Home Tuning Vipec And Link G4 Skyline Plug In Ecus Thread .

[Dale FZ1]

I believe the Vipec doesn't show lambda values, just the petrol-specific AFR calculated off lambda. If that's the case, the target AFR is way too rich on cruise for sure.

Adrian if you wanted to eke out the absolute best fuel consumption then I'd recommend setting it up for closed loop lambda. An alternative is to spend time logging and reviewing what the thing is doing. Over time you can get the fuel table nearly spot on and forget having the wide band sensor installed fulltime.

Either way, it looks like there is some work to do.

[Lithium]

He has closed loop lambda on, going by the screen shots.

[Dale FZ1]

The trick with the Link is the actual AFRs aren't necessarily what are in the target table, plenty of people disregard that table completely - however I set up my fuel table as much as possible like a VE table and enable "Open Loop AFR" and make sure the AFR target table a very reliable indication of what actually happens as it makes tuning way easier

^^ Agreed, and echoing my views above

Edited December 3, 2013 by Dale FZ1

[discopotato03]

Thanks for the feedback , my wideband (Tech Edge WB3A2) reads lambda and I kind of wish the Vipec did too . Surely this is an option .

Now , this car spends most of it's time round the burbs so I don't get much of a chance to drive on the open road - meaning better than 80 posted limits . However I did get out towards Campbelltown on the freeway the other day and the TE was reading around 095L but going rich at times with slight throttle movements . It's the transients I'm trying to get right particularly at the boost thresholds .

That AFR target table was set on the rich side in recent times to get around drivability problems , now that the lowish boost area issues are not so bad I'm starting to lean out these areas and that should make a difference . It may sound silly but I sometimes set the target AFR table to a point and note the amount of correction and make alterations to the active fuel table . Also the timing table to try and home in on best torque "feel" . Trial and error is all you can do without a dyno .

Yep more to do , cheers A .

Edited December 4, 2013 by discopotato03

[Lithium]

Thanks for the feedback , my wideband (Tech Edge WB3A2) reads lambda and I kind of wish the Vipec did too . Surely this is an option .

Now , this car spends most of it's time round the burbs so I don't get much of a chance to drive on the open road - meaning better than 80 posted limits . However I did get out towards Campbelltown on the freeway the other day and the TE was reading around 095L but going rich at times with slight throttle movements . It's the transients I'm trying to get right particularly at the boost thresholds .

That AFR target table was set on the rich side in recent times to get around drivability problems , now that the lowish boost area issues are not so bad I'm starting to lean out these areas and that should make a difference . It may sound silly but I sometimes set the target AFR table to a point and note the amount of correction and make alterations to the active fuel table . Also the timing table to try and home in on best torque "feel" . Trial and error is all you can do without a dyno .

I think the new Link+ family can do lambda. If the going rich moments aren't excessive and it will be on the dyno soon then don't fret too much, acceleration enrichment will get involved in that and you have to find a balance. Again, steady state tuning on a dyno makes life a crap load easier - if you can assume the base map is suited to the engine's efficiency with no other intervention then you can fine tune accel enrichment etc on a post-dyno road tune to get it looking and feeling right.

I've used closed loop lambda corrections as an indicator for road tuning, too.

[89CAL]

I thought the Techedge could output an analog signal to corrospond with AFR in a stoich ratio.

Although I may be thinking of another brand of wideband.......

[discopotato03]

Waste gate duty cycle table .

A .

[discopotato03]

Shortened version of PM to Mr Lith .

AFR target table altered but my engine does not cope with indicated stoi or 1 Lamba mixture . With a bit of stuffing around I got it to work acceptably between 0.90 and 0.98 L and it feels 95% as good as it did with slightly richer mixtures . Basically it doesn't dip into the 8s nearly as easily as it did .

AND , for the record , I DID try mixture ratios in the 9s when the plug in was first fitted and tuned and they felt terrible . I think the issues were inlet cam switching settings which I changed and more recently the low end of the closed loop boost control - basically let the turbos actuator do its own thing initially .

This is what the AFR target and active fuel tables look like now .

Next step is to have a fiddle with accell and where the AF target table dips into the 13s , then see what the consumption is like .

A .

Edited December 4, 2013 by discopotato03

[wolverine]

Are you running closed loop?

When you say it runs terribly what do you mean? Something hinky is going on if the car runs poorly at stoich on light load.

[Dale FZ1]

I'm puzzled by the Y axis scaling.

Why have such small increments?

The ECU you are running has IMO got a VERY good capacity to interpolate between points. You can achieve smooth progression into richer target AFR as loads increase.

I have trialled maps that use heaps of load points not that dissimilar to your screen shots. It just created a LOT of needless work poring over datalog streams as I trialled different cell values in the fuel map. I discovered things became much easier when I moved to wider gaps in the scale. Just my experience.

As per Wolverine's comment, something appears odd if it doesn't feel happy going near stoichiometric AFR. You have got non-standard cams. Were they degreed when installed?

[discopotato03]

Latest update , went for a spin down the Princes Hwy this evening for a bit of open road tuning and my maps now look like this .

With a full tank - to the neck - I went down the expressway with a quick stop at Waterfall The Burg and Dapto to dial a few things in . Last fiddle was at Albion Park before this lappy ran out of volts and amps . Then back to the servo at Gymea to top up - to the neck . ODO said a hair over 157 km and the pump said 21.26L which crunches out to 13.54/100 .

On a feathered throttle this thing now cruises , on the level , at ~ 0.96 to o.98 Lambda which are numbers I didn't think I'd ever see . BTW the fiddles along the way weren't just to the AFR target table , a bit on the fuel table and a tad more timing in the 50-70 Kpa absolute ranges in the 2600-3000 rev areas .

One thing that did help the cause was reviewing the closed loop AFR conditions , I wasn't real happy about the live results I got once the manifold pressure went positive . It had been set to go open loop at 110 Kpa abs and I reset it to 100 because I don't think I need closed loop control on boost . MUCH better as over atmospheric the AFR drops to about 0.87-88 Lambda which feels good . Sailed up Mt Ously at 80-85 in 5th and pulled like a train . This is at around 22-2300 revs and where I used to get boost issues .

For those that asked , I'm not sure if you can build a larger AFR target table because I agree a few more rows would be good . Note I changed the pressure axis numbers in the top three rows .

Anyway consumption getting better for ethanol and it will be interesting to see what it gets round town .

Cheers Adrian .

[discopotato03]

Don't really know why it didn't like stoic at light loads though it was running the top of the target map at 50 kpa abs before I changed it . It had flat spots so the feel good factor was a fail . I can try again with a tad more timing in the flat areas . Possibly in a slow turning engine with a slow burning fuel and low dynamic compression it needs more timing there .

Yes Andy it runs closed loop 02 correction .

I think there may be an issue when tuning these boxes and that's having enough resolution to cover the whole pressure range in the AFR target table . If you use the auto tune to map the on boost areas with fine resolution it may not leave enough for the below atmospheric range , and I'm only using atmo and lower pressures in closed loop anyway . It's something I'll ask Scott when I see him . I'm probably not running the latest firmware update so maybe a few things have changed in revisions , don't know .

Cam timing not sure . I do know that head was machined before I got it and was decked again when Harris did their thing on it . There is a chance that the timing is retarded because of the deck height changed but I think they would have mentioned it if it were a problem . My engine has some of the same things done to it as the the SK RB25 though my bottom end is original . I'm pretty sure Gary had an adjustable inlet cam pulley on theirs and I must ask him about that . I think he has the gadget you need to make the exhaust cam side adjustable as well .

Very sorry I didn't know the Neo 25 differences back then because if I had my time again I'd have done a Neo or Stag head because I think the chamber and piston crown revisions would have coped better with lean emissions friendly - from the factory point of view - mixtures .

Slightly shorter timed and higher lift cams would have been good too , Poncams would have been a given .

Thanks for the continuing feedback , cheers Adrian .

Edited December 4, 2013 by discopotato03

[Dale FZ1]

Poncams might be "drop in", but the importance of having cams that are correctly degreed is widely glossed over. The engine might be performing "adequately" or even "good", but having those sticks in exactly the correct position will make a difference to overall efficiency and best torque for a given tuning strategy.

I understand you are trying to eke out the best consumption for a given amount of mumbo. The target AFR from 100-120kPa absolute just looks too lean for my liking. Try richening it up a small amount there eg 0.2 AFR points. The thing needs fuel as it comes into boost as you make it pull up those inclines in higher gears.

Ignition mapping just looks way too conservative - "nice" on petrol but you're tuning for alcohol fuel and its advantages. While you're experimenting, add 4-5 degrees everywhere above 1500rpm and below 150kPa absolute.

[discopotato03]

Yesterday I made up a modified AFR target table with more resolution in the 40-100 Kpa absolute area and it gets the very light load areas into the 0.97-1.00 L range . It seems to cope well enough like this and I'm shooting for 100 or better km from 1/4 tank (13.75L/100) and I'll find out tomorrow .

I modified this target table again inching the pressure rows higher but I have not tried that one yet due to destroying an expensive tyre and getting it replaced . This second fiddle includes a bit more timing in the 2-4000 area because it may be a bit conservative there .

I'm curious to see if ethanol copes with leanish and advanced settings - and still "feels good" .

These are current and next try target and timing tables .

A .

Edited December 6, 2013 by discopotato03

[discopotato03]

Not 100% sure but I think I'm now getting more like 14/100 or a tad better ATM round the burbs . I've noticed at times that the water temps can be a bit higher and can't smell as much ethanol from the exhaust . It seems you can get more heat from this fuel in part throttle use but I'm really stumbling in the dark timing wise . I've no idea how much is right and if the exhaust gas temp can get too high .

At this stage an EGT probe pre turbo would be handy , cheers A .

[scotty nm35]

The exhaust temp can run very hot on e85, I have seen 700c+ on cruise. Always handy having a pre turbine temp gauge, it stops the tuner blaming high exhaust temps for not leaning on the boost some more.

[discopotato03]

I'm having a go at using a bit more timing in the sub atmospheric area 2-4000 revs . It floats around in the 30s now and doesn't seem to drive too badly . It's hard to tell how much is too much and all I can do is try feel more or less torque and any less throttle for the same torque . The fact that the mixtures change slightly with timing changes proves altered combustion but trying to home in on sweet spots is a bit hit and miss . The 02 feedback and trimming percentages are interesting to watch .

Coolant temps are sometimes a bit higher like going uphill at lowish revs and high gears so the EGTs must be up at times too .

Beyond the scope of this thread but I'd like to know how much of a difference it made when Nissan went to more compact chambers and flatter pistons in RB25 Neo turbo engines . To justify what they did the R33 spec RB25DET probably wasn't going to cut it emissions wise with leaner mixtures and detonation avoidance in the later 1990s .

A compact chamber would have a bit less surface area as would a flatter piston crown so maybe a bit less heat absorption , maybe better water jacketing around any hot spot areas as well . If I was going from scratch I'd do a Neo 25 for sure .

A .

[ARTZ]

end of the 90s was when we really started to see higher octane petrol on the market too so no doubt the engines changed accordingly..

[Dale FZ1]

It's a bit hard trying to second guess EGT based on slight variations in ECT on a hill, except perhaps if the engine was heavily loaded for a decent period of time. Airflow and thermostat cycling can have a decent impact here.

Get a pyrometer - you should even be able to use the thermocouple's output as a datalogging input for the ECU.

Have you attempted datalogging, and reviewing the information stream? That cuts out a lot of guesswork.

Also can you share any lessons (presumably... ) learned from the Vipec forum or the help functions in your software? Be good to hear a little input from your use of those resources.

[discopotato03]

I bashed out a different response , Dale , but deleted it afterwards .

Basically no I have not been to Vipecs forum for ages and there wasn't many Skyline people there at the time . The Help section is good but doesn't often answer questions on tuning specifics , too many variables .

No the answer for me was to go back through Guilt Toys threads on E85 and his Vipec install and tune . There are lots of useful pointers particularly in the E85 threads regarding AFRs and timing . The biggie for me was lower EGTs with ethanol than 98 when tuned lean for consumption . Also 30 pages in he mentions in that his car liked 13.2 AFR at idle , will try that .

I know he had a lowish CR RB30 and a 1.06 AR GT3582R but I think trends would be sort of similar in an RB25 , cruse and in the burbs stuff I mean .

I'm now braver with leaner AFRs particularly in the 2500-4000 rev area but the 1500-2000 areas are creeping up as well . As long as the drivability remains I'll keep slowly leaning in light load areas .

One area I need to play with is the closed loop enabled parameters - MAP and TP deltas because they are set at 2kpa and 2 degrees which is 3/5s of 5/8s of SFA . If it switches out at very small transients then that could be causing slight rich spikes with very small throttle changes opening and closing . It makes the correction system work a little harder to maintain constant AFRs at fast cruise .

We need Guilt Toy back in Oz !

Cheers A .