I'm having an intermittent issue with boost control on my car and suspect the BCSV on my turbo may be the issue, I have trouble reaching a higher target pressure of 1 bar and get stuck around .7 bar ~10-11 PSI when the boost control is not working. It's an 8374 with the "standard" medium WG canister, the car does not creep at all. I'm controlling boost with my PFC and have checked continuity on the harness to the solenoid valve, I also pulled the solenoid valve off cold and it switched back and forth when 12vdc was applied so I ruled it out but I'm going back to it. On cool mornings I have no issues but it seems as if when it warms up outside and I romp on it I get a pulsing which I assume comes from the WG under hard throttle and the boost control stops working.

I'm planning on buying a new BCSV to try out, have any of you experienced a similar thing with their EFR when using the factory BCSV?

 

Higher density at turbo intake will give more power and more turbine energy for the same nominal boost. If the spring is marginal for you target boost, ambient conditions can be enough to push you peak boost up or down. Can you add preload?

 

Pre-load was added during the dyno tune. When the boost control is working it holds a solid 15 psi on the high setting and 12PSI on the low setting with no issues.

 

Post a datalog of the problem. What boost and duty settings do you have in the PFC?

 

Thanks for the reminder to get my laptop out for the ride home today! Setting 2 (high boost) is 1.00 and 49% for both primary and secondary which works well for holding close to a peak of 1.0 bar when the boost control is working. going up to 53% will yield slightly higher and 1.03-1.05 peak, the tune is to 16 PSI, plenty of fuel.

 

Ever thought you have a boost leak? a big one....

 

If there is a significant leak on the intake side it should be going richer than tuned too.

 

An intermittent boost leak? I've checked all the connections, vac lines, charge pipes, etc. Everything is fine and tight,

It's not going richer than tuned when I can't hit the high boost level.

You just need the text files, correct? If so, they are attached. At the top of the first pull in #3 is where I heard the weird popping sound and it was quieter than usual. Going into logs 4 and 5 you'll see the max boost reached during the pulls is lower, there was no change to the boost control setting. The pre-control % for boost control looks to be about the same for both as log 3 regarding reaction but I was no longer able to reach the same boost level.

I'll buy a replacement solenoid soon in lieu of testing this one. If the new one works I'll test the old one, I have the feeling that after it is hit with hard boost a few times it begins to stick in the closed position and stops spilling/venting.

 

Not an exhaust side gasket somewhere between ports and turbo opening up after getting hot?

 

 

Were you seeing a flutter on your boost gauge?

It sounds like a misfire but does not feel like one when it happens, i'ts a "ptffft, ptffft, ptffft, ptffft" sound when it happens if that works to describe it and it occurs on high boost only. After I hear it I let off throttle and normally have lost boost control(can't reach the "low" 12PSI setting or the "high" 15PSI setting. I've thought it could be an exhaust leak or a leak past the interal recirc valve but the recirc valve diapraphm is good and seals properly. All vacuum lines are tight, properly sized quality tubing that is ziptied or clamped on!

 

Sounds like surge. Isn't a rag in the intake, happening at lower rpm/throttle not 100%? Is your timing very soft?

 

Surging at WOT because my exhaust is too restrictive (RB Dual tip, 3" resonated midpipe w/ Vibrant resonator, and 3" DP)? The theory makes sense because it's louder with colder IAT's when it happens.

I have no issues with the noise on the low boost setting or part throttle, it's only occasionally at WOT on high boost and I don't see any creep nor does the PFC register a max pressure that indicates creep.

I can't answer the timing question, I know very little in regards to tuning. It is tuned richer up top because I didn't want to run AI.

 

Try switching to a closed loop boost controller like the older Greddy Profec B. . . .

 

- At what RPM does the flutter occur? 2.5k - 3.5k RPM?

If it is, then it's definitely surge. Try plotting your datalog on 8374's compressor map to check it yourself.

 

It's much higher up, I'm thinking it may be the CRV getting pushed open at high boost.

Ihor @ IR Performance sent me a new BCSV and has a stiffer CRV spring and 90* cover on back order. This is at no charge, I can't say enough good things about how helpful these guys are, they've never left me hanging!

 

I'm very impressed with everything on the EFR turbos except for their stock solenoid or their stock wastegate assembly. Its not that they're of poor quality but these turbos are high pressure, and that these components I'm complaining about tend not to function well at those pressures.

 

Just to close this out the issue was not the components, I remote mounted a new solenoid, replace the CRV, and still had a problem. I finally got to pulling the ECU cover and checking the signal wire for the solenoid and it was making intermittent connection to the ECU. The terminal was messed up when it was re-pinned, I removed it and put in a spare terminal with lead that I cut out of an old harness to test my theory. It worked and I was at 16PSI again!

I asked Chris @ LMS-EFI about purchasing a new connector body and terminal with the correct color lead for my harness, he sent one out for free! They are a fantastic vendor, my wiring harness is top notch.

 

Chris @ LMS-EFI is AWESOME!