Relocating Radiator

[endeavor]

I'm trying to move weight rearward, and considering relocating the radiator on my '76 Bronco to a location behind the seats and rear firewall. I've scrounged every pic in the skunkworks, and searched the forums. I can't find much. A couple of questions I have;

Will I have any issues with the stock water pump pushing thru the extended piping?
What material is recommended for the piping? The few pics I've seen show a combo of radiator hose and some type of metal tubing.
Any gotchas that you know about?

Thanks -- Scott

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[johnnyweb]

i would not do it unless it is a real serious race machine because yes the water pump,air ducting,air getting trapped in lines,fans etc. all of this needs to be right or it is going to be a over heating night mare. does the branco have a w/shield? if so it probably wont work well with out major air ducting. the natural floe of air through the grille is hard to beat. radiator mounted stock position,fan shroud, stock type engine driven fan works great all the time. i have tried other arangements and went back to stock system and it worked the best for use. the trophy truck guys usually run radiators out back but they take up the back window area and run high dollar equipment as well.

[endeavor]

i would not do it unless it is a real serious race machine because yes the water pump,air ducting,air getting trapped in lines,fans etc. all of this needs to be right or it is going to be a over heating night mare. does the branco have a w/shield? if so it probably wont work well with out major air ducting. the natural floe of air through the grille is hard to beat. radiator mounted stock position,fan shroud, stock type engine driven fan works great all the time. i have tried other arangements and went back to stock system and it worked the best for use. the trophy truck guys usually run radiators out back but they take up the back window area and run high dollar equipment as well.

Thanks for the response. I'm building it to race the SCORE series. Probably isn't a "serious" racer to many, but it's serious to me. It does not have a windshield. I was going to run electric fans(obviously), eliminating the front fan and shroud. The issue that you bring up of air in the lines is something I'd like to hear more about, as well as water pump issues.

[sickrick]

I would agree that it is most likely more trouble then it is worth (if weight bias is your only reason). I can tell you that the waterpump will have no problem pushing the water around. Getting the trapped air out is important, make sure to put bleeders at any high points in the system and that should take care of it. I think if you factor in the cost/hassle of all this compared to the gain in weight bias that you would be better off putting that money toward something else to lighten your front end (like aluminum heads).
One other thing to consider is safety. Two years ago at fall Crandon one of the car class racers came over the jump right after turn one and we heard a loud pop followed by a cloud of steam. I would guess buy the way he was acting after he got out of the car that he was burned pretty bad. So if you do mount it in the rear make sure that if a hose fails or you are in a bad crash that you are protected.
I hope you have alot of fun with your bronco, I have owned a few of them and they always put a smile on my face. The best thing about an old bronco is with that short of a wheelbase it always seems like your going really fast.

[ntsqd]

Search the electric fan topic here, there is at least one discussing an OE Ford fan to use.

Aluminum tubing seems to be the prefered choice. You need to think about how to mount it so that it doesn't chafe or fatigue. Bonus is that it acts a bit like an inline radiator so keep that in mind with regard to routing and occupant safety.

Invest in a bead roller if you use hose couplers. Use the blue silicone hose if you opt for hose couplers. Or use the Wiggins Couplings.

[Stephen]

For moving weight around it's hard to beat moving the rad, it's way up front compared to any other component so it helps the pitch moment of inertia in addition to moving static weight. Problem is you add overall weight to the vehicle because of the extra water and plumbing, it takes up cargo space can be hard to get air to.
one employee had to go with a stewart pump on his sbc to get his rear rad to work even halfway OK so I wouldn't rule out a good pump.
Raffo's K5 that you may race against has the rad horizontal behind the seats and works really well. It's a bit of a pain to bleed but not bad and in reasonably cool weather doesn't have to have the fans on all the time to stay cool, meaning the ducting and airflow is good. There are some general vehicle pics on www.offroaddesign.com in the custom rigs section.

[Josh_K]

I second or third the point that moving the radiator is a difficult thing to do.

If you build an engine that makes 400 or more hp, you will need to remove the windshield or have some major ducting that scoops air form off the burble that is behind the cab and windshield.

Second, a nice aluminum 19"x 31" wont do the job at a race pace when slowing or stopping to let it cool isn’t a good option. I had to go to a one off 24"x 36" with 2 Taurus fans pulling to keep my truck cool and I have no wind shield and I trap about 70% of the air coming thou the cab.

Another thing that sucks is the aerodynamics of trapping cab air is really bad. I can only hit 107 mph and I am almost certain that if I had a windshield and some decent fairings covering the bed cage I could get to 115 or near 120 mph.

Josh

[roach]

my current class 3 project is a 96 ford bronco, and its radiator is going in the back. i agree with everyone saying it is somewhat of a pain, but it can be done, and it can be done to work good. sounds like people are brining class 3 back, huh? that would be cool.

[Stephen]

Off subject but important:
I certainly hope there are more people coming to class 3, I'd like to have a class around when I finally get to race something of my own. I just wish score and bitd could agree a bit more on the rules so we could build for more than one series. I guess most of the smaller series run score rules so maybe bitd is the only one that's "non standard". Maybe it's time for a new thread.....

Back on subject:

I agree on the wind resistance thing, we pull the duct work off the racer when we tow it since it creates considerable drag at highway speeds. I guess you poor guys in CA don't have to worry about that since you can only go 55 but we usually run 70+ till we hit the CA line and the ducting is a big deal. I can only imagine what it does at higher speeds. Not that we have to worry about 100+ in a class 3.

[endeavor]

Not that we have to worry about 100+ in a class 3.

Man -- I'm glad You said that!! My little Bronco will have about 525 hp, but I don't think I'll be screamin along at the speeds Dalton is talking about with that short wheelbase!

These responses have been real helpful for me -- thanks a bunch.