Turbocharger Cooling System Plumbing

[rinmak]

Hi guys,

At the moment I am installing a plazmaman plenum on my RB25 and I have a few questions about bypassing the standard cooling system setup for a much simpler one.

At the moment the system goes like this:

* Water in from just near thermostat

* Goes up to the bleeder nipple where it is tee'd off

* - - One side of the tee goes through the throttle body and then back into the block via the big water fitting at the rear (see pic label TB return)

* - - Other side goes through the intake manifold just above the injectors then comes out again and then goes around and becomes the turbos water inlet.

What I want to know is:

1. Can I bypass all of this and block off labels: IM1, TS1, and the other end of where IM1 gets its feed from (at the other end of intake manifold)

2. Once these are blocked, can I just run the bit labeled New turbo water feed to the turbo and will it work in the same way as before?

3. Obviously if it does then I will need to plug up the water inlet/outlet on the throttle body...is it ok to do this or is there a vital reason for water to go through the TB?

4. Since I wont have cooling running above the injectors anymore is this a bad thing? Or is the system just over engineered in the first place?

Thanks for reading...hope it made sense!

[PM-R33]

Pretty much the coolant running through the throttle body is to get the throttle body warm on start up due to places like japan where they have freezing weather (throttle body freezes shut). A lot of cars run this from factory to accomodate for certain parts of the world. Therefore in Australia it isn't really needed unless you live in a really cold place. So yes you can just piss it off and bypass it.

You dont need to change anything on the throttle body and you can actually remove the ugly studs where the coolant lines go into with a bit of effort (did this myself).

Now as too blocking the lines off, yes i believe you can do this, however i didnt just cause i didnt have my engine out like you and its really hard to get to that rear line. Just double check on this part. I pretty much just ran the line from the bleeder niple into the back of the block above the injectors and hid the line a bit.

Let me know if you have any more questions bud.

[rinmak]

Thanks mate much appreciated. I didnt think it would be necessary at all

Just need a few more things confirmed from some of the other gurus out there:

* Is it ok to bypass the coolant that runs on top of the injectors? I guess it would serve the same purpose as what was said above but want to double check.

* Also, is it ok to use the hose labeled "New turbo water feed" as a water feed for the turbo? Only asking as I dont know if it would disrupt flow...im only guessing with most of this stuff!!

Cheers

[rinmak]

Bump....can anyone shed some light on the questions above?

[discopotato03]

I think the TB water plumbing is to stop it icing up in cool humid conditions . I think what happens is the moisture in the humid air freezes to the throttle plate and the inside of the TB itself and the engine struggles to breathe through the reduced gap at smaller throttle openings .

People have told me that it used to be a pain with carburettor/s that metered fuel through low speed transfer ports rather than AFM's and things got loopy in low speed or cruise conditions .

The cure at the time was to stop and let the engine heat melt the ice and go again till the ice set in .

I think mostly manufacturers used to water heat carburettors for anti icing and those diabolical water temp regulated cold start enrichment devices .

With EFI TB's the idea remained to prevent icing on engines sold to widely varying markets/locations .

Cheers A .

[Sydneykid]

You need to have a high mounted water system bleed so you can remove any air trapped in the cooling system. It shoud be connected to multiple places on the engine, the more the better. The standard bleeder has 3 connections for that purpose.

In order for water to flow there has to be a pressure differential between the feed (higher pressure) and the return (lower pressure). The turbo water return goes in to the LHS of the block around cylinder #4. By plumbing the turbo water feed into the rear of the block (near #6) there is not going be enough pressure differential for water to flow. I try and ensure as a much water flow as possible to the turbo, you can't have too much. So I take the feed off the back of the thermostat (TS1 in your picture). That's a high presure area as the thermostat (even when it is fully open) forms a restriction hence higher pressure behind it.

Cheers

Gary

[rinmak]

Thanks Gary.

In regards to the missing bleeder, would it be ok to just tee off of the back of the thermostat (TS1) and have one line of the tee going to my turbo as a water feed then the other line can go straight up to be at about the height of the engine and will be used as a bleeder instead?

This will then chop off all the throttle body/injector cooling shenanigans as im trying to cut down on piping to make the install look as neat as possible.

Cheers.

[rinmak]

Bump...anyone....sk?