what is the stock turbo's limit on the ms3?

[fourthmeal]

Laloosh, your explanations after the one I've quoted down below this reply all sound pretty much correct, but it was this quote that threw me off greatly. As I said, I think you just meant it backwards.

you could still drive partial throttle, just watch how much boost it makes under how much gas you give it. Im not sure where this car goes closed/open loop but most cars are around 50 percent throttle. Say you are in 6th at 47 percent floored, your boost is set to 18 and you are hitting 18 at 47 percent throttle, You are still running off the pre programmed settings that are inbedded into the ecu. When you cross 50 percent, or wherever this car is set, it starts relying more on sensor to adjust everything.

Put it this way, its safer to be floored at 18psi then to be at partial throttle at 18psi. Just watch your guages, and drive normal. Or you can just floor your car in 6th at 3k rpm and hope it holds together.

The only reason why I bring this up is that if people are following you closely (and trust me, many do because of your success on the strip), I want them to know that this isn't correct the way it was worded. With this quote in mind, do you see why I was trying to correct what you posted?

Ideally, I think you meant that:

In normal closed-loop operation at below 50% throttle or so, the ECU runs off pre-programmed maps and gets feedback from the O2 sensor to adjust its trims.

In WOT, open-loop operation, the ECU stops adjusting the trims and runs off a pre-programmed map adjusted with adjusted trim values learned during closed-loop operation.

Both modes, open / closed still use the MAF (and the knock sensor!) to determine what the engine needs.

In essence, I agree with what you posted but I wanted to make sure that people got the right information from it. I whole-heartedly agree that a partial throttle overboost of 18psi is going to risk the engine far more then a WOT run to it. This just makes sense given the engine is striving for a stoich air/fuel ratio at partial throttle. No engine I know can stand 18psi at 14.7:1 for long!


The solution to this issue? It would be nice if we could get a boost controller that was able to read what boost and throttle opening (perhaps the throttle pedal more so then the wacky throttle plate itself with our cars) and adjust the maximum boost allowed at that opening. Say below 75% throttle, the boost controller limits boost to stock levels or less if that is even possible. And at WOT, all bets are off and we go to "Hi-Boost" as HKS calls it.

 

[tru-boost]

my MBC is pretty good about part throttle boost. it seems to build boost progressively depending on throttle position. if i go to 50% throttle i only get about 10-12psi.