need help guys.what is correct way to preload the spring.i have stock 8 turbo.installed 25psi actuator.first i made it fit without turning the turn buckle.then i turned 3 full turns grab on the rod and put it on.at wot it shows 21-22 psi.shoul it be 25psi or what i have is ok?i have 3 port(not connected) ,so no mbc here.at the moment line from turbo housing connected to wg actuator.thanks guys.

 

before u get flamed for not searching, check this out...

http://store.forcedperformance.net/m...Info_wastegate

 

are you even tuned for that much psi?
looks like your just running straight wg psi.

to set preload read the link above. but u basically did it from what i read in your post.

 

So, if I am reading your original post correctly, you installed the 25 PSI actuator and added three complete 360* rotations to the spring pressure. Is this correct?

Also, you disconnected and plugged the two vacuum hoses that were connected to the WGA and the compressor discharge tube ( aka, j-pipe). When you road tested it you got a peak boost reading of 22#. What gear did you test it in?

The FP actuator on the car with zero preload should be full open by 18#. Had you tested it with zero preload when you first installed it? That is did you do a WOT run to establish base pressure with the new actuator before adding the three additional turns?

If you want to try you can add another 180* rotation (a half turn) to it and see how that impacts the situation. To play it safe although originally you added complete turn increments, now work in half turn increments. IMO you are pretty close to what I consider to be an ideal spring pressure level. That is 2-4# below peak boost level. A two PSI margin being kinda radical.

 

This isn't an FP HD actuator for the VIII turbo since FP does not make one for that application. So, it is either MAP/Turbosmart, or Forge, right?

 

guys,yes I'm tuned for this much psi.the actuator is from map but it says kinugawa and it's 1.7 bar.sparky that's correct i added 3 360* turns and used some force to put it on.then plugged together vacuum lines from cold side turbine housing(nipple) with wg actuator.no i did not road test with free preload.at wot i was in first and second and third.it does not spike it just holds around 22psi.I'll try to add another two turns.thanks everybody for you help guys.

 

Play it safe and do just one more complete turn at a time and retest boost level after one turn. This will tell us exactly how many PSI each complete rotation of the turnbuckle equates to boostwise eliminating guesswork.

 

ok I'll do it.but should i stop turning until i see 25psi on the boost gauge?

 

What is your peak boost level gonna be? I like spring pressure adjusted to where it is 2-3 PSI below my peak level. So , for a 25.5# peak I'll preload the gate to 22-23#. But, you need to do a WOT run in 4th gear just to mske sure that boost is not creeping. As long as peak boost holds rock steady you'll be OK.

 

I like setting preload just the way that you describe above. I will adjust actuator spring tension until I reach my desired peak boost level. Then I back it off one & a half, to two full rotations. I always make sure that there is no creep whatsoever.

So, let's say that you want to run 25# peak. First, I incrementally adjust preload up to 25#. Once peak boost level has been attained via the turnbuckle, then I back it off one and a half to two complete turns, leaving it at 22-23#. So, I end up with 22# spring pressure and from that level on up, the boost control device allows boost to rise the other 3# up to the 25# peak ceiling.

The above method gives me the quickest spool as it keeps the flapper valve shut longer, thus achieving a higher cracking pressure. There are a couple other methods that I am not a fan of. Among these is the three additional turns after determining base spring pressure method. The other generic method involves adjusting actuator rod length to the point where the hole in the turnbuckle flat covers half the flapper valve peg or something like that..

 

got it,thanks a lot man.

 

ok,i turned 8 half turns and it spikes at 25 and holds at 21.afr about 11.0 at wot in 4th gear.I'm on E85 btw.Raignman24 posted the video from FP and i tried the higher preload.i think it's good enough,so ***** it i think rest of it in tuners hands.thanks brothers for your help.