Weird partial boost surging with AEM Truboost

[lithium14]

Some background:

Engine was rebuilt three years ago and along with the upgraded 57-trim that went in, I also installed an AEM Truboost. Anytime I was in 0 to low boost, there would be a pulsing noise, sensation as if the wastegate was opening and closing repeatedly. I knew it was related to the truboost, because when I plumbed the wastegate back to stock, it went away but just didn't boost as high. Now this didn't bother me too much because a simple solution to the surging/pulsing was to simply give it more throttle and up the boost and it would go away. However due to some newb idiocy (didn't prime the motor long enough to fully oil the new turbo), I had to rebuild the turbo until a new stock one could be found.

I have now found the new one and am just about to finish rebuilding it as well. As such I want to try and get rid of all issues to make this turbo last longer than the one year my upgraded one did. Has anyone else had experience with setting up the Truboost and having to deal with what feels like wastegate pulsing at low boost?

Another probable issue is that I was running a 57 trim turbo on stock ignition/fuel and air. Granted that ignition is now upgraded to a COP setup and fuel has an AEM pump with AFPR but still stock injectors. Stock AFM and housing. I have been told that it's OK to run a 57 trim with this set up but I want to confirm that as well. If having an upgraded turbo with stock fuel/ignition and air is indeed OK, then I might consider putting the upgraded compressor, compressor housing, shaft and exhaust housing on the newer in spec center housing (which is what went bad on the old turbo, bearing surfaces were worn way out of spec and scored from running dry). If it's not such a great idea, then I'll be OK with just using the completely stock turbo to hold me over until my manual swap/standalone install is complete.

Thanks for your time, looking forward to some educated input =D

 

[lithium14]

Upon more research I am finding that a 57 trim is OK on stock fuel as long as I don't exceed fuel cut, which for me is around 10-11 psi depending on weather, but I have seen it spike up to 12 on cold nights as per the max reading on the Truboost. So now my issue is mainly the pulsing/surging of the wastegate that seems to be a problem related to tuning the AEM Truboost. I set up years ago and remember experimenting with all kinds of set ups for the wastegate and the best I could do was make it open later which got rid of the pulsing but it made boost spike so quickly I hit fuel cut almost instantly.

 

[suprajim54]

I also use the Truboost but with a 60-1 CT26 and the 11psi wastegate from Driftmotion. When I installed the Truboost I had some problems dialing it in and experienced some boost spikes and surging. I followed the AEM directions and set spring pressure at 8 (3 below WG Spring). It would spool up too quick and I'd hit fuel cut. Even if I kept the A/B settings low, the car would surge during acceleration. After lots of tweaking, I finally ended up with a lower Spring Pressure and A/B duty cycle settings. Now I have the Spring Pressure set to 4.3. With the Truboost "OFF", I hit 8psi consistently. There's a little lag, but not too bad. Feels a little faster than stock. I put Setting A at 65 which gets me to ~14.5 PSI. Setting B is 45 which yields about 12PSI. However, if I do a pull on a cooler night, it'll hit 17-18 PSI on setting A. On those days, I'll just switch over to my B Setting which gets me back to my preferred limit of ~15 PSI. The power comes in pretty smooth with the exception of a little lag, but once the turbo kicks in it pushes you back in the seat. Long story short, the Truboost is not perfect, but after some tweaking I was able to get it right for me. I'm pretty happy with it. I have 3 different settings which is enough for me- "Stock", Setting A (Warm Day Max) and Setting B (Cold Day Max). For my weekend car, I don't need anything else.