Map Issue

[Steve4694]

Howsit guys,

Been using VT for some time now, but recently did further upgrades to my car and now things are not going well. I have posted a 3rd gear and a 4th gear log of a WOT run. The 4th gear log is partial as I hit a fuel cut due to overboost conditions. The map I am using is the Base 95EU map with a maf cal and wgdc set at 0 at this point.

These are my conditions:
5500ft above sea level, 85kpa
20C ambient temps
level road

My mods:
BNR stage 2
Grimmspeed EBCS
3" CAI
Cobb Tip
3" downpipe and full exhaust
Water-to-air cooler
water/meth injection (not running on these logs)
ITV22
GReddy BPV, full recirc (original part)

Any help would be great.

[mituc]

Post your tune here so that we can figure out why your car cut. The MAP values are below the aftermarket tunes threshold (which is somewhere around 235kPa) and in your 4th gear WOT log there's no indication of any cut - you should have posted that as well instead of trimming it from the log. If the ECU cut the fueling in the upper RPM area most probably you're commanding too high WGDG at high RPM and/or you're experiencing boost creep.
Also, drop the STFT and add the fuel rail pressure instead in these logs.

P.S.: when going big turbo consider very seriously hiring an e-tuner. I did that and the tune I've got doesn't look like anything that I could have done. Also, pretty much all these OTS K04 tunes we're using as a starting point inherit a lot of flaws from the stock tune and when going big turbo these flaws tend to bite our asses even harder, and the e-tuners know what these flaws are and eliminate them from the very beginning.

[Steve @ VersaTune]

Please post your tune. Tuning at 5500 ft altitude is a little different that at sea level. You really need to pay attention to all the tables with Barometer as an axis.

[Steve4694]

Thanks a lot for the feedback so far Mituc. My issue is that my WGDC is set to 0 in my tune. I will post my tune as soon as I am at my laptop. I am seriously considdering a professional tune as I am running into different issues I cannot seem to fix.

Like you say, at 5500ft its a different game all together and on a hot day its over 35C and if its cold its -5C.

This is my tune, basic base map, but had to take BCS DC to 0 because even at 5% it would boost to 230kpa about and a load of 2 even with commanding 1.8 or less.

[Steve @ VersaTune]

2.0 load at 0% BCS DC indicates a mechanical problem with the wastegate. Ensure that the wastegate is opening properly. What PSI spring is in the WGA? If the wastegate is too small it can cause boost control problems with a 3" DP especially if it's catless.

To prevent the fuel cut, increase the Overboost Protection Fuel Cut and Overboost Protection Throttle Reduction table values. Look across the 85 kPa row. You can see that you are exceeding these values.

These are lower at altitude to protect the little K04 from overspinning and operating beyond the efficiency range.

[Steve4694]

The BNR 2 has an upgraded spring in the WGA, but can't find the exact figure. If it is the Wastegate, can it just be replaced? In South Africa they have no strict conditions on cats, so all our DP's are catless. I actually want to control my boost and stop it at about 200kpa, yet at 0% BCS DC it spikes and is even worse with any value greater than 0.

[Steve @ VersaTune]

You can test the WGA spring pressure and actuator movement with a bicycle tire pump that has a pressure gauge on it. Connect the pump to the WGA diaphragm and see at what pressure it moves. Make sure it moves through the full travel. You should see the swing arm rotate at least 30* on the turbo housing. Do not put more than 15-20 psi to the diaphragm though.

Worst case, you may need to take the turbo off and port the internal wastegate passage and opening. Do not open it larger than the wastegate swingvalve cover or else you will take forever to build boost.

I had to do this with my ATP GT3071R. I had a 3" catless DP and there was almost no boost control until I ported it.

[Steve4694]

Thanks Steve, I took your advice with the bicycle pump and gave it a go. Everything seems fine, at about 18psi it moves and goes through what I would say is 30* at minimum. Guess I will need to port the passage.

[mituc]

The BNR 2 has an upgraded spring in the WGA, but can't find the exact figure. If it is the Wastegate, can it just be replaced? In South Africa they have no strict conditions on cats, so all our DP's are catless. I actually want to control my boost and stop it at about 200kpa, yet at 0% BCS DC it spikes and is even worse with any value greater than 0.

200kpa is about 29psi, which means that the actual boost is going to be like 14.5-15psi or so depending on the altitude you're at. The stock peak boost is 15.7psi or something. So most probably you want more boost than that. If you're looking at the MAF g/s values you're flowing as much as a stock turbo 2.3 disi engine with a conservative tune.

And yes, load >1 (at load 1 you're like running normally aspirated at full potential) with 0% bcs means that the wastegate may not be opening and it's jammed in a closed position, this making all the exhaust gases flow through the charger turbine. or the EBCS is not correctly connected meaning that it's not able to report anything properly and you're running at WG spring pressure.

[Steve @ VersaTune]

If the spring pressure on the WGA is 18 PSI, that explains the high boost. With that WGA, you will hit around 2.0 load at 0% BCS DC.

The GT2871 compressor has a max pressure ratio that is (depending on the compressor trim) a little over 3.0

So at your altitude, 85 kPa *3 = 255 kPa max MAP. As you can see from the compressor map below, the MAP ceiling is lower at higher flow.