Engine and Turbo Questions

[blackhawk1402]

I recently upgraded my turbo to an evo III 16g with 550cc's 190 pump, and an afc neo. Now, I have the turbo running off wastegate pressure (the vaccum line from the wastegate actuator is "T'ed" into the vaccum line running to the blow off valve.) I had the car tuned and we hit max boost at about 20-21psi. From what I have read/heard, if you run off wastegate pressure then it should be around 8-10psi. Is it a bad idea to run the vaccum line from the turbo back to how it was with the stock turbo? (un "T" the line) The reason I am asking this is because my BOV flutters a little bit under low boost but the adjusting screw is almost all the way loose. Also, will this ruin my tune?

 

[Gstclipse69]

First if you run off wastegate pressure you should run the line from the actuator to a pressure source like off your j-pipe, not off your blow-off valve. Leave the blow-off valve line alone. If you dont have a nipple on the j-pipe then all you have to do is drill a hole, run a tap through it the same size as the threads of an 1/8" barb fitting and screw it in. And for good measure put some jb weld around it. Definitely leave the blow off valve line alone tho!

 

[GST racer]

did the boost stay at 20 psi or did it quickly drop back down?

Just try what ^ said, run the vaccuum line from the wastegate straight to the J-pipe, or close intercooler pipe. You were right about the stock wastegate, it should open up at about 7-8 psi. When you T'd it to the BOV line, you just delayed the amount of air running to the wastegate, thus causing a fluttering and spiking up to 20psi.

 

[blackhawk1402]

No, it stayed at 20.

 

[GST racer]

Yeah just move that vaccuum line. hope it all goes well.

 

[blackhawk1402]

move it into the J pipe or move it into where it was on the stock setup

 

[Gstclipse69]

The best place is on the compressor housing or the closer the better. I put mine right after the bend going down on the j-pipe. Anywhere on the lower ic piping will work though, much better than the bov line.

 

[MrBoxx]

As mentioned, don't use the BOV line for a boost source.

Drill and tap the J-pipe for a nipple fitting and use that for your boost source. Is the turbo ported?

 

[blackhawk1402]

yes, ported with upgraded wastegate flapper