CA18DET Throttle body - coolant lines

[935Baby]

Hello,

just quick question, how does coolant flows around throttle body? Please see attached picture.
If my understanding is coorect, only throttle chamber (just flap) and rear cover are heated by coolant.
There goes no coolant inside of throttle body casting (no coolant channels inside).
[IMG][/IMG]

[raddy.]

exactly as you noted..

[skyshack]

The rear one is the Turbo cooling. When engine is switched off Turbo makes steam, it rises to condense in rear of plenum and sucks water in to turbo from block. Without this thermal syphon cooling, turbo life is about 20K miles / 32K Km from new. If removed you need a pump on a timer that runs while engine is on and for a few minutes after it's switched off like Renault/Volvo and others use. Can possibly be deleted if a fabricated tube manifold is fitted as these don't hold as much heat as the stock cast manifold. Vital on ball bearing turbos.

The front is just throttle body and only needed if you are subject to throttle icing. (I suspect you are if used in winter, UK is OK unless in far north.)

[hd46510]

Hello, I can also confirm, that the plenum is not integrated in the cooling system from either sides.

skyshack, interesting idea. where do you have it from? Did you experience this 20k miles turbo failing?
I had to delete the hoses from the plenum end cap.

Here are my thoughts:
I considered it more a bleeding point, as being the highest point in the cooling system. There is headless screw which would be the bleeding screw then.

The coolant enters the end cap only to leave it throuh the adjacent connection. This cannot have much impact in cooling down steam(if there is any buildup) to condense.

The thermosiphon effect is a good point. But I came tho the conclusion that this effect should be present anyway, as long as the entry point (turbo) is lower than the the exit point (collector pipe)

Cheers
Martin

[skyshack]

Before they water cooled the turbos on Silvia S12 and Bluebird exec they failed at 20K. All the non water cooled water turbos Renault 5 etc of the mid 80's failed at very short life. There weren't any 3 year warranties in those days.

You can hear the bubbles of steam imploding back to water after the engine has been switched off, ping, ping, ping from the rear of the plenum. It uses the plenum as a heat dump. A rubber hose even if covered in braid won't dump heat, the steam collects at the high point.

[suixo]

I did a diagram a while back when rebuilding my CA, may be of use.


https://i.imgur.com/yk4sQEN.jpg