I am in the process of installing a bigger turbo and I had the stock size drain lines for that old turbo, but for the new turbo should I upgrade those lines too?  If so, how much bigger?  Would too big of a drain line hurt anything?

I forget the stock size hole/lines, but the new lines are 7/8"OD   3/4"ID  and I had a hard finding anything to match that size so I upped it to 1"OD   7/8" ID...  Will that cause for any issues?  Now for the feed line, I am going to have to bush the inlet down to match the sending unit hole...  Not by much I hope, but will that cause any problems? 


Thanks!

I just used a 5/8" brass heater hose fitting that ATPTurbo.com sells along with 5/8" silicone oil hose, and it was the stock size.. I did a GT2871R turbo on the stock T2 manifold flange and have about 10,000 miles on it and no smoking or problems.