R33 Gts25t W/ Apexi Avc-r Boost Problem

[h2k]

I have a RB25DET with:

-3" exaust from stock turbo and back

-Apexi air filter

-Large front hybrid intercooler

-Apexi AVC-R boost controller

Before I installed my AVC-R boostcontroller the original 2-stage boost controller used 0.45Bar boost up to 4500Rpm then it jumped to 0.65Bar all the way up from there. In other words:

2000rpm-4500rpm the boost is 0.45

4500rpm-7000rpm the boost is 0.65

Before installing the Apexi AVC-R solenoid controller I removed the original solenoid controller.

The problem is when I reach over 0.80Bar boost the engine studders, kind of like when you hit the rev limiter but more random and in shorter bursts.

-Is this what is called "flatspots" ?

Im running Denso spark plugs but I do not know the model nr or gap. Will regapping them to 0.8 help ?

-Does my engine have a fuel cut or a boost cut?

Would a fuel cut defencer fix this?

Where is the original ECU's pressure sensor, would blinding this hose stop fuel/boost cut?

-Or am I getting to little fuel?

Will a Apexi digital Fuel controller fix this?

-How much boost are you other R33 gts25t owners running on your stock turbos and what have you done with fuel?

Why don't you just keep the boost under 0.80Bar then? well if I program the AVC-R to boost 0.75Bar it quickly adjusts boost so I reach 0.75 as fast as possible in the rpm register but as soon as I pass 4500Rpm the boost spikes to 0.95Bar.

If I adjust the boost to 0.5Bar with the AVC-R it still jumps to about 0.9 something bar when I pass 4500Rpm.

I've tried to adjust boost duty cycle but it still overshoots. I find this very weird since I HAVE removed the original solenoid controller and still it seems like a 2-stage boost controll happens at 4500rpm.

-Now where is the best place to connect the AVC-R boost hose that control the solenoid on the turbo, just after the turbo known as the "hot side" or the "cold side" after the intercooler?

Edited May 29, 2006 by h2k

[paulr33]

standard ecu rich and retard protection being activated by too much airflow (as a result of increased boost pressure).

stock ecu has no boost sensor or map sensor to monitor boost pressure, it is just seeing a stack load of airflow via the airflow meter and actives its self protect.

if you can get around the stock cut it should be ok to drive with, try lowing boost pressure and try again, try about 0.70bar and see if you hit it

either;

(in order of preference)

a) get apexi safc piggyback

c) get aftermarket ecu (powerfc)

b) remap stock ecu

d) get a boost cut defender