Vacuum/Boost Thought.

[Nicelyphe]

I was in my engine bay today and noticed that there is a tee in between the turbo wastegate, teed off to the BOV and the throttle body i believe. If i recall remember ready that its not good to tee off the BOV like that and such. Is this true/ What source can i run the BOV off of? Also if im not mistaking i feel as if there is some shuddering, such as a little bit of turbo surge. Could this be the problem, should i re run line?

Boost gauge does sit at -20 when off throttle.
93 S13
S13 blacktop
T25
Stock setup
HKS SSQV BOV

[jr_ss]

The HKS SSQV needs to be plumbed to a port behind the throttle body plate, i.e. vacuum. It needs to see the pressure differential to blow off. The wastegate only needs to see boost pressure, not vacuum. So that could be hooked up to a port before the throttle body, such as on the hot pipe or one of the nipples right before the T/B plate. I'd correct the lines and go from there...

[Nicelyphe]

So ima have to make a nipple in the ic piping?

[jr_ss]

You don't have to... There should be a few ports on the throttle body before the plate. You can use those. If you want to run less vacuum line you can weld a nipple on if you'd like.

[KiLLeR2001]

So ima have to make a nipple in the ic piping?

More than likely, yes. Unless you are using the stock IC piping which has a nipple for the wastegate.

Throttle body -> BOV (vacuum)

IC piping -> wastegate (pressure)

[Nicelyphe]

Aftermarket piping. No nipples in it sadly. Can I use the bottom tb nipple? It's currently plugged on my car

[KiLLeR2001]

Not for your wastegate. You need a pressure source from the IC piping.

Either weld in a nipple or... Turbo Quick Tap Fitting for Boost Source (http://www.frsport.com/Turbo-Quick-Tap-Fitting-for-Boost-Source_p_7854.html)

[Nicelyphe]

Should it be in between bov and turbo. Or can it be in between fmic and bov

[jr_ss]

There should be a boost pressure source at the throttle body. Pull your coupler off and look at the inside of the TB. On the bottom you should be able to see two small holes for boost source. Pick one and use it.

[Nicelyphe]

Yea i ended up just ordering the quick tap fitting, never know when i may need it again anyways. I just really rather run everything with separate lines then have them tee'd like they are now.

[Nicelyphe]

Alright, so I fixed those lines, Wastegate to hotpipe [On coupler out of turbo due to the quick fitting]. Bigger nipple on TB going to my HKS SSQV. Issue being I don't really see a positive difference in performance or anything. More or so it seems as if my idle has became a little bit unstable, not much. Just being that it fluctuates up and down probably about ~100-150 rpms here and there. Also sometimes you can hear a diff tone in the exhaust but doesn't show a change in rpms on the needle.

[jr_ss]

You need to make sure that the nipple going to the SSQV is actually a vacuum source. Just because it's off the TB does not make it a vacuum only source at idle.