Erratic Boost spike?

V8killR4U

Active Member
Joined
Jan 21, 2003
I have noticed on my recorded runs on my Power Logger the boost is very erractic. During a 1/4 pass boost reads between 21 - 25 lbs of boost for about 75% of the run. At the end of the run Boost spikes to 29-31 lbs then drops to 20 then spikes back up to high levels of boost it does this towards the end of the run and it happens at least 3-4 times. What could be causing this?

I have a HD actuator with a RJC boost controller. Never really noticed this until I recorded the runs on the PL. Aany suggestions on how to get the boost to stay steady? :confused:
 
I would verify the issue with an analog gauge first. If the gauge exhibits the same behavior then I would suspect that the RJC boost controller is sticking somehow. But if the gauge is steady while your powerlogger readings are erratic, then it's a voltage issue - bad ground or MAP sensor, loose wire etc. Good luck.
 
I will have to double check my analog boost guage. Wouldnt the MAP sensor reading me more accurate however, its normally the boost guages that are off...
 
I would verify the issue with an analog gauge first. If the gauge exhibits the same behavior then I would suspect that the RJC boost controller is sticking somehow. But if the gauge is steady while your powerlogger readings are erratic, then it's a voltage issue - bad ground or MAP sensor, loose wire etc. Good luck.

How does the RJC boost contrller get stuck...Isnt it just a spring and metal ball?
 
If everything voltage and gauge wise checks out, then maybe this.
Reading your signature, it says PT70 P-trim turbo.
1st, are you running a normal 3" THDP ? If so, did you port the wastegate hole in your turbine housing to just smaller than the puck size?

Too me, it sounds like the wg puck is bouncing off the face as you're going down the track. there could be some carbon buildup inside the RJC valve that's causing the ball to stick, or carbon that's causing the puck to stick, but I'm betting the hole is not ported enough if ported at all.

All P-trim and our HP62 and larger turbine wheel equipped turbos need to have the wastegate hole ported out for smooth boost control when used with an internal wastegate actuator. Especially on a combo such as yours.

Let us know.

Patrick
 
If everything voltage and gauge wise checks out, then maybe this.
Reading your signature, it says PT70 P-trim turbo.
1st, are you running a normal 3" THDP ? If so, did you port the wastegate hole in your turbine housing to just smaller than the puck size?

Too me, it sounds like the wg puck is bouncing off the face as you're going down the track. there could be some carbon buildup inside the RJC valve that's causing the ball to stick, or carbon that's causing the puck to stick, but I'm betting the hole is not ported enough if ported at all.

All P-trim and our HP62 and larger turbine wheel equipped turbos need to have the wastegate hole ported out for smooth boost control when used with an internal wastegate actuator. Especially on a combo such as yours.

Let us know.

Patrick


I will have to take the DP of and take a look see. Thanks for the advice.
 
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