Just when you thought you'd seen the last of them, I did this:

 

 

It wasn't complete guess work though, I read this thread and some other stuff

 

http://forums.vwvortex.com/showthread.php?5700226-Wastegate-Actuator-Spring-Mod

 

Basically what I'm trying to do is cure a running issue with my car, for those who followed my dyno thread they'll know my boost is dropping too far below specified from about 5100 rpm.  It all seems to point to a weakened actuator spring so it can't overcome the pressure at the top end to shut and/or stay shut.

 

Been a nightmare trying to find suitable springs, thought I'd got one off ebay but it turned out to be 12lbs/inch, too much.  Ideally you want springs between 5 and 10 lbs, sellers don't seem to know the rate very often so it's a bit of trial and error.  However, I was in my local hardware shop the other day after some bolts, and found these which felt ok compared to the 12lbs I tried 'in the hand'.  They did feel a bit too weak if anything so I figured I could double them up, 2 together felt nice.  Put them on the actuator and they're a little long, however, peak boost was held for longer, and didn't tail off until 5400 rpm. Still below specified but it seems I'm on the right track!  I reckon the same length springs with higher rate or shorter, similar springs should do it.  Will go and have a dig about again and see what I can find!

 

So it seems the actuator spring is the issue, but this will save 4 hours labour or a major scrap with the car on the driveway.  This will do in the meantime until I'm better placed to fit my refurbished one.

Good work!

Sick init, just needs a touch more spring rate and them being a bit more snug (preloaded) at the rod end.

You just can't beat a good pikey mod! Did you just go straight to the two springs or a bit of experimenting?

You just can't beat a good pikey mod! Did you just go straight to the two springs or a bit of experimenting?

I went straight for the 2 mate as they felt a bit softer than I wanted (best so far though) and could do with being an inch shorter so didn't see the harm in slapping them on. Thing with this mod is it increases spring rate without messing with the stock settings. Winding the nut up reduces the gate flap and thus increases temps so at some point will have adverse effect. I did consider preloading by just one turn but as it's getting to peak boost ok I'd be reducing the gate for no real reason. Sometimes stock settings shouldn't be adjusted I feel, often they're there for very good reasons.

I agree buddy adjusting the rod isn't really recommended especially when it might cause a turbo failure. I've just looked down at mine it looks buried from the top. Did you do it from underneath?

Went underneath to hook it round the vacuum and can just get arm through from above (jack it down) to grab it and hook it on the rod. Wasn't much thread to hook onto so with 2 springs the 2nd was a bit precarious, so just screwed that nut down to stop it popping off. There's a washer between the loops and the rod nuts as well to stop them riding up. Iirc the rod is a 6mm thread, think that's the nut I found anyway.

Mmm you've got me thinking now. What did the boost drop off feel like? Was it a gradual tail off or like hitting a wall sort of feeling. Yours has done a lot less mileage than mine (122k). i can't believe yours has a weak actuator spring on your mileage.

Hou could just fit a restricter in the hose from the n75 to the actuator for the same effect.

Mmm you've got me thinking now. What did the boost drop off feel like? Was it a gradual tail off or like hitting a wall sort of feeling. Yours has done a lot less mileage than mine (122k). i can't believe yours has a weak actuator spring on your mileage.

It is a strange one, again I put it down to a bit of a history of light use, now it's pretty much daily and mapped it's shocked a few things into submission if you get my drift. The tail off is gradual, to be honest you don't feel it, although seeing the logs made me more aware of a lack of puff towards redline. I don't often go to redline though, I tend to use the peak boost and torque between 3 and 5500.

What I would say before you panic is see if you can log block 115 and you'll soon see if you need to worry. Apparently it's a common thing on the older 1.8t, but you're not guaranteed to have a problem. Also consider that the ko3s is known for running out of puff a little bit; so don't be surprised if you go a little below specified, just mine was a notable tail off, albeit quite gradual. Can't remember what it drops too, think it's by a few psi by the time it gets to redline from 5200 (before spring mod, now drops a little less and from 5400 now).

I've never felt it lacking power tbh. Higher up in the rev range means I'm travelling plenty fast enough (old age again!). With you tracing it to the actuator spring got me thinking on my mileage. For the sake of jacking it up and a few quid on some springs it might be worth doing.

I've never felt it lacking power tbh. Higher up in the rev range means I'm travelling plenty fast enough (old age again!). With you tracing it to the actuator spring got me thinking on my mileage. For the sake of jacking it up and a few quid on some springs it might be worth doing.

Yeah see what you can find, 5 - 7lbs and around 5.5-6 inches long. Mine were 6.5 and a smidge too long I think. Prepare for a few trial and error buys before you find the right one. Quite important to log as well though to see the difference. When I reckon I've got it spot on will do more logging, only checked boost today.