Changed Pressure source & spiked to 21 lbs

[Boostin2High]

Ok, so i just took the vac. line from the MBC off my BOV line and put it to the FPR, and ran the BOV straight to the manifold..I wanted to put it to the compressor but I have a 13G so there is no nipple on it nor the J.pipe...Now im spiking from a normal 15 lbs to 21??

Ive been reading alot about it and all I'm finding is go to the compressor housing or the jpipe wich like I said is not possible for me unless I Tap and thread. What about the line to the actuator? Can that line be integrated in any way?

 

[turbosax2]

This subject has been beaten to death.

The answer, like you said already, is to drill and tap either the compressor housing or the j-pipe and screw a nipple in (or have one welded on).

 

[Mikael SS]

was boost staying at the level you wanted it at before? is so quit messing with it

 

[Boostin2High]

Yes sir boss man sir!
And just so have you know..if you were to read any thread pertaining to this subject. Any mod or ANY 1 at that matter would suggest "Messing" with it and fix it!

 

[kenamond]

I'd search around for folks who've added the nipple to the j-pipe and then consider just doing it that way. Controlling the boost by using a pressure source far away from the actual boost producer causes a delay to the WGA which causes more spiking. The BOV line is pretty far away from the compressor, too. I get 1psi boost spikes using a Joe P IL MBC from the compressor outlet and fairly short vaccuum lines (MBC is zip-tied to the top of my rad fan). And you mentioned tapping into the actuator line...do you mean the WGA vaccuum line? If so, that'd be kind of like plugging the male end of an extension cord into its female end (forming a loop) to power your Christmas lights.

 

[Boostin2High]

Thanks Mack. That is what I'm going to do, and as far as using the BOV line I was actually coming up 1 lbs short of what I had it set to. I'm thinking if I up the MBC an extra pound it will get me where I want to be, but in the same token is that going to be to much stress on anything else?

 

[turboglenn]

If you decide to drill the nipple into the compresor housing, it's super easy. Just get a "Q" sized drill bit (they come in numbers and letters) and use a 1/8th NPT pipe thread tap. Then you can choose from a standard barb from a hardware store or use "push to lock" pressure fitting like you see on meth injection kits for your vacum lines to and from the MBC. As for the spiking, i would put it back how you had it before if it was acting fine then, at least untill you come up with a way to get your boost source squared away.

 

[kenamond]

Thanks Mack. That is what I'm going to do, and as far as using the BOV line I was actually coming up 1 lbs short of what I had it set to. I'm thinking if I up the MBC an extra pound it will get me where I want to be, but in the same token is that going to be to much stress on anything else?

Tapping the BOV line for the MBC is frowned upon around here. Some folks have no problems with it, but if you want peace of mind, I'd plan on adding a nipple to the compressor housing or j-pipe in the near future. The BOV protects your compressor wheel from surge, and the MBC might affect the BOV so that it doesn't do its job as well. Perhaps someone else can chime in with a more detailed description of the risks/problems; I don't know them for certain and can only make educated guesses. The other problem is that the BOV vaccuum line ties into the intake manifold which is down-wind of the throttle body. So at part throttle, the IM is at much lower pressure than the intake tract between the turbo and throttle body. So the MBC isn't aware of the actual boost level being generated by the compressor. The same is true for the FPR vaccuum line (also after the TB).

Anyway, I'm one of those folks who think that the closer your MBC is to the compressor outlet, the better.