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We're using the large separators in from the BMW six banger. The BMW uses one, we use two. The BMW 4.4L V8 uses two smaller separators, which are nice and mirror/symmetric for a V8. But we wanted the bigger ones since they fit. For most other 928 engines, I think the mirror image BMW V8 separators would probably be fine in terms of sizing.
The separators are going into the intake inside the oval-tube air cleaner. They have further breather filters to smooth out any oil mist ingestion over time, it's a breather filter inside a regular intake filter setup. It should work well, but we'll see. (We didn't go with a knife into a gunfight, so we have all sorts of other options to plumb it to the intake, including by pulling a crankcase vacuum using the boost pressure from the intercooler bottom tank and a venturi jet pump.)
John checked the leakdown and the notes on the new engine, everything in line with other known good engines. Some turbo oiling system adjustments still to be done to deal with the pan spacer.
Please tell me how his engines hold up to the load that they do?
Everyone's got an opinion about how to do these engines. John's opinion appears to be to make the minimum number of changes to the stock engine and furthermore only the changes that are actually solving a specific problem. I am more into random experimentation, let's just say that my motto is that "I'll try anything twice."
One thing that I think most people agree on is that as long as the rpms are kept reasonable and the lateral g-forces aren't higher than what street tires allow, these engines are quite durable. Little more cylinder pressure doesn't seem to be a big problem for a completely stock '87 engine, for example.
Originally Posted by BC
What as the reasoning for using the stock FPR instead of a modern, Rising rate, larger orifice setup? Apologies if it has been said previously.
As you know, the FPR-like devices in the front are dampers. You definitely need dampers with large injectors and batch fire. Those are 951 dampers.
The FPR in the back is stock style. I experimented on a electronically controlled return-style FPR that could drive the pump, but that aftermarket setup was not reliable. So now the fuel system is very stock like.
I don't think we need a raising-rate FPR. The benefit from a raising rate FPR would be the ability to run shorter duty cycle at low rpms and off boost. Since this is a gasoline car, we should be able to run big enough injectors with constant manifold-relative fuel pressure.
With a modern ECU with pump control and self-calibrating correction logic, you could flat head it. At this point, this is a solution to a non-problem, in my opinion.
Originally Posted by V2Rocket
That BMW AOS is really cool!
Nice find...any notes on the diameter/length of that unit?
BC - RRFPR? I thought you were against 1980's tuning methods...
The BMW separator can be connected to ¾” gas in and outlets and ½” oil outlet hoses. Those are in round numbers, good enough for government work in a country still using the imperial system...
We're close to hooking up the pipes. The pipes are bigger and there's no room left, so everything is an effort, even getting the right clamps for the pipes.
At this level of force, which is reasonably low, I think the clamps are more of an issue with fit and finish and design (which are easy to evaluate) than the metallurgy (hard to evaluate). Two kinds bring evaluated below.
The really thorny clamping problem, MAF to air box and to the throttle body has been solved. It's basically a completely different fastening solution there, with the air box bolted to the engine with massive brackets.
These gentlemen are getting excited about the system getting installed and tested soon;
Euripean vs. Asian clamps, both appropriate for this job in terms of strength,
09-10-2016, 08:33 PM
