[BB_cuda]

Deezy, I think that 48 psi is psia as in absolute pressure. You need to subtract off atmospheric pressure.

[supermann125]

@iaknown do you know if BPC is modifying the waste gate or having over boost issues with the complete "iaknown" package on their 2+ tune? Would like to know if I'm going to be DIY with that tune so I can handle with everything off

John@BPC

[BB_cuda]

BPC actually feels the waste gate mod isn't necessary. I believe its in this thread or another related one.

[f00dstamps]

Originally Posted by BB_cuda

BPC actually feels the waste gate mod isn't necessary. I believe its in this thread or another related one.

I've logged up to 40 lbs of boost on my BPC 2.5 + iaknown turboback exhaust + race pipe. The internal wastegate cannot evacuate the pressure fast enough. I purposely lay off of full throttle because I am still considering an external wastegate option.

[kydiesel35]

Originally Posted by f00dstamps

I've logged up to 40 lbs of boost on my BPC 2.5 + iaknown turboback exhaust + race pipe. The internal wastegate cannot evacuate the pressure fast enough. I purposely lay off of full throttle because I am still considering an external wastegate option.

If you send them your dde they can fix overboost issues... 40lbs does sound a little rich for 2.5, may be wrong though.

[Deftronix]

TDI - did you end up cannibalizing an egr cooler to make the piping? The end that connects to the exhaust manifold looks the exact same as stock (flex pipe and piping that extends passed the flange)? Would like to do this mod for peace of mind afters deletes but dont want to sacrifice my egr. Imagine the angles are pretty tough to get right. Probably have a little more room in the x5d engine bay so maybe a little more forgiving.

[TDIwyse]

Originally Posted by Deftronix

TDI - did you end up cannibalizing an egr cooler to make the piping? The end that connects to the exhaust manifold looks the exact same as stock (flex pipe and piping that extends passed the flange)? Would like to do this mod for peace of mind afters deletes but dont want to sacrifice my egr. Imagine the angles are pretty tough to get right. Probably have a little more room in the x5d engine bay so maybe a little more forgiving.

I did use the EGR flex pipe at first, but it didn't last. I then moved to a hard pipe ~2 years ago: http://www.e90post.com/forums/showthread.php?t=1111590

However, I still used the compression section and the flange from the original EGR connection. Just got rid of the flex section that is prone to cracking/breaking...

[Yozh]

Originally Posted by Deftronix

..dont want to sacrifice my egr.

Can go for something like this from an older E46/X5 with an M57. They come up on eBay europe once in a while for little money.

[Deftronix]

Love this forum, thanks TDI!

Yozh - That should work perfectly as a starting point, very much appreciate you pointing me in the right direction. Great idea!

[iaknown]

Originally Posted by supermann125

@iaknown do you know if BPC is modifying the waste gate or having over boost issues with the complete "iaknown" package on their 2+ tune? Would like to know if I'm going to be DIY with that tune so I can handle with everything off

John@BPC

Some interesting info about this I wanted to pass on..... Although it seems universally agreed that the wastegate mod isn't necessary, I found out some information that disproves it actually does harm to the turbine housing. A while back Bob and I were discussing this and he stated they had a car w/ the mod come in that was losing power during the turbo switch. Turns out the wastegate was most likely cracking from the slight spike of pressure when the turbos transition and the increased surface area on the wg flapper from the mod. He said the turbine housing was replaced and that solved it.....

Well, I found out I had the same issue on my car. When the turbos switched I could see a spike and then a huge drop in boost. But I knew that there had to be a way to lower the spike by adjusting the transition of the turbo switchover. I hounded Jarek about this and he did similar testing on a car he had inhouse on the dyno. He adjusted the switchover characteristics and updated my tune and this solved my issue, the boost is now rock solid and much smoother during the switchover. So a software adjustment was all that was needed. Thought this might interest some of you.....

[Yozh]

Originally Posted by iaknown

... I hounded Jarek about this and he did similar testing on a car he had inhouse on the dyno. He adjusted the switchover characteristics and updated my tune and this solved my issue, the boost is now rock solid and much smoother during the switchover. So a software adjustment was all that was needed. Thought this might interest some of you.....

Nice. Jarek is a wizard.

[Deftronix]

Any of you guys have experience with the SCG-1 boost controller/wideband gauge?

[BB_cuda]

Originally Posted by iaknown

Some interesting info about this I wanted to pass on..... Although it seems universally agreed that the wastegate mod isn't necessary, I found out some information that disproves it actually does harm to the turbine housing. A while back Bob and I were discussing this and he stated they had a car w/ the mod come in that was losing power during the turbo switch. Turns out the wastegate was most likely cracking from the slight spike of pressure when the turbos transition and the increased surface area on the wg flapper from the mod. He said the turbine housing was replaced and that solved it.....

Well, I found out I had the same issue on my car. When the turbos switched I could see a spike and then a huge drop in boost. But I knew that there had to be a way to lower the spike by adjusting the transition of the turbo switchover. I hounded Jarek about this and he did similar testing on a car he had inhouse on the dyno. He adjusted the switchover characteristics and updated my tune and this solved my issue, the boost is now rock solid and much smoother during the switchover. So a software adjustment was all that was needed. Thought this might interest some of you.....

Iaknown, so you had Jarek change software some to reduce spike at transition. Are you still running the turbo housing that has the opened up WG port? I have open up WG port too and wondering if i'm suffering a little at transition.

[iaknown]

Originally Posted by BB_cuda

Iaknown, so you had Jarek change software some to reduce spike at transition. Are you still running the turbo housing that has the opened up WG port? I have open up WG port too and wondering if i'm suffering a little at transition.

Yes, and I am still running my ported housing with no issues. It wasn't the 1st time Jarek saw this so I think it motivated him to change the transition a little on all aggressive tunes. You should try to monitor boost closely or even put a camera pointed at the wastegate arm to see, either should tell you if it's cracking.

[BB_cuda]

Originally Posted by iaknown

Yes, and I am still running my ported housing with no issues. It wasn't the 1st time Jarek saw this so I think it motivated him to change the transition a little on all aggressive tunes. You should try to monitor boost closely or even put a camera pointed at the wastegate arm to see, either should tell you if it's cracking.

Thank you. I presume I could get same correction from Andrew.

[Asonchadwick]

Hi, newby here. I am about to get my exhaust dpf delete does anyone still think i should just enlarge the wastegate hole while i have it all apart or just leave it alone. Ill be going jr 2 race i think and may upgrade later.

[Torqu3]

Originally Posted by Tucson335d

Hi, newby here. I am about to get my exhaust dpf delete does anyone still think i should just enlarge the wastegate hole while i have it all apart or just leave it alone. Ill be going jr 2 race i think and may upgrade later.

2 opinions here. First, just go ahead and spring for the 2.8 and put in new boost hose seals and vacuum lines. That's exactly what I did and have had zero problems. Much easier and less time consuming than upgrading over time. And you'll thank me later for the power and MPG gains.

Second, don't worry about the wastegate. The tunes now are advanced enough that they aren't really necessary. Like it has been said, it won't be damaging if you did want to do it, but you don't really need to do it. Get a Turbosmart BOV from Whitbread Performance Innovations, and all will be good.

[chuckn0rr1s]

I just did the Stage 2+ tune from BPC I am very happy with the results! Next mods are airlift performance kit, wheels, and Intercooler

[Bmwaddict03]

Hello everyone, lots of great info. I'm hoping someone could perhaps give me some direction. I seem to be in a similar rut as iaknown where ive tried several things to remedy code 4521 for an overboost. I have a tunezilla tune, vrsf downpipe, egr, dpf, scr and swirl flap delete. Ive replaced both pressure converters, vacuum lines, map sensor, and charged air hose from turbo to intercooler. While cruising on the highway under slight throttle ill get the halfway check engine line momentairily and then after a few seconds it goes away. Has been an ongoing thing for quite some time. I am considering porting the wastegate port however Ive seen people saying thats no longer needed. Any direction would greatly be appreciated. Been about over a year and a half ive been dealing with this!

[lnxguy]

You've got a vacuum leak somewhere.

[Bmwaddict03]

Thanks for the response. So over the weekend i again tested vacuum, all turbo actuators including wastegate, turbo bypass and compressor bypass hold and don't leak down. EV valve holds, pressure converters hold when energized as they should, vacuum pump hits 30 inches mercury and holds after engine shut off, bleeds off after about 5 to 10 minutes. Vacuum reservoir box holds. Have smoke tested charge air curcuit and not found any visible leaks. When driving vehicle aggressively it responds proper but somehow still get the halfway check engine light at times. Any further advice? Thanks