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Discussion Starter #1
I have a stock gen3 swapped 93, has a CT27, tuned by UMS tuning in Tempe AZ on a Link MR2Link V3. Makes 270whp on 18#.

When I go full throttle, especially at high load (high gear or lower rpms), the engine seems to cut power. Feels like an ignition cut. I can't see anything in my tune that would be causing this. I don't think it's anything mechanical, the whole ign system is pretty new. I can post the tune if anyone thinks they can help

If this belongs in another forum I can move it.
 

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Maybe a defective TPS. If the TPS indicates throttle closed, it may cause the ECU to cut fuel. If that is the case, you may be able to prove it just by disconnecting the TPS.
 

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Discussion Starter #5
What are the TPS values in your EMS when the throttle is closed, and at full throttle?
.47V closed 3.36V WOT

I'm stupid, I think it's the MAP engine protection. MAP Limit is set to 235kpa at operating temps, which is 19psi and change which seems consistent with where my ign cuts. However it seems way more harsh than it should be, and also I have an electronic boost controller, controlled by the ECU.

has a start cut at 15%TP, 30% cut, 100%TP start cut 60% end cut 90%

Not sure how I can try to get the boost more consistently lower.
 

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Discussion Starter #6
Boost target is set to 210kpa or a shade under 16psi, not sure why it keeps going so high. CT27 is mated to an ATS 3" dp and no restrictions in exhaust. Needs a bigger wg? Not sure if possible on a stock turbo.
 

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Sounds like you need to tweak the PID gains on the boost control output. Does Link use a feedforward strategy where you specify a base boost control output duty cycle, and then a PID algorithm trims it on top of that? That's the most common method I've seen, and if that's the case, you might need to tweak the base boost duty cycle by turning off PID feedback for boost control and doing some pulls and seeing what the base duty cycle gives you. With that dialed in, tweaking the PID variables will give you much more control over different behavior of the boost output. The D gain specifically tries to calm the system moving quickly past the setpoint. You might have too much P gain and not enough D.

But I'll be honest, some standalones just don't have the best control algorithm implementation. I could not get my MS PNP2 to give good closed loop control in all circumstances, with a system that seemed both slow to respond and very sensitive to adjustments like it had a long refresh time but used high background gains to try to overcome that. I gave up after experiencing low RPM boost overshoot like you are seeing on your setup. My AEM Infinity has excellent boost control response though, with a super fast refresh time on the PID algorithm.



Also, I'd raise the boost cut a bit. No reason to run it just a few psi from your target boost, as you get into situations where small amounts of overshoot trigger it.
 

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Discussion Starter #8
Also, I'd raise the boost cut a bit. No reason to run it just a few psi from your target boost, as you get into situations where small amounts of overshoot trigger it.
Ran into slight knock at 19psi on the dyno, I think it was because I was on 4 or 5 month old pump fuel at least. Stock gen3 has knock sensors, right?

I'll give it a shot. I'll do some more research on the boost control algorithms the Link uses.
 

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All 3S-GTE have a knock sensor, but it's 100% up to the tune to do something about it. I can make my AEM Infinity pull 20 deg of timing and richen up to 10:1 with knock, or do nothing, or anything in between.
 
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