vacuum lines...still can't figure it out

[CASPERAMC]

i searched for this and i did check the sticky but i still can't figure this out...

ok i have a picture of the turbo


I know either the blue or red one goes to the yellow (wastegate). which one? and what do i do with the other one?

Green (surge valve) gets hooked up to a boost line on the engine side of the throttle body, or does it matter which side?
there is also a nipple on the cold side pipe from the intercooler, is that one safe to hook up to a boost guage? or should that be T'ed from the same line going to the surge valve?

Can i just hook the map sensor from my megasquirt to the same boost line as the surge valve?


i think that is it, unless I am forgetting a boost line somewhere. any ideas?


thanks a lot guys
-mike

[turbodudey]

I know either the blue or red one goes to the yellow (wastegate). which one? and what do i do with the other one?

Green (surge valve) gets hooked up to a boost line on the engine side of the throttle body, or does it matter which side?
there is also a nipple on the cold side pipe from the intercooler, is that one safe to hook up to a boost guage? or should that be T'ed from the same line going to the surge valve?

Can i just hook the map sensor from my megasquirt to the same boost line as the surge valve?


i think that is it, unless I am forgetting a boost line somewhere. any ideas?

Green: The surge valve is open to atmosphere. That little nipple doesn't get hooked to anything.

Red goes to yellow (with optional boost controller on that line).

Either plug the blue one, or you can tee the blue and red together and run both to yellow.

Boost gauge and MAP sensor should come from the intake manifold. The brake booster line is an easy place to tee in for those.

[Kevin_GP]

I know either the blue or red one goes to the yellow (wastegate). which one? and what do i do with the other one?

Green (surge valve) gets hooked up to a boost line on the engine side of the throttle body, or does it matter which side?
there is also a nipple on the cold side pipe from the intercooler, is that one safe to hook up to a boost guage? or should that be T'ed from the same line going to the surge valve?

Can i just hook the map sensor from my megasquirt to the same boost line as the surge valve?


i think that is it, unless I am forgetting a boost line somewhere. any ideas?

Green: The surge valve is open to atmosphere. That little nipple doesn't get hooked to anything.

Red goes to yellow (with optional boost controller on that line).

Either plug the blue one, or you can tee the blue and red together and run both to yellow.

Boost gauge and MAP sensor should come from the intake manifold. The brake booster line is an easy place to tee in for those.

Yep, the only thing is I would T the blue and red going to the waste gate, I got better results that way with no boost dropping off.

[CASPERAMC]

ok thanks a lot guys

[CASPERAMC]

are you sure about the surge valve not being hooked to anything, some people are telling me i need to hook it up too

[turbodudey]

are you sure about the surge valve not being hooked to anything, some people are telling me i need to hook it up too

Yes. I'm sure.

[BlackRoseRacing]

got to love mis-information

[NiteHawk]

dont hook up the surge valve!?

god i hope you're only kidding with him man

for gods sake, hook up the surve valve to the throttle body vac source! otherwise you'll get compressor surge!

i know its a newb question guys, but dont tell him how to kill his turbo!

[esteinmaier]

Blue - Cap
Red - Run to yellow with a boost controller or boost controller solenoid in between
Green - Run to intake manifold vacuum source

Anything else will either destroy your motor or turbo.

[turbodudey]

Huh. I didn't know that. The surge valve spring is so weak, I assumed it would open without a vac source. My bad...

[esteinmaier]

Running a surge valve without a vacuum might open on it's own, but keeping it closed is the problem. You just create a huge boost leak and overspin the turbo.

[turbodudey]

Oh yeah... oops. I never used the stock surge valve, so I guess I never thought about it long enough to realize that.

[MyNeonSaysHi]

Running a surge valve without a vacuum might open on it's own, but keeping it closed is the problem. You just create a huge boost leak and overspin the turbo.

I upgraded the spring on the stock surge valve from 4lb {stock} to the 8lb PTP spring. Any views on a stronger spring? I bought it basically so it doesn't blow off all the time in vac, was curious if this is okay for stock boost levels 12-14 psi. Don't mean to hijack but it pertains to this thread and I don't want to hurt my car.

[esteinmaier]

A blow off valve, a recirc valve, a surge valve, are all the same thing. The only difference is that a blow off valve vents to atmosphere, and a recirc or surge valve vents to the intake piping before the turbo. Very little performance difference. Just noise difference.

When the pressure in the intake manifold is lower than the pressure in the charge piping, it opens. This is what happens when you close the throttle blade.

Then when the pressure is the same, the spring keeps the valve closed. This is what happens during boost.

The spring also keeps the valve closed in vacuum.

A blow off valve works by placing a plunger of sorts on a diaphragm between 2 zones of pressure. When you let off the gas, the intake manifold pressure drops, but the pressure in the charge piping takes more time. So the diaphragm actuates toward the zone of less pressure, which opens the valve. The spring is only in place to create some preload on the diaphragm. If there was no spring, there would always be slightly less pressure in the intake manifold than the piping, and the valve would be perpetually open.

The only reason to get a stronger spring is if the bov opens prematurely. That happens often at idle with a spring that's too weak. The stronger the spring, the more pressure differential it takes to open the valve. It has nothing to do with the amount of boost you are running, as long as the spring will hold closed when there is the most pressure differential, usually at decelleration in gear. If your stock spring does that just fine, adding a heavier spring is only allowing more surge to get back to the turbo and wear out the bearing prematurely.

[Kevin_GP]

I thought a recirculating valve was more efficient? I know the 300zx TT had recirculating valves and everyone swore they were better than a BOV until x amount of power/boost. Regardless, I didn't keep the surge valve so I don't know how its hooked up, but I know for a fact that T-ing the 2 vac lines on the compressor scroll is the way to go, my boost controller was more stable that way. I know Weber had a problem with boost spikes/falling off when he plugged one of the holes.

[esteinmaier]

That can be done. They are both going to the same place pretty much, but higher and lower pressure zones in that volume can make averaging the signals a little more stable. Easy is to use just the one. More accurate is to use both.

[CASPERAMC]

wow that saved me from a disaster lol thanks guys still working on the project...

[MyNeonSaysHi]

So 4lb to 8lbs is really a big difference? I know the Boomba piece has a 13lb/16lb/ and 19lb spring... Wouldn't that be horrible on the turbo?

Great explanation BTW.

[MyNeonSaysHi]

From PTP Performance on your comment esteinmaier:

I would like to know where you got that quote from.

1st: there is a huge avantage to getting a external BOV. Recircing the hot compressor air into the inlet is going to cause even more hot air that the intercooler has to deal with.

2nd: that is why we built this spring is because the BOV opens to soon. The stock spring is a 4lb spring, that is nothing for the system to over come and it to weak.

Last: Wear out the thrust and cause more surge? WTH, we have sold over 250 of these in the last 2 years and I have yet to hear of one thrust bearing failure because of them or some of the other and much higher sprung aftermarket BOV's. Who ever you quoted this from must love Mopar because it sounds like a Dale Seely post all over again.

Your going to be fine and your spring will not increase surge and it will most likely keep the surge at bay more because the stock BOV spring can not dance back and forth during venting due to it being so week that it bounces off the seating surface.

[BlackRoseRacing]

1st: there is a huge advantage to getting a external BOV. Recircing the hot compressor air into the inlet is going to cause even more hot air that the intercooler has to deal with.

The effect is not that extreme like there making it sound. Recirculating the blown off pressure back into the intake of the turbocharger will help with spool up and decrease lag. Thats one of the reason's why most oem manufacturer's still used the closed system like they do.

[esteinmaier]

From PTP Performance on your comment esteinmaier:

I would like to know where you got that quote from.

1st: there is a huge avantage to getting a external BOV. Recircing the hot compressor air into the inlet is going to cause even more hot air that the intercooler has to deal with.

2nd: that is why we built this spring is because the BOV opens to soon. The stock spring is a 4lb spring, that is nothing for the system to over come and it to weak.

Last: Wear out the thrust and cause more surge? WTH, we have sold over 250 of these in the last 2 years and I have yet to hear of one thrust bearing failure because of them or some of the other and much higher sprung aftermarket BOV's. Who ever you quoted this from must love Mopar because it sounds like a Dale Seely post all over again.

Your going to be fine and your spring will not increase surge and it will most likely keep the surge at bay more because the stock BOV spring can not dance back and forth during venting due to it being so week that it bounces off the seating surface.

He has more experience with the specific application. If the 8lb spring is working well for everyone, chances are pretty good it will be fine for you too.
He's not saying anything I particularly disagree with, except the part where he voices his arbitrary opinion of me.
People from performance shops have a tendency to try to lead on that they are the only people available that know what they are talking about. It's part of their business. You can't really blame them for that. Just keep in mind that people in his situation will talk down on everyone else because as long as they are the "smartest" source of information for you, you will continue buying parts from them.
I should also add that if you are recirculating instead of blowing off, it's not nearly as important to have a strong spring, as the spring is mostly there to prevent unfiltered air from entering the charge pipes. With a recirculation, that's not an issue at all, since the air is still filtered even if the valve is wide open at vacuum sucking in all kinds of air.

[hul kogan]

Just keep in mind that people in his situation will talk down on everyone else because as long as they are the "smartest" source of information for you, you will continue buying parts from them.

haha, isn't that the truth. normally when i get into a situation like that i will just nod and listen, unless they say something i rly can't agree with at all. it saves the hassle to just listen and dissect the good information out later...

btw, great info so far!

[esteinmaier]

From PTP Performance on your comment esteinmaier:

I would like to know where you got that quote from.

1st: there is a huge avantage to getting a external BOV. Recircing the hot compressor air into the inlet is going to cause even more hot air that the intercooler has to deal with.

You know, I just thought about this. Compressing air makes it hotter. Decompressing air makes it cooler. So if air is compressed and then decompressed, it should return to it's original temperature. Now it might go up a few degrees just from passing through a hot turbocharger, but not enough that the tiny bit of air coming back through the recirculation relative to the huge gulps of air coming through the intake for a tiny bit of time between gears and at the first blip of throttle (While the intercooler has pretty much no work load) will make a bit of difference.

I like the noise. Because of that I'll keep using blow-off to atmosphere valves. But I don't see them having a performance advantage, besides, you can safely use a smaller spring and vent the compressed air earlier with a recirc valve.