Getting some kind of hard cut on the track?
 

Running a custom E85 tune which I experience some kind of hard cut over 6000 rpm in 4th or 5th gears. It feels like I've hit the limiter but obviously I'm no where near that RPM. It isn't consistent in that yesterday at the track I could do a 10min session and not have it once, then go out an hour later and have it occur every single lap. Haven't experienced it on the street but I had the same scenario occur when I tried the OFT E85 tune last year at the same track.

Have uploaded 2 logs, log0076_extract.csv definitely had it happen at the end.
http://www.datazap.me/u/dave/e85?log=1&data=15

Stock tune doesn't do it so I'm convinced it is something related to the tune. Had my tuner there so tried increasing the Engine Load or MAF Limit's but didn't help and not game to play with anything else while not on the dyno. His normal platform is tuning Evo's so has asked me to investigate here in the hope we can find the issue quicker.

Couple of variables, car is stock bar overpipe back invidia exhaust. Weather isn't a factor as it did it when ambient ranged from 25-35 deg C. Fuel level is irrelevant as it occurred with a near full tank.

assume your talking about at time 2975 seconds ?

can see throttle close with rpm arround 6000 not sure if that is you or not.
you speed is in excess of 140 kmh its my understanding from other track guys that even if traction vsc is OFF , at speeds in excess of 140 kmh it will kick back in trying to save you if it detects vehicle traction loss or slide. you have to do pedal dance to disable completly.

maybe does not do it on stock tune due less power at 6000 rpm than tuned on e85 so does not try to break traction

note your iam is 0.78 which indicates your getting significant knock somewhere. dont think that is problem though. but wrth looking at

arround 5000 rpm at load .7 your pulling 3 and 4 degrees flkc with iam at 0.7
your ltft is between 6 and 9% so unless you e85 mix is off i would be pointing that out to tuner
your afr and commanded afr are also significantly different at wot may be 02 scalng limit but again worth checking

Last time I tracked I experienced a lap when I could not rev past 6000rpm. The car only did that on one lap and I checked the temps, the oil was 115degC and the water was almost at 120degC. It was my second to the last lap of the day, and I just went straight to my cool down lap. Driving the car home, I could rev it past 6000rpm again. Maybe another safety net with high temps I suppose? I'm installing a tranny oil temp guage, maybe it has something to do with that. I was using e85 that day.

The track is Phillip Island ([ame="http://en.wikipedia.org/wiki/Phillip_Island_Grand_Prix_Circuit"]Phillip Island Grand Prix Circuit - Wikipedia, the free encyclopedia[/ame]).

I should have added that I am doing the pedal dance as the speed on semi's through the big sweepers had the V-LSD feature kick in even with TC/DSC off and was very unsettling. While log0076_extract.csv is going around turn 12, previous experience has had it happen after the car was already on the straight after that turn. Steering inputs or lack of traction are not factors here.

I can't comment on the IAM or knock values you mention. Car was tuned on the dyno using United E85 and was running the same fuel at the track.

Also not heat related. I have a setrab 19 row oil cooler which keeps temps under 110degC even on a 35degC day and 20 min sessions. Water temp would not have gone higher than 105degC.

My tuner suspected some sort of MAF or Load limit being reached so was hoping one of the tuners here could comment.

I'll check my gopro footage later and upload to YouTube if there is anything which shows it.

Any experienced ROM editors/tuners care to comment? @Kodename47 @mad_sb @Shiv@Openflash @DeliciousTuning @Td-d @moto-mike

We can't replicate it on the dyno and I'm not in favour of testing tweaks on the fly at the track, not at least without a wideband hooked up. Though I might have one mounted in the stock header and wire it up for that purpose if need be.

I'm not against paying for another tune or the time for a pro's experience but we're thinking it is something simple and others more familiar with the platform might have seen before?

I'm actually surprised no one has experienced it with the OFT E85 tune as I tried that with no alterations and had the problem.

My first call would be one of the load limiter tables, since the most obvious impact of E85 would be a significantly higher potential engine load. The stock tables (b, and c) cap out at 1.3 - but, this is generally a problem at lower RPMs (and you are achieving loads up to 1.35). Second call would be the MAF limiter, 200 g/s stock - but you're not hitting over 176 g/s.

You open loop maf scaling seem quite a bit off your sensor is pegged rich limit of scale 11.3 (it may be running richer) where your commanded afr is 12 from about 5000 to redline, about 8% or more error.

If you correct the maf scaling it will also reduce the load calculation by similar amounts the ecu does which will likely reduce your load values to below the max limits.

That was the initial thought also. Defs for ZA1JA01G don't have an Engine Load Limit C? Only A & B that I can see.

Need to switch back to stock 98 before I play around there. But the scale being used is from OFT Stg2 EL A01G v2.061. Also regarding your earlier comment about IAM being low, my tune has all the stock knock correction tables so it starts at 0.7

You can do maf scaling on E85 as long as you have a consistent mix. If you only use united E85 its guaranteed 85% and consistent so you can scale maf on it. I have done that and it works great. my load is now below 1.30.

Yes I assumed your tuner had set IAM initial to 1 (most tuners do this) but I was wrong. however their is still knock evident even with IAM at 0.7 your also getting knock on each shift over 5000 is your tuned rom based on an A01G ?? if its an earlier rom ie A00G 900G 700G then their was an error in the setting of the Transient Ignition Retard table and TIR was disabled above 5000 in the A01G and later roms it was fixed and disable set to above 10000 ie its always active. The Transient retard not being active was believed to be a contributing factor to di seal failure due knock with guys who drove cars hard especially on track.

http://www.datazap.me/u/dave/e85?log...zoom=5914-6456

I didn't read the whole thread but you shouldn't use MAF scaling to do e85 fueling. Otherwise you will exceed the load limits and need to adjust accordingly. None of our customers have this issue but we use EcuTek and directly adjust fuel vs trying to band aid it with MAF scaling.

All the transient ignition tables are unchanged from the stock A01G map I pulled from my car so that isn't an issue.

My tuner also advised against playing with MAF scale. The trims weren't so bad when we first tuned it so I'll keep logging and if the trims remain excessively high we'll chuck it back on the dyno for some fine tuning.

Why not if E85 is actually consistent? All year long and only ever use E85?

Can you explain how MAF scaling would be a bandaid?

dave look at the logs it pulling 4 degrees flkc all the time , maybe its not TIR related but its pretty bad knock, even if your iam is initially set to 0.7 the ecu will try to increase the iam and hence the timing. Your pulling -4 degrees with an iam of 0.7 after considerable run time on E85 their is something wrong with the tune. You can see the positive flkc where the ecu is trying to add timing then it pulls 3 or 4 degrees negitive consistently thats what is keeping you iam less than 1.

When you alter MAF you alter load. Load is used extensively in modern ECUs and it affects every bit of operation from where it applies knock correction, startup fueling, timing maps, and everything else in between. When you mess with MAF scaling to correct a fueling issue, you're altering all of that. By a whopping 40% when you factor in e85. It's a technique of last resort (i.e. when you can't directly alter injection values) but a much more effective method is to alter injector scaling or fuel constant (i.e. nissan).

In this case it looks like MAF may have been used but load limits are still capped.

Thanks for your reply, here are more questions if I may.

So how would one know that their injector scaling is off for E85?

Is it not possible to use how much extra E85 in percentage is required to create the same amount of energy as pump, then apply that to the scaling? then use maf scaling to actually sort out the intake characteristics/engine volumetric efficiency?

Also, are we not actually creating more cylinder pressure/load by adding more timing?

Stock fuel pump? You might be at its threshold, especially with E85.

Mike, when you talk about injector scaling do you mean port value (that has been lowered 30% compared to stock tune) or one of the DI tables ?

Yeah it is but if I was at that limit it would do it constantly and many others would have mentioned it. I'm still running stock headers which many others aren't.

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But this is now less about my hard cut issue and more the inconsistency found in logs. I'm starting to think that the quality of E85 when we tuned the car and what I've filled up with since is quite different (same brand but different locations).

This is the same custom E85 tune but reflashed to reset everything, not the same fuel batch as above. LTFT's are average
http://www.datazap.me/u/dave/e85-res...g=0&data=12-20

This is the OFT E85 Stage 2 tune flashed yesterday on same batch of fuel as logs above. LTFT's are even worse, total rubbish even. I basically went up and down the fwy on cruise control at 100.
http://www.datazap.me/u/dave/e85-oft?log=0&data=10-18

But if I go back to some logs I did immediately after the car was tuned for E85 on the dyno, still running the same fuel that was in the car from when it was tuned, the logs look quite a bit different. LTFT's were good. Both cruising and giving the car a belt on a really hot day.
http://www.datazap.me/u/dave/e85-cus...g=0&data=10-18

Will finish off the E85 in the tank and switch back to stock tune and log to see if there is anything suss with the car and go from there. Might be time to stick a wideband in somewhere, getting access a dyno isn't easy.

If you using OFT maf scaling on united E85 tunes your ltft are always going to be around 10% positive as the usa dont have a guaranteed e85 mix like united. Their fuels are arround 60 to 75% average it appears so thats what the tune was set up for around 70% ethanol. United being e85 to E90 will result in high fuel trims on standard maf scaling and injector scaling levels. I think the oft guys also jack maf values a bit to make ure the tune will run an the rich side when ethanol % changes.

unfortunatly jacking the maf values also increases the ecu load calculation as moto mike says and it does appear you hitting load limit which is likely the cutout.

if your tuner rescale your maf to suit the consistly high e85 your using the load calc will be less and you will probably not test the load limit.
and you open loop fueling will follow the commanded afr like its supposed to and not be about 10% different and your closed loop fueling will be corrected and your ltft will be low like less than 4% on united e85..

better to fix the problem than alter mare stuff tryng to bandaid it

pi scaling is injector scaling brz
di scaling is di fuel presure targets.

after maf scale you may have to adjust fueling and timing again.

then see if that knock goes away and your iam stays at 1.

most tuners set iam initial to one as its a hassle to run the car for a few minutes to get the iam to 1 after a flash so you can do dyno pulls and check timing ect.

if they have iam initial set to o.7 and dont let it get to 1 before dyno pulls your tune will then advance the timing 3 or 4 degrees in places once the iam returns to one after some driving posibly causing knock problems.

i am starting to think this is what your tuner did as on the track your iam is at 0.7 whereas after a bit of sedate driving you can see the iam quickly go to 1.

ie your tuner has tuned for max timing with iam at 0.7 instead of 1.

Yeah I won't be playing with any of that stuff, was more curious on which tables were being spoken about. I compared the OFT tune and mine while looking for scaling etc. The OFT tune must have been used as a base because the differences are primary ol fueling, timing, intake/exhaust avcs, calculated and requested torque. The rev and knock tables have been taken from the stock tune however. So the MAF scale is identical to OFT Stg2 EL A01G v2.061.

Interesting theory about the IAM and timing, makes sense as you're doing dyno pulls and flashing changes constantly so never long enough for IAM to reach 1 in that scenario which in hindsight isn't ideal.

I'm thinking finish the E85 off, switch to stock tune and do the MAF scaling process on BP98. Tuner can use that scale and and retweak timing/fuel with IAM=1.

If we can't organise dyno time, a friend mentioned I can have his Innovate LC-1 Wideband. If I can replace the secondary O2 in the factory header with that then great otherwise will have a bung welded in somewhere.

Went back to stock tune to see if there was anything suss going on after the fuel trims differed so much between initial E85 tune and a few tanks. Car threw P0420 Cat Efficiency code after less than 20 miles and an hours run time. Have the factory header with Invidia over pipe and catted front pipe.

Have noticed a bit of condensation leaking from the exhaust between overpipe and frontpipe so wouldn't surprise me if the bit between the header and overpipe was too. Bolts are tight so must be poor flanges/gasket. Either that leak is enough to throw the rear O2 out or the stock header cat is stuffed?

Process of elimination now, what a pain in the ass.

i would just change gasket between overpipe and header, unlikely its between block and header if its never been off. I suppose its possible the primary cat is stuffed , think csg mike stuffed his cats on stock car stock tune on petrol on the track.

but a gasket costs stuff all and pretty veasy job and you can probably shine a torch in and see if the cat has disintergrated or their is bits floating arround in the overpipe.

The car has done a lot of track days (20+) so it hasn't had an easy life that's for sure.

Looks like I gotta find some hoist time tomorrow and try the gasket. Wonder if I can get a bung for the wideband O2 done at the same time...

So found the cause of trims going to shit and cat efficiency code....

Factory cat had totally disappeared and also had a leak between front and over pipe flanges, though the lack of cat would have to be the issue here.

Seems they don't like constant tracking but really hate the sound of every aftermarket header I've heard!

Be worth checking second cat its probably stuffed as well or has all the bits of front cat jammed in it. :) at least you know what problem is

The cat in the front pipe looks absolutely fine, not clogged up or anything so no idea where the primary cat disappeared to....

Blasted air through the front pipe and muffler with the compressor, got a lot of particles which were probably remnants of the OEM header cat. Haven't decided on what to do with the header as yet but we replaced the over pipe (flange was warped) which fixed the exhaust leak. Obviously it threw the P0420 CEL after about 30mins of driving but not concerned with that right now.

Car has OEM A01G tune in it with no alterations. Did 2 log sets:
http://datazap.me/u/dave/stock-oem-a01g-tune
http://datazap.me/u/dave/stock-oem-a01g-tune-pt2

I know the OEM tune had some minor knock on our fuel so I'll flash the OFT V2 Stg1 A01G T K S 98 ROM to start with and do another set of logs tomorrow as a baseline.

performing inline with stock tune by the looks of log bit of knock and iam around o.8.

just disable the p0420 code in the T K S 98 TUNE as its for catted header so not disabled.
some guy on this forum just cut and welded a pipe where the cat was to make it flow better than a gutted cat. Aparantly it performed pretty well on par with catless header.
sinceyou likesound of stock header probably an option then just run the CatlessEL header tune and make timing andtemp compensation mods similar to the tune above.

should work fine and cost sod all.

Yeah that was what I'd hoped. I checked the rom before and noticed the code, easy done.

Had that idea today but didn't have pipe or welder handy hehe.

2 log files with @steve99's OFT V2 Stg1 A01G T K S 98 ROM. Log 1 is cruising around and Log 0 is giving it some stick on the fwy.

http://www.datazap.me/u/dave/stg1-a01g-t-k-s-98?log=1

look pretty good, but i am biased :D

pretty hard to completly eliminate all knock on our 98 especially some brands, BP and Shell probably the pick even then adding 5 litres of E85 to tank helps

maybe pull another 0.7 out of map 5000-6000 around load 1 to 1.2 if your kean just to get that flkc below -1 correction.

IAM soild at 1 so ecu not to worried about that level of knock

Yeah I used that and stock for baseline logs because they're a known quantity.

Will do more logs for MAF scale and tweak then look at redoing E85 and hopefully sort out how this whole episode began! Thanks mate.