wastegate line

[Mr. Spool]

My tial wastegate line is pressently being ran from the hot pipe on the turbo. is this a problem? Should I have it on the cold side of the smic or just leave it were it is? can this affect the amount of boost that I am getting and the amount of boost fall off over 5k rpms?

this is on a ka-t at 4.5 psi.

thanks.

[Jeff240sx]

Yea. It does. All intercoolers have a pressure drop across them, and it's usually a decent ammount. Spearco cores are generally .3psi, but OEM units (I know z31 specs offhand) are much less efficient. A z31 core is 3psi pressure drop at 6.8psi. By making the line on the hotpipe, you will get 6.8psi at the turbo, but only 3.8 after a z31 core. And a slight ammount less after the piping and throttlebody.
My WG line is tapped into my brake booster, right off the intake mani.
-Jeff

[Chernobyl]

Interesting. So, I'm confused here... will plumbing inot the hotpipe produce more or less boost as compared to the cold pipe?

[orion::S14]

Without a boost controller, having the line from the hotpipe produces less boost.

Say you have a 7psi WG spring...and an intercooler with a 2psi drop.

You'd get 5psi in the manifold, b'c the wastegate would regulate the pre-intercooler boost to 7psi, but then 2 would be lost over the intercooler.

Now, add a boost controller, and the best place to put the WG feed is from the hotpipe, for response and to prevent surge with a compressor that is kinda-mismatched.

I still run mine from the intake manifold, but...optimally it'd be from the compressor outlet.

- Brian

[Mr. Spool]

My boost gauge is ran off of the brake booster line. Is this reading accurate or will it change after I move the waste gate line?

also My bov line is ran from the brake booster, should I leave it there and just plug the hole that the wastegates line comes from?

and does it matter which side the bov comes from as well.

[RBS14]

anyone have any idea what the pressure drop on a starion ic is?

thanks

[Jeff240sx]

Look it up on Google for the starion. Its not that bad iirc, but don't remember the numbers. I have everything running off the brake booster. What is your boost gauge reading?
-Jeff

[Mr. Spool]

my boost gauge is reading 4.5 psi but then proceeds to drop down to 3.5 psi.

[Mr. Spool]

can I t off the line going to my bov for my wastegate or should I run its own line.

[RBS14]

thanks jeff, i'll check around.

mr. spool: those are both things that you want to have the best response possible, so i'd run one for each. that's what i'm doing atleast. the brake booster is a good place because the line runs over to that side of the engine bay.

[Mr. Spool]

Does it matter what type of line I run? the reason I ask is becouse I ran some flymbsy hose and I think that caused my boost to drop to 3 psi and hold steady there. Could this be a problem. Thanks.

[Jeff240sx]

Yea, you want thick-walled silicon hose on the blow off valve. The wastegate doesn't really matter much. The BOV does, because of the cyclic boost-vacuum-boost-vacuum. Whatever hose you use anywhere won't account for a 3psi drop.
-Jeff

[Mr. Spool]

so I odviously got a boost leak, that sucks. I might be using the wrong size hose as well. If the hose slides over the nipple real easy can this cause a boost leak?

[Jeff240sx]

Yea. First, figure out how a wastegate and bov work. Then what those lines do. You'll see that you can have a slight boost leak, but you'd also have a slight vacuum leak, and notice it. There are a few causes of a 3psi drop. Boost leak. Pressure drop in the piping/ic. Bad wastegate (or wg spring), or a dying turbo. There are probably a few more, but hey.. it's 3am.
-Jeff

[Mr. Spool]

well the line didint turn out to be the problem. so I guesse I have a boost leak some where else. is there a way to check for a boost leak while the car is not running.

[Jeff240sx]

http://www.vfaq.com/mods/ICtester.html

-Jeff