Half Baked Ideas #1: Chassis radiator...

[Stealer Of Souls]

Okay... Was half baking some ideas on totally novel (and most likely stupid) ways to improve a purpose built car...

My first idea was to replace the radiator. i figure that the average radiator (complete with water) probably weighs around 4-5kgs, and sits in front of the front wheels. It's weight is purely front end weight (when thinking about weight distribution).
I wondered to myself if there was a better way. Now I'm reasonably sure that dedicated drag vehicles would utilise a bulk container of water located in the cabin area somewhere to cool the engine. IE no active continuous cooling, they just replace the water after each run.
This seemed like a good idea... but there's that need to keep replacing the water. IE no long term running.
So I got to thinking..
What if you brazed a whole heap of copper tubing into the floor pan of the car?

Method: Take the radiator and weigh it (wet weigh including water). Take the equivalent weight of copper tubing (filled with water). Cut the tubes in half. Braze these half tubes to the floor plan (in some pattern???). Hook the cooling system to this.

Okay. Now the supposed benefits... Well.
Weight distribution. Okay spread 5kgs out over the centre of the vehicle may not be much, but it's a start, some times every little bit helps.
Frontal air flow. If you run an FMIC then you can optimise air flow through the IC as you don't really need to worry getting flow through the radiator. And if you don't have an FMIC you can probably run a sealed (or almost completely sealed) front section. This would improve aerodynamics which will improve top end, high speed acceleration, and mileage.

Disadvantages.
Reduced cooling capacity. I doubt that this arrangement would perform as well as a proper radiator. But hopefully done right it would get close.
Excessive cabin heating. If the car could be used effectively for long periods(perhaps motorway cruising where there is low load) then the cabin would slowly heat up. Eventually it could become quite hot...
Reduced applicability. A vehicle with this sort of setup couldn't be used for anything that required high output for extended durations. Probably good for cars that compete in sprint type races: hill climbs, hill descents, motorkhana, drags, drift, low lap sprint races.

I'm sure there are many more good and bad things, as well as issues and problems with this idea... but heck... I'm here for critiquing.

Thoughts?

[Jebus]

I think you should lay off the meth

How is running water through pipes on the floor of the car going to cool anything?

[wde_bdy]

Why not just relocate the radiator to the rear or even run two smaller ones mounted into the sides of the carwith ducting to feed them. Generally though any weight saving is offset by the longer pipe runs needed. One of the drag cars in this months performance car mag had the radiator mounted behind the motor, but obviously not running for that long so not a big issue.

Callum

[Stealer Of Souls]

I think you should lay off the meth
How is running water through pipes on the floor of the car going to cool anything?

But the Meth makes me happy...
The piping is really half rounds brazed onto the floor pan. The idea being trying to use the thermal mass of the shell to dissipate heat.

Why not just relocate the radiator to the rear or even run two smaller ones mounted into the sides of the carwith ducting to feed them. Generally though any weight saving is offset by the longer pipe runs needed. One of the drag cars in this months performance car mag had the radiator mounted behind the motor, but obviously not running for that long so not a big issue.

The idea was to try and get the weight into the middle of the car. So the two smaller might work. But then you're right, you'r offsetting the weight shift/saving by adding more piping and more water, and you'll have a whole heap of piping inside the cabin, which may or may not be an issue.
My obersevation of the cooling system in my car says that I wouldn't need more capacity (for normal use). By having roughly the same initial mass and by having the connections (distance wise) close to the original length, I'm not really adding much weight. By having all the bits under the car, there's no additional cabin intrusion. And if it somehow performed nearly as well as a proper radiator there would be little or no issues with sustained usage. Better than a drag radiator which is only good for a few runs.

Think, drive to track, perform runs all day, drive home, no added hassle.

[RedMist]

I dont think its such a bad idea. Low COG, utilize the shell as a heatsink. I think the lowering of the COG is more important than fore aft weight distribution.

Three things I can see as being an issue.
High likelyhood of puncture from a foriegn object.
Torsional movement cracking the brasing.
Low airflow as there will effectively be a boundary layer sitting on the bottom of the car.

[pc]

Torsional movement cracking the brasing.

This was my first thought.

A relocated radiator might be the best bet.

[Stealer Of Souls]

A relocated radiator might be the best bet.

I started with this thought too. I figured mounting a radiator type thingy on the underside. But for the life of me I couldn't figure out how to get airflow across or through the radiator.

I dont think its such a bad idea. Low COG, utilize the shell as a heatsink. I think the lowering of the COG is more important than fore aft weight distribution.
Three things I can see as being an issue.
High likelyhood of puncture from a foriegn object.
Torsional movement cracking the brasing.
Low airflow as there will effectively be a boundary layer sitting on the bottom of the car.

COG. Hadn't thought of that... But that is another benefit.
True about the issues too.
Puncturing chances definitely go up. Although on a normal car the floor rails will sit a lot lower than the piping. I'm expecting the pipe diameter to be in the order of 20mm, possibly (logistics allowing) a 30mm. So it would only extend half that distance from the floorpan. And if you laid the piping in the raised sections you could minimise the extrusion (is that the right word??).
Alternatively, it may be possible to semi-encase the pipework in a sort of air tunnel, with the air pickup at the front edge near the front axle.
Torsional movement could be quite the issue too. I guess this one depends on what vehicle doesn't it...
Low airflow. How thick would the boundry layer be? I would've guessed a virtually static layer approx 1-2mm thick... But that's a totally unqualified answer. And the moving air should provide a reasonable heat transfer/flow shouldn't it?

[nzae86]

Why not fit an oxygen removal system to your intake ? That way with no oxygen it will stop combustion and prevent heat build up, then no need for a radiator, simple really!

Go and work on your car and stop thinking of weired stuff!!!

[Lloyd]

Why not just lay a radiator down flat under the car with a stone gaurd type setup over it and ducting air through it. Keeps weight down low, be a lot easier to fabricate and you know its an efficient unit

[RS13]

Most hardcore drag cars don't run radiators, as methanol burns much, much cooler than petrol. I often wondered about modifying the aircon system, so that the block would be filled with refridgerant.. but you'd need to seal the system something wicked!

Nice thought regarding the radiator, but you'd think that if it was a good idea.. someone would've done it already! I like the idea of putting it in the boot, but only as a last-ditch effort to get maximum flow over the i/c or if I really had to.. say, dropping a straight 6 into a KP!

[fangsport]

Why not just lay a radiator down flat under the car with a stone gaurd type setup over it and ducting air through it. Keeps weight down low, be a lot easier to fabricate and you know its an efficient unit

exactly where my thinking was heading. a heap of vans and people movers duct air from the front, across a horizontally mounted radiator / A/C condenser.

[Jebus]

No prizes for guessing what theyre for

[Snoozin]

Most hardcore drag cars don't run radiators, as methanol burns much, much cooler than petrol. I often wondered about modifying the aircon system, so that the block would be filled with refridgerant.. but you'd need to seal the system something wicked!

Nice thought regarding the radiator, but you'd think that if it was a good idea.. someone would've done it already! I like the idea of putting it in the boot, but only as a last-ditch effort to get maximum flow over the i/c or if I really had to.. say, dropping a straight 6 into a KP!

Dropping an inline 6 into a KP has crossed my mind on more than one occasion.....

[Stealer Of Souls]

Why not just lay a radiator down flat under the car with a stone gaurd type setup over it and ducting air through it. Keeps weight down low, be a lot easier to fabricate and you know its an efficient unit

Clearance. A normal radiator plus the inlet and outlet piping would be quick thick. Fine on the underside of a van, but under I would think it would be highly susceptible to taking damage, especially from those errant speed bumps.

Nice thought regarding the radiator, but you'd think that if it was a good idea.. someone would've done it already!

The sheer logistics of actually "building" this would generally put this sort of idea in the "too hard" basket. Couldn't imagine factory cars doing this. Imagine when the system springs a leak from old age. How do you replace it with minimal fuss? You can't. So I can see this as an idea that is only applicable to a small number of performance vehicles, designed for reasonably specific conditions.

Why not fit an oxygen removal system to your intake ? That way with no oxygen it will stop combustion and prevent heat build up, then no need for a radiator, simple really!

Because that would make me a retarded mechanic from the south island...
<Rant Begins>
Come on dude. Innovation and inspiration are often the winning factor. When everything easy has been done, time has to be taken to get an innovative idea to work. Sure there may be no gains. But you won't know unless you try.
I mean have you built a complete undertray for your car? How about optimised aerodynamics on the front/topside? Vortex generators (www.airtab.com, check out the new EVO) to improve drag at high speed? Tried a fuelstar (improved mileage, even on the track is good. Better mileage means less fuel to carrier, which means less weigh, which is always good)?
A sealed nose cone for the car would reduce drag by improving airflows, which if you were running in a tightly (power) controlled catagory could mean the difference between a win and being first loser.
Without innovative people we wouldn't have ball bearing turbos, variable geometry turbines, Variable valve timing systems, the internet, Windows (I'm not actually sure this is a good thing), hybrid cars, DVDs, Blu-ray, HD-DVD, SACD, LCD screens, flash drives, space shuttles, concord, trip computers, segways (sp???), EWPs, ABS, AYC, DSC, the list goes on and on.
<Rant Ends>

[Santa'sBoostinSleigh]

drag cars generally run W2A intercoolers rather than A2A (FM or TopMount) as A2A IC's soak the heat producing lag from the start line

[wde_bdy]

If I was going to do it I would run a normal radiator under the car but raise the floor to give it enough ground clearance and duct air to it. I've done similar to my car to fit an exhaust under, sufficient strength can be returned to the floor with minimal weight. Relocating radiators is not a new idea, you just need to find the approach that suits your end goal. I've seen demo derby cars with the radiator and fan mounted in the glovebox area, was surprisingly effective.

Callum

[sergei]

why not mount it in the boot horizontally, with holes in the bumper and shroud to direct air from under the car, through radiator to the back of the car, win-win situation: increases low pressure under the car, using low pressure behind the car, more room at the front of the car, better weight distribution, increased coolant capacity.

[Stealer Of Souls]

If I was going to do it I would run a normal radiator under the car but raise the floor to give it enough ground clearance and duct air to it. I've done similar to my car to fit an exhaust under, sufficient strength can be returned to the floor with minimal weight. Relocating radiators is not a new idea, you just need to find the approach that suits your end goal. I've seen demo derby cars with the radiator and fan mounted in the glovebox area, was surprisingly effective.
Callum

Does that sort of work require certification? I hadn't really considered modifying the floorpan to suit (at least not in this manner)...

why not mount it in the boot horizontally, with holes in the bumper and shroud to direct air from under the car, through radiator to the back of the car, win-win situation: increases low pressure under the car, using low pressure behind the car, more room at the front of the car, better weight distribution, increased coolant capacity.

Definitely a possibility. Although the added weight of the extra coolant lines and ducting may reduce the benefits. Also this approach will not benefit the COG, although this may be offset by the improvement in ground effects downforce (I think that's the correct term).

I'm still preferring my arrangement, as it shouldn't increase the vehicle weight by any significant amount. I'm increasing thermal mass by utilising the car body (which is already there) in addition to an near identical mass of water and copper to the original radiator, and possibly increasing the radiating surface area, although decreasing cooling efficiency.
I'm shifting weight (F-R distribution) and COG (lower, more central).
And assuming it gave similar performance to the original system, it's very multipurpose (eg not just useful for drag racing), allows for improvments to front end aerodynamics and doesn't intrude into either cabin space or ground clearance.

It is however most likely not to work due to physical damage potential, chassis flex, overall poor cooling performance due to poor heat transfer, and sheer difficulty of construction and maintenance (long-term).

Worth a try? At this stage, I think yes. Might as well prove that it doesn't work. Proof is always in the pudding after all...

[wde_bdy]

Pretty much anything along these lines will require cert if there are any changes to the structure of the car. Assuming its not a standard car just do all your mods at once and get them all certed together. Speak to a certifier BEFORE you cut anything, they will let you know what sort of mods they will sign off on.

Callum

[Stealer Of Souls]

I figured as much.
I was thinking that if I did decide to try out this idea then I'd do it on the next car.
See how things go. Gotta finish my plans with my current machine first...