How do you do the plumbing for using twin radiators in the side pods?

A. Water pump, pipe to rad 1, pipe across chassis to rad 2, pipe back to engine.

B. Water pump, y or t piece, pipes to each rad, then another t piece, back to the engine.

C. Water pump, thermostatic t piece, pipe to rad 1 and rad 2, then back to a t piece, back to the engine.

Cheers

Mike

Why the need for 2 rads?

[Edited on 20/11/07 by Fatgadget]

Big engine, located in the middle of the car, small nose.




This appears to go with option A.

Cheers

Mike

WTF is that

Freind of mine with a scratch build 1950's racer uses option B and this works well (tuned V8). A nice Y piece and near identical piping should help even the flow split between the two rads.

I guess option A will not be very efficient as most of the heat will be lost in the first rad, and the second will not have a high water to air temperature. But having said this if you have two thermostatted fans this would basicly stage the cooling, the second fan would only come on when needed....

Cheers

Dan

quote:

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Originally posted by nick205
WTF is that

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quote:

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Originally posted by nick205
WTF is that

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i would go with option B as it makes most of the cooling effect.

the bigger the difference in the temp of the water and air the faster the heat loss. thats why air cooled engines work best in the desert.

ditch

instinct would say to me that you don't want to run with A as (as above) you get the first rad seeing the hottest water, then the second rad seeing pre-cooled, so it might not act as efficiently.

In reality I doubt it would make a great deal of difference but if it's close on cooling ability then it could just tip it over the edge.

I think I would go for two thermostats - that way each rad should operate independantly.

I've seen it done on racecars with option a, just two linked in series effectively.

Ned.

Looks like your going to get every opinion!...

Cheers

Dan

the waterpump must have to work harder with A as the water will go in the top of rad1, fall to the bottom out the side and up again to the top of rad2.

Id go B but Im no expert lol.

water will take the path of least resistance and there is no guarantee that water flow will be equal in both pipes/radiators in option b); at least in option a) you know all water will flow through both radiators.

I'd go with Raz on this one, if you've got a stat in each "top hose" then each rad will only both be in use when required, you do need to ensure that from where you split the feed & rejoin for the return that the hoses follow as near to the same path as poss. This means your 2 rads should ideally be mirror images of one another & your feed & return "Y" pieces central. HTH

I think if you you did a calculation you may find the theoretical cooling is exactly the same with either layout.

In any situation you are going to have half the total radiator surface hotter than average and half colder. If you go with series the the hot half is one side of the car and the cold half the other. If you go with parallel then you end up with the top half of each rad being the hot bit and the bottom half of each being the cold bit.

A normal radiator can effectively be looked at as two (or any other number of) radiators in series anyway.

I'm prepared to be proved wrong but I'd personally go for series then you can be sure both rads are getting the full flow.


As an aside: If using a parallel system I don't see the point in using two 'stats. There doesn't seem to be an advantage over one and if one opens first you may (although I doubt it's likely) end up with all the flow going through that rad and not enough flowing going through the other stat's bypass to heat it up and open it!


[Edited on 20/11/07 by matt_claydon]

[Edited on 20/11/07 by matt_claydon]

I'd go for A, less pipe work and as stated above rad area is rad area no matter how the temp gradiant across each rad works out

Cheers

Fred W B

I'd go with a & run different temperature switches to the fans ..... that way if you think about it lots you can probably have more control over the cooling & therefore reduce the thermal difference the engine sees.

although i've got no experience of what i'm talking about

All motorcross bikes use option b. I'd go with this. The cooling capacity will be exactly the same as you have the same heat-exchanger area.

If you run a 'stat, you'll only need one. If it runs too cold, duck tape on the rad fixes all!

As someone who knows parrallel (Naz) and has built Countach replicas myself (Naz has built both Diablo/countach).
From thermostat to first rad, link to second rad, back to water pump.
Just install a fan thermostat in each rad and control each fan seperately.
Your rad stats control the fan operation and the engine stat controls the flow.
This set up works well in this car, even on a trackday.

in simple thinking, the same voloume of water flows torugh the same radiator surface so you would think the water wold be cooled by the same amount.

but I suspect it is not that simple. the only think I know for sure is that heat transfer is proportional to temperature difference but thinks like how long the water is in each radiator and how much heat is removed to the air will be different for both set ups.

Just think of it as correctly sized radiator cut in half (for location purposes) instead of over complicating things!
Even big rads have twin fans!

That makes a lot of sense when you put it like that Come to think of it, two stats might get confused with each other fighting for flow.

[Edited on 20-11-07 by RazMan]

Thanks Guys

No need to over complicate things then.

Cheers

Mike