Porting the oil relief hole with no balance shafts?

[d j]

hey guys... think about this for a min.. what does the NT oilpump-setup do with all that extra pressure? ...figure that out and apply the results to the turbo block. you wont have to port anymore.

i kept my ported housing for one reason alone... i like the factory oil cooler w/ its housing (opposed to the middle-man unit found on ebay). i haven't ported another housing since i found the difference.

[GSX_Dan]

The way I see it if you're building ~80psi of oil pressure by 3000-3500rpm and then the relief starts to open you still got a problem that's why I'm extremely happy with clipping the spring as well. Now I have 25psi at idle instead of over 40, and as the revs climb so does the oil pressure 10psi for about every 1000rpm. This is very unlike the stock setup where it pegs at 80psi half way through the RPM range then the relief opens and holds that pressure but I will be inspecting my main/rod bearings this winter as they are fresh and see how they survived so far...although i'm expecting them to be washed out from when I was running tremendous oil pressure pre-spring clipping for a good 1000miles...I blew through some perfectly fine journal turbo seals because of it and the motor revs much easier seems like...I never had a noticeable issue with valve float due to non collapsing lifters even on my FP 3x cams reving to 8K...also the non turbo internals even if different(I honestly didn't see/experience any difference and the piston/spring had identical dimentions) aren't setup to deal with the extra pressure from blocked ballance shafts. How sure are we the non-turbo motor simply doesn't run higher oil pressure? An accurate test would be to take a stock turbo and non turbo motor and record the oil pressure readings at specific RPMs and under WOT. I would do it but I don't know anyone with a non-turbo willing to let me use their car as a guinee pig

[90laserRSfwd]

I've read all 4 pages of this thread so far and I think I get the idea. Could someone post a clear (as clear as there camera will get) pic of a bone stock piece and after the porting is done? I just want to make sure I know what I'm doing before I start.

[mavisky]

Originally Posted by 90laserRSfwd

I've read all 4 pages of this thread so far and I think I get the idea. Could someone post a clear (as clear as there camera will get) pic of a bone stock piece and after the porting is done? I just want to make sure I know what I'm doing before I start.

[onebadtsi]

Great info in this thread! Ive been looking for a cure for my 100 + psi oil pressure after my build.

[90laserRSfwd]

wow you really have to look to see whats going on... I didn't realize that you really need to take away so little material. Thanks mav....

[Strm Trpr]

The black portion in the picture is how you want to port your oil relief hole.
You want the leading edge of the pistons larger diameter to just seal the flat portion you create in the oil relief hole shown as black in the pic.
You want to create a wide and flat opening nearest the source of pressure.
That way the piston doesn't have to compress the spring 1/2" or so to relieve the oil pressure.
It's all about flowing volume of oil, not oil pressure.
The larger you make the hole really doesn't help, it's at the top that you want to open up,
make it flat and flow a rectangular volume of oil instead of a half moon volume of oil.... get it.
I've done three oil filter brackets using this same method, and have had excellent results.
The best was with a 92 6-bolt previously pegged his oil pressure gauge to 100+ psi at 4k rpm, now at 7k he only sees 90psi...

[Morpherex]

So have we figured out yet if the NT air cooled housing has a different spring than the turbo air cooled housing?