Overboosting

stumo

stumo

Active Member
skiddusmarkus said:
Ok, I think I understand now.So it probably needs another turn or 2 on the thread to get some more tension on the spring to make it work properly then.Ah well, off comes the turbo again I guess.
Click to expand...
YES , adjust the actuator rod so that the hole in the rod is halfway over the post on the wastegate arm, as in the bad drawing.

You should have to pull quite hard to get the rod onto the wastegate post.

after doing that pipe up the actuator and see what happens

once you know everything is ok then you can use the boost controller.

Turn the gain down and then then it up gradually till you don't go over your target boost.

"overboosting" is fine as long as the parameters in the ECU haven't been exceeded, if they have you're into uncharted territory (a bit like Captain Kirk and we all know the shit he got into).
 
campbellju

campbellju

Moderators
Staff member
Just a thought, are we dealing with boost surge or over boost here?

I can't remember if your 3071 is .86 or .64 ar housing? I had the .64ar and I never struggled with boost surge until I swapped my OEM elbow to a full 3" system and then spent the next 6 months trying to stop it.


For boost surge the solution is to port your waste gate and take your boost pressure reading as close as possible after your compressor.
 
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skiddusmarkus

Active Member
I have the 0.86 a/r, I read up and saw some had problems with the 0.64 and that the 0.86 seemed better overall.

Couple of pics to help anyone searching similar stuff in the future.



 
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skiddusmarkus

Active Member
Ok, I have just tested an old turbo actuator by connecting my foot pump to it and watching what happens as I pump it.At around 10ish psi the actuator opens the wastegate.It stays open and the pressure holds inside the actuator until I open the valve on the pump.
When I did the same to the forge one, I held my hand against the rod to feel if it moved and it doesn't.It also doesn't hold the pressure inside the actuator it leaks out losing 30psi in about 2 seconds.I am thinking that it could be the diaphragm is damaged so cannot overcome the spring pressure and open the wastegate.
Thoughts appreciated.
 
PobodY

PobodY

Moderators
Staff member
Sounds like a reasonable assumption to me; that or it's not sealed around the edge (so air is escaping past it). - How old is it? I'm pretty sure it's easy to get hold of replacement diaphragms, but if it's new I wouldn't have thought it would be split so soon.

There are a few people who've had a problem like this with the forge actuators aren't there?
 
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skiddusmarkus

Active Member
No, have emailed forge asking about it, I imagine they'll send me a replacement diaphragm and if I am lucky I will be able to replace it in situ as the access is from the top.


Edit:had a look and you can' take the top off in situ as one of the grub screws is obscured by the gearbox.
 
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skiddusmarkus

Active Member
Dropped off car closing time saturday and spoke to garage today, the diaphragm had ripped like I though.I asked them to remove the 2 spacer nuts I had used on the actuator if possible so if it happens again I can maybe take the top off with it still on the turbo(Perrin21 said Spikey could get to his on standard turbo) but they tried and came to same conclusion I did when fitting it that couldn't get enough tension on the rod without them.A bit more thread on the rod would have done it though.Should get it back tomorrow morning and then just a bit of messing with some things and will be ready for remap on wednesday.
 
T

Tim

New Member
Mine did this with the standard setup after I had the gasket blow between the turbo and exhaust manifold and stupidly carried on lapping at a track day. We opened the actuator up on a lathe just to make sure too, I still have it in fact :lol:
 
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