BNR S3 Boost tapers up to 17.5psi from spring pressure??

[MPS_Fan]

Today i just started to monitor my car because Cobb AP is no supporting EU Cars. After my first log run with my BNR S3 i noticed that my boost tapers up from 14psi to 17.5psi at redline. At the moment i am running just from spring pressure, because there was no AP support before. Shouldn´t the boost stay at about 14-15psi? Does it mean that i have a mechanical issues (Wastegate doesn´t open far enough) or is the inner line diameter (4mm) i´m running to the WGA to small? Don´t want to start custom tuning without being sure that everything is fine.

[Lex]

17.5 psi is not too bad since you'll target at least 20psi by redline. Sounds like you have a bit of creep. Do you have a catless downpipe?

[MPS_Fan]

No, i have stock downpipe, testpipe and 3" Catback. I always thought, that BNR S3 has no problems with creep?

[Lex]

I generally don't see it creep but even if it gets to 17psi it's not a huge amount. Does it spike at all when it spools?

[MPS_Fan]

No Problems with spiking. It climbs to 14-14.5psi at 3200rpm then holds at 14-15psi and starts tappering up at 5000rpm.
So you think everything is fine? If yes i will hook up my Grimmspeed and start dial in my boost and MAF calibration tomorrow.

[Lex]

Originally Posted by MPS_Fan No Problems with spiking. It climbs to 14-14.5psi at 3200rpm then holds at 14-15psi and starts tappering up at 5000rpm. So you think everything is fine? If yes i will hook up my Grimmspeed and start dial in my boost and MAF calibration tomorrow.

Yup you shouldn't have a problem.

[atvfreek]

This is the first I've seen or heard of a bnr creeping, but as lex said, you will be targetting higher boost. So you shouldn't have any issues with tuning

Freekn tappin

[MPS_Fan]

I have to check the heat shileding on my turbo. I reused the old and put it on my bnr. I cut it out, so that the WGA has enough room to move. But maybe its touching somehow the sielding on higher rpm and cant open enough. I will check today…

This boost creep leads to traction problems in first gear. I think i have to use the throttle correction to reduce boost in first gear.

[speedy308]

If i understand correctly, you are using an AP now. Use the APP translation tables to limit throttle in 1st gear.

[ms3blackmica]

Just as everyone said, if you are seeing a max of 17.5 on just spring pressure then I am sure you will be fine when tuning for higher boost.

You shouldn't have any issue controlling higher boost levels.

Good luck with your tuning adventure. I am glad to see that Cobb has taken care of mazdaspeeds worldwide now!

[skeurton]

Originally Posted by MPS_Fan I have to check the heat shileding on my turbo. I reused the old and put it on my bnr. I cut it out, so that the WGA has enough room to move. But maybe its touching somehow the sielding on higher rpm and cant open enough. I will check today… This boost creep leads to traction problems in first gear. I think i have to use the throttle correction to reduce boost in first gear.

I was going to do the same thing and cut that one heat shield to make it fit, but decided to just leave it off in order to avoid any risk of interfering with the WGA.

Before installing it, I checked the spring pressure. The flapper cracked open almost exactly at 1-bar. After installing it, I ran spring pressure and it would hold around 15.5 psi and reach around 16.5 psi near redline. I'm tuned at 22 psi now and it holds like a champ across the board.

So just like everyone said.... it shouldn't be anything to worry about it.

[MPS_Fan]

Originally Posted by skeurton I was going to do the same thing and cut that one heat shield to make it fit, but decided to just leave it off in order to avoid any risk of interfering with the WGA. Before installing it, I checked the spring pressure. The flapper cracked open almost exactly at 1-bar. After installing it, I ran spring pressure and it would hold around 15.5 psi and reach around 16.5 psi near redline. I'm tuned at 22 psi now and it holds like a champ across the board. So just like everyone said.... it shouldn't be anything to worry about it.

Yes, thats nice!!! I done today another run. I see 17psi at redline. So everything should be fine. i will start populating my WGDC Table with 20 and see what boost i get. Target is 18psi tappering up to 20 at redline. Don´t want to VTA my block on german autobahn

BTW, our gas here in germany is the shit! I´m running Stage 2 98oct map and use 95 (E10) gas. Getting 0 KR all the way

[dr_banano]

Originally Posted by MPS_Fan I have to check the heat shileding on my turbo. I reused the old and put it on my bnr. I cut it out, so that the WGA has enough room to move. But maybe its touching somehow the sielding on higher rpm and cant open enough. I will check today… This boost creep leads to traction problems in first gear. I think i have to use the throttle correction to reduce boost in first gear.

yeah take it off that was my problem also i was hitting 18 psi on just spring and saw that the shield was pressing the wastegate arm causing this .....so rip it off better...

[MPS_Fan]

Problem solved, it was the heat shielding. I've bent it a little bit, now the WGA can move freely. He was slightly touching the shield. After bending i got about 15.5psi up top. This should be ok.
ATM i dial in my boost (18psi tappering up to 20psi). Car pulls great even with OTS timing values.