I originally just had a boost controller and tried setting it for just under the normal boost cut/fuel cut/whatever range. This worked ok, but I could never get any consistency from day to day. On my turbo Hondas I would set the controller for 15 psi and it would stay there no matter what.
MBC's are very well known for being inconsistent. That's not just a Mazda thing. The principles which the controller works under are affected by weather, temperature, as well as a litany of other surrounding conditions.
So I added a Boost Cut Defender, but didn't have much luck with that. Saw AFRs that were just way too rich (like 9 or less). Safe, but all that extra gas was just choking out any extra power that could be made by running more boost.
The BCD was a quick fix that, even at the time they were "in the market", were a lazy man's solution for a map clamp.
The car runs rich. It just happens. The ECU will not allow it to be lean in the stock tune. There is a car that ran 10's at WOT with a GT40. If you don't want to run rich, you need to tune it.
I then added a downpipe and midpipe (both catless) BPV, and an intake. Then I started seeing the boost go above safe levels even on the stock tune (spiking past 20). I also noticed my fuel pressures were dangerously low, and was constantly getting KR.
Running catless is well known causing boost creep. This is nothing new. I don't understand what you mean by "dangerously low" fuel levels... until the point you get cut there's really no threshold...
Knock sucks on these cars- you just have to monitor and respect it.
I forked over the $600 for a Cobb AP, and had zero luck with that. I was using the OTS maps (v 1.02 and later 1.03 when they were released), but was still getting way more KR and boost than I felt was safe. Spiking and holding past 19-20 when the target was 17-18, still getting fuel/boost cut...still seeing low fuel pressures.
No one has ever really brought the Accessport into question- it sucked when it came out. The ability to tune it has made it a more worthwhile product... but there are simply too many small issues that happen on an individual basis to think that an ots tune is going to solve all your problems.
So I upgraded the fuel pump (that worked just fine...fixed the low pressures) and sold the AP. Back to the stock boost/tune. Got bored really fast. I switched back to the MBC route and went with a MAP clamp this time. That actually worked for a while, but still was seeing loads of KR in the higher gears, low AFRs (expected), stuttering, inconsistent boost, and generally running like s***.
Well, what do you expect? By selling the AP and going back to simply running MBC/MAP you essentially took a large step backwards in the developments people have made with tuning this car.
I just recently took the MAP clamp, BPV and MBC off and am back to stock again. I'm having issues with the boost going all over the place, but I'm pretty sure that is just the ECU trying to recalibrate itself. If it doesn't, I'm just going to take the intake and exhaust off and go back to 100% stock
Again, if you are still catless, the boost is going to move around.
So anyway, long story...but anyone else disappointed in how difficult it is to modify this car and have it run right? What is up with all the overboosting, Knock Retard, low fuel pressures, gear-limited boost, throttle body that won't open all the way, etc?
- You are overboosting because you're running catless without a tune or any kind of wastegate modification
- Knock is the result of a few things which have been discussed in great detail.
- Partial throttle knock largely is the result of the ECU running stoich in boost
- Low load knock is the engine pulling timing via the sensor
- The knock sensor is a harmonic device, and certain sounds resonating in the bay can lead to knock
- The engine just plain knocks once in a while- the car runs rich as s***, it's going to happen
- Low fuel pressure have been completely resolved with a 200-some dollar mod- it's a DI thing, not a Mazda thing. Check out the vag guys.
- Gear limited boost can be completely removed- no one does it beacuse it's retarded to try and handle 16PSI in first gear on a daily basis... not to mention why would you want to beat on your trans like that?
- Throttle body opening can be done via the tune too... many people do it with good results when they switch over to larger turbos.
It just seems like you are frustrated with many of the issues that have arisen while working with a new platform... and I don't blame you. This community has sucked- but it is making advancements. There are guys running 300-330HP daily with meth and tunes... not to mention one recently hitting 433HP on n2o. It's just the challenges you face when trying to work in a niche market without the support of larger companies like Evo's, STI's, and SRT's get.
If it's not thing for you, then it isn't... but it seems like you're largely just caught up on issues that are now the past.
You're not alone with the frustration, but this is just kinda what you face when taking on a new platform.
Best of luck.