Jump to content
Ultimate Subaru Message Board

Running LESS than stock boost.


Recommended Posts

I have an idea. Just to make sure im going to do this right. In order to run LESS than 7psi (stock EA82 boost) i need to lengthen the arm on the wastegate.... right?

 

-Brian

 

Correct, cut in half, thread with die, use coupling nut between the two pieces (allows adjustment, longer or shorter).

Link to comment
Share on other sites

I had an easier idea. I just want to make it longer, I will use my Manual Boost Controller to make stock and more than stock boost, but since Im going with higher compression pistons, I wanna be able to turn down the boost to just above 2 to 3psi if possible.

 

Got pix of my mod, will post them soon.

 

-Brian

Link to comment
Share on other sites

Brian, I do not think changing the rod length

will change when the waste gate opens.

How far yes, at what boost pressure?

 

- the spring in the waste gate controller needs weakened

so the control arm will move at a lower pressure.

 

Just the opposite of adding a spring for more boost

Link to comment
Share on other sites

Ah skip, i believe your right. This is the idea i had. While looking at the wastegate setup, i thought instead of modifying the arm, i'd modify the mounting of the wastegate. So I removed the 2 bolts that hold the wastegate to the turbo, found longer bolts and put some washers between the two.

 

DSC00716.jpg

 

key is, its something thats easy to return to stock. I my old turbo as well, along with its wastegate, so maybe I will pull that off and fiddle with the spring inside.

 

-Brian

Link to comment
Share on other sites

I believe it's a sealed unit as it must respond to pressure.

There is a diaphragm separating the internal halves

 

If you change the rod's static position

you could prop the wastagate flapper open

thus delaying the boost

or in essence introduce more turbo lag.

Link to comment
Share on other sites

Brian, I do not think changing the rod length

will change when the waste gate opens.

How far yes, at what boost pressure?

 

- the spring in the waste gate controller needs weakened

so the control arm will move at a lower pressure.

 

Just the opposite of adding a spring for more boost

 

It does, lengthening the rod in effect lowers the static spring pressure (not rate which what you are talking about which will do the same thing). Basically the flapper will "crack open" at a lower psi then with a tight rod (high spring pressure because it is compressed more).

 

We've done this lots of times on many different turbo cars, it works.

 

Junkie's alternate method of the washers works equally well on cars where you have easy access to the wastegate actuator mount. Just not quite as easily adjusted but definately quicker, easier, and cheaper.

Link to comment
Share on other sites

Then Poof goes the HG right? FTL!!!!!!!11!!!!!1!! :D

 

sorry had to do it...good going junkie....i wanna see 4 black marks on the pavement after it is done.

Something else will probably give before all 4 tires do. I see plenty of grenaded WRX trannies from punk@$$es dumping their clutches, trying to spin all 4. First, put four bald drive55/80R13s on before you try a 4-burn. If that doesn't work, you can always try cyclones!:headbang::burnout:

Link to comment
Share on other sites

Dylan, what you are saying is no doubt true but

these WG have very little static pressure on the spring.

I went to my turbo department and had a look.

vf11.jpg

I believe you will intro turbo lag instead of lowering the pressure as you say.

 

 

I like the counter spring idea, mount it on a threaded rod and "dial down" the pressure.

Link to comment
Share on other sites

Sorry, guess I am use to T03's that you had to have a pair of pliers to pull the rod back onto the flapper arm. Haven't modded the little itsy one on the GL yet, got a low mile TD04 on the shelf that was going in.

 

Nice pile of turbo's, have worked on several of those before ;)

 

Nevertheless, I've never had any lag issue before and the hybrid on my Neon came with a factory threaded rod.

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...