wastegate actuator travel

[MaxPSITalon]

Ok so i put a evo 3 big 16g on my 2g talon, and i had a major boost creep problem. So i ported out the turbine housing and o2 housing, i also put a 34mm wastegate flapper on. Anyway, i noticed the the tech article that i followed said to port behind the flapper so the flapper is able to open 90 degrees. After i spent a reasonable amount of time doing that i decide to see how far the wastegate flapper actually opens, so i put air on it and it only open maybe 40 degrees or less.

Is this all that the flapper should open... and the tech article needs to be changed, or is my actuator bad?? Or is there a way to make it open further?

http://www.dsmtuners.com/forums/showthread.php?t=186525

Thanks

 

[kenamond]

Welcome to the world of evo3b16g creep! The WGA doesn't have enough throw to open the flapper 90*, and 40* seems typical from what many others have posted.

The typical options are:
1) Port (but you tried that)
2) External wastegate
3) Get supporting mods to run 20psi (or wherever it creeps to)

I'm still dying to see someone track down a different WGA with more throw and enough preload to keep the flapper closed until it's supposed to open. I'm almost 100% convinced that this would be the easiest solution to the problem (assuming someone has identified a suitable WGA).

 

[romeen]

A large, free flowing exhaust contributes to boost creep also. Some guys running a 3" exhaust w/out cat found that replacing the cat created just enough backpressure to alleviate the creep. Just one more option to consider.

 

[MaxPSITalon]

one of the problems is that it creeps until fuel cut, but that was before i upgrade the wastegate flapper and ported it a little more some i am hoping the creep issue is gone. i was just conerned with the the flapper only opening <40 degrees, heck if there was a WGA like Kenamond described boost creep would be an easy fix.

The main reason why i started this thread was to hopefully save people some time when porting there turbine housing and not port behind the flapper, since apperantly it is a waste of time.

I would reply to the tech article, but i am still a "new member"

Thanks again

 

[c4uldr0n]

you could always try to alter the pivot of the WGA and have it open a little more too

 

[kenamond]

you could always try to alter the pivot of the WGA and have it open a little more too

This isn't recommended, especially on a larger flapper.

You'd have to shorten the length of the lever so that the same WGA arm throw would give you more turn on the lever. However, that gives you less mechanical advantage (leverage) on the arm which means that the spring preload inside the WGA can't hold the flapper closed as hard. As boost is rising, the backpressure in the upwind side of the turbine housing is pretty high and is pushing hard on that flapper door trying to push it open. A few folks have had problems with the larger flappers leaking boost before full boost is reached, which creates slower spool - and that was without tinkering with the lever. So shortening the lever may lead to a leaky WG flapper, especially if it's a larger flapper (larger flapper means larger area for that backpressure to push on).

You might get away with a little bit on a stock flapper, but who knows what is too much? You might have to try a few different lengths until one actually held the flapper closed *and* opened the flapper up more when actuated.