Rear Mounted rad n other trickery!

[RedDevil]

What about a belly pan radiator? Basically a thin metal plate on top of which you can route a coolant bearing tube. Keeps the mass center point low, improves aerodynamic properties and solves your cooling needs.

But I agree on the CAI concern. If the air you take in gets hotter it raises engine temperature under the same load, raising the radiator temp, raising the intake temp again.
Saw that happen this winter as I took the snorkel off which leads cool air to my intake (behind the rad). Snorkel needed to be back on when ambient rose above 10 Celsius.

Seems you can just mount a flat plate bridging the gap from the top of the radiator to the area just below the intake. In that way hot air from the radiator won't mix with the cool air flowing over it, so the latter can reach the intake.

Even a partial or full LGB can have that effect. Less air through the lower grill means lower under hood pressure and more air through the upper grille, flowing over the radiator etc.
I still run a full LGB. When I took it out as to not confuse the dealership when I had it serviced, the intake temp rose beyond the values I see normally. LGB back in then temp stays pretty much the same as ambient on the highway, even in summer weather.

[kach22i]

Originally Posted by niky

Simple solution........move the cone behind the headlight. Build an insulated box to isolate that area from the rest of the engine bay ..............

That is basically the stock configuration on my Chevy S-10 pick-up truck, and many cars as well. They all seem to be able to breath pretty well, and it's a long path of travel for leaves/mud/rain before they can do harm.

The KISS method; keep it simple stupid.

[niky]

Originally Posted by kach22i

That is basically the stock configuration on my Chevy S-10 pick-up truck, and many cars as well. They all seem to be able to breath pretty well, and it's a long path of travel for leaves/mud/rain before they can do harm.

The KISS method; keep it simple stupid.

Pretty much. That's how I mounted my intake. Moved my battery and coolant bottle, freeing up a huge amount of real estate behind the headlight, then installed simple heat shields to isolate that part of the bay. Not as efficient as a CAI, but that area of the bay is noticeably cooler than the rest thanks to the insulation, and the dyno and butt-dyno both show benefits.

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Rear mounted radiators would be nice, but a PITA to fabricate and install. All that weight savings goes MIA when you consider the extra gallon or two you'll be carrying in extra piping and tubing, plus the brackets for mounting the rear radiators. Might be some aero benefit to be had from sucking air from under the car and spitting it out back, but this exposes the radiator to muck and debris. Having had radiators mounted thusly in some of my vans, I can tell you, cooling absolutely sucks.

[Frank Lee]

Oddly enough, many mid-engine cars put the radiators in the front.

[darcane]

I think you may be overlooking the obvious here. You removed the A/C system. Have you sealed up the ducting from the grill to the radiator to keep warm air from recirculating back through? The air should be forced to flow through the radiator and down under the car, otherwise it will get hot under the hood and not cool the engine effectively.

I think the rear mounted radiators will do little other than show off your ability to fabricate. As Frank said, many mid engine cars have front mount radiators. My MR2 was like this as it was a better system in spite of all the plumbing issues it created.

Speaking of fabricating stuff, any more info on your Ultragauge setup? That's pretty slick. How do you access the buttons?

[wyatt]

Why not just duct the hot radiator air into the low pressure area on top of the hood, like the GT40 or Motorsport Elise do? It looks like you have space in your engine bay, and it should help aero, especially if you button up the underside of the engine bay.
As for your question about sealing the front of the car up and moving the radiator(s) to the rear, it should help aero, but you are going to have to duct air to the new radiator location(s). Where are you going to get the air? Tire well? Under the car? Side scoops? Roof scoop(s)? I think the execution of this ducting would play a big role in how much improvement you see, but that's just me thinking.

[oil pan 4]

You could also put a smaller radiator up front to give you that gap you need between the radiator and body by putting in a smaller radiator. Then you could do a remote mount radiator using a heater core or motor cycle radiator some where and split coolant flow off to it.

Or do what I did, cut away the body.

From this:


To this:


I did this to expose more of the radiator to air flow. If I did not have the large diesel radiator there would be no radiator behind what I cut away.
The next day I welded up a nice solid 1'' angle iron reinforcement to go around the new opening I created.
Then I installed grill shutters just for good measure:
http://ecomodder.com/forum/showthrea...tml#post379284

From your pics it looks like relocating the battery or washer fluid bottle would be easier.
Feeding the engine hot under hood air through an uncooled supercharger sounds like a bad idea.

[kach22i]

I stumbled upon a Prelude today, took some pictures.

Maybe the proposed CAI is too low and would ingest water, I'm not sure.

Automobile 2 - Odds And Ends Photos by kach22i | Photobucket




It's a blocked off plate now, looks like valuable Real Estate to me.

[Mudgey]

Hey guys, thanks to all for the suggestions. I am going to keep the exterior appearance at the front untouched, that means no bonnet vents, scoops or headlight modifications etc
Turns out my current rad is far too large for the engine and seems to keep the engine cool by convection alone, its an astonashing 30c today in the South West of the UK and sat in heavy traffic I never saw the engine go over 92c. I was seeing IAT's of around 55c.

So in my mind I am thinking about the following ideas:

1. Run a smaller 3/4 width radiator which is also thinner and tucked further forward so I have more room infront of the engine, run a radiator cowl with a 3" bulkhead hose fitting inthrough the other 1/4 width of where the original rad used to be, on one side of the rad cowl would be the air filter (infront and to the side of the radiator), and on the other side a pipe feeding the TB. In total the pipe would be 0.5m long, if that!

2. Split the radiator in two and mount it at the back, run a closed front grill apart from an opening to promote a small amount of airflow through the engine bay and for an air filter box. I like the idea of removing a lot of heat from the engine bay to keep everything as cool as possible. This might also be the best time to run an electric water pump. So the benefits of all this would be reduced front end lift at speed, reduced drag from the large front rad grill opening. Hot air being released in the low pressure region at the back of the car. And if I went electric water pump then less drag from overspinning the water pump when its not required.

hmm, lots to think about!

kach22i:
Good idea, however on my car the fog lights are located below the indicators. There is also no direct route into the engine bay, everything is blocked off and I don't fancy cutting the chassis incase I change my mind about things in the future, for instance if I go turbo charged there may be a better way to direct cold air to the back of the engine bay. Did somebody say twin charged

darcane:
Well I like doing things that are different, I have seen a few bonneville top speed cars, drift and Euro Rally Cross cars run rear mounted radiators, I also think this helps protect the radiator and keep an even weight distribution for the rally cross cars rather than for aerodynamic purposes in the case of the bonnevile cars I have seen.

I found a supplier for the original switches and mounted them on the front panel below the silver switch with some extension wires. I wanted everything to be mounted properly and am not a fan of gauge pods and gauges stuck to various parts of the interior. Here is a picture from the back but I hadn't got the wires soldered on at this point.

[freebeard]

I see two things:

The piping to carry the coolant is subject to corrosion. Water-cooled vanagons have piping that is suitable.

The low pressure wake may not be as helpful as you might think. VW bus owners argue about this. What's more important is the ducting. Maybe you could replace the rear decklid and wing with something Porsche-like with the radiator mounted at an angle, canted to the front. The inlet and outlet can be as llttle as 1/6th the area of the gross dimensions of the radiator itself.

To answer the question, if the internal drag of a sealed engine compartment plus the ducting and radiator (which has a lot of drag just by itself) in back is less you win. So it sort of depends.