solved the 99+ turbo intake banjo bolt installation problem!

[j-dawg]

We all hate that banjo bolt. It's the worst party of working on any piece of this car. Regularly costs me an hour to remove and another to replace.

I bypassed the coolant loop. The common theory seems to be that the warm coolant keeps the PCV system clear; to me that ain't worth the suffering. I'd rather replace the PCV every 50k than deal with this bolt every time the intake comes off, which for some reason is pretty often on my car. This setup worked ~fine for cars before 99 so I don't see a reason it couldn't work for mine.

I haven't seen this arrangement suggested in the past so I encourage you to consider it. Would have saved me hours and hours of scraped knuckles and curses if I'd done it years before.

[bmdubya1198]

That's a good point... just how much could that really be doing, anyway? It makes sense to bypass it, especially if you drive your car harder at least occasionally.
I think the PCV is more likely to get clogged up due to constant passive driving and low revs than the lack of being warmed by coolant.

[RickHaleParker]

I bypassed the coolant loop. The common theory seems to be that the warm coolant keeps the PCV system clear; to me that ain't worth the suffering.

Stock up on Banjo bolts. The heating loop is there to keep the Banjo Bolt warm and flowing.
It is a hedge against clogged Banjo bolts.

Hum .. I wonder if the manifold could be piped and the Banjo bolt relocated to a more accessible location.

Perhaps a nipple in the manifold then run a hose to the new Banjo bolt location. When one goes to remove the manifold one pulls the hose off the manifold instead of trying to unbolt the Banjo bolt. Still need to dream up a fixture for the Banjo bolt and a location for it.

[j-dawg]

That's a good point... just how much could that really be doing, anyway? It makes sense to bypass it, especially if you drive your car harder at least occasionally.
I think the PCV is more likely to get clogged up due to constant passive driving and low revs than the lack of being warmed by coolant.

And by not having regular oil changes. But yeah, I'm not that worried about the difference. The 850-style system worked well enough.

Hum .. I wonder if the manifold could be piped and the Banjo bolt relocated to a more accessible location.

Perhaps a nipple in the manifold then run a hose to the new Banjo bolt location. When one goes to remove the manifold one pulls the hose off the manifold instead of trying to unbolt the Banjo bolt. Still need to dream up a fixture for the Banjo bolt and a location for it.

Seems to me this would add lots of un-heated length of small-diameter tube to get clogged up instead.

Most of the PCV system makes sense, but the line through the banjo bolt I don't get. Why connect the intake upstream of the turbo and the intake manifold? Not saying it's a worthless connection, or that a smart engineer somewhere didn't design it for a reason, but I don't understand it.

[abscate]

You probably get away with this in warmLA. In cold climates, we get the oil sludge problem in the PCV from cold running.

[bmdubya1198]

Basically the vacuum line going to the banjo bolt on the RN is in place of the vacuum line going to the side of the manifold on the N, right? I can't remember exactly where that hose goes on the PCV, so I don't know how necessary that connection is.

Edit... never mind, I missed the part about the banjo bolt still being in place! You only bypassed the coolant connection, right?

[RickHaleParker]

Most of the PCV system makes sense, but the line through the banjo bolt I don't get.

The turbo does not boost all the time. Most of the time the pressure in the intake manifold is less then atmospheric pressure. In short most of the time a turbo charged engine is naturally aspirated.

[j-dawg]

The turbo does not boost all the time. Most of the time the pressure in the intake manifold is less then atmospheric pressure. In short most of the time a turbo charged engine is naturally aspirated.

Yes. My guess for that line's purpose is that when the turbo is not making boost the gases can be pulled through by manifold vacuum instead of through the turbo, which isn't pulling as hard.

I'm willing to risk modifying it, since it seems to me most of the venting capacity of this system comes from the intake pipe. Under boost, where crankcase ventilation will be most acutely needed, the turbo will be pulling hard through that path. An occasional dipstick or glove check at idle will let me know if the banjo bolt is getting clogged and needs a brake cleaner flush.

[RickHaleParker]

The vacuum before the turbo goes missing when the engine is idling or lightly laded. This is line to the intake manifold is for.

From Vida:

Engine coolant heated crankcase ventilation (turbocharged engines)

To counteract the risk of freezing in the crankcase ventilation pipe, it has been equipped with engine coolant heating. The heating is achieved by the coolant pipe being laid parallel to the crankcase ventilation pipe. The pipes have a common insulated sleeve.


The heated coolant comes from the rear of the engine. The pipe inlet is connected to the engine using a banjo coupling. The coupling hole diameter is calibrated so that the removal of the coolant should not affect the engine's normal coolant flow. The outlet is connected to the thermostat housing.


To ensure that there is always negative pressure in the crankcase ventilation, the hose between the PTC resistor and the flame trap has been equipped with an extra suction pipe. At the other end this extra suction pipe is connected to the engine intake manifold with a banjo coupling. The clutch hole diameter is calibrated so that the vacuum of the flame trap is held by the vacuum in the engine intake manifold up to 90 km/h (110 mph). After that the vacuum is taken from the turbo charger intake manifold.


The pipes for heating the crankcase ventilation pipe are aluminum and the rubber hoses used are extra tolerant of heat.

Without the Banjo the Crankcase would build a positive pressure when idling and just cruising.

In short: the air system is tapped in two places to insure there is always a vacuum to work with.

[j-dawg]

I'm a good guesser!