Guardian Angel
 

ok so I'm replacing my turbo and going bnr s4. but i'm on stock block and its my dd. so the thought of a secondary safety device to prevent the turbo from blowing my pistons to the moon in the event of over boosting. And with stock block this seemed like a no brainer... but i'm thinking the versatuner tunes off load logic. and not by boost psi like ap. so with the ap. if you were running 19 psi and it spiked to anything above 20psi the guardian angel would save you a$$. but with versatuner doesn't that mean that to get to a certain load value. versa might have the turbo spool to 22 or 25 psi but go back down as needed for it to hit the target load value. but with that said doesn't that mean that the guardian angel would have to be set to such a high psi that the car could still over boost? if say it went to 25 psi when it should only be at 17 or 19 in that part of the load tune.(meaning normally it should be a 19psi at that rpm on that tune. but say if a bov or bcs hose disconnected and its overboosting in too low of a rpm. where it could hit that number no problem later in the rpm on that tune). so there for its over boosting but if I set the guardian angle to 19 so it wouldn't let it do that then it also wouldn't allow it too go past that in the later rpm's when its perfectly safe?

I know there is a secondary switch to have a secondary trigger. is there a way to hook up the secondary trigger to versatuner in a way where when versa or the ecu rather detects over boosting and initiates fual cut that it can also do the secondary trigger for the guardian angel. im gathering everything for my build now and want to know what need to do. so when I get to that point I know what I need to do... thank I appreciate the advice!!:lew:

I uh, what

http://www.mazdaspeedforum.org/forum/foru...1&d=1487841325

I read on one of the write ups that if you go bt that the factory ecu fuel cut and throttle cut wouldn't be fast enough. And that by the time those kicked in that you would have already hit full boost and blew up your motor.

I seen another speed running a guardian angel but they were running it with ap not versatuner. AP is tuned by boost. Versatuner is tuned by load. So with ap you should never go over the set boost psi. And u can set the Guardian angel to a notch above that. All is well.. but with versatuner boost psi will fluctuate. And will more then likely hit a number at that rpm that at a lower rpm will be really bad. How do u set it up then ?

Like it might go 25 psi at 4500 rpm (GOOD) but then it might over boost and hit 25 psi at say 2000 rpm (BAD)

I think I'm over thinking it. I'll just set the angel to a notch above peak boost of map I'm running.. just making sure I cross the T's and dot the I's.. bt & stock block... my bad

You can load tune with an AP as well. The boost based logic is just a toggle within the ECU that Cobb made available. VT has acknowledged its existence but didn't chase it because load tuning is pretty superior to boost tuning.

To answer your question, the GA will open the BPV at whatever pressure you set it to. The turbo won't be able to surpass that pressure because opening the BPV is a HUGE pressure drop and only extremely massive turbos (like 80mm+) would be able to make boost with it open. And the factory cuts work just fine, you'll find that out the first time your face hits the windshield.

Thanks man, I appreciate the help!