Originally Posted by VargasTurboTech
Yeah, I just don't see any evidence of the DME intervening and killing boost. Through what mechanism would it do that that we haven't already checked? Why would it "limit" boost at 17psi tapering to 15psi and not 20psi tapering to 18psi, for example? We run more boost than this with the stock turbo at lower rpm all day long without issue.
Regarding the VT3s and your tuning, you were using the DME to control the wastegate and you were not fully opening them. It was not giving you full vacuum at the gates. You should not need to dig deep for that. It's the first thing any tuner would check. And the first thing I checked on these. If there was not full vacuum at the gates then I'd say this is definitely a tuning issue. Or if the throttle was closed, or the DME was pulling timing, or if AFR was way out of whack, etc.
You keep crying tuning but we've got the Cobb N55 flash software suite. I've one of the few tuners who has flash tuned N55s on a dyno to measure the changes being made. N55 flash tuning currently is not where it needs to be to properly tune a turbo like this. Try to find a flash tune only N55 making 390rw like we make on the OEM flash using a JB4 and maybe you'll appreciate the limitations. PS. Here is a dyno of the stock turbo @ 7 degrees advance and 12 degrees advance. The 12 degree advance run is using a Cobb back end flash with higher load targets internally, richer air/fuel targets, etc. Barely any change from the stock flash.