5cylinder turbo and n75 issues

Dad's quattro seems very laggy since last I drove it. I'm struggling to find a replacement n75 Audi don't recognise the part number .

Anyone know what is a "good" valve , or is a manual boost controller the way to go? Plumbing the lines aren't a concern , and it doesn't have an engine management light.

 

Which engine and control system?

 

Audi s2 3b with Motronic .

 

Yup, apparently the end letter makes a difference.
That 034 number was dropped by Audi in 2015.

 

^^You got to be very careful with "ebay" bits, especially if there is no experience of the parts.

 

This is a check you can to. It does have some risk and you have to know when to back out!

Disconnect the waste gate sensing to line negate the effect of any turbo control.

Run the car up using the same starting speed and gear you used when you thought the N75 is causing the 'lag'.
If the car is still laggy, then you have a problem with your turbo.