I don't think my profec B is hooked up correctly. can someone quickly tell me which side of the profec B controller I need to 'T' into?

I was told the 'in' on the profec B goes to the side of the WG and the 'out' goes to the top...is this correct?

FYI, the car started and when I pluged the factory boost sensor in, the car jumped to 15ish on the WB O2...I shut the car off very quickly.

 

Search Grasshopper,

https://www.rx7club.com/forum/showth...ghlight=profec

 

Thanks, I did search and I saw that post, but I still am not clear how to hook it up,
what is the charge pipe...where does the line hook up on the turbo?

 

Very easy to do, friend:

On your turbocharger, you've got two wastegate feeds (if you're using an external with that T78). One of those feeds is the side feed; the other is the top feed.

The side feed, when pressure is applied through it, is used to open the wastegate poppet valve, releasing exhaust gas around the turbine housing. The top feed, however, is in opposition to this -> when pressure is applied to it (from an electronic boost controller configured to work with two ports specifically), it applies force against the pressure in the side feed, helping keep the wastegate shut and/or maintaining a solid intake manifold pressure level.

The PROfec B can control both of these. In the user's manual, there's a diagram on how to configure the four DIP switches -- You want to set them to 'External Wastegate' (I believe it's the 3rd option if memory serves).

The PROfec cockpit unit itself has a vacuum port running to it that's about 4mm or so. Run a vacuum line from, say, your boost gauge to this. Make sure the line doesn't get crimped or pinched anywhere along the way.

The PROfec B has a black, rectangular stepper motor that has two ports on it -- IN and OUT:

-) For the IN line, you want to find an intake manifold source (some say pull straight off of the compressor housing or housing outlet pipe but I prefer a source past the throttle body), tee it off of that, and run two outlets -> one outlet will go to the IN on the PROfec B black box and the other will go to the side port on the wastegate. Those vacuum feeds will be about 6mm in diameter (1/4"ish) so find a good, fat, nice source of vacuum and don't tee off of a smaller line.
-) For the OUT line, run a vacuum line straight from the OUT on the PROfec black box to the top-feed of the wastegate. This one is also 6mm (1/4"ish) in diameter.
For both of these hoses and what not, make the plumbing as short as possible.

That oughta do it.

B

 

Wonderful! thanks a bunch!
So when someone says 'charge pipe' are they refering to any portion of the intake after the turbo and before the engine? (the pipe that holds the air charge) ?


-D

 

Probably, yep -> 'Charge' referring to intake charge, so it stands to reason they're talking about the pressure side.

Here's the skinny on that (using heavy-pressure side vs. vacuum side for the IN line on the PROfec):

When you use the heavy pressure side for the side-feed on the wastegate, say where the compressor housing is, where the intake charge pressure is considerably higher, you'll wind up with better overall control of your boost levels. However, if you run that feed from a source after the throttle body (where it's under more vacuum more of the time and less pressure under boost), you'll sustain higher boost pressures inbetween shifts, run a slightly higher-than-spring rate boost pressure, and will get quicker response and acceleration out of the turbocharger earlier in the RPM band. It's an give vs. take sort of thing.

B