MAP reading confusion in logs

pulled logs on a customers drift car recently during a event.

Rb20det, e85 , Link G4X PP

All parameters seem to make sense but the MAP seems to read unusually high for some reason?.

As visible in the screen shot of the log it reads up to 30psi @ 7000rpm even though boost target is approx 24psi Closed loop.

What am i missing for it to be ready such high boost??

Can you log wastegate duty cycle? It may just be suffering from boost creep. You could test by bypassing any boost control, run your vac line straight to the gate to verify gate pressure controls boost to redline.

Hey Ben

I have just reviewed the wastegate duty cycle.

it seems to mostly operate at 50% but leading up to the boost spike it seems to waver around from 50% to 20%, 24%,26% and then 0% right at the point of 30.3 psi @ 7223 RPM.

I am pretty sure rpm limit is 7500 + but those boost levels are concerning. It does have a new manifold which seems to be good quality, Turbosmart 44mm gate.

The fact you're seeing 0% duty would indicate your closed loop boost control is working correctly and although it's possible there are other issues, given that it has a new manifold, I'd guess that it is genuinely boost spiking. The wastegate position may not be picking up enough of a priority flow from the manifold. Is the gate plumbed back into the dump pipe or vent to atmosphere? You could try a softer spring, larger gate, redesigned pickup point for the gate feed or a combination of all these things to rectify the issue.

Currently it is vented to atmosphere.

The plot does thicken here as i have also noticed the target boost pressure is 32 psi! That being said the boost target and control appears to be working perfectly if the target is actually 32 psi?

The target does move up and down in the log but i presume this is normal.

But the main confusion is im amazed the tuner would have set this little car at such a high figure.. as it is a stock rb20

I will attach the duty cycle table for you to confirm it is actually setup and tuned at 32 psi

Are you sure that's a boost pressure (i.e PSIg), and not an absolute pressure(ie. PSIa)? The difference would be 14.5 psi.

It would make alot more sense if it was absolute pressure. How can i tell the difference for future reference? I cant see on any tables PSIg or PSIa

Side note: G4+ uses a boost target + 14.5 psi Atmosphere pressure?? So this would make sense if i subtracted 14.5 off these figures it would give a sensible target. Man this is a real trap for new players!!

Can anyone confirm im heading in the right direction?

If instead of posting pictures, if you uploaded the actual data file and ECU Configuration, then we could answer those questions. For example, I would like to see throttle position in that data trace above -- how the MAP sensor responds with a high RPM, closed throttle would be revealing.

How can i tell the difference for future reference?

You would look at the MAP pressure under various running conditions. What does the MAP sensor read when the engine is stopped? 0 psi would be gauge pressure, ambient pressure would mean it's absolute pressure. You might look at the MAP sensor calibration. You might get the part number off the sensor and look that up.

Hey David , this is the tube in question

That's absolute pressure. MAP is measured manifold absolute pressure, and Link boost targets are in absolute pressure.

Subtract baro pressure from those values and that's your actual boost level.

Thanks very much for every bodies input. That does clear up something that has confused me for months.

Am i too naive to think this is just a Link think?

I did search through the logs and configuration to try and identify the difference between MAP & PSI but didnt see anything that was clear, my main concern is seeing boost figures of 30-40psi is nothing unusual nowadays so this is why i didnt really question it in the past.

Targeting a MAP makes more sense to me than targeting a boost level especially if you want to maintain a power level as barometric pressure changes, but I also understand it can be a surprise if it's not what you're used to or expecting.

I will say I have requested this be labelled clearly on the table, because you're one of many to be caught out by it.