Waste Gate Vacuum Line Info - Important

[Edub1]

I came accross an artical from Garrett, "Turbo 101 or something." The artical said that a WG is not designed to see vacuum and should never be set up to refference manifold pressure and should only refference boost.

So, I guess the spot with the least vacuum is right off the compressor. Perhaps that's why manufacturers use the compressor. Hope I didn't damage mine yet.

[Neejay]

So is this diagram right (which is why it says "Optional"?)?

[crzycav86]

It says optional on that line because a boost controller is optional.

[Neejay]

It says optional on that line because a boost controller is optional.

Ah, ok. So where does the top nipple go?

[WDRacing]

For the record, on both of my SKylines all of my friends Skylines/180's/GN's and Supra's we reference the boost signal from the intake manifold and have never has a wastegate fail. In fact, we do it that way to make up for the pressure loss of the FMIC.

But thats my opinion only...I'm not an engineer. I just know I've done it that way on Garret turbo's for the last 8 years or so...be them internal or external.

Merry Christmas!!!

WD

[NateDogg]

Wouldn't that only affect the wastegate, not the turbo?

Garrett is probably concerned about people running higher boost than they anticipate by using the intake manifold, thus damaging the turbo or their engine.

[PapaSmurf2k3]

For the record, on both of my SKylines all of my friends Skylines/180's/GN's and Supra's we reference the boost signal from the intake manifold and have never has a wastegate fail. In fact, we do it that way to make up for the pressure loss of the FMIC.

But thats my opinion only...I'm not an engineer. I just know I've done it that way on Garret turbo's for the last 8 years or so...be them internal or external.

Merry Christmas!!!

WD

+1its been fine til now, I'm not changing

[Neejay]

Where exactly are you tapping for the vacuum line?

[Edub1]

The Garrett artical said that a WG diaphram is not designed to deal with vacuum and can be dammaged. I have everything running from the big line that used to go to the charcoal can. I'm going to change it like they say.

This might pertain to their WGs, aftermarket ones might be different. I'm just repeating what they said.

[WDRacing]

I'm thinking its an internal Gate thing, which is ok, cause internal gates sucka$$ anyway.

[Florida240sx]

Signal at turbo is most accurate to protect your turbo. Because then the turbo will only produce 8lbs... But through your fmic you may only get 6-7lbs to the mani. So if you tap your signal from the mani you get what you plan for, knowing that the turbo is probably pushing 9-10lbs instead of the 8 you see....

[Neejay]

Signal at turbo is most accurate to protect your turbo. Because then the turbo will only produce 8lbs... But through your fmic you may only get 6-7lbs to the mani. So if you tap your signal from the mani you get what you plan for, knowing that the turbo is probably pushing 9-10lbs instead of the 8 you see....

So if you're getting 8lbs to the manifold, the turbo is actually making more. If you're definitely getting 8lbs from the turbo, then you're actually running on less than 8lbs to the engine?

[LanceKA-T]

Well, I know all people here tap their boost gauge to somewhere from the intake mani.

And by tuning for let's say 10psi on the boost gauge you are unaware of the exact boost the turbo is making anyway.

I've had my JGS wastegate hooked up to my brake booster vacuum line for about 8 months now with no ill efffects. I had a problem with the line getting too hot from the turbo and cracking causing an overboost problem. To me this is safer by keeping it away from so much heat, and have actually heard that the vacuum will help the valve close faster.

[Edub1]

Well, I know all people here tap their boost gauge to somewhere from the intake mani.

And by tuning for let's say 10psi on the boost gauge you are unaware of the exact boost the turbo is making anyway.

I've had my JGS wastegate hooked up to my brake booster vacuum line for about 8 months now with no ill efffects. I had a problem with the line getting too hot from the turbo and cracking causing an overboost problem. To me this is safer by keeping it away from so much heat, and have actually heard that the vacuum will help the valve close faster.

It's probably a bad idea to money with the break booster line.

I will still run my boost gauge to the manifold for accurate reading, but my WG to the compressor tap hole. But yah, sure there is a pressure difference because the air is cooler.

[Florida240sx]

So if you're getting 8lbs to the manifold, the turbo is actually making more. If you're definitely getting 8lbs from the turbo, then you're actually running on less than 8lbs to the engine?

Yes. Don't beleive me put a boost gauge on the hotpipe and one on the fpr. You have all the bends to compensate or and the FMIC. There is going to be a loss there no way around it. A guy did this a while back. Running 12lbs he only saw 10. And then reverse he ran 12lbs and turbo was pushing 14 at the hotpipe.Same thign with my IAP kit. I was only making liek 4.5lbs of boost with vaccum tapped off the hotpipe, when tapped off the FPR I made the 5.8psi which the spring was...

[WDRacing]

Signal at turbo is most accurate to protect your turbo. Because then the turbo will only produce 8lbs... But through your fmic you may only get 6-7lbs to the mani. So if you tap your signal from the mani you get what you plan for, knowing that the turbo is probably pushing 9-10lbs instead of the 8 you see....

Thats reatrded...protect the turbo? From what? If you're running a turbo that close to shelling you're an idiot in the first place.

I've never even heard of this no vacuum thing...EVER. I'm not saying it isn't true, the diaphram may not be designed to see boost. But what did they say would happen?

My point is this, you CAN use pretty much any vacuum source to control the wastegate. Using one from the manifold eliminates the pressure loss caused by the FMIC and plumbing. 1.5 to 2 lbs is usually the difference on a good cooler setup. The EBAY ones are probably slightly worse, but I've never seen one tested.

In the end, hook up the WG to whatever you think is best, both methods work well. One will require a boost controller to actually get the full amount of boost to the motor and one will not. But to me, 2 lbs is roughly 20WHP...I'll stick with the manifold vacuum source.

WD

[Florida240sx]

Signal at turbo as in you are running it at peak flow rate. So therfore if you do mani pressure than you'd be outside the flow rate and become a heat pump am I correct on that WD??I run all my signals off the FPR line.

[WDRacing]

The flow rate for the turbo reall has nothing to do with where you reference the vacuum source. Other then a plus or minus 2 psi difference, which simply keeps the wastgate closed a tad longer to to reach that amount of boost.

WD

[Edub1]

Was reading that artical again. It is about the internal WG actuator.