Gauge fluttering, wastegate baseline???

[rossbaxt]

I’ve got a stock 15viper motor with 180 mpi trail kit no afr gauges.
Just plumbed in a cheap $30 boost gauge, and tied in bpv(was never hooked up). I also had to repair my broken waste gate mounts, and in process shortened the mount a bit. Also Noticed EABC wires frayed coming out of controller, still hooked up but I’m unsure if it’s working. I was advised to set my wastegate to 2mm preload.
i Fired up the sled and the boost gauge was bouncing between -12 and 0 at idle, but would level out in the negatives just off of idle. Initiall test i was seeing 12lbs boost and adjusted it down to 6. So at wot gauge bounces and is unreadable. At 7/8 throttle and it levels out at 6 lbs.
Anyone know is the gauge just junk, or is there something else going on Here?
Assuming the boost gauge is junk, is there a baseline measurement for the wastegate that should get me close to the pressure i need?
How much boost can I run safely with stock motor and no afr gauge?

I know I’m going to hear “get a different boost gauge” but not possible before my next ride

 

[ateick]

Cheap gauge isnt helping by my AEM boost gauge would bounce like crazy in vaccum, it would settle into solid numbers in boost.

Without headshim no more than 6#'s on stock internals.

You should have an AFR gauge for safety IMO especially if you have had ongoing reflashes. The fuel maps have change alot over time it appears.