Who has run the vacuum line for the wastegate off of the compressor housing?? is there a difference as opposed to running it off the intake manifold?(after the TB, or before the TB?)
Just curious.

 

the instructions for my tial WG say to run it from the intake mani before the TB...im just gonna weld a hose barb onto the charge pipe right before the TB. I have a friend who runs every singe vacuum/boost line for his whole setup from one source of the manifold, and his car works fine. Others run off the compressor housing too. To me, it seems most ideal to run off the manifold pre TB.

 

Thats how my turbo crx was setup. I didnt ever try it the other way(post TB). Now that i think about it more it would make sense to run it after the TB. reason being the wastegate may see pressure a little later in spool time due to the distance fromt the turbo. Dont really know if this is practical, or if it would help spooling times. also when the throttle is closed, would'nt the wastegate close from the vacuum in the line piped after the TB?

 

You wll loose about 1-2lbs of boost using the port on the compressor, because of the intercooler. There are three other places you can T it into: brake booster line, FPR line, or cruise control line.

 

I've heard knowledgeable people recommend running it off the compressor due to less chance of spiking. Sure you will lose pressure through the intecooler and such, but you can always make up for that by cranking up the wastegate.

 

Everyone Really needs to get Maximum Boost by Corky Bell! It explains all this stuff.

 

I would never run it from the intake after the TB. The boost spikes would be huge when you got off the throttle and the wastegate will respond weirdly when you are at part throttle and cruising. The wastegate should be watching the output of the compressor with nothing interfereing with it. Picture what would happen to the turbo rpm if you had the wastegate line at the TB and the connection at the intercooler popped off. The wastegate would not open and the turbo would spool as fast as it could. Not a good scenario.

I use right off the compressor so the feedback loop is as small as possible. Quick response is what you need from a wastegate so the closer to the turbo the better.

As for the intercooler, just adjust the wastegate for the extra drop in pressure.

Randy

 

you guys have some good feedback. was just a theoretical question. thanks for the intellectual input

 

so likewise, if you have a boost controller, you should tap that in right after the compressor too, right?

-Xerxes

 

Well, if he had mentioned having a boost controller it would be a totally different question wouldn't it? I have a vac line from my Tial t'd into my fpr line and it works better without boost spiking. Of course, if the qualty of the wastegate s substandard and you have your BOV adjusted to its hardest setting you are sure to see boost spike. As said before if you want more boost, you need to tap into either three of those lines that I mentioned earlier.


[Modified by maxim, 6:33 PM 1/27/2002]

 

makes sense but compressor seems to be a good choice just crank up the boost

 

does any1 know how much boost is lost through the intercooler? i kno it will vary based on the amount of boost and the setup but what would be a safe way of testing it out

 

Thanks for info

 

Think of it like this. If you were wanting a boost refrence would you want to get it from the turbo housing before it enters to IC then out the IC throught the charge pipe and in the manifold. If so you would see more boost there but by the time it got to the manifold the boost would be lower. Now if you pulled it from the manifold you would get the boost levels as close as you can get before it enters the head. Make sence??? You may get some spikeing but there are other fixes for that.

 

Man, is this info incorrect and outdated.. I'll work on a new writeup asap.

 

Did we ever get updated info about this? Browsing the FAQ and came across this old thread. Would be nice to have it here since it's already linked from the FAQ.

 

Shodan, if/when you decide to write a new Vac line thread, let me know and i will switch the link in the FAQ so people can avoid this messy thread

 

I'm assuming this never happened?

 

this was long before I became a Moderator and switch job positions. Interest seemed to wane, so I wound up creating several other tips/tricks for turbochargers outside of this.

Really, the best location is the intake manifold, and not the compressor cover as most diagrams read. I didn't say the intake manifold was the strongest vacuum source, which is different than the most consistent vacuum source.

Perhaps I'll have time later to make a full write up. In the meantime, the above was the solution I'm stating.

 

The only reason I bumped this was it was a sticky in the FAQ section and figured someone would want to hear your thoughts. I had my wastegate go to the intake manifold as well. Thanks for replying

 

No... Thank you.