MBC on UICP?

[Calan]

Is there any difference between sourcing an MBC off the UICP vs. the J pipe?

I've got all new piping, FMIC, etc. and need to mount a nipple for my MBC. The best location from a mounting standpoint is on my UICP just before my GM MAS.

Any good reason for not doing this? (assuming I don't have any boost leaks between the compressor and UICP).

EDIT:

Also, if I come off the J pipe, can I just drill and tap a 1/4 FPT hole and use a barbed brass pipe fitting? That would be easier than welding a bung to my super thin UICP. . If so, will Teflon tape hold up to the air temp at that location?

Thanks

 

[96gstdsm]

Well i don't know if i am correct or not, but i think one problem from having it there is that the further away from the wastegate, the more chance of boost spike there can be. It seems like keeping the vacuum lines the shortest possible is the best. I researched it and came to a conclusion that it is better to just source it off the turbo nipple. I just attached it to the same place where the stock one was, and it has worked great for me. Please someone correct me if i am not correct about this, but this is how i did it and i have had nothing but great experiences.

 

[Spooling99]

What kind of MBC do you have I know the TurboXS is different then most. But I have mine setup like, Boost source is on my WG actuator, and my vaccum is going to my LICP wich makes very short lines wich is good for boost response.

 

[Calan]

it's a custom made ball and spring, "L" configuration type.

 

[No_Skillz]

Well i don't know if i am correct or not, but i think one problem from having it there is that the further away from the wastegate, the more chance of boost spike there can be. It seems like keeping the vacuum lines the shortest possible is the best. I researched it and came to a conclusion that it is better to just source it off the turbo nipple. I just attached it to the same place where the stock one was, and it has worked great for me. Please someone correct me if i am not correct about this, but this is how i did it and i have had nothing but great experiences.

This guy is correct. You want the MBC as close as possible to the boost source. T-25s have a nipple right on the compressor cover. 14Bs do not and you will have to resort to the J-pipe, which will do nicely.

As for mounting the fitting, I don't see how tapping it and trying it with teflon tape will hurt, since if it doesn't work you can always resort to welding. Just be sure to do a boost leak test afterwards.

 

[Phantom DSM]

sorry to butt in, but i have a question too. I installed a dual stage turbo xs boost controller, and had to tee off the the bov line going to the intake manifold.
It was the only way since the 2g install kit i have on my 16g does not have a nipple on the j-pipe. I have it set to 13psi for now, but on the gauge it spikes to 15 psi, then settles to 13psi.
What should i do ? Drill and tap a nipple on my j pipe ?
Thanks guys

 

[Low Impedance]

yeah. just tape the j-pipe. i have the same thing you have with the source from the manifold and i really really need to change that asap.

 

[Phantom DSM]

Thanks for the reply.
I have seen wiseman talk about tapping off the j -pipe, but i spoke to vendors and they say its quickeroff the j-pipe but not as accurate as tapping off the bov line .
Im not sure if its spiking because i have it set too low on dual stage mbc. what do you guys think thanks

 

[Spooling99]

Thanks for the reply.
I have seen wiseman talk about tapping off the j -pipe, but i spoke to vendors and they say its quickeroff the j-pipe but not as accurate as tapping off the bov line .
Im not sure if its spiking because i have it set too low on dual stage mbc. what do you guys think thanks

TurboXS often tells their customers to tap the BOV line for boost reference which is a big no no, especially with a TurboXS mbc, double check how it is hooked up. The fitting perpendicular to the body goes to compressor housing or licp, the fitting opposite but inline with the adjustment knob goes to the wastegate actuator, neither should see vacuum. The adjustment knob direction is also opposite of a typical ball and spring, CW (in) = less boost, CCW (out) = more boost. The reason I think the issue is mbc related is because 11-12psi = stock actuator spring rating which indicates the MBC isn't doing its job, the chance of issues like leaks, wastegate, turbo....etc. resulting in a steady 12psi is slim, not that doing a boost leak test is ever a bad thing.

Stolen from Bruce in another thread. This might help you.

 

[Phantom DSM]

hmm interesting .....I have it hooked up correctly like oldman said, its weird, i might have leaks but it weird that it spikes that. Do you mind giving me the link to that thread you got the quote from?
Greatly appreciated

 

[Spooling99]

hmm interesting .....I have it hooked up correctly like oldman said, its weird, i might have leaks but it weird that it spikes that. Do you mind giving me the link to that thread you got the quote from?
Greatly appreciated

http://www.dsmtuners.com/forums/showthread.php?t=254452

At your request.