it should be from the intake manifold to bov line so you don't get spikes

 

Use the nipple coming off the turbo compressor outlet. If you tap into the BOV line with a manual boost controller you are bleeding of boost pressure that is used to keep the BOV closed. Causing it to leak under boost, and also give you a unsteady boost pressure.


Edit: Also since this is a manual boost controller it takes some time to react to boost changes which is why you want it as close to the source as possible, ie: turbo outlet nipple. By putting it closer to the turbo the mbc will open earlier causing less of a boost spike.

 

Here are the pros and cons of both hook-ups

1. Hooking it up the compressor outlet nipple:
A. This way gives you less spikes but slower spool up.
B. It does not seem to give repeatable boost. It seems
to fluctuate more with the temperature.
C. Boost seems to be harder to control below 15 psi or
above 22 psi. Almost everyone who wrote me
said this.
D. It is easier to hook up this way. No cutting any
boost lines. Plus the lines are kept shorter.
(Thus the less spikes).

2. Hooking it to the hose between the BOV and the intake:
A. This way seems to give slightly faster spool up than
the other way.
B. It gives more repeatable boost. It doesn't seem to
fluctuate as much with temperature differences.
C. The boost seems to be more controllable down to
stock turbo levels. (Like down to 7 or 8 psi for a 1G
with a stock 14B turbo).
D. It is more work to hook up. You have to cut the hose
between the BOV and intake and tee it in. (Not
that this is hard, its just an extra step so I put it
in here)
E. Both Hallman and Extreme tell you to do it this way.

 

You must have a different set of instructions. My Hallman instructions state to use the turbo nipple. [Huh, Huh, I said nipple]

 

I will be either T'ing into the BOV source of finding another Vac source off of my intake mani for the reasons listed above. I agree w/ every one of them.

 

take it into the BOV line.. i had some kid flipping out telling me that was the wrong way to do it and i was going to wreck my car, yet i was getting non stop spikes the other way. If your measuring boost in the intake manifold its all that should really matter, if temperture or some other factors are causing a loss in boost.. then your turbo will work harder to make up the difference.. if the opposite is true then the turbo will not push as hard.

 

I've installed many MBCs on evos, using both methods, and I concur with what is in this post. I've seen the same results. I prefer the BOV line, but there is VERY little appreciable difference.

 

The instructions with my Hallman said to T at the BOV.. That's why the T was included in the kit, along with two nipple plugs. One for under the intake and one for the turbo compressor.

Heh, I said nipple too!

 

I went off the compressor housing. It seemed easier and that's the way my MBC's instructions said to do it.

 

I have been having problems since I switched to the BOV line. I would go back to the turbo nipple but I can't because of the Buschur Deluxe FMIC kit. (it has no turbo nipple) Is it hard or recommended to tap a new nipple in the turbo outlet pipe, Also knowen as the Lower I/C pipe.

 

I just compared today the diff... i got more spikes and overall variation from using the turbo nipple... and this was with vary'n lengths of hoses... shorter gave best results that way... but, it's staying hooked up Tee'd into the BOV because
A. No spike and boost held more solid overall (less taper)... plus, over a distance when car was warm, it didn't require a tweak like the turbo-housing method...
B. slightly-slightly better spool
C. Using manifold pressure is the better method as you're not losing anything through the IC and piping...

 

The turbo bible called "Maximum Boost" which is a very detailed yet accurate reading also gives the pros and cons of both hook ups but in the end tells the "proper" place is to source the compressor housing.

http://www.amazon.com/gp/reader/0837...20#reader-page


Amen.

 

Damn, after everything I read before this msg, I was going to tap at the BOV, but now you say this document gives the nod to the turbo outlet. Can you say what the final reasoning was on why compressor housing is the proper source?

 

It all boiled down to the heat in each area. They liked the compressor housing because of the temperature differences. They also said the pressure can vary more in the intake area as well.

If you were to install 3 boost guages. 1 before the intercooler, just after the intercooler and @ the intake you will probably see a variance in pressure. Esp. when you turn the boost up and you start reducing the efficiency of the intercooler and producing more heat from the turbo.

Not my opinion..but science as we know it. So I'm sticking with the facts rather then creating my own science project and experimenting.

BTW, I have a full open exhaust and I don't see the spool up issues...they are minute enough not to hardly be noticed. If you have a 3" TBE, spool up is almost a non-issue at that point because the turbo can now breathe better because of the exhaust.

 

Ok, guess I'll go with the compressor housing. I want a setup that allows me to switch back to stock unnoticeably, and this way should be easier.