 37 36 36 33 29 29 28 28 28 28 28

20 22 25 31 33 33 33 33 33 33 33 35 33 31 31 30 30 30 30 30

20 22 25 31 32 32 32 32 32 32 32 33 33 31 31 30 30 30 30 30

20 22 25 28 31 31 31 32 31 31 31 32 32 31 31 30 30 30 30 30

20 22 25 27 30 30 30 30 30 30 30 30 30 30 29 29 29 29 29 29

20 22 25 27 29 29 30 30 31 30 29 29 30 30 29 29 29 29 29 28

20 22 25 25 26 26 28 28 29 29 28 27 27 27 26 26 27 27 27 27

20 22 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25

20 22 25 25 25 25 25 25 25 25 25 25 25 23 22 22 23 23 23 23

20 22 25 25 25 25 25 25 25 25 25 25 25 22 21 22 23 23 23 23

20 22 24 24 24 24 24 24 24 24 24 23 23 21 21 22 23 23 23 23

20 22 24 24 24 24 24 24 24 24 24 23 23 21 21 21 22 22 22 22

20 22 24 24 24 24 24 24 24 24 24 23 23 21 21 21 22 22 22 22

20 22 24 24 24 24 24 24 24 24 24 23 23 21 21 21 22 22 22 22

Edited September 6, 2012 by discopotato03

[AngryRB]

i think im getting around 350km per tank, i was getting upto 450km with the 98,

Its on the rich side id say because its tuned for varying content with just a power fc

if its helpful i could try and paste a copy of my map for you..

Edited September 6, 2012 by SliverS2

[discopotato03]

yep , I'd like to see what others use in the way of numbers .

A .

[AngryRB]

my map looks similar to yours, but i have 15 in the first few columns and in the middle where you have 40 , i have upto 44

[Piggaz]

did you have to change any fuel hoses on the car?

i recently changed all mine to these http://mrparts.com.a...product_id=1434 they are rated for E85 specifically

No you don't. This stuff doesn't make your car melt to the ground in a pile of jelly like the internet rumours would have you believe!

[ARTZ]

My around town stop start fuel economy ain't so great..only 250-300kms a tank at best..but I have an as yet, unsorted idle issue

But, my on track economy is very good, and a highway run netted me 350kms for 45lt..which is pretty good I think.

I then filled up with pulp with 15 or so litres of e85 in the tank..switched to my petrol tune which from memory is slightly rich anyway and my afrs were only slightly leaner than on e85 and nothing to worry about ,no pinging..that's running closed loop as well..

[discopotato03]

Interesting , I'm finding that being up around 18 and 22 degrees made a big difference to my cars low speed drivability though I do have to stick the wide band back in and check the mixtures because timing changes can effect AFRs .

I tend to think that a reasonably well designed 4 valve engine with pent roof combustion chambers can take more low speed and light load timing because they tend to burn more efficiently and have reasonably small chamber volumes . 15 degrees isn't a lot before top dead center and if the fuel is a slow burning one like ethanol I think its possible to start the fire earlier and 18-20 degrees worked ok for me .

My guess is that being around stoi (lambda 1) is where the mixtures need to be to make in burn cleanly which should help drivability - and to a degree consumption . Its always a juggle setting the fueling for steady state and accel for the transients . Mine feels about right at start/slow speeds meaning gradual throttle openings but not 100% if you open the throttle quickly in 1st gear or if you move off back off and open again . I think its to do with how and where a PFC goes from closed throttle fuel cut to injecting again . Also I probably need to stick some throttlebody cleaner in it to remove any carbon round its plate and clean out the idle bypass housing again .

I'm finding with advanced timing and around stoi my engine makes good part throttle torque and I can pull higher gears in many places which helps with consumption .

I think you get a lot more leeway with E70/E85 meaning it can be a bit rich or lean but unlike petrol it wont carbon the engine up or eat things as easily if its leaninish . Not sure about being lean at high loads but I don't aim to go there myself .

I'll show my fuel map as well but remember that I'm using Nismo 740s and 48% in the injector correction settings .

A .

1.039 1.039 1.035 1.035 1.023 1.023 1.023 1.023 1.023 1.027 1.027 1.031 1.031 1.031 1.031 1.031 1.031 1.031 1.031 1.031

1.035 1.035 1.035 1.035 1.027 1.023 1.023 1.023 1.023 1.027 1.027 1.031 1.031 1.031 1.031 1.031 1.031 1.031 1.031 1.031

1.035 1.035 1.035 1.035 1.027 1.023 1.023 1.023 1.023 1.027 1.027 1.031 1.031 1.031 1.031 1.031 1.031 1.031 1.031 1.031

1.035 1.035 1.035 1.035 1.027 1.023 1.023 1.023 1.023 1.027 1.027 1.031 1.031 1.031 1.031 1.031 1.031 1.031 1.031 1.031

1.035 1.035 1.035 1.035 1.027 1.027 1.027 1.027 1.027 1.027 1.027 1.027 1.027 1.152 1.199 1.297 1.297 1.297 1.297 1.297

1.035 1.035 1.035 1.035 1.035 1.035 1.031 1.031 1.031 1.031 1.031 1.031 1.031 1.199 1.199 1.297 1.297 1.297 1.297 1.297

1.035 1.035 1.035 1.035 1.039 1.039 1.035 1.035 1.035 1.035 1.035 1.035 1.063 1.254 1.297 1.297 1.297 1.297 1.297 1.297

1.035 1.035 1.035 1.035 1.043 1.043 1.043 1.043 1.043 1.063 1.063 1.063 1.152 1.270 1.297 1.297 1.297 1.297 1.297 1.297

1.035 1.035 1.035 1.035 1.047 1.047 1.063 1.063 1.063 1.063 1.164 1.180 1.199 1.270 1.297 1.297 1.297 1.297 1.297 1.297

1.035 1.035 1.035 1.035 1.051 1.102 1.145 1.148 1.148 1.148 1.148 1.199 1.238 1.270 1.297 1.297 1.297 1.297 1.297 1.297

1.035 1.035 1.035 1.035 1.109 1.160 1.203 1.203 1.203 1.238 1.238 1.238 1.238 1.270 1.297 1.348 1.348 1.348 1.348 1.348

1.035 1.035 1.035 1.051 1.109 1.164 1.203 1.203 1.223 1.238 1.238 1.238 1.238 1.273 1.297 1.348 1.348 1.348 1.348 1.348

1.035 1.035 1.035 1.051 1.109 1.164 1.203 1.203 1.238 1.254 1.254 1.297 1.297 1.340 1.348 1.348 1.363 1.363 1.363 1.363

1.035 1.035 1.035 1.059 1.109 1.164 1.203 1.203 1.238 1.254 1.254 1.348 1.363 1.363 1.379 1.438 1.453 1.453 1.453 1.453

1.035 1.035 1.035 1.059 1.109 1.164 1.203 1.203 1.238 1.254 1.254 1.375 1.379 1.414 1.453 1.469 1.469 1.469 1.469 1.469

1.035 1.035 1.035 1.059 1.109 1.164 1.203 1.203 1.238 1.254 1.254 1.398 1.398 1.430 1.453 1.469 1.469 1.469 1.469 1.469

1.035 1.035 1.035 1.059 1.109 1.164 1.203 1.203 1.238 1.254 1.254 1.398 1.398 1.430 1.484 1.484 1.484 1.484 1.484 1.484

1.035 1.035 1.035 1.059 1.109 1.164 1.203 1.203 1.238 1.254 1.254 1.398 1.398 1.430 1.496 1.496 1.496 1.496 1.496 1.496

1.035 1.035 1.035 1.059 1.109 1.164 1.203 1.203 1.238 1.254 1.254 1.398 1.398 1.430 1.496 1.496 1.496 1.496 1.496 1.496

1.035 1.035 1.035 1.059 1.109 1.164 1.203 1.203 1.238 1.254 1.254 1.398 1.398 1.430 1.496 1.496 1.496 1.496 1.496 1.496

Edited September 7, 2012 by discopotato03

[GTSBoy]

Just a tip. It's "stoich", pronounced with a k sound at the end. Short for stoichiometric.

Edited September 8, 2012 by GTSBoy

[AngryRB]

certainly is awesome fuel, my tuner was laughing how easy it was to tune, put 6degrees extra on the whole map and knock levels have never gone over low 20's on the power fc, even with 3 adults up a steepish hill 3rd gear full throttle.. just amazing.

the V8 boys came in to see what was doing.. they reluctantly gave a nodd to the results..

Edited September 8, 2012 by SliverS2

[discopotato03]

I had a minor driveability win today when I found out what the PFC idle speed parameters meant , the main one was the fuel cut revs for electrical load and no load . My idle speeds load/no load are 850 and 700 and the fuel cuts are set to 1050 and 900 .

I'm curious to know what others are using for their GTS25Ts , cheers A .

[AngryRB]

i think your refering to the rev/idle part of the menu..so heres mine for you

rev limit ....6900

1100

1200

800

850

[discopotato03]

I set the fuel cuts lower because I was getting a bucking kicking thing going on when the injectors resumed at 11-1200 revs . I have a lightened flywheel and I was blaming some of my issues on that though now I think its not the case . My car had an annoying habit at very low revs of going crazy because it wouldnt drive and wouldn't stall and it could get quite violent backlash in the driveline .

I wasn't quite sure about the four settings above as in were some of them cold idle ups and or fuel cut resume speeds . Anyway after searching I found through wiki of all places what they were in a Skyline L Jet PFC so now I can set up as I like .

Also my car idles fine at 700 and if anything the no elec load fuel resume could possibly be set even lower ie 800-850 because it works fine for me even with the light flywheel .

A .

[AngryRB]

interesting , my car does have the bucking symptoms your talking about, around 1500rpm somtimes it will get quite jerky,its when im very light on the throttle trying to keep it in say 4th gear, i spoke to the tuner and on two occasions he played around with the maps while on the dyno, he was of the view that the poncams could be doing it, but also the TPS setting which was adjusted and the jerking is still there.. so would be interested to know eactly how you fix it .

[discopotato03]

If you have Datalogit change your fuel cut resumption settings to lower revs . I think the problem is that the engine tries to "come alive" at that resumption point and the IAC and small throttle settings fight for control of engine speed . If the engine gets no fuel down to say 900 revs with the throttle shut it wouldn't matter what the IAC valve did because theres nothing to burn in the cylinders .

I was finding my RB had reasonable pull at 1300 revs especially when I didn't want it to . I still have to stick the wide band back in to look at the mixtures because I had been trying different things with timing and fueling in this 8-1200 rev area thinking is was something else .

I have to read through the Co Pilot thread here to see if its worth looking into .

Cheers A .

Edited September 23, 2012 by discopotato03

[Race__24]

i think your refering to the rev/idle part of the menu..so heres mine for you

rev limit ....6900

1100

1200

800

850

From memory

6900 - rev limit

1100 - fast idle. when you back off the engine will sit at this RPM for a couple of seconds before going back to idle

1200 - Injector pickup, ie. when you back off the injectors cut out untill this RPM

800 - idle speed

850 - air con idle

If you increase the 1200 to say 1300 you will notice that when the revs drop they will come down softer, ie. the last 200 RPM will be more gradual. Adjust this if it seems to be overshooting too far below the fast idle.

I could have the 1200 and 1100 around the wrong way, it has been 5 years since I've touched a PFC. It is very easy to figure out when you know what to look for

Edited September 24, 2012 by Race__24

[discopotato03]

I think its more a case of knowing what they mean as in elec load vs no elec lod load fuel resumption revs and elec load vs no elec load idle speed .

I had the Tech Edge wide band back in mine today and as I thought it was running a little lean in the light load low to medium engine speed areas .

I richened up the very low engine speed areas when loaded ie 400 and 800 rev colums at higher airflow rates . Thhis makes the idle torquier and less likely to stall with very small throttle openings when moving off . With the fuel resuming at 12-1300 revs nothing I did fixed the bucking kangarooing problems I had .

ATM I'm idling at 1.01 - 1.02 Lambda but it can go lean towards 1.08 at hot restarts which doesn't give any drivability issues . Light load cruise is around 0.98 to 1.00 L . As the load ramps up its falls to 0.95 and around boost it gets into the 0.92 to 0.85 range . If I go WOT as it comes on boost it gets to 0.80 L and I had to look up petrol L/AFR to see what it equates to .

To save you looking the tables I found show this

Lambda .....Petrol AFR .... E85 AFR

0.75 ...........11.03 ............. 7.32

0.80 ...........11.76 ............. 7.81

0.85 ...........12.50 ............. 8.30

0.90 ...........13.23 ............. 8.79

0.95 ...........13.97 ............. 9.28

1.00 .......... 14.70 ............. 9.77

1.05 .......... 15.00

I'm getting a better handle on what the E85 Lambda numbers mean but I had to go back and search for some petrol Lambda numbers to see what the corresponded with in petrol AFR . I did go to start a new thread on Lambda vs AFR but I didn't think too many would be interested a didn't post it .

Something I would be interested to knoe is Lambda numbers with E70 because most of the tables and calculators only show E85 and Lambda = 1 or 9.77:1 AFR . Logically E70s chemically correct mixture would be a slightly higher AFR number because of its higher petrol content .

The difference wouldn't be huge but if we could gain a slight consumption edge thats not a bad thing .

Just on cost I love paying $1.15.9 for Eflex when its cheap compared to Ultimate 98 at $1.70.9 when its not . I think in rough terms I'm paying 2/3 the price of Ultimate was a while back and getting 3/4 of the consumption I used to get though my petrol tune wasn't real good . Eventually I will go back to Ultimate just to clean my petrol tune up but overall I prefer the Eflex E70 .

Ongoing , cheers A .