I did some searching but I couldn't find anything on this topic. I recently installed my turbo and I had to custom make my oil lines. For the drain line I have a 20" line with -8an fittings. The turbo is a TD05 and coming off the turbo i have a 1/2" NPT to -8an fitting. In the oil pan I have a 3/8" NPT to -8an.

The turbo is oil and water cooled. It doesn't make noise but then again I have only had it on the car for a few days.

My concern is that the -8an fittings are too restrictive but according to the links below, 3/8" NPT is fine.

http://revlimiter.net/blog/2010/07/drilling-for-oil/

http://www.bellengineering.net/templ...ons_BEGi-S.pdf

When I was looking at the fittings before the install, the 3/8" NPT looked to be the same size opening as the -8an so I figured it would be safe but I just want to hear your opinions.

BTW the car is a 99 making 8psi but I intend to bump it up to 10psi eventually.

 

Disconnect the line from the pan and aim at a container. Start the car, and watch your flow.

 

I'm not sure what I would be comparing the flow to

 

So you are not worried that it *isn't flowing* you are worried if it is flowing enough? Honestly with the pieces you describe above there should be no flow issues. -8an is 1/2" OD, so I'm guessing probably 3/8 ID or close.

 

If you're not blowing mass amounts of smoke right now then you are flowing fine.

 

Whenever I checked my drain line I would just pop it off the oil pan fitting and stick it in to a coffee can, then start the car and shut it off. I usually would check the feed line while I was at it, and usually before I'd check the drain.

 

Thanks guys. This is exactly what I needed to know. I know most people use a -10an but I just wanted to make sure I wasn't risking anything by using a -8.

 

If your turbo doesn't die and start screaming (literally) on your first full range rpm pull you are probably ok. no smoke is a sign of happy turbo too