Oem wastegate crack pressure

[Sv3kai]

Hi
I would like to know if it’s possible which is the crack pressure of the oem wastegate actuator on a cx7 2.3 disi 260hp 2008 with the oem k04 turbo.
Thank you

[mituc]

It's the same as on any MPS. These turbos have a 8PSI spring in the wastegate so the crack pressure should be around that, but it really depends on various things (how freely everything moves on the turbo, if the boost source line from the turbo compressor housing is intact or has some wear/kinks).
If you are experiencing a certain problem you can also lay down here the symptoms...

[Sv3kai]

Firstly thank you for your reply. I explain. My cx7 was tuned on dyno at 1.35 bar. After that I installed fmic and a tial qr recirculated bpv and retuned with the same boost target. When I left the dyno the pressure was 0.9-1 bar max. I figured out that the fmic connections lost pressure. I fixed the connections with leakage test and now the pressure is 1.1 -1.2 maximum. Do you have any idea where is the problem?do you want a log?

[Sv3kai]

Log.csv

(46.21 KiB) Downloaded 4 times

Also my car has fmic(max 450hp), tial qr, hpfp autotech internals, 1 step colder plugs with 0.7mm gap, 76mm downpipe 200 cell cat, 70mm custom exhaust, custom intake (oem diameter) and custom tune. In my log with 3rd gear on spool have 1.1bar with 15 % wastegate duty and at wot 0.9 with 0% duty.

[mituc]

Do you have any idea where is the problem?do you want a log?

Yes, add a log.

Also my car has fmic(max 450hp), tial qr, hpfp autotech internals, 1 step colder plugs with 0.7mm gap, 76mm downpipe 200 cell cat, 70mm custom exhaust, custom intake (oem diameter) and custom tune. In my log with 3rd gear on spool have 1.1bar with 15 % wastegate duty and at wot 0.9 with 0% duty.

There is a difference between the boost required to make the wastegate open (partially or fully) and the boost you get when applying 0% or100% wastegate (EBCS) duty. The result is a complex combination of many things:
- the amount of air the EBCS valve and lines flow;
- turbo backpressure (past an airflow value it becomes a restriction for itself);
- overall backpressure combined.
Also, remember that turbos flow volume, not mass, not pressure differential (boost). They pack air volume into the fins of those propellers and then they push them through the turbo housing and then into the engine which has on its own the capacity to eat up (or not) that amount of air. And then you have the exhaust side of the engine on which past a certain power (thus exhaust flow generated by the intake flow) creates a backpressure which requires more effort from the turbo to overcome.
So boost is less relevant, or not relevant at all. Boost is like big torque when you are trying to go fast, you need to transform that into power (air volume, which translates into a certain mass at a given temperature) somehow (longer gearing, higher RPM, and so on).

Also, considering the boost values you're getting on your car I reckon the power figures are somewhere between factory and the OTS base tune for the CX7 (so less than that).

But let's see that log (I just hope it has relevant parameters in it) to understand where you're at.

[mituc]

Ok, I just saw you posted a log, but why would you use forscan to get it when you have versatuner?!
Download the attached dashboard preset, open your versatuner go to Dashboard -> presets -> import and then load the newly created preset. Then take a WOT log in 3rd gear from 3000-ish to 6000-ish rpm on a flat and long stretch of road with good visibility, no police, no cats or dogs, no pedestrians.

CX7-Full-Logging.vtpre

(1.85 KiB) Downloaded 6 times

Also, in that log I can see you get about 250g/s or air at almost 1BAR of boost (0.96-0.98). In a cold day with a FMIC maybe you can get as much, but you may still have a boost leak, even with a FMIC you may need probably 1.2BAR of boost for that air flow.