Some X02 Wastegate tips.... from my recent experieince.


Pro Stocker
Feb 7, 2005
Philly Area
First off, I am not a turbo guy but I seem to be getting there by virtue of all the time I've put into helping my buddy with his single turbo/blow-through Chevelle the last couple years!

We had problems with his "cheap knock-off" X02 wastegate. I won't bore you with the details of our problems but suffice it to say there are some things you should ckeck before you install one. In our case it is the "big" wastegate X02 sells, not the "little" one. ot sure how different they are but I suspect they are fairly similar.

First off, the nut that fastens the diaphragm/spring cup assembly to the valve shaft inside it is just a plain old nut. It can back off over time. Ask me how I know. Either loc-tite the sucker in place or replace it with a nylock nut before you EVER install the wastegate on the car.

Secondly, the 3 springs supplied with it are not labeled or identified as to what boost pressure they will open up at (where they limit the boost level). With the adjustment screw all the way backed-out (lowest boost pressure), these are the approximate boost levels they supply, assuming no additional bosst controller is used:

Large diameter spring: 5-6 PSI
Small diameter spring: 8-9 PSI
Medium diameter spring: 14-15 PSI

You can use them in combination to achieve higher boost levels if that is what you need.

FYI- there is no shaft seal on the pressure side of this wastegate. It will bleed pressure. The fit between the valve stem shaft and the guide it rides in is not super-tight. Nowhere near as tight as, say, a valve guide is around a valve stem in a cylinder head. The bleed is significant enough that I would seriously consider using the largest possible line to feed pressure to it as well as keeping the length of that line as short as possible.

We're considering smearing some anti-seize on the valve stem shaft where it goes through the guide before re-installing. We're told they tend to "stick" when they get some age on them. Should provide some persistent lubrication as well as some mild amoutnj of corrosion resistance on those critical surfaces.

Hope this proves useful to someone else someday. Gear

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