How much coolant...

Blackflag533 · Post by **Blackflag533** » Thu Feb 24, 2011 8:58 pm

Evening all,

As the title, how much coolant should I be looking to have in the cooling system of a 3.9 Rover V8...?

The engine is in the back of my autograss car that I bought part finished so the cooling system will be built from scratch.

Thanks in advance.

Ian Anderson · Post by **Ian Anderson** » Thu Feb 24, 2011 9:10 pm

It does not matter.

So long as it has a full systen (no air bubles) a sufficiently sized radiator, water pump it will do the necessary and cool the engine

That said, block, inlet and outlet pipes and a feed pipe to a header tank will be abut 7 - 8 litres - with very short top and bottom hoses.

Make sure (if you can) that it will always self bleed in case you have a hot spot and small boiling area will cause bubbles.

Ian

Blackflag533 · Post by **Blackflag533** » Thu Feb 24, 2011 9:15 pm

Hello Ian,

I have an electric water pump & controller, a Serck rad from a Renault 21 diesel with twin fans - I'm not convinced fully the rad will be up to the job.

Any ideas...?

Thanks.

Ian Anderson · Post by **Ian Anderson** » Fri Feb 25, 2011 8:56 am

GT40 has a 4 core ali radiator with a 300 * 600mm core
It copes well (40 + degrees in 1 hour of stationary traffic going to Le Mans Last year and it sat at 85 degrees - I melted!)

Not sure how big your Renault Rad is and how many cores but the above area will give you something to aim at.

Also make sure it gets a good airflow through it Fans are good but in reality only move air at about 15mph so anything over that make sure you use natural air flow

Ian

kiwicar · Post by **kiwicar** » Fri Feb 25, 2011 1:32 pm

Hi
How long is a race? just you can "crutch" and undersize rad for a short time with extra coolent capacity in the system, basically an oversize header tank, also using ally pipe will help. Most of all good ducting around the rad will help enormously especially if you can get the air out efficiently.
Best regards
Mike

Ian Anderson · Post by **Ian Anderson** » Fri Feb 25, 2011 1:51 pm

kiwicar wrote:Hi
How long is a race? just you can "crutch" and undersize rad for a short time with extra coolent capacity in the system, basically an oversize header tank, also using ally pipe will help. Most of all good ducting around the rad will help enormously especially if you can get the air out efficiently.
Best regards
Mike

Mike

You should add that the specific heat capacity of pure water is 4200 joules per kg per degree celsius

The crutch may end up being a 44 gallon drum!

Duct air in to the rad - at least 1/3 the area of the rad in open duct

Ian

kiwicar · Post by **kiwicar** » Fri Feb 25, 2011 4:21 pm

Hi Ian
I was thinking of sprint type races where you are talking very few laps (maybe 1) and I have seen alot of people use this aproach very successfully, also consider the drag racer's habbit of running dry block!
The biggest gains in any racer over a road car is that generally you can make much better use of well designed ducting that means you can use a rad that would be totally useless in a road car.
Best regards
Mike