Cooling tower idea

Pepper · Post by **Pepper** » Tue Nov 26, 2002 8:37 am

hhmmm. what if i had a stat controled fan on thr so it can come on when the motor fan isnt doing the job.. kind of like a Honda set up..

Baja Wes · Post by **Baja Wes** » Tue Nov 26, 2002 6:30 pm

Belt driven fans suck a lot of HP at higher rpm. I wouldn't use one.

Todays thermo fans are much more efficient, that's why cars today use them.

The calculation would be more complex than you think. The water pump flow and radiator core size effect the water to radiator convective heat transfer. The core material effects the heat conduction. The air velocity, fin design and core design effect the radiator to air heat transfer. Add all these together and you get a complex calc. You may be able to find some empirical tests that may help you.

If your still keen I suggest going to
http://www.daviescraig.com.au/trade.html

The site is explaining the advantages of their electric water pump design, but it has various empirical data data charts that you may be interested in.

They have a graph of specific heat disapation vs air velocity for various water flow rates. It shows the water flow rate has little effect on that radiator.

there is a graph of water pump input power vs engine rpm, which shows the cubic relationship between the two. A belt driven fan will have the same consumed power curve shape, so you can see a belt driven fan will use a lot of HP at high rpm.

INSAYN · Post by **INSAYN** » Wed Nov 27, 2002 5:02 am

Pepper, this is just an idea, and you can toss it out if you like. Take your fuel tank out of the front, and put it over the rear package tray, plumb it as necessary, for proper fuel delivery. Then you have a nice big square hole to fill with radiator, in the front. Get ahold of another hood, and have it louvered, or creatively scooped. Duct the airflow from the hood down through the radiator, and assisted with fans, blown out and the front wheel wells.

You will need to fashion up some kind of water flow to and from the motor, through the body somehow. I like WES's idea of false floor. My thoughts in the past for this, would be to gut the car of all loose and heavy items, and tip it on it's side for surgury. Taking a air powered sheetmetal nibbler, and cut the bottom of the tunnel out leaving about a 1" shelf. Route the waterpipe through the tunnel, and out the opposite side of the bulkhead, from the master cylinder.

While the tunnel is open, repair anything else that may be worn, or broken in the that lives in there, maybe also pull out the old fuel line.

Then with a new piece of sheet metal, reweld this to the 1" shelf that remained from the old tunnel bottom.

My thinking here, is clean, safely hidden hot water pipes, as well as, an easy way to add a heater to the front of the car.

From the source water to the radiator, you can T off of this, and run it up to a heaterbox from any small car, and back to the exhaust side. When you have the heater on, it will cool that water, and return it to the return line to the motor. When you don't have it on, block both ends with lever activated shutoff valves (taken from any car), so as to keep the return water from causing a vacuum against the heatercore. I am not sure if this would actually be an issue, so trial and error would be required.

I am contemplating installing a Rabbit/Jetta motor in my Orange Baja, so this pipe configuration may happen in the future for this car. Then if I ever decide to go bigger, it is just a matter of bolting on a bigger motor, and upgrading the radiator.

INSAYN

Pepper · Post by **Pepper** » Wed Nov 27, 2002 6:35 am

Holy cow! I never thought about removing the gas tank! Hhmmm?. Are you saying put it in the inside the cabin, when you say ?rear package tray? I?m a noob and I don?t know all the ?Lingo? yet

INSAYN · Post by **INSAYN** » Wed Nov 27, 2002 6:45 am

Yes, the package tray is behind the rear seat, over the tranny, and below the rear window. There is plenty of room in a bug to do this in. Almost ALL baja's that still have stock bodies, put the fuel tank there.

INSAYN

------------------
'74 Baja
'?? Tube framed Baja Project
www.blindchickenracing.com

Baja Wes · Post by **Baja Wes** » Wed Nov 27, 2002 6:09 pm

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by INSAYN:
<B>Almost ALL baja's that still have stock bodies, put the fuel tank there.
</B><HR></BLOCKQUOTE>

In the US maybe. In Oz we have problems with the legal aspects of putting a fuel tank in the passenger compartment

------------------
Wes offroadvw.net

INSAYN · Post by **INSAYN** » Wed Nov 27, 2002 10:25 pm

Wes,
Even if you build a fume tight fire wall for it, behind the seat?

I also noticed you seam to be required to have full width fenders, bumpers, and a wire mesh cage around the motor. What is all that about?

Baja Wes · Post by **Baja Wes** » Thu Nov 28, 2002 2:03 am

Maybe if you make a fume proof enclosure.

In oz we have to have the wheels completely covered by the fenders. The 8" wide rims on my car are pushing the limits of what is legal.

You need full width bumpers, and the has to be enclosed by a cage. You have to cage the engine to prevent a pedestrian from touching the hot exhaust or the fan belt.

Stupid rules but that's the way it is. That's why oz car's look so tame. If it looks wild it probably isn't legal.

And another funny point, 2 inch is the legal limit for a body lift kit here. Oh and wheel adapters are illegal.

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Wes offroadvw.net

TIMBERWOLF · Post by **TIMBERWOLF** » Thu Nov 28, 2002 3:43 am

Sounds worse than UK Wes! How do the Manx guys get by - there is no fume seal between the tank and driver or an engine enclosure. Your road rules are like our competition rules, marshals have to be saved from burns etc while they're dragging you out of your wreck! Also fume seals are mandatory. Just another reason for modifying my buggy.

On the subject of the post. It would be better if with Insayn's idea if the air went the other way, from underneath and exited near the screen. Lower aerodynamic lift quite important if you've going to put speed on your bug (put on some mega watt motors and suck your front end down

!!) and heating for the screen. It would just be a bit harder to duct. Definitely go with the flat thermostatic fan approach. Landrover competition cars in GB have a rad in the back in virtually static air, they can cool 5.5 litre V8's with two big fans. You just need a very good rad - fine alloy fins and maybe some water wetter.

Best of luck.

INSAYN · Post by **INSAYN** » Thu Nov 28, 2002 8:14 am

Man, with all those extra precautions you have are required to build into your offroad buggies, I would be more apt to ditch the offroad scene and go with a street screamer. As much as that would kill me to convert over to the dark side (sports car).

Wes, what are your material, and height requirements for the bumpers? Can they be made of 1.5" tubing?

INSAYN

------------------
'74 Baja
'?? Tube framed Baja Project
www.blindchickenracing.com

Baja Wes · Post by **Baja Wes** » Fri Nov 29, 2002 12:47 am

With a manx the tank isn't in the passenger compartment, and there is no roof anyway so it's not an issue. But a manx still has to have the engine covered to prevent touching the exhaust or the fan belt.

Not sure exactly how small you can go on the bumpers, probably just as long as it looks reasonable.

All the modifications I have done and am doing have to be engineer approved and I need a special modification plate with the details attached to my car. It is a pain, but the only alternative is to move to the US

INSAYN · Post by **INSAYN** » Sat Nov 30, 2002 10:17 am

Well my neighbor's house is for sale, and I would be willing to help you get all that extra weight off you baja so you can go faster. Oh, and you may have to convince your baja engine that it can rotate the same way in the US. (bad joke, sorry)

INSAYN

------------------
'74 Baja
'?? Tube framed Baja Project
www.blindchickenracing.com

Post by **Piledriver** » Sat Nov 30, 2002 3:45 pm

This is an evil plan I worked up for a WBX install, but consider the idea...

A 911 fan housing, with a radiator in the front, the exhaust ducted out the front plate ala a doghouse cooler.

Cons:
A sealed engine compartment likely needed to prevent hot air suck back.

Having to spend big bucks on the 911 setup

Pros:
Massive forced airflow
Very Compact size
No holes in body
No plumbing outside the motor
Direct bolt in any T1.(assuming neat compact plumbing)
No holes in body.

RadCib · Post by **RadCib** » Wed Dec 04, 2002 4:03 pm

Pepper.. could you get ahold of me.. I'd like to talk to you about a project I"m working on

-Rich

RadCib · Post by **RadCib** » Wed Dec 04, 2002 4:13 pm

[email protected] if you can