I've been suffering a strange noise within the downpipe and first section of the Milltek system. Took the car to Paul at Extreme Scoobies and he pinpointed it by gripping the wastegate arm with pliers whereupon the noise seemed to disappear! The shaft which goes to the wastegate 'button' has 0.5mm vertical play but I would have thought that if the actuator pre-load was correct, this would not be easily moved? It could be that the button is not seating firmly and is 'fluttering' thus causing the noise? Got a feeling I need to check the pre-load and re-set How many turns on the pushrod for the correct pre-load?
The turbo is an MDX321T

JohnD

 

We used to do it to half hole preload.
Ie wind the actuator rod in/out till half the hole of the rod was over the actuator pon, then using pliers pull it over the pin

Hth

 

Set it to the above - was confirmed by Lateral performance.

JohnD

 

Sorry to hijack, i need to adjust my preload on a 95 wrx TD05 (original turbo) car is mapped to 1.3 bar, is it still the same as above, half the hole covering then pull the rod to fit onto the nipple of the valve ?

cheers

 

It seems a basic setting value. Usually equates to 3 turns of the rod.
Be sure to check for possible overboost afterwards - see my other thread re-wastegate pre-load
https://www.scoobynet.com/general-te...did-it-go.html

JohnD

 

cheers.

i have adjusted to 8 half turns so this made the eyelet 3/4 away from the nipple it had to sit on (wahay LOL)

i had to adjust it 6 half turns before the eyelet didnt even fit, so it was well out of any preload.

will test tonight when roads are empty as its uber busy round here until then and wil see if i get boost cut or just lots of boost :-)

 

well, no overboost or any issues with the 8 half turns i did, it spikes to what looks like 1.4 Bar boost then tails back to 1.3/1.2 and stays at 1.2 to redline in most gears then stays at the 1.3 bar in 5th.

My question, shall i add more preload until i hit overboost, as for that brief few seconds of what seems like extra boost helps, i know it tails off, but if i add more preload until i get fuel cut/boost cut will this help ? basically keeping the wastegate shut for longer to generate more boost into the system before the system says too much and applies boost cut ? or am i talking crap and leave it as is for now ?

 

Leave it!

JohnD

 

I`m assuming the boost shouldnt go passed what its set too, mine is mapped to 1.3 bar and with 8 half turns it looks like it hits 1.4ish then lowers to 1.3/1.2, so i might back it off to 7 half turns so it should hit 1.3 and stay steady

 

My boost control is via an Apexi AVC-R controller and is set to 1.65bar target. It drops to just over 1.5bar after peaking. After re-setting the pre-load, the boost hit 1.79bar. Fortunately, adjustment of the boost solenoid duty on the AVC-R brought the peak boost down to the target figure. Without the AVC-R I guess a trip to the mapper would have been required!

JohnD