Explain to me the purpose for the 2nd vacuum line coming from the Greddy Type s going to the lower IC pipe. I only have one vac line and its been fine so far but if this method is better please enlighten me.





#333
www.dsmlife.com

ditto

It uses a boost source to help it open a little faster. People have put a line on and plugged it with no ill affects.
I had mine plugged for awhile but ended up hooking it up to cure a compressor surge issue.

Along the same lines, what is this mod for? I found the pics, I kinda think it works on the greddy BOV, but no idea why or how.

Looks like the same as what I said above but they're using the stock BCS as a boost source. :scratch
Don't really know for sure but thats what it looks like. I have no idea why they wouldn't be using a MBC at that point since they have upgraded UICP and BOV. :shrug

Originally posted by eclipzGST
It uses a boost source to help it open a little faster. People have put a line on and plugged it with no ill affects. I had mine plugged for awhile but ended up hooking it up to cure a compressor surge issue.

Tony stated it well. I don't fully understand how it works exactly, but for me the idea of the Type-S needing "closed system" is what makes the most sense. Since the Type-S can hold higher boost numbers without leaking, the piston mechanism inside the BOV is stiffer than normal, so it needs more than just a vacuum source to pull it open when the throttle plate closes. It needs a pressurized (i.e. boost) source to help more efficiently push the piston open and get better response under heavy throttle, etc. By leaving the bottom nipple unblocked or even capped, the sytem is still "open" and lacks the pressure source to push the piston open.

For the most part, it is a case by case basis by which people get by without using the bottom nipple, but it's usually arbitrary as to whether it works effectively or not. Once I get my engine reinstalled, I'll just tap a nipple in the Lower IC pipe and run the line to the bottom nipple from there. The lower IC pipe is where the bottom nipple should unequivocally attach to.

One thing Jeff showed me over the weekend: If you look at the bottom of the 1g BOV (when you take it off, there is a hole on the bottom where it meets the flange), it has a "second nipple", i.e. an opening for a boost source, but it is internal on the 1g as opposed to external on the Type-S. When people say to leave the type s unhooked because the 1g doesn't have a bottom nipple, they are missing the fact that the 1g does have a second (boost triggered) nipple, but it is always active without being tapped elsewhere.

Interesting crazy wacky stuff.