plenum pipes

[project 112]

on the bottom of my rv8 hotwire plenum chamber there are two pipe outlets about 1/4 diameter i,ve read that these are meant to prevent "icing" to the throttle body and are not really needed and can be blanked off. is this ok? why would rover fit them if they were not needed?

[stevieturbo]

project 112 said:

on the bottom of my rv8 hotwire plenum chamber there are two pipe outlets about 1/4 diameter i,ve read that these are meant to prevent "icing" to the throttle body and are not really needed and can be blanked off. is this ok? why would rover fit them if they were not needed?

to prevent icing in cold weather...strangely enough.

A Car sold to Saudi Arabia will still have them fitted.

Edited by stevieturbo on Saturday 14th February 12:13

[spend]

Whilst it is common and valid to disconnect it, I do think consideration should be given to what you do instead. I've always wondered if Rover left it as is for some valid reason. It is the highest point that coolant reaches in the engine and seems an ideal point to trap and bleed off air?

[GreenV8S]

spend said:

Whilst it is common and valid to disconnect it, I do think consideration should be given to what you do instead. I've always wondered if Rover left it as is for some valid reason. It is the highest point that coolant reaches in the engine and seems an ideal point to trap and bleed off air?

I think that honour falls to the blind hose leading to the coolant temp sensor?

If it's designed properly the cooling system should degas itself anyway, you wouldn't want to compromise power by heating the air intake just to improve degassing.

[project 112]

so i can blank them off then, as "strangely enough" i,ll not be going to northern Russia or Saudi Arabia in the near future

[eliot]

Here's what it looks like inside:

As Stevie says, It's to prevent icing. On the TVR Griff 500, they were left disconnected.

[project 112]

thanks eliot looks more hassle piping them up than what its worth using them

[GreenV8S]

If you get carried away and decide to leave the cover off the bottom of the heater chamber (as pictured), bear in mind that two of the screw holes go through to the air intake and would need to be blocked off. That's no problem to do, but if you don't realize you need to then you end up with a huge unmetered air leak which causes running problems.

By the way, what does the 112 in your user name refer to?

[eliot]

GreenV8S said:

If you get carried away and decide to leave the cover off the bottom of the heater chamber (as pictured), bear in mind that two of the screw holes go through to the air intake and would need to be blocked off. That's no problem to do, but if you don't realize you need to then you end up with a huge unmetered air leak which causes running problems.

Very good point, mates westy had that problem.

[project 112]

thanks for the info,i,ll leave the bottom fitting on and just blank the pipes.Project 112 was the name given to the lamborghini countach before it was named the er...countach as i,am building a lambo replica i just thought it would be a good username!

[GreenV8S]

The two hoses you can simply connect to each other, or blank them both off it that's more convenient. The spigots on the chamber can be left open to fresh air.

[Steve_D]

I think the hose started at the top of the inlet manifold, into the underside of the throttle body, then to the top of the rad.
I would connect it all up properly myself as you can still get icing even in our climes.
Failing that I would run the hose from inlet to rad as that will bleed off any air trapped in that side of the inlet manifold and head.

Steve