Breather tanks

**Mr Ed** · 29-11-2006, 03:09 PM

Hi all, Im considering putting a breather tank on my setup in the near future. Ive been told a bit about them, Ive read a bit about them and Ive quite a few of them around the place but I have never found out how they need to be designed to work effectively.

Im considering one for two main reasons:
1. To increase my cooling system capacity
2. To eliminate(or at least reduce) the posibility of air in the system.

At this point in time I dont think I am having problems with air in the system or 'hot spots', but as my radiator is not designed for the heat my engine produces and I have had the temp gauge bounce off the top of its scale a couple times in these last few hot days, Im thinking that increasing the system volume might be the easiest, cheapest and most effective way to upgrade before I go and spend $700 or so on a bigger radiator.

AFAIK I need to run a fairly small tube from all of the high points in the system to a tank which is positioned as high in the engine bay as possible, to bleed off any bubbles into the tank. I assume I will also need to divert one of the radiator hoses (probably the bottom hose) to go through the tank in order for the extra water volume to actually circulate through the whole system.

Questions:
How big a tank should I use? (Thinking of around 2L but that might be too big)
Whats the general idea of the do and dont of a breather tank?
Once the air is collected in the breather tank, how is it vented without water venting out as well??
Do I run the radiator overflow line from the breather tank or leave it where it is?

I dont suppose Bill has done one of his big explanations on breather tanks before has he? (I did search but had no luck)

Any help much appreciated!

**thechuckster** · 29-11-2006, 09:33 PM

copy Bill's swirl tank and mount in the highest spot in the engine bay.
-close off cap on radiator
-overflow cap is now on swirl tank
-plumb rad and engine to swirl tank
-attach over-flow line to swirl tank
-air is vented when you top up the system (open the cap)

if you can find a copy of issue 5 of RACE magazine, you'll see how the porsche 962 has a swirl tank for the cooling system (radiators each side of the car) mounted way up high above the engine.

cheers,
Charles

**Mr Ed** · 29-11-2006, 10:57 PM

Ok, thanks for the tips.

Dont suppose you know which way the cooling system flows through the bottom radiator pipe? (Into or out of the radiator). I'll hook it up so the coolant flows into the top of the tank and out the bottom, with the pipes on an angle to promote a swirl.

I suppose the air will vent when it reaches the radiator cap pressure too.

I might see I can grab a copy of that mag just for interests sake too.

Thanks again mate! +rep for you!

**roadsailing** · 29-11-2006, 11:24 PM

there is a really good diagram in one of carrol smith's books, i think it is in engineer to win but might be in tune to win.

ill see if i can find a copy of the page,

it has bleed lines to aid in filling from dry, and will help out in a lot of ways. look at the system in a BA falcon for ideas.

also, fix the problems you have, adding water will not give you any more cooling capacity any more than putting more fuel in your tank will give you more power (maybeye not quite like that) it would only work in this way if you had an enorumous tank, which would just add weight to your car, and it would take longer to cool down too, think about it!

**Mr Ed** · 29-11-2006, 11:32 PM

I dont know if the fuel tank adding power comparison is really relevant but I understand your point. To be honest I hadnt really thought about it all that much, Ive just always heard that a larger capacity cooling system will make a considerable difference.

Dont suppose anyone has any good data/experiences of how effective a larger capacity cooling system really is??

**roadsailing** · 29-11-2006, 11:37 PM

yeah my fuel example isnt really the right one, but im glad it got you thinking.

as an example, my car had a screwed thermostat for ages, for a while i ran it without a fan too (smart eh?)

when driving along at speed, the temp would get really low, like "cold" on the gauge. when i pulled up at lights or got stuck in traffic it would go to half way and on to "hot" and when i started moving again it would go back down to "cold"

what i'm getting at is that you want your cooling system to work in steady state conditions, adding water will make your car take slightly longer to overheat (and longer to cool down as i said before) but it isn;t really fixing anything at all. i'd suggest getting your system checked out or just giving it a good look over yourself, as you shouldn;t be overheating unless something is wrong (or if you are caning the car with a turbo engine and a radiator that isnt big enough)

**Mr Ed** · 29-11-2006, 11:47 PM

Its the original MA70 (turbo model) radiator but Im running a 2JZ-GTE which seems to run alot hotter than other engines Ive had. I dont really drive it that hard apart from a short stomp everynow and then to get upto highway speed from a standstill, etc....

Only time Ive noticed it was the other day when I gave it a bit of a stomp and dropped back to 4th at around 110kmhr (plenty of airflow), had the air-con on and the temp gauge went right upto maximum and started flashing at me. I cruised along at 80km/hr in 5th with aircon off and it sloooowwly came back down to middle of the range temps. (Its a bar graph gauge, I have no idea what the temps actually are)

Im a little disappointed that I cant give the engine a bit of a push in hot weather as Id like to do a bit of track work when I get the suspension done and I dont want it to be a strictly winter only sport.

Bigger radiator will come but for the moment Im trying to think of some ways to inprove the cooling system that I can do mostly myself.....increasing system capacity seemed to be by far the easiest method, and a breather tank seemed to be the best way of doing so.

So.........am I just going to have to bite the bullet and shell out some $$ for a bigger radiator??

**Mr Ed** · 29-11-2006, 11:49 PM

System taking longer to heat up is a good scenario for me at the moment as it only gets short lived high strain driving on the street.........on the track the strain will be continuous and a system that takes longer to cool down is really going to hurt me.

**kingmick** · 30-11-2006, 12:33 PM

Have you got a decent oil cooler on it? if you dont, this will nock a bit of heat out of the system with your current system!
Besides the fact you radiator might need a proper flush and if both those dont work get something like a VT V8 commowhore radiator, if they can handle 800+hp at the wheels they can handle a 2j

**Mr Ed** · 30-11-2006, 01:31 PM

Yeah Im gonna do the thermostat, not sure how much effect that will have though.

Hadnt really thought about getting an oil cooler yet. Might give that a go, will be easy as Ive already got a remote filter setup. Are the lines normally pressurised?