R33 Gtst Track Build

[iruvyouskyrine]

Also can i request some pics of your engine bay (specifically the breather setup)

[Dale FZ1]

On 9/24/2019 at 11:01 AM, iruvyouskyrine said:

Also can i request some pics of your engine bay (specifically the breather setup)

I'll do my best to give clear idea of the approach.  Might need a few more pics but the following few are from various stages of development.

There is a log of crankcase pressure, but with a max of 2kPa and engine revs in 6-7000 range and MAP 230kPa it doesn't show much.  Really just showed me that the setup I've run is able to push air out without big restriction against flow.

These few shots show the original LHS can that was configured with feeds from the RB26 cam covers with baffle kits.  Can has an internal baffle, and a drain/vent to/from the sump.  No one-way control of airflow.  Sheet metal in the sump provides a diverter to discourage oil trying to push up that hose.  All lines are big diameter, and the breather is via a 50mm filter. The scalloped out piece in the can is required to allow the big turbo drain hose to be routed without problems.

The yellow sump shows 2 x AN fittings, one plumbs to the LHS can, the other to the non-Neo head drain.  Big internal diameters to provide easy passage of air or oil, whatever was being passed up or down from head to sump.

Choice on the RHS was for a barbed fitting, as much for compactness in a tight area as anything else.  I'll get a pic or 2 of that up at some point, plus a reasonable description.

LHS, in operation showed that there was no oil pushing through the cam cover vents into the LHS catch can.  The hoses were more or less dry internally after running.  The conclusion was that majority of blow by gases in the crank case were not pushing up the rear of the block, but were able to take the path of least resistance via that "drain back" straight from the sump. 

How did I conclude that?  Ran a brand new white sock on the filter, and there was a very light discolouration from oil.  So air was passing out the filter, and minimal oil being entrained.

The answer to an obvious question - yes it is very tight to package.  Fiddly and relevant to track use only.

 

[Dale FZ1]

The can plumbed to the RHS of sump is effectively only an expansion chamber.  This one was a rushed afterthought and needs more work.  No diversion baffle in the scraper plate sheet metal, and oil was not prevented from being pushed up the hose.  Once it's in the hose, a bit of airflow can make oil go up the 500mm and out a similar filter (but using a 40mm pipe).  Oil losses were probably in the order of 1-200mm, but it goes everywhere. The RHS can is mounted under my remote brake fluid reservoirs, general design is simple and probably about right.  No brake booster - earlier pics in this build show it's running floor mounted pedals with bias adjust.  Again, not relevant to road cars.

Pics will follow.  But this is one mod I think is very very useful in venting air from the crankcase, and allowing oil to flow back downstairs rather than be trapped upstairs and leading to pump cavitation

[Dale FZ1]

Here's another one that is relevant (I think) to those people running Precision turbos.  I originally used commercially available oil drain fittings, and encountered smoke out the exhaust that people seem to comment on about PTE setups.

To their credit, PTE do a very direct/specific tutorial on their site, and on YouTube as to their turbos requirements on drains.  It mostly relates to the shape of their drain port, and I did not find any compatible setups that could meet their requirements.  So we made one, and used hose and fittings as large as we could physically fit.  Yes, there were routing problems, and yes, there were concerns about heat.

But this setup does work, and no smoke.  I do not like that we were put to the test to fix this issue (PTE should have a specific fitting made/supplied with their design to avoid dramas), but it tells me things about people who simply whine online rather than get a competent fabricator, and be prepared to work out the issues.  This is a good turbo IMO.  How it compares to competitors is open to discussion but I'm not complaining.  The oil feed filter is visible in pic.

[Dale FZ1]

Pics showing design and positioning of the RHS can.  Simple construction, hollow/unbaffled internally.  Main body is 63mm tube with a 40mm neck to suit filter.  AN nipple on the bottom to take the hose fitting.

The most important aspect of this was to have a constant fall in the house routed from the can to sump level, nowhere for oil to pool and be blown out the filter by crankcase gases being vented.

As per previous comment, the two cans are effectively used to vent blow by gases direct from the sump.  Understanding the behaviour of oil within the sump while the engine is operating at speed/load, and with lateral/longitudinal acceleration loads is not easy, but we learned quickly that a diverter/guide near the sump fittings is necessary to deter oil climbing the crankcase wall and being pushed into the vent hose along with gases.  Once it's there, it will get pushed upwards and be spat out.

[No Crust Racing]

Great info.