okay, whats the difference. and what am i having...? while in high boost (dyno and road) as my boost climbs, the needle bounces like mad and eventualy kinda evens out. it never goes over my preset boost and only does it in high boost. isn't boost spike when you go OVER your preset boost? whats bouncing within the range? is that just my boost controller (profec B spec II) needing to be dialed in better? heres what it looked like on my dyno runs.

http://forums.2gnt.com/dcboard.php?az=show_topic&forum=4&topic_id=61183&mesg_id=61183&page=

Check for leaks. EVAP system, brake booster, cruise control system. Compressor surge is primarily when the throttle plate closes and the lack of a BOV forces air back into the compressor. I guess the boost controller could cause fluctuations in boost pressure, but I'd say that you're leaking boost somewhere and the controller is adding more. Just a guess.

Yeah, a spike is when you overboost. Thats not what you have. I'm not sure what you have. My hunch is that it has something to do with either the wastegate or the controller. Its like the wastegate is fluctuating open too far. I don't know shit about those Profecs though. :shrug

Definately nice pull though. :7


95 Eclipse RS : 5 speed
15.7 @ 87.9mph
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

Fuzzy logic boost controllers do that. It modulates the boost signal to the wastegate much like an ABS system, so minor fluctuations will happen until the "fuzzy logic" unfuzzies itself.

MBCs rattle the needle, if the gauge is sensitive enough.

Yeah it sounds like you have a leak somewhere,and the Profec is trying to keep it steady, but it's having a hard time..What are you using as a boost source to the Profec solendoid? From my understanding of the Spec II, you should use the compressor as a boost source for the solenoid, and the intake mani boost source for the "boost in" vac line to the controller..And as info, the Profec Spec II, is NOT a fuzzy logic EBC..I've done quite a bit of research on this unit as I am contemplating buying one :)

I'm considering buying one soon as well. And if a boost leak is indeed what Tim is experiencing, I'm very impressed with the Profec B's reaction.

The profec e-01 is killer. I use it on the Z, along with the emanage I love it. I set my boost to a 6 psi flat once, and being only .5 psi over the wastegate spring setting it held it very well.


I actually have a brand new one in the box at home that I am tring to sell if you guys want it.

How much you asking?