RB25DET NEO Tuning

[AUSBen31]

Hey guys,

New to the forum have been messing around with nistune for a bit and reading alot about it. Have a few questions to pretty much figure out whether im capable of tuning it or not (i have complete access to a dyno/wideband/map reader ect. Mainline 2WD.

So i put an RB25det NEO into my R31 about 3-4 months ago, specs of it

- Standard head rebuild, new head gasket + headbolts, all seals replaced ect
- 21U highflow GCG turbo
- 3" turboback exhaust + highflow cat
- Turbosmart 12psi gate + boost T set to lowest boost atm (12psi)
- New coilpacks (gen nissan) BKR6e 0.7 plugs
- Aeromotive 340stealth
- (new additions hence now needing to tune: Z32 afm and 650cc sards)

Im running a stagea image on my R34 ecu also.
Resized my injectors to 650cc and found injector latency to suit online (1500us)
Changed AFM to Z32 after this and let both these options rescale everything for me
Car has a slight miss on idle now after doing injectors and AFM which has me a bit stumped

Started it up and wideband was reporting 11.7-12.5 (coldstart), eventually evened out to 14.4 - 14.7 on idle and cruises perfectly at 14.7ish without adjusting K at all (its 349 instead of 348 after changing AFM and injectors)

Initially the load scalers were almost factory (208 and 160 max TP like stock 34 map) however bringing it up onto boost was only accessing 120 on 12psi so very basically adjusted the scalers (i need to learn more about the scalers as its not perfect) on boost it is alright however running 10's AFR with the fuel map being reduced down to 20's in top end and doesnt really seem to be making much difference. i tried to disable o2 sensor feedback to check base mixture settings however i cant turn the o2 feedback off as the whole NEO map is flagged. the FTL sits on around -10% IIRC, tried to adjust K down (up goes richer) and it doesn't really do much. Now ive also read that the VE map must be tuned (i dont know anything about this unfortunately either)

Do i need to tune the VE maps to tune my ECU properly ? Should i not have values alot larger than 20 in my fuel map? i have all the facilities to tune the ECU however trying to nut these few things out.

[Matt]

Post your tune here and I'll go through it

[AUSBen31]

Here it is Matt, i havent set the scalers properly as it slams into RHS column but any advice for what ive asked would be great!

Is the stagea image on 34 board common ? i only tried it because i read it in multiple spots that after you delete T/C it causes issues

[Matt]

Put your TP min table back to factory (something I've found is that there is a +128 offset on these tables on NEO ECUs)
132 132 132 132 132 132 132 132 132 132 132 150 162 170 176 200

Current K constant is close to stock which means nothing else should really be affected. Latency is rather high however. Are you sure that is the value @ 14V?

Your ECU part# came up as AA502 (R34) rather than Stagea. I've never heard of issues using a stage image. Something I found however last week with NEO ECUs is they use the 'DTC filter flags' to switch on and off functions

So an R34 AA502 base image with
'Throttle motor sensor'
'ABS TCS comms'
'ABS/TCS control'
'Motor throttle circuit'

Should function without those items when unticking the DTC filter boxes. So this means there should be no need to use a stagea image now that we can control the functionality with these flags (based on my going through the ECU code)

There are no specific closed loop flags on NEO ECUs (or any ECU with VE maps). What I have found also (and need to document further) is that the value 0x80 (128) is a special flag for closed loop in the fuel map. You will notice that you cannot go leaner than this value either

Above this the ECU uses normal fuel calculations, in combination with the VE map (TPS vs fuel) for working out fueling

Your load scalers are correct when your load cursor goes across the map enough (but not too far) to access the fuel and timing maps

There is no O2 sensor feedback disable in these ECUs. Grab the latest test version 1.2.15 which has all the NEO flags updated based on my recent research

Use the K constant to adjust your base fueling (with latency) and then adjust the fuel map for the rest

[AUSBen31]

i have tried getting it going properly over the last few days. Still havent had solid time on dyno yet.

The injectors in it are SARD yellow 650ccs and latency according to the site is at 1.50ms @ 14v which i converted to 1500uS... does seem very high, however if i go much lower it runs like shit.

Ive tried uploading the correct basemap modified with my settings (AA502) however i cant seem to find where to disable the items youve listed, i have feedback swithches 1-4 and none of those settings are in there. And on initiation of consult throttle motor sensor is unchecked however still get the fault code. How exactly do i disable these properly?

Has a pretty shitty idle still, definately sounds like a slight miss (only apparent after installing these injectors and Z32 afm (it is genuine nissan i have checked, not cheap china POS)

the FTS/FTL i can never seem to get neutral either, within how close to 0% are they supposed to be, i try to get to 0% neutral on idle with no success, it does cruise nicely at 14.7 but FTL is always fluctuating after periods of time, going to -10% mostly on the 349 k constant and 1500uS latency.

Also as said my fuel maps largest number is 30 which seems awfully low compared to the stock '60'... does this sound right for 650's?

i put my TP min back to standard as said, made little to no difference. Im starting to think these SARDS (which i had cleaned and flow tested) are just fucking SHIT. Is there anything i can log for some help / advice?

[Matt]

They are not the best injector out there...

To disable items, put Nistune into 'expert mode'
File > Configuration > User mode

When all of them are unticked there should be no fault code (after you clear the codes)

Slight miss is caused from what? If AFRs are okay then it could be your injectors... given AFRs are only an average of all six cylinders. Try cylinder balance test to see if one is worst than the rest

FTS/FTL about 1-2% would be ideal but usually I've only looked at this whilst on cruise on the dyno. Wouldn't think they adjust at idle or in neutral but never looked at it too closely in those situations

Normally as K increases the flatter your fuel map will go (because the fuel multiplier is larger). That is normal to have smaller numbers in the map. Having a larger MAF offset your injectors but due to being able to read more load affects this also.

Apart from pulling your injectors out and trying with the original ones is my only advice at the moment

[AUSBen31]

The slight miss is on idle only and only once warmed up, while reving at 1400>1200>1000 ect its perfectly fine no missing, idle is set to 725 so might try raise this up to 850 where i prefer it and see if it makes a difference, to do the balance test i just go, active tests > select cyl 1-6 then press start yeah?

I disabled the DTC's in expert mode thanks matt worked a charm now have "ALL OK" up. So there is that problem sorted.

Interesting read here though

viewtopic.php?f=12&t=1044&hilit=volumetric+efficiency

Have read it might be a good idea for me to set my VE map to 128 so i can get my mixtures / afrs correct? I was looking at the map and it would explain why my idle / cruising keeps fucking with my STL/FTL's. I had a quick play (its 11:30 at night and didnt want to annoy neighbours) and found i could easily munipulate idle mixture dropping the corresponding VE map block and adjust the FTL/STL to whatever i wanted to. Would setting my whole ve map to 128 (100% neutral?), setting k constant to 14.70 (would it not be perfect now it is not getting conflictions from VE map differentiating the trim under idle / cruise?) setting load scalers, then going back to the VE map and using it for only corrections if needed / setting cruising higher than 14.70? Im new to VE maps and don't 100% understand how they work. However what ive said makes sense in my head. If i could get some feedback on this that would be great. Ill probably try the 128 approach in VE tables tomorrow morning and see how i go. Have wideband already hooked up so worst thing that can happen is i copy paste stock VE map back in. Thanks in advance and for the help so far.

edit: Gave it a shot on the way home tonight, got trims within +/- 3% while cruising at different speeds, soon as i hit idle though AFRS went to 18, added latency and ruined everything else lol. Is it bad to use the VE map to fix idle by reducing the numbers by a decent amount? Have dyno for a few hours tomorrow so will try and put this in to practice again properly.

[Matt]

Hmmm why are idle mixtures going to lean then? It shouldnt be necessary to tune for that once K is in the right place. Yes the rest on adjusting through the VE map appears to work as expected

[AUSBen31]

Here is an upload of my current tune / log, have altered timing / fuel tables so they are accessing almost correct columns but ran out of time, dyno tomorrow so hopefully all will be well. i tuned more of the VE map thismorning under different cruising conditions, have everything within +/- 5% pretty much also put a slightly higher value at idle in VE map which cleared up the lean spot too... Would you be able to go over my tune ? k constant is a bit low but everything seems to be running very well...

will upload log and tune now from thismorning, one thing ive noticed is my TP has stopped showing the [xx] numbers which allowed me to set the TP scales, only raw TP value? i know how to work it out but its a bit annoying, how to i re-enable this feature? Also in the log youll notice how it comes on boost across a few columns, is it supposed to dash across? or should i set the scales differently so on 12psi as is it sits on maybe the third column from right and then use the last 2 collumns for my higher boost settings tomorrow?

ive also noticed that once i let off gas after WOT, its extreamely laggy to get back on boost, are Z32 afms more sensitive to reversion than rb25? I notice my AFM voltage drop low after WOT run, have stock bov plumbed into 3" metal intake pipe however the return point is closeish to AFM.

[AUSBen31]

so far made 220rwkw on the dyno im using which reads very low for some reasonn (mainline) (rb25det neo with T67 on 22psi made 247 and another 25det neo with 300rwkw reading at JPC dyno made 245 for perspective. Was spitting spark with the .9 BKR6e's, just put BCPR7ES which i gapped down to .7 and stopped it spitting on test drive so we'll see what it makes tomorrow! Scales are pretty good now, would you mind quickly going over my new file to see if you can notice anything funny? one in above post is previous tune file with log.

[Matt]

Injector latency still higher than I like but rest seems to look fine.

If you unplug your MAP sensor (top of the engine unplug) does that help response at all? I've found when upgrading the MAF it can cause the engine to bog. So far I've worked out that the MAP is used to compensate for MAF response but still working through it. Unplugging the MAP sensor makes it use a default limp value making the vehicle respond better in most cases

[AUSBen31]

Injector latency still higher than I like but rest seems to look fine.

If you unplug your MAP sensor (top of the engine unplug) does that help response at all? I've found when upgrading the MAF it can cause the engine to bog. So far I've worked out that the MAP is used to compensate for MAF response but still working through it. Unplugging the MAP sensor makes it use a default limp value making the vehicle respond better in most cases

MAP sensor is unplugged / deleted (boost sensor im assuming) and DTC flag disabled. response issue was fixed with setting the map out properly and scalers, was running 14.7 too far into boost (1-2psi) making it lazy. Have some dyno time coming up during week so will post up result, has been a very informative process lol.