Im pretty sure its boost cut. But not boost cut on its own. Looking at the ECU map, the boost limit is setup on a 2d table refference to coolant temperature. And the limiter is set to low when the coolant temp is cool. And set to normal boost pressure at normal engine temps. And at high engine temps the boost limit is low again. And im pretty sure this may actually be the issue. As i only seemed to notice it after a lap or so. Once the temps were up. So id go out there nail it for a lap, the engine temp would ruse and the boost limit would drop below actual boost and then cut cut cut.

But i also think the wastegate might be having a hard time controlling boost aswell. As even after removing the EBCS and running spring pressure. Then reducing spring pressure further, it was still showing more boost than the rating of the springs i was using.

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Doing it for all the wagons out there

Was getting similar symptoms, on second hard lap when everything was hot I was getting a misfire at about 6k rpm so was short shifting around.
Haven't had the issue at Rallysprint as obviously it's not getting hammered for as long so another issue to iron out.

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Could be the same thing. Ill have to look at my default ECU tune and compare to the current tune, but its possible that is just a default setting and hasnt been setup specifically. Im sure Justin would have set the MAP limit. But he may not have set it at all the different temerature cells, just the standard ones? My coolant temps werent exceltionally high. But i did notice my oil temps getting up there. I guess the PC fan on the sideways oil cooler isnt very effective.

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Doing it for all the wagons out there

Save your current tune to a PC / laptop

Then just change the waste gate duty table. I had the same issue on mine and had to take 7% duty out of it across the whole table to stop it hitting boost cut.
It's easy to do and as you're not touching fueling or ignition it has no impact other than dropping boost. Obviously if you're adding boost it becomes an issue but not removing it.

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605whp
Quarter Mile in 10.9 seconds @ 135mph /217kph
0-100 kph 3.2 seconds

Well. What i did was remove the EBCS, plumb it dirrctly for gate pressyre plumbing, and just fit wastegate springs only. (I have all 6 springs available for the hypergate, so can select any pressure upto 25psi. I tried going down to 19psi worth of springs. And it still just wanted to sit higher than that. About 22psi.

But the cut issue im having seems to be temperature related. As the temp increases, the boost cut decreases. So it goes fine until the temps and boost reach the crossiver point in the Boost limiter / ECT table. Then it cuts.

I just need some more time to play with it. I will put the EBCS back on, and put the same springs it was tuned for back in. Then try adjusting the ECT adjuster in the boost limitet. And try that. If that works then i will probably look to increasing cooling capacity. Maybe a larger radiator. Or free-er air flow out of the engine bay.

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Doing it for all the wagons out there

For reference here's my MAP Limit Table.
As you can see when my Coolant temp is between 60 and 100 degrees C my boost cut is 1.95 bar. Outside of that temp range the boost cut threshold drops so if I try and do a WOT run on a cold engine i.e anything below 60 degrees C my boost cut will be at 1.2 bar if I do it at anything over 100 degrees the boost cut threshold drops the higher the temp gets.

If you're hitting boost cut when yourcoolant is within the normal operating temp range then you're just hitting too much boost.
Is the ECT sensor reading correctly?

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605whp
Quarter Mile in 10.9 seconds @ 135mph /217kph
0-100 kph 3.2 seconds

Yeah. Mine is the same principle. (But obviously different values.) And i believe the problem is the 100 to 110 cells. There is about 1 bar difference between the 2 cells. And because of the way the ECU interpolates between the 2 cells to fill in the numbers inbetween, it means the boost cut rapidly sets in, as 1*c rise will mean 0.1 bar. (1.5psi).

And im pretty sure its a temp related cut as the first lap in the session, the car performs well. (The warm up lap.) Then you start your 2 flying laps and it starts happening. So annoying.

The ECU is set up to log. But i havenet had enough time since friday to actually spend some time going over the logs. Saturday i finished of Dzenads car, then dropped it back. Sunday was Kobies birthday, sunday night family roast. Monday back at work. Monday night organising another big job. Tuesday working. It never ends.

But yeah. Im pretty sure its that.

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Log shows temps getting around 100-104°c. And both the main limiter and the boost cut limiter are both refferenced to ECT. The main limiter drops allowable engine RPMs at 100°c. So it could be either one of them. Probs why i had to modulate throttle to keep boost down AND short shift to keep RPMs down.

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Doing it for all the wagons out there

It's doing its job then in protecting your engine. So although its hitting boost cut that's not the issue the hot temps is.

Can't remember if you've gone FMIC or not?

If so are you still running the scoop? Mine always struggled with temps there in the summer my plan was to delete the scoop and have a flat vent in its place.

The problem you have with an FMIC AND the scoop in place is the warm engine bay air cant escape. You have warm summer air being forced into the engine bay via the hood scoop which is stopping the hot air in the engine bay escaping which means temps just climb (including intake temps).

If you just put a flat vent instead of the scoop you improve the flow of the hot air out of the engine and temps will drop significantly.

This was an issue on a Time Attack car I worked on. The first lap or two were ok but temps started to climb after that and for 20min sessions that was no good.

Although we didn't have anything to replace it with we just removed the scoop completely and the problem went away. It was a cheap fix. Certainly worth a shot in your case.

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605whp
Quarter Mile in 10.9 seconds @ 135mph /217kph
0-100 kph 3.2 seconds

Was 37 deg that day too

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