I finally installed a boost gauge today and found that my evo 5 is only hitting 13psi and then dropping off to about 11psi at around 6500rpm. It's got a turbo back 3" exhaust and free flow pod filter. I thought boost doesn't drop off so much with a full exhaust?

Isn't this quite low for factory boost? Wondering if I install a boost controller if it will hold higher boost, or if something else is limiting it?

Cheers.

 

You have a boost leak. Tbe has nothing to do with boost psi.

 

Whenever I have upgraded to a full exhaust boost has gone up about 1 - 2 psi. Whats best way to check for boost leaks, check all the hoses etc?

 

Changing the exhaust will effect boost.

Stock boost for Evo 5/6 is 1.1 or around 16 psi so your not that far off from where you should be. I doubt your problem is a boost leak but you can check for that. My gues is maybe the solenoid is going bad and not bleading enough pressure away from the actuator.

 

I just had a look at the factory boost controller and noticed that the line going to the actuator is connected like normal but the other vacuum line coming off the solenoid is not connected to anything...

There is an after market external BOV which was already setup when I purchased the car, wondering if that second line was pulled out of the factory one and just left there going to nothing.

Could that affect boost? Should I T-connect that second vacuum line into another vacuum line such as the one going to the after market BOV.

 

& search

 

To my above, would that seem like the obvious problem that the Soleniod wont even be doing its job and the computer or wastegate has taken over and just limiting the boost?

 

Is there a way to test for a faulty Solenoid? Or can I just connect a manual boost controller and bypass it and see if the boost raises?

PS: I should add the evo also has an after market external blow off valve which was already on the car. I've heard that can sometime cause boost levels to drop...

 

Run a hose directly from the WGA's nipple to the nipple on the compressor housing discharge tube's nipple and increase boost by rotating the turnbuckle on the WGA rod inward. PM me if dubious..

 

Yea I was going to try plugging up the line to the Solenoid and see if its exactly the same which would tell me a faulty Solenoid am I right?

...And on that note, does it matter too much about the brand of booster controller if I were to purchase a manual one?

Such as this cheaper brand (DPR): http://www.drivenperformance.co.nz/s...?idproduct=691

Or this more well known brand (TurboSmart): http://www.redlineperformance.co.nz/...cts&part=23960

 

I've just installed a GFB manual boost controller directly to the actuator and capped the turbo compressor housing and capped the solenoid inlets.

I have the boost controller wound as far as it goes clockwise (so should be low boost) and it's still hitting 18psi but then cutting out when it gets that high.

Any ideas? What should a evo 5 cut boost at?

 

Whoah! Turned all the way in clockwise should be HIGHEST boost possible. Since you have the compressor outlet tube's nipple plugged off, then you must be taking the boost reference source from a "T" fitting installed into the line that connects the DV to the intake manifold, right? You must also block off the now unused nipple in the MAF tube, right?

 

I was told clockwise and it says in the instructions start from clockwise which should be lowest boost. Is that incorrect?

The boost reference side can be left to atmosphere which I have done and also tried T fitting it to the line that connects DV to the intake manifold..

Could the boost reference being left to atmosphere have much of a negative effect? I've heard that's what some people do.