I've seen this before, and these pics are from the jgtc so I'm curious what it's for. There's like an extra coolant resevoir with a rad cap in line from the rad on the way to the real coolant resevoir. What's the purpose of it?

 

bad description but what i assume ur talking about is the expansion tank

 

well, they say the brakes are watercooled, so i would guess thats what they are cooling. but thats just assuming the pictures you have are of cars with watercooled brakes.

which cars are these?


Modified by Tyson at 10:08 AM 12/21/2004

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dohcbag &raquo;</TD></TR><TR><TD CLASS="quote">bad description but what i assume ur talking about is the expansion tank</TD></TR></TABLE>

So you didn't look at the pictures before posting...

I looked at them for quite some time and can't figure out what's going on, unless it's solely to provide extra overflow capacity. What really throws me is that in the first pic, even the secondary tank has two connections.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JeffS &raquo;</TD></TR><TR><TD CLASS="quote">

So you didn't look at the pictures before posting...

I looked at them for quite some time and can't figure out what's going on, unless it's solely to provide extra overflow capacity. What really throws me is that in the first pic, even the secondary tank has two connections.</TD></TR></TABLE>

actually i did.

that is the point of an overflow tank.

the second one confused me, because it was a pic that didnt show all of where the lines went

 

It's called a surge tank. Here's a post I made a while ago on http://www.k20a.org:

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 909edge &raquo;</TD></TR><TR><TD CLASS="quote">A while ago we were discussing the surge tank setup on the Team Pac-man k20 crx. Art (ALLMOTORPACMAN) was nice enough to hook me up with a whole cd full of pics and videos, most of which will be shown by nikos soon. Heres a little preview, these pics clarify the routing of the custom radiator surge tank setup.









and here's an explanation from the C&R Radiators site:

SURGE TANKS

Also known as expansion tanks, fill cans and header tanks

Using a surge tank as part of your racecar cooling system is a very good decision. Any proper racecar cooling system will incorporate a surge tank. When used properly, it is the ideal manner of filling your system, trapping air, and moving the radiator cap from vulnerable areas where pressure surges can unseat the cap momentarily.

On the return side of a cooling system, pressure can surge as high as 45-50 psi. This is due to sudden changes in pump speed (RPM related) and characteristics of the heat cycle as well as circulation in the system. When the radiator cap is on the radiator, particularly the return side, it is susceptible to this condition. A surge tank isolates the cap from these areas.

Surge tanks should be mounted as high as possible, at the highest point in the cooling system, to serve as an air trap and means for expansion. Plumb a –10 line to the water pump and a –6 line from the highest point of the radiator to the surge tank. This draws air to the tank where it is trapped. Approximately 1/3 to 1/2 of the tank should be air space to create an air “spring” allowing for temperature expansion. Purging all air from the system is the ultimate goal. To optimize the cooling system and insure that all air is purged, use a swirl pot in the return water line in combination with the surge tank.

Due to the unique nature of swirl pots, C & R recommends that each specific application and system be evaluated to determine optimum performance. Therefore, C & R Racing does not offer a “generic” swirl pot, but will tailor a custom swirl pot to your system.

C & R Racing specializes in customized racing cooling systems, and can insure maximum protection for your engine investment and performance.</TD></TR></TABLE>

 

If you notice, the first overflow has a pressure cap on it. The second is open to atmosphere.

 

One more pic to show hose routing which was not shown in the previous pictures...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson &raquo;</TD></TR><TR><TD CLASS="quote">which cars are these?</TD></TR></TABLE>

Drift ones, so they must not have watercooled brakes


On pacmans car I can see the point of it, I mean there's no spout/cap on the radiator. These have the normal spout and cap on the radiator, then runs to another capped tank, and then to a normal resevoir. I dont get it

 

WRX's have that from the factory. I think they run the turbo coolant lines thru that to have some kind of circulation thru the turbo when the car is off, or maybe just run a different pressure thru there? Or was it to vent the steam out of the turbo?

 

its basically an air seperation tank...

 

Most you guy's missed this from the C&R article posted up-

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Using a surge tank as part of your racecar cooling system is a very good decision. Any proper racecar cooling system will incorporate a surge tank. When used properly, it is the ideal manner of filling your system, trapping air, and moving the radiator cap from vulnerable areas where pressure surges can unseat the cap momentarily.

On the return side of a cooling system, pressure can surge as high as 45-50 psi. This is due to sudden changes in pump speed (RPM related) and characteristics of the heat cycle as well as circulation in the system. When the radiator cap is on the radiator, particularly the return side, it is susceptible to this condition. A surge tank isolates the cap from these areas.</TD></TR></TABLE>

They have caps on the surge tanks to make sure the radiator cap doesn't open on a pressure surge. Once pressure is lost in a very hot cooling system, all the fluid will boil - not a good situation. If the radiator cap does open, the surge tank will hopefully not be affected by the pressure spike and will keep pressure in the system to prevent the whole thing from boiling over.

There should be no fluid flow through these tanks unless the radiator cap is open(on the first ones pictured), so I don't know why you guys are saying they're for air removal...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Def &raquo;</TD></TR><TR><TD CLASS="quote">Most you guy's missed this from the C&R article posted up-

They have caps on the surge tanks to make sure the radiator cap doesn't open on a pressure surge. Once pressure is lost in a very hot cooling system, all the fluid will boil - not a good situation. If the radiator cap does open, the surge tank will hopefully not be affected by the pressure spike and will keep pressure in the system to prevent the whole thing from boiling over.

There should be no fluid flow through these tanks unless the radiator cap is open(on the first ones pictured), so I don't know why you guys are saying they're for air removal... </TD></TR></TABLE>

ahhhh, I understand now. I read the C&R article, but it didn't sink in (I'm retarded) I wonder how often these pressure spikes happen.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sporkcrx &raquo;</TD></TR><TR><TD CLASS="quote">ahhhh, I understand now. I read the C&R article, but it didn't sink in (I'm retarded) I wonder how often these pressure spikes happen.</TD></TR></TABLE>

A guy at C&R(owns a 240, so read it in a post) said they happy VERY frequently with almost any type of driving. Changes in RPM(fast acceleration, shift, braking etc.) drastically changes the flowrate of the waterpump, and can cause pressure surges at the cap.

Makes since to me since the coolant hoses are relatively small volume, high flowrate, and the radiator is a large volume, which would create a pressure wave whenever the flowrate was rapidly changed at one of the small inlet/outlets.

 

I was gonna say "remote reservoir dampers" since I saw "JGTC" before the pics loaded up!

 

The rules require a catch can for the coolant system. It cannot be part of the pressurized system.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Marauder &raquo;</TD></TR><TR><TD CLASS="quote">I think they run the turbo coolant lines thru that to have some kind of circulation thru the turbo when the car is off</TD></TR></TABLE>

correct, it circulates through after the engine is off