Radiator hump cut out - an issue?

fiatmonkey

fiatmonkey

Tim Hoover
I had a friend come by and show me his handy work in body work he has been doing to his X he has been auto-xing but now wishes to race it. He did something that I have often wondered about how it should be done but would never do it. He basically cut out the ENTIRE tub that separates the radiator from the front boot. He created screen cutouts in the hood and welded a sheet metal wall that acts as the barier to force the air up and out the cutouts in the hood.

I have never actually seen how this is typically done in a racer X but I know some X racers do it, so I couldn't comment. But my question now is what affect structually will this have? This is a lot of metal and I would think removing it would seriously compromise the structual integrity of the front of the car.

Anyone have any thoughts?
 
I did something similar to my Scorpion...

Which is very similar to the X1/9 as far as the radiator hump area goes. I kept the hole pretty small, and then surrounded the hole with the "base" of a chimney to restore any lost structural integrity. I would also be hesitant to cut out the whole hump, or even a larger chunk than I did.

Here are some pix of what I did.

DSCF0119.jpg


DSCF0120.jpg


DSCF0118.jpg


Pete
 
That makes sense and looks good. I wish I took a pic but he cut out a LOT of metal literally from end to end. I was blown away.

I am wondering if its even reversable at all.
 
whoops

You *must* close up the bottom of that arrangement if you vent out the top. Air doesn't *force* through the radiator, it's *drawn* through it by low pressure. Having both top and bottom open short-circuits the this effect, and your airflow through the radiator will drop dramatically. You *will* suffer overheating. Ask me how I know.

Chris
 
cmice said:
You *must* close up the bottom of that arrangement if you vent out the top. Air doesn't *force* through the radiator, it's *drawn* through it by low pressure. Having both top and bottom open short-circuits the this effect, and your airflow through the radiator will drop dramatically. You *will* suffer overheating. Ask me how I know.

Chris
Click to expand...

Chris - when you say bottom of the arrangment are you saying that you need to close off the bottom of the car - under the chassis where the air would normally escape correct? You did something like this on your Lemons car right? Do you have any pics by chance?
 
I haven't observed that...

Chris, I'm not sure if you were talking to Tim or me. If it was me...

I understand what you are saying, but I have observed just the opposite. Cooling at speed is the same as it was previously (air is being "rammed" through the radiator, and the fact that it has two exit paths instead of one does not seem to have an effect), and cooling while stopped or creeping in traffic (which is really what this mod was intended to handle) is vastly improved, since the heat can follow its natural path upward. I never understood the "wisdom" of the original design, forcing the air downward and under the car... this leaves the radiator to bathe in its own heat.

A couple things that may set this car apart would be a large Griffin aluminum radiator, and the fact that a Scorp has a fairly blunt nose compared to an X, with the radiator front and center behind the "flat". Plus, the size of the hole is not as large as the radiator frontal area, so if I entirely blocked off the bottom, I would be relying on the top hole that is maybe 1/4 the size of the radiator to exit all the air, and I'm not sure that's a viable plan.

In any event, it's working, so I'm not complaining! :D

Thanks for your input,
Pete
 
Actually I'm with Pete on this one as well. I haven't closed off the bottom and have been venting through the top for years now. I had actually taped window screen to the hood openings just to see and they bulged up at anything more than 30 mph indicating upward air flow. I'm positive that the low pressure on the hood, just behind the nose curve is higher than the low under the car, hence the direction.
 
As others have said... and...

... if ya stand back and look at the stock configuration... the engineers tried to make the air go up through the radiator and then go DOWN on the back side of it.

At speed, and with the front spoilers in place.. this works to some extent. Remove the spoiler or install the radiator WRONG in one of the other two positions in front or behind its top mount... and cooling suffers tremendously.

If you remove the box and cut a hole in the hood... the air that is directed UP and THROUGH the radiator can now just KEEP GOING UP and OUT... with even a somewhat "venturi effect" sucking it out as the air flows over the hood of the car.

In traffic or in a slow speed situation... the hot air simply RISES as it always does... and goes up and out.

TWO problems though... and our Ferrari brothers (308s, 328's for sure) are well aware... 1.) You loose some trunk space and 2.) If you have no top or an open sunroof... hot air flows over and into the cockpit.

But for racing... its really the best way to go as MOST find: 1.) Their engines are cooled more efficiently and 2.) the airflow also creates a bit of DOWNFORCE on the nose improving traction for braking and handling.
 
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