Rb25neo, Nistune, fast acceleration cutting Issues

[TimTurboZ]

Fast acceleration it cuts around 4500/5k less throttle it will go smooth to redline, ive played with my dwell settings *LS2 coilpacks*, adjusted fuel maps, changed timing but nothing is getting rid of the cut

~18psi On 91octane, but i dropped it to 15psi still cuts.
Z32 maf
R35 injectors

Is anyone familiar enough with Nistune to help me out possibly look at my tune?

Ive done alot of reading, my plugs look good copper ngk's, ls2 coilpack all function, new fpr *41psi idle*, walbro 400, newer z32 fuel filter.

Hallman boost controller
Tial wastegate
Ive checked my harness wiring, and tested resistence on the coilpack harness.

Tps is at .5v at idle
Maf signal only reaches 4v at full boost does not max out.

Boost leak tested to 1.3 bar [small air tank]

Afrs all flow smoothly thru rpms and into boost til full boost.

Full boost i have tried: 10.3:1 10.5:1 10.8, 11.3 etc

Timing at full boost 12deg [felt terrible lol] 14/15deg, 17, 19,

I was slightly worried about 17 or 19 deg on 91octane at 18psi so 14or15 seems reasonable.

Been going crazy for awhile

[TimTurboZ]

I have eliinated any cut caused by the ecu, removed limitations on fueling, I have been over and over what I need to change with Matt Brown at Nistune.

[USMCgetsome]

best to data log all your sensor readings when you WOT and see what happens at fuel cut then. You'll then be able to see if under voltage or over voltage of the sensors. same with MAF. The maf should scale up with when you are on boost not the fact that it maxes out but you should see it rise when it draws in more air on the boost.

[USMCgetsome]

also I read a few months back that most people were running DUAL Z32 MAF on single turbo with some special wire adapter and converter so that the MAF would not MAX OUT AT HIGH BOOST. HOLD FOR LINK

[USMCgetsome]

http://www.z1motorsports.com/product_in ... ts_id=3986

apparently the z32 has better resolution for tuning and instead of running one q45 maf you can run dual z32 with this converter and should be maxing out the afm.

Also have you seen the fuel pressure at the FUEL CUT?

[TimTurboZ]

I have not had it on a dyno again or relocated the fuel pressure regulator so I could see the fuel pressure at cut

I dont think its a fuel cut

[USMCgetsome]

DATA LOG REPORTS PLEASE

[TimTurboZ]

I was recommended to run a shielded MAF wire, mount my coilpacks so they are stationary, and to try iridium plugs vs the copper plugs

Would anyone back up that the plugs would be worthwhile. It was his 1st recommendation before looking under my hood seems reasonable except that so many people run the copper plugs I was sure id be fine. My rb20 never cut like this with copper plugs at 1bar. My current setup flows more aire faster Im sure tho so spark blowing out I could still see being the issue.

[TimTurboZ]

I mounted my coilpacks, bought iridium plugs and new spark plug wires . its better but still cutting.

Im about to check the plugs one by one cranking the motor and look for a weak spark possibly...see if a coilpack is my issue.

I will log some runs and try and upload a video of the log or some screen shots.

Is there a better way to test the coilpack to see if its operating correctly.

[Yellow4g63]

wiggle your cas pig tail? maybe something funky going on with the wiring.

[TimTurboZ]

Matt Brown repeated that I only adjust the dwell time and not to touch the duty table, but after alot of reading i should keep them at 3.0ms at the lowest thru the rpm range. Which means changing the dwell duty... it was gong below 1.0ms around cut stock

[TimTurboZ]

I had changed it to stay at like 1.3ms at the same rpm just to try it out worked better but now I must try to raise it up! Definitely seems like a weak spark being less than half its power it could be

[TimTurboZ]

I previously had been to a dyno and have that old tune saved for reference even tho my car had many issues.

How my tuner set my dwell duty table prior was close to 3ms across the rpm range. Even after adjusting it the car is cutting. so open to ideas

[TimTurboZ]

I richened my tune in boost range for peace of mind. I also changed timing from 18° to 24° from full boost ~4k up to the 6k rpm range. this is really what made a difference with what seems to nearly eliminated the cut!

Basically below 24° it seemed to cut even at ~6000 rpm*dipped down to 23°

Im visiting my tuner for him to check my tune over and drive with me monitoring on the laptop do a little street tuning with someone with more experience then me.

Just seems high for 91oct I have wiseco pistons that are 8.5:1CR... if that changes things enough to need me to run higer timing???

I have logs saved as well

[Yellow4g63]

I run 24* on 91 too but I'm running meth injection.

[Darius]

That seems like a lot of timing up top for pump gas. I'll check my old PFC logs for comparison. It sounds like your plugs are not gapped down tight enough. Do you know what they are gapped to? The LS2's should allow you to do whatever you want at your power level and on non-ethanol fuel, but you never know with these systems.

If that doesn't help, I'd look at the CAS like Yellow4g63 said. These motors are notorious for having CAS noise issues up top and can potentially cause the motor to blow. What are you seeing for knock numbers?

Post those PFC log files!

[TimTurboZ]

I have Nistune! So its different but I will try later tonight when Im free.

CAS noise up top? What would it do to blow a motor? Spike in timing?

Honestly my CAS was grounded really poorly *fixed* and a few times I debated replacing it. This past weekend I had a new CAS from Raw Brokerage in my shopping cart about to purchase JUST so I knew that mine wasnt faulty, but I decided against it.

At $200 brand new Its not a bad pricewise but just to order it really based off nothing seemed foolish.

[TimTurboZ]

Plugs are the NGK BKR7EIX they looked about .08 so I left them how they came.

I had tried the coppers how they came 1.1 and then gapped them down to .08 previously. Yeah the ls2 coilpacks SHOULD fire at the bigger gap no problem i know :/

[Darius]

I have Nistune! So its different but I will try later tonight when Im free.

CAS noise up top? What would it do to blow a motor? Spike in timing?

Honestly my CAS was grounded really poorly *fixed* and a few times I debated replacing it. This past weekend I had a new CAS from Raw Brokerage in my shopping cart about to purchase JUST so I knew that mine wasnt faulty, but I decided against it.

At $200 brand new Its not a bad pricewise but just to order it really based off nothing seemed foolish.

I checked my old logs and I was running about 18 degrees of ignition timing at about 18 psi. I wouldn't recommend going much higher than that until you get things sorted out.

Yes, when the CAS goes bad and gets noisy, it starts sending the ECS false signals and it results in the injectors and ignition timing being off. I believe it was Shocker that went through a motor because of this but that was several years ago. He tracked it down to a bad CAS.

I'm sure Ricky would let you return the CAS if you found out it wasn't the issue. He's a pretty reasonable guy as long as it doesn't get dinged up in the process.

Have you set the base timing with the engine warmed up? I know it is a dumb question, but it hasn't been mentioned and could be the reason why you are seeing less of a problem when you begin to advance the timing.

[TimTurboZ]

I triple checked on the dyno awhile back it was 15° (after the LS coilpack swap) but I wouldnt mind checking again. Also the stock RB timing map is Really aggressive I had tried taking it down so it flowed smoothly down to 18 degrees but having that under boost it just wasnt working out. Im trying for 15/16psi so I keep it safer.

[TimTurboZ]

Solved

0.8mm gap NGKcoppers cuts at 4500
0.3mm gap NGKcoppers cuts...oh doesnt at ALL!

My ls2 coilpacks must be garbage, thats such a small gap! The car drives well, goes fast, and redlines but the idle isnt as consistent as it once was, idle afrs rise and fall. The coil pulse length recorded in the ecu sort of jumps around thru the rpms, i think it shows me an average of all 6coils So if one coilpack is weak I could see that being the reason the coil pulse is fluctuating.

Any ideas on how to test each coilpack for functionality?

Tim