throwit

I am considering replacing the stock coolant tank with an aftermarket one, which generally ranges from 1 to 3 quarts capacity.

Anyone now what is "too small" when it comes to the coolant reservoir capacity??

This is for road racing applications only (if that matters).

Thx

davidfarmer

I have no idea on this one...... I consider it an expansion tank, basically an air tank to allow pressure/heat to expand, and refill the system as it cools. I don't know if there is a formula to calculate the "perfect" size.

Why are you thinking of changing it? I've used OEM tanks with high pressure caps, including some very very hot racing in Puerto Rico, and never had a failure.

sperkins

Weight savings?

throwit

Saving weight would be great if the capacity could be lessened, but I really want to relocate it closer to the cabin/firewall and off the tire. With the shape they made it (and because its plastic), it requires allot of fab to do that...so I figure it would be allot easier to buy an aluminum "box" or "cylinder" which could be screwed or riveted into place.

John Shiels

Your perfect formula could be derived from watching it as you use it first. When real hot how much room does it need?

stairman

I am using this one on a C4 that I transplanted an LS6 into, it works just fine. its the 1-1/4 quart.

http://www.cantonracingproducts.com/...&category=8020

Aardwolf

I went through this recently and ended up with a surge tank under a quart. With fairly even temps and some cool down there is very little surge. Turning the car off when it's real hot will surge a bunch out. Mine will overflow that to the ground, then have to be topped off.

davidfarmer

seems like a lot of trouble to me. Adding extra hose, clamps, plus the weight of the canister itself. Even if you reduce 2 quarts and move 1 quart, you are still talking about less than a pound of water. There are easier weight savings/relocations that seem to make more sense unless it's an all-out race car.

throwit

Agreed.

It is an all out race car...

geerookie

One of the guys on here is running a 1 quart expansion tank with his LS6. I don't know the formula to calculate but I would think a quart should be plenty.
I'm going to move mine to the firewall also.
Better weight distro, since it's behind the axle and also weighs much less.
Just make sure it's mounted so the water level is always higher than the top of the radiator.

It also gives you clear access to the top of your shock if you need it for adjustments.

Aardwolf

That is a nice tank listed above but would be to costly for my budget. I used a tank from Ebay, it was $20. There was no additional anything for changing over on my C4. I mainly changed tanks because the stock tank was very large and covered area in the nose that I would like to add cooling ducts to. The larger your surge area the less you'll have to check the level.

froggy47

You can save weight with a stock tank, just don't fill it so high, it'll still work fine. GM added a lot of volume just to be safe for those who don't check coolant until the idiot light comes on.

For relocating weight you would need a smaller tank.

On my 95 M3 it's maybe 12 oz of coolant in a 20 0z bottle.

brkntrxn

Hmmm, hadn't thought about that. To your point, a person should be able to run the coolant down to the very bottom of the stock tank when the coolant is cold, right? All of the room in the tank is for hot expansion, correct?

However, as David pointed out, we are talking minimal weight savings of less 2-6 lbs so it is only worth it if you are looking for the last little bit of weight.


-Kevin

davidfarmer

does the plastic tank really weigh much of anything??? Aluminum has mass too....I can't imagine this saving more than a pound or so total. Again, I'm talking to the street car guys mostly.

brkntrxn

The empty windshield washer tank and the little bitty pump in it were 1.9 pounds when I took it off my car. The overflow tank is very similar in size so I would think the weight would be the same.

throwit

Yea, the weight savings is minimal I think (MAYBE 2 pounds)...its more for relocating the 5lbs (or so) when full that it does weigh. Not sure why a street car would do that...unless they had some remote reservoir shocks and really wanted the adjuster there

froggy47

I run the coolant (cold) about 1 inch off the hole in the bottom of the tank & empty windshield washer tank. Water about 8 lbs a gal. So between the two I guess about 2.5 gal less weight?

Up high too.

coffey

Here is the one on the GrandAm car I built. It's an off the shelf tank with some extra bracketry