BNRS4 won't boost past 10psi.

[Prometheus]

I am running a v1 BNRS4, with a Corksport ebcs, and Tial 44mm external wastegate, it's setup as an interrupt style, and upon visual inspection the lines seem to be properly routed. I've pressure tested it recently and it held 20psi so I don't think it's an boost leak.

I'm tuning with Will and he targeted 20psi on this map. He told me that it could be because of the ebcs, the routing for it being wrong/leaking or the ecu.

I tried driving it with the ebcs unplugged and received no change to the amount of boost, I am confused because the wastegate is set to 15.95psi, so if the wastegate had an issue I would expect it to boost to at least 15.9 right?

How can I go about testing the EBCS? I did realize the connector is broken during the visual inspection but it still seems to be deep enough in to be making contact just not clicking. It is firm and doesn't come unplugged when driving also.

 

[Tricks]

I am running a v1 BNRS4, with a Corksport ebcs, and Tial 44mm external wastegate, it's setup as an interrupt style, and upon visual inspection the lines seem to be properly routed. I've pressure tested it recently and it held 20psi so I don't think it's an boost leak.

I'm tuning with Will and he targeted 20psi on this map. He told me that it could be because of the ebcs, the routing for it being wrong/leaking or the ecu.

I tried driving it with the ebcs unplugged and received no change to the amount of boost, I am confused because the wastegate is set to 15.95psi, so if the wastegate had an issue I would expect it to boost to at least 15.9 right?

How can I go about testing the EBCS? I did realize the connector is broken during the visual inspection but it still seems to be deep enough in to be making contact just not clicking. It is firm and doesn't come unplugged when driving also.

Did you figure this out because im having a similar problem

 

[Gabriel Buscema]

My v3 BNRs4 only hit 13psi on wastegate when it was supposed to hit "anywhere between 14-17 psi”
Justin said that's completely normal. altitude could affect it, I'm at 5200 feet.

 

[Prometheus]

Did you figure this out because im having a similar problem

Still not fixed
I can boost to between 14-15 psi now, I think I fixed a leak a bit ago
However the boost controller still does not respond to waste gate duty cycle, as it is stuck in the 14-15 range.
I have tested the EBCS with a 9v battery and can feel it functioning, and if I switch the NO port and the NC port, the wastegate is disabled allowing it to boost past spring pressure 25+ psi.

I feel this eliminates the EBCS, routing mistakes, or leaks as the issue and meaning the boost controller is just not getting anything from the wires.
How can I further diagnose the wiring to the controller?
Will said the region of the ecu responsible for boost control could be damaged, I don't want to reprogram a key and mess up my mileage that bad.

My v3 BNRs4 only hit 13psi on wastegate when it was supposed to hit "anywhere between 14-17 psi”
Justin said that's completely normal. altitude could affect it, I'm at 5200 feet.

I'm at 7000 feet, though Will knows that and he says the car is not responding to additionally wgdc he added to later revisions.

 

[Enki]

However the boost controller still does not respond to waste gate duty cycle, as it is stuck in the 14-15 range.

You absolutely cannot know this without looking at logs (which you should be posting if you want someone to diag).

 

[Prometheus]

You absolutely cannot know this without looking at logs (which you should be posting if you want someone to diag).

3 4th gear pulls tc off, the first two staring around 2k and going to 6k slowly. The 2nd of the slow ones has smoother throttle application.
The faster one starts at 3k and goes to 6k.

 

[Enki]

Need to log accel pedal position bro.

 

[Prometheus]

3. 2.5k-5.5k
4. 3k-6k
5. 2k-6k
6. 2.5k-6k

 

[Enki]

Does it only hit 10 PSI after a reflash or ECU reset? If so, you're probably out of comp room (tune issue) or the comps are set too conservative. It honestly looks like it's doing what it's being told to do.

 

[Prometheus]

Sorry for the confusion- at 10psi I had the wrong springs in the wastegate, which i fixed letting it reach the 14-15 range.

Will told me "the boost not moving even though i added wgdc is telling me the issue is mechanical" and that I would know I fixed it when it made 'proper boost' (20psi target). I put a 15 or 16 pound spring in so it's just spring pressure and the boost controller isn't doing anything. Which I feel is confirmed by unchanged boost levels when leaving the ebcs unplugged.

 

[Enki]

That actually depends. On more than a few setups, you won't see any movement in boost pressure until about 40% WGDC. Also, the spring pressure is actually tied to exhaust pressure, not boost, so if your setup is backed up quite a bit, you might need more than what you have.

That said, the fact that the WGDC isn't going for 100% is kind of telling, esp if it's off by more than a few PSI. I forget, have you tried swapping EBCS with someone else and see if that does anything?

Edit: If you do the above, make sure to reset your ECU so you don't pop on the first pull.

 

[Prometheus]

Very interesting about the exhaust pressure, this never occurred to me. My downpipe is some cheap catless crappy one, looks like it's a 2.6 inch or 66mm which is basically stock size. The rest of the exhaust I pulled off a junkyard speed3 and don't recall the size but it did fit on my stock turbo. I never measured it though.
In my defense I bought an BNR S3 but the part-out account on instagram sold me an BNR S4v1. And on that tangent it was welded shut by the previous owner so room for error there too
I have a 3.5inch corksport intake on it also.

As for the other ebcs, this is my second corksport one, somehow misplaced the first so can't get logs with it, but the behavior was identical

 

[Enki]

Nothing else changed before having this issue?
Do you have a diagram of how the EBCS is connected?

 

[Prometheus]

Not that I can think of

 

[Enki]

Huh, maybe try a different EBCS?

 

[Prometheus]

Will do, a buddy has a 3 port I should be able to try soon.
Do you think the downpipe/exhaust size is restrictive for the turbo?

 

[Enki]

Not for a K04, no.

 

[Prometheus]

For a BNR s4?

 

[Enki]

Oh right, sorry, long day for me yesterday.

Basically, engines are big air pumps; the better you can get them to flow, the more efficient they will be (better spool, better topend, etc). I had a 3.5" intake on my KO4 back when I was still mostly stock, so, you can probably extrapolate from there. If not, look up turbo exhaust size HP, which can give you a better idea.

 

[Prometheus]

Took my wastegate off and saw soot, so reinstalled it with an airline to compress the piston while i tightened the clamp. Saw maybe a .5psi difference peaking at 15.06psi but no higher despite increasing wgdc.
Found my original ebcs- which did have damaged wires, somehow they melted together. Put electric tape around them and same increasing wgdc (peaking around 70%) but no higher than 15psi of boost.