Saabscene Saab Forum - Saab Technical Information Resource banner
1 - 20 of 21 Posts

·
Registered
Joined
·
249 Posts
Discussion Starter · #1 ·
Fitted a Forge actuator onto the aero today. Made up my own bracket (quite chuffed with it too
) However not very impressed with the results

I more or less copied the length of the rod as the stock actuator, maybe a little less rod length to turn boost up. Took the car for a drive and turbo spool up is much slower and then there's an almighty kick in the back and continously hitting overboost.

I have lengthened the rod a few turns to bring boost back down but now the car is hardly boosting at all. The boost guage gets to 0 bar and then it takes ages for the turbo to spool up

Have I simply buggered up base boost (hope not as don't want to perform the stupid base boost check - I'll just disconnect the APC) or is it because the actuator is new so will take some time to 'loosen up'?

Has anyone had any similar experiences?

Zahid
 

·
Registered
Joined
·
494 Posts
if you have a small hand vacuum pump with a gauge attachement, try plugging that into the APC solenoid line, pump it up until you move the rod (with it disconnected) and make sure you are holding vacuum. your problem sounds a bit like what i was experiencing with a leaky (and very very old) stock wastegate actuator diaphragm.

check that the vacuum figures required to move the rod compared to what is required with the stock actuator.

before checking base boost, also check that all vacuum hoses are in good condition and properly connected

HTH
 

·
Registered
Joined
·
113 Posts
Hi Zars, I had same problem with Forge Actuator took it off everything was ok for a while then overboost came back few weeks ago have disconnected apc (New valve) everything is ok

I will leave it for the time being..
 

·
Registered
Joined
·
249 Posts
Discussion Starter · #4 ·
Had another fiddle about with it yesterday, still not happy. May put the old actuator back in


cheers
Zahid
 

·
Registered
Joined
·
249 Posts
Discussion Starter · #6 ·
Had base boost checked today, -0.6bar

Will adjust at the weekend


Jezmond, don't suppose you know the length of your rod
 

·
Registered
Joined
·
249 Posts
Discussion Starter · #8 ·
Jez, what on earth did you think I meant

A rough idea of the length of the actuator rod in it's place would be ideal for me to know if I'm close or way off. I know there's other factors that affect base boost but a starting point nevertheless.

Zahid
 

·
Registered
Joined
·
1,597 Posts
What about guessing it vs. the length of the old rod. At least that might get you into the right ball park (eg some positive boost!)
 

·
Registered
Joined
·
249 Posts
Discussion Starter · #10 ·
that's exactly what I did the first time round However something went wrong. Could have been the moment when lots of [expletive deleted] under the car decided to fall onto my face Yes I was comparing the two whilst under
 

·
Registered
Joined
·
249 Posts
Discussion Starter · #12 ·
Arrghhh, when I think I've got somewhere
Thanks for that Bill, good to know otherwise I may have been basing the level on inaccurate info.

I'm going to have a fiddle with my rod ( ) at the weekend and see if I can get a good set up. I've discovered a road which is ideal for a base boost check, will have to be late at night though

Zahid
 

·
Registered
Joined
·
14,305 Posts
It sounds to me like you've made the rod too long now and thus the wastegate isn't holding closed at all. You need at least 1-2mm preload on the actuator to ensure the wastegate stays shut.

What spring rating was the actuator?
 

·
Registered
Joined
·
249 Posts
Discussion Starter · #14 ·
There's a 5-10psi spring in it at the moment.

I also have a 9-15psi spring.

Can I just confirm about the preload and make sure I'm understanding it correctly. With the rod disconnected do I flip the pivot upwards and then pull on the rod a little so it slips over the pivot?
 

·
Registered
Joined
·
8,948 Posts
Originally posted by ZARS:
[qb]There's a 5-10psi spring in it at the moment.

I also have a 9-15psi spring.

Can I just confirm about the preload and make sure I'm understanding it correctly.  With the rod disconnected do I flip the pivot upwards and then pull on the rod a little so it slips over the pivot? [/qb][/b]
Upwards as in an anticlockwise arc so that from underneath the lever points to about 1 o'clock.

From here there should be about 1-2mm of pre load (depending on spring)

Andrew
 

·
Registered
Joined
·
8,948 Posts
Originally posted by ZARS:
[qb]Thanks Andrew, I think mine is more like
11 o'clock    [/qb][/b]
Yes your right, considering that this one is at 12 o'clock and is still slightly open...



Andrew
 

·
Registered
Joined
·
8,216 Posts
Originally posted by Bubbles:
[qb]It sounds to me like you've made the rod too long now and thus the wastegate isn't holding closed at all.[/qb][/b]
Even with the rod completely disconnected so the wastegate falls completely open, there should be positive pressure. I know - I had the usual "Aero disintegrating wastegate clip" problem some years ago and the boost gauge still went a bit into the yellow. My bet's on "experimental error".
 

·
Registered
Joined
·
249 Posts
Discussion Starter · #19 ·
Guys, I've got to admit I've kopped out Have put the old wastegate back on and the car is it's former self
Really enjoying having the boost back and the dump valve hissing away


However I will still get the Forge one set up after I've fitted the bigger I/C and intake pipe. Just running out of time now fiddling about with the actuator so I'll have to leave it for another time.

Watch this space...

Zahid

ps. thanks for all your help and advice, much appreciated
 

·
Registered
Joined
·
494 Posts
ZARS, did you ever try doing a vacuum test on the new actuator? if you had and mentioned it, i must have missed that in your post. i am curious as to whether or not your new actuator may actually be leaking.
 
1 - 20 of 21 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top