Front air dam vs underbody belly pan

[freebeard]

It's a start. You could plan it so it becomes the front support for a partial pan under the engine compartment and/or front wheelwell air curtains.

Everything depends on what's happening upstream, so working front to back is a reasonable strategy.

[67-ls1]

Originally Posted by freebeard

It's a start. You could plan it so it becomes the front support for a partial pan under the engine compartment and/or front wheelwell air curtains.

Everything depends on what's happening upstream, so working front to back is a reasonable strategy.

I had it on the lift recently and noticed a few things that would be (in my mind) problematic.
First off, the bottom of the front bumper is WAY above the front suspension. So the fist part of the belly pan would be pretty steep angle. The the catalytic converters hang down even with the bottom of the transmission pan. Beyond that the frame spreads out to the perimeter of the car.
I’m not saying it can’t be done but it would be tough. Had I thought of this when I had the body off, I could have added tabs, etc in strategic places.

[freebeard]

IIRC a step is better than an angle.

[euromodder]

Originally Posted by 67-ls1

First off, the bottom of the front bumper is WAY above the front suspension.

Is the lower part of the suspension a lot below the air dam ?

Ideal would be to lower the airdam further to where the belly pan could be , and sideskirts down to belly pan level

So the fist part of the belly pan would be pretty steep angle.

You'd scoop more air underneath, that's not so good
You want less air going underneath the car

A second stepped airdam in front of the suspension might work - and help retain some clearance- curved in planview, and pushing air out to the sides.

The the catalytic converters hang down even with the bottom of the transmission pan.

You could fill in the voids with a partial belly pan, leaving the tranny pan, cats and mufflers as the lowest but uncovered parts


Put spats in front of the rear wheels
Airflow tends to be outward, angled aft, between front and rear wheels - where not blocked by side skirts

[aerohead]

here's a link to CAR and DRIVER's 'Crisis Fighter Pinto' of March, 1974.
They wrapped their 'low' airdam all the way around to the front of the front tires.( at the elevation future rocker panel extensions would pick up, had they chosen to go deeper into drag reduction [ think Pontiac Firebird Trans Am ])
While they were at the nose, they blanked off any superfluous grille opening, and added Plexi headlight bubbles to give some radius.
Under the hood, they went from a 4-bladed cooling fan, to a 2-bladed. A thermostatically-controlled electric cooling fan, pusher, or puller, would be the ticket now. Above 40-mph ram-air essentially takes care of your cooling.
https://ecomodder.com/forum/member-a...vement-mpg.jpg

[67-ls1]

Originally Posted by aerohead

here's a link to CAR and DRIVER's 'Crisis Fighter Pinto' of March, 1974.
They wrapped their 'low' airdam all the way around to the front of the front tires.( at the elevation future rocker panel extensions would pick up, had they chosen to go deeper into drag reduction [ think Pontiac Firebird Trans Am ])
While they were at the nose, they blanked off any superfluous grille opening, and added Plexi headlight bubbles to give some radius.
Under the hood, they went from a 4-bladed cooling fan, to a 2-bladed. A thermostatically-controlled electric cooling fan, pusher, or puller, would be the ticket now. Above 40-mph ram-air essentially takes care of your cooling.
https://ecomodder.com/forum/member-a...vement-mpg.jpg

Very interesting article. I’ll have to look around and see if I can find the rest of it on the web.
My air dam is pretty low. It also seals the lower part of the radiator opening so everything that goes through the grill goes through the radiator.
I have zero cooling issues. I can be in stop and go for 15-20 min before the electric fan comes on and runs for less then 3 min. Then another 15-20 before it comes on again. Normal driving it never comes on. I wonder if I could/should reduce air through the radiator. Is there a fan on-fan off knee that one should shoot for?
I do have radial tires but they are wide. 8” rims with 9.5” tires in the front and 10” rims with 11.5” wide tires in the rear. Probably a lot of extra rolling resistance there. That was a conscious concession to my hot rodding past.

[67-ls1]

Yikes! I found another small piece of the article. It show the mpg with the changes.
I would have thought a Pinto got better mpg before the mods

[aerohead]

Originally Posted by 67-ls1

Very interesting article. I’ll have to look around and see if I can find the rest of it on the web.
My air dam is pretty low. It also seals the lower part of the radiator opening so everything that goes through the grill goes through the radiator.
I have zero cooling issues. I can be in stop and go for 15-20 min before the electric fan comes on and runs for less then 3 min. Then another 15-20 before it comes on again. Normal driving it never comes on. I wonder if I could/should reduce air through the radiator. Is there a fan on-fan off knee that one should shoot for?
I do have radial tires but they are wide. 8” rims with 9.5” tires in the front and 10” rims with 11.5” wide tires in the rear. Probably a lot of extra rolling resistance there. That was a conscious concession to my hot rodding past.

Seems like we've had dedicated threads about this. MPGUINO- controlled servos or such, operating some form of radiator shutters.
AEROCIVIC had a sideways guillotine air-valve, return-spring default opening, with cable-operated opening ) if memory serves me )
Current low-drag variants of passenger cars all seem to offer some type of grille-shutter technology.

[aerohead]

Originally Posted by 67-ls1

Yikes! I found another small piece of the article. It show the mpg with the changes.
I would have thought a Pinto got better mpg before the mods

No kidding!
My '67 El Camino, with 325-hp 396 -cid big block and slush-box got nearly as good a highway fuel economy.

[Piotrsko]

See aerohead calls them slush boxes, too!