You should subscribe to the post ...Low boost...by AX650 ...I will give it a bump , it seems like you both have a very similar problem ?

 

Addis,
Do you have a dyno jet tuner? I wonder if you have a log so we can compare. I only have stag 2. My log seems to point to the waste gate blowing open and not closing to hold proper boost level.

 

also might check that your BOV is working properly if it is opening, or not shutting all the way it will leak off boost too. Another thing to keep in mind when having issues like this is that if the tune is requesting higher boost than you are achieving it will keep the wastegate closed (if it's not a wg blowing open issue) and over spin the turbo creating excessive heat that could damage your turbo, so my advice is to be careful while troubleshooting this so you don't cause any damage to the turbo.

Do you have or have access to a mightyvac? or something similar? If not get one and hook it up to the wastegate actuator and pump some pressure in and see at what pressure the wastegate starts to open that is one quick way to see if that is all working properly.

 

Yes I have that tuner, I am fixing to record a data log so I can send to mike @ AA. Shoot me your email and I will send one to you as well.

I’ve ruled out a BOV issue as when wiring the gate shut it built up plenty of PSI.

 

when you wired the wastegate shut and was able to get 25 psi, did you shut it down as soon as you saw that much boost and it could have went more or was 25 the max you saw and you were running it wot under load?

 

I let out at 25psi in fear of causing damage, it would had kept building.

 

Any updates ?

 

If you have replaced the wastegate and it makes boost when you wired it closed I would check the boost controller for proper operation. It's mounted on the driver side rear engine compartment. It sends the reference signal to the wastegate for boost control.

 

I just went through exact same issue. If you wanna pm me I can walk you through on the phone what was causing the problem and how I fixed it.

 

If you dont mind please share your findings....That is kinda what the forum is all about ...Thanks in advance

 

Sure. A lot to type but here I go. So basically I would pinch off or disconnect boost control hose to Wastegate actuator. The boost control hose basically puts out positive pressure to actuator. So it controls when Wastegate opens to prevent overboost. If the turbo is overboosting with Wastegate actuator wired shut that would tell me there are no other leaks in the system. Basically wat I found on mine was there needs to be a small about of preload from the actuator on the Wastegate to keep it closed. Mine didn’t have preload and actuator had Wastegate cracked just a kunt hair to leak boost.

 

Thank you for your response , that is good information. Question ....you said the wastegate must have some preload. Are you adjusting this by adjusting the wastegate actuator rod ? Or did you have to replace the WG actuator all together because it was bad? What is the correct preload that you are referring to ...crack pressure at 7 psi ?

Thanks

 

And by no means I claim to be an expert. I just learned( Rzr turbo system) all this the last 2 weeks from talking to people and spending countless hours in the garage. Hopefully this will solve someone else’s problem also.

 

Here's a copy paste from AA's website if it may be of help to anyone..I'm no turbo expert, but this seems to give a pretty good description...

Not getting the boost? Normal boost should be within 1psi of target which you can view manifold pressure vs. target boost if you have the PVCX and data log. If you are lower than this and not getting anywhere near the boost you should, it's time to start digging. Here are the things to check: waste gate too weak or sticking? Use an air pump with a low PSI gauge to push 6psi at the waste gate actuator. This should start to move around 5-7 psi depending on adjustment. Any lower and you probably need to replace it. Is your turbo shot? Remove the intake tube and take a look at the compressor wheel. You can usually tell if it's been hitting the housing. You can also use a needle nose pliers to wiggle the shaft and check for excessive play. These turbos do have a good amount of play in them when cold, but when hot have much less. I'd suggest checking them after running it (be careful, hot!) just to make sure. Boost leaks are another very common issue. If your charge tube is not sealing correctly on the turbo or throttle body it will definitely cause an under boost or no boost condition. If your blow off valve is not working properly that will also cause a lack in boost pressure. MAP sensors not working correctly or having an issue with the wires going to them will cause issues as well. Swapping these sensors with known good ones is the best way to test, or data log if you have the Powervision. You have 3 MAP sensors. Your atmospheric pressure sensor located before the turbo in the intake tube. The other 2 are the same sensor and measure boost/heat before and after the intercooler. One is in the charge tube and the other is in the intake plenum. The electronic boost controller could also be bad causing a low boost condition, or the boost lines running to it. The boost lines run from your intake plenum, then T off with one line going to your boost controller, and the other to your blow off valve. If any of those lines are blocked or pinched it will cause a low boost condition. An air restriction in the airbox with a clogged filter, collapsing intake tubes... ect can also cause low boost. The last cause for low boost can be caused by improper clutching. Boost works off engine load, when the engine is loaded it will create boost. Unloaded it won't. The simple version; if you don't have enough clutch weight, it may not create the proper amount of boost (normally not off by a huge amount, 1-2 psi low). Keep in mind that target boost vs actual boost will many times be off by roughly .5 to 1.5 psi as a cushion for over boost protection.

 

Crack pressure depending on your tune. I think most tunes are 6 to 7. I fully closed the Wastegate with my hand and left the actuator slight shy of reaching where it bolts up the Wastegate, then used positive pressure pump to slight engage the actuator to reach the Wastegate arm or where it bolts up. This way the Wastegate always had a little pressure from actuator to keep it fully closed. Hope this helps.