Strange cut under load.

[Tommey]

Hi, i have a European S14a with Nistune.
It was mapped last year and because of engine problems the engine was rebuilt this winter.
Just a proper overhaul but no changes exept upgrading the clutch and changing the transmission to Z32 (yes the neutral switch is connected).

It was measured to 420whp and 640nm at 1.5 bar of boost and now i only run it at 1 bar until i get it checked on the dyno again.
Getting some weird cuts under load, seems like fuelcut but i can`t understand why.

Edit: A/F ratio is good until it suddenly cuts.
Specs:
SR20DET
-Forged internals, ID1000cc injectors, z32 AFM and GT2871 Turbocharger.

As i said, nothing else but the internals have been touched.
Log file attached, let me know if you want other LOG`s.

All input and help is appreciated.

NIStune_2014-07-24_1959_42.csv

(27.94 KiB) Downloaded 124 times

[Matt]

Need the tune file also

[Tommey]

Of course, i`m sorry.

I have tried messing around with tp cut / limit, no changes.
Maybe i should try to adjust the TPS?

200 Lars Map endring 3 gir.bin

(64 KiB) Downloaded 130 times

[s200rat]

what fuel you using? 22deg on primary timing map throughout peak tourque and gt2871 is far too much for 98-95oct. you'll be det'in

[s200rat]

and your TP Cut is set too low, you have it 141 on your bin but your logs show you exceed this so you'll need to update you TP cut tables and burn it to ecu for it to give you a new limit.

But note, your scalers in your fuel and ignition tables only go to 112. You need to fix this and tune it first

[s200rat]

also speed cut is set at 125mph, would be worth while raising this as well to eliminate issues in the future

[Tommey]

I`m running E85, should have said that earlier.

So i have to re-tune/adjust the map if i change the scalers?

What is the function of these scalers and TP cut?
I am new to this and to Nistune.

Any theories of why this is an issue now, and not last year running the same setup?

Thanks!

[s200rat]

Timing makes a bit more sense if your running e85.

Scalers is just the load scale. It's a calculated number based on air flow.
You will need to adjust your tune, because of the size of increase to your scalers you will have to double check the tune is still ok.

Tp cut is a load cut, when the ecu sees a load in excess of stated tp at certain rpm it will cut fuelling to protect the engine.

Youll need to adjust your tp cut to suit the loads your seeing. Bear in mind most tuners just disable it and max out the numbers. Not good practice in my mind, I usually set it to max tp + 10%.

Was anything changed during the rebuild?

[Tommey]

I just remembered that the speedometer reads about double speed because of the z32 gearbox and sensor.
Need to install the speedometer signal converter.
Do the ECU use the speed for anything?

Only clutch and internals are different from last year, everything else is as it was.

Thanks for explaining!

[s200rat]

There is a speed limiter, yours is set at 125mph if I remember correctly, if the ecu sees that speed it will cut fuel

[Tommey]

125mph = 201 km/h.
speedo shows 260+ in third without any problems.
I will do some more testing tomorrow, thank you for your input so far!

[Matt]

Just bump up your limiters (TP load limit, speed limiter) for now and see how that goes

[Tommey]

I disconnect the speedsensor and it worked, I then installed the Dakota Digital speedometer converter device and adjusted it correctly. Still working perfect.
A little odd that the limit is set to 201kmh but does not engage before well past 250kmh.

Thanks for your help so far!

Should I recall the scalers before going to the dyno again?
Needs more boost!

[Matt]

Look at where your 'TP' cursor is tracing on the fuel map. If its not going far enough or going up the last column then the scales need adjusting

[Tommey]

This was solved, the problem was that the speelimiter kicked in.
After adjusting the speedometer the car worked perfectly.