need some help from the gurus (n75 related)

**JDM EJ1 95** · 08-23-2008 01:09 PM

well ive been having an overboost issue for a little time now..

28psi is not good for tubros.

so i took the car partially apart today and tested both wastegate hoses.. to my suprise they are perfectly fine.. ok.. now..

there are 3 ports in the N75.. the boost ref port (from the compressor housing) , the wastegate port, and the other one that goes to the part of the spider hose (ambient pressure)..

i put the vac tester on the ambient pressure side and it doesnt hold vac..

now.. on this diagram.. if correct.. it shows that that ambient pressure side is its own... it doesnt share with the other 2.. so shouldnt it hold vac?

or is that where the boost bleeds off is into the ambient port?

**The_Jerbel** · 08-23-2008 01:54 PM

It definitely shouldn't hold vac. It's there so the ECU can sense the ambient pressure. It's not a sealed air line.

**JDM EJ1 95** · 08-23-2008 01:56 PM

got ya.. well im in the process of just updating all the vac lines on the car.. in hopes of maybe there is a small small leak that went unnoticed..

will update.

**Unispeed** · 08-28-2008 09:14 PM

I noticed the diagram above and it seems like the big nipple on the N75 valve connects to the little can at the center of the spider hose.... Currently I have removed the f hose and made a straight connection on the front part of the manifold... on the spider I capped the line that went to the F hose like this:

Now my question is, can I disconnect the N75 from the spider hose and just cap the spider hose nipple... Will I create some kind of leak if I do this. I am starting to hate the spider and want to keep as many systems off of it as possible... Maybe Jerbel has some insight on this..

Another question I had was related to that valve that connects to the y pipe... why do we need it? heck, with no more f hose and no n75 leaching off the spider hose why do I even need a spider hose back there? Can i Just put a filter on each crank case vent and call it a day and get rid of the homosexual spider for good?

**AAAA** · 08-28-2008 10:36 PM

i think you need to read up on what the pcv system really is. yes, some say you don't need it, and to a point they're right. but you can't cap off hoses and put filters on the crank case. it has to have a way of relieving pressure and vapors. the y pipe connection you can cap off, but the hose that leads to it, or where it originates should be lead to some sort of catch can so that it still does its job.

**Unispeed** · 08-28-2008 10:54 PM

Originally Posted by AAAA

i think you need to read up on what the pcv system really is. yes, some say you don't need it, and to a point they're right. but you can't cap off hoses and put filters on the crank case. it has to have a way of relieving pressure and vapors. the y pipe connection you can cap off, but the hose that leads to it, or where it originates should be lead to some sort of catch can so that it still does its job.

^^^^ what? the spider goes to the Y pipe because of emission regulations... the crankcase gasses will come out of a filter too wont they? Idk, maybe some more inmput on this...