slash695

Hi guys,

I'm building a LS3 conversion into a RX8 chassis.
I have reached a little hiccup and would like your LS expert advice.

I need a radiator, problem is the room from the front chassis of the engine bay to the front of the crank pulleys and accessories is barely enough for a 42mm radiator with slimline fans from mishitomo. Whilst it may go in just barely, there is a chanc I would have to cut the front brace, notch it about 20% of the brace thickness to give me room from the slimline fans to the front of the engine.

Personally I don't want to be cutting any more of the car than I have to, and I'm not too certain a 42mm dual pass radiator (26inch by 19 inch total size, including end tanks) is enough to cool the system especially with people saying the mishitomo slimline fans are a bit weak.

The reason why I have the radiator hard up against the brace is because I need the top radiator hose to be slightly higher than the water pump outlet. I'm presuming the top hose is where it's fed back into the radiator??

My question is, and I want to keep it as simple as possible...

Can I move the radiator forward and under the brace where there is space. But the radiator will be lower than the outlet?

That way I can run a much thicker radiator and big powerful spal fans, shrouded of course.

I presume I would get a radiator without a cap or fill point, in the top radiator hose put a In line filler neck and preassure cap from summit. This would then be the highest point in the system for bleeding and filling?

I presume those in line filler caps come with an overflow point which I can put into a catch tank. If the hose is all the way in the bottom of the tank will this then refill the radiator when it cools??

The steam vent I'm planning to tap all four points in the heads and run them together, but where do I run the steam vent tube to. To another in line point in the top radiator hose from jags that run? Or weld a NPT point to the bottom of the in line filler neck below the overflow valve so it goes to the highest point in the system the radiator fill point.

I will run the heater lines to the heater core in the rx8, nothing special but lines there.

Keep in mind I'm going for the simplest system without surge tanks etc.

Here is a little diagram I have drawn.

Help school me, is there a better way of doing it? Am I overthinking it and will the 42mm with slimline fans work?

For note it will be a Cammed ls3 running 470 flywheel hp.

Thanks!!!

slash695

Or do a coolant expansion tank with the bottom hose plumed into the heater line, steam line to the top half above the water in expansion tank. Then no cap at all on radiator?

slash695

Or like the below diagram.....

In this one I would plan to have no radiator cap at all and fill from the pressurized tank?

So the pressurized tank would have the four steam vents from each head to a distributer block which then feeds the top of the tank. Above the water line.

Below the tank a line running to the heater line which is Teed in.

On the preasurised tank a normal preassure radiator tank cap 16psi?? And an overflow to an unpreasurised tank. Maybe not even needing the unpreasurised tank as it's just air it's releasing right??

The only thing I can think of is ease of filling the radiator, maybe by removal of the top pipe. And bleeding the radiator?

Any help appreciated for both setups. Trying to get the easiest set up.

s14hunter

iTrader: (1)

There are plenty of small tanks out there to choose from. I run a degas/surge tank on my car and it's awesome. There's so many advantages to running one:
Deaeration of the coolant for better cooling performance.
No need to bleed or burp the cooling system.
Extra coolant capacity.
Being able to check coolant level with engine hot (if using clear tank).

I'm currently not running an overflow tank on my car.
It's not really "needed" unless you're going to the track.

My vote...get a surge tank and use this diagram for reference.

slash695

Thanks mate!

Just a question. Will this still burp the system even though the heater in the car is not on. As if it's not on will the flow still run. Or is it always heating the core but not blowing air through it?

Could I run a radiator without a cap, and use the expansion tank as the fill point? Would I need a bleed point on my radiator hose or bleed nipple on the radiator?

Cheers!

s14hunter

iTrader: (1)

The heater core always has flow.
You would either run no cap on the rad or a cap with a higher pressure than the cap on the surge tank.
No bleed point or nipple necessary.