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Old 08-09-2008, 12:19 AM
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Default Body mod, aero improvement?

I'm getting ready to put the 82 bumper on my car, and I'm looking at it sitting in my room here wondering if I should block off the grille openings with fiberglass. Sort of how the license plate section is blocked off, just stapling a piece of matte recessed 1/2" in each of the grille holes then glassing over the matte.

My questions, do you guys think that this would look cool? Any appreciable difference in downforce/ minimizing lift. And would I still get enough airflow from underneath to cool the radiator?
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Old 08-09-2008, 12:42 AM
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You going to burn up the engine first time on the freeway and forget all that bullshit about damn air damns and spoilers and crap...you block off that area where a license plate goes and on either side, you in deep shit....

I know this because with my stock '72 grills when moving to Florida I had to remove the front tag filler in piece and the backer/mounting board....thereby ditching the front tag assy and that reduced my FLORIDA freeway temps by a good 20f.....

ymmv.....

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Old 08-11-2008, 02:58 AM
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They "say" the airflow to the radiator was increased by what ? (20%) between '79 and '80..... I'd think it's because of the bigger openings/grills.... if you don't need a front license plate open that area too if you want more air
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Old 08-11-2008, 06:48 AM
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My motor never gets hot, never creeps past 180 no matter how hard I thrash it no matter how hot it gets outside. I can sit in traffic for 2 hours with the electric fans diconneted and it will still stay around 200.

I'm more concerned with aero improvements than cooling. Although, I have thought about stuffing a long slim intercooler right behind the nose. I'm thiking that it woulod be much more efficient it I keep it away from the heat of the radiator.
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Old 08-11-2008, 01:34 PM
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You seem to have a good awareness of the cooling personality of your setup. I say go ahead and make some modifications, and make note of what happens afterwards. If you find you don't need that extra amount of air passing through the radiator (and getting trapped under the hood), then it ought to be a net aero improvement. Keep us updated on what you find.
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Old 08-16-2008, 04:13 AM
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Any air you can keep from going under the car will be good. Any air you can keep from being turbulently blocked in front will be good. If you can reduce the pressure build up in the front by a combination of smoothly sending it over the top & around the sides plus 'absorbing' it into the grill with minimal turbulence, that is really good. Simply blocking air intake with block-off plates in the grill is probably not best for it will create turbulence, affecting both under & over (body shell aerodynamic) & into (radiator= cooling, & undercar) air flow streams.
My thoughts (but I ain't got no fuckin' college degree, just readin' & cipherin' with charcoal on a shovel in front of the fire in the log cabin after I'm done splittin' fence rails with an axe all day) are that you want to open up the gill vents enough to adequately exhaust pressured up engine bay intake air coming in from the grill area, thus being able to suck enough air in through the grill openings to reduce turbulence over the hood while still getting enough airflow through the radiator for cooling. Keep the turbulence inside the shell (engine bay) and promote smooth laminar air flow on the exterior of the shell.
Open up the side gills & front grill area but install an air dam under the nose, aft of the underneath 'snout' openings, to reduce undercar pressure build up. This will help reduce engine bay pressure build up which will promote smoother air flow through the engine bay which will increase radiator airflow & thus cooling ability. It will also reduce frontal turbulance thus promoting smoother laminar airflow over the body shell for reduced drag which means increased efficiency which means better performance.

hey i gotta go, jae's on the phone--
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Old 08-20-2008, 09:10 PM
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I think the best experiment you could do is tape some cardboard over where you want to glass in and drive it around to get a feel for the effects as far as aero goes. This will also allow you to measure the effect on your cooling system. I agree that opening the gills will help the air flow out of the engine compartment too.
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Old 08-22-2008, 03:48 PM
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Quote:
Originally Posted by theandies View Post
I think the best experiment you could do is tape some cardboard over where you want to glass in and drive it around to get a feel for the effects as far as aero goes. This will also allow you to measure the effect on your cooling system. I agree that opening the gills will help the air flow out of the engine compartment too.
I think this a good approach. You can save yourself alot of time and aggravation if it doesn't work. Personally I would not restricted any airflow to the cooling system. Remember that your current bumper still has grills in the front now which help keep it at the temp your saying it stays at. Blocking them off may prove differently.
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Old 08-23-2008, 02:22 AM
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You should be OK, try it out. I blocked most of my grill off with brake ducts and didn't see any cooling differences even when running hard on a road course at a recent HPDE.

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Old 08-23-2008, 02:45 AM
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You should be OK, try it out. I blocked most of my grill off with brake ducts and didn't see any cooling differences even when running hard on a road course at a recent HPDE.

how long on the track and at what ambient temps?? and what speeds???

also what kind of fans you have??? radiator size?? engine??


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Old 08-23-2008, 09:12 PM
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how long on the track and at what ambient temps?? and what speeds???

also what kind of fans you have??? radiator size?? engine??
Well, lets see .....

Track - Road America
Ambient temp - not too bad, I think in the high 70's / low 80's
Time - four 25 minute runs on the 1st day, two 25 minute runs on the 2nd day
Speeds - 70 mph avg with top speeds in the 110-120 mph range (~5500 rpm) in 4th gear

Fan - stock mechanical
Radiator - Griffen aluminum stock replacement
Water pump - Moroso low drag aluminum pump
Engine - 350 ZZ4
Tranny - Richmond 5 speed
Rear gears - 3.08 stock

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Old 08-23-2008, 09:26 PM
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I think this car was pretty successful until peter klutt

Knuckle head racing


Last edited by Yellow73SB; 08-23-2008 at 09:31 PM..
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Old 08-23-2008, 09:41 PM
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I think this car was pretty successful until peter klutt

Knuckle head racing

interesting car there, in that the spoiler looks like something I maybe want to do, and the front grills on both sides are essentially blocked to airflow, looks as if there were lights in there of some sort?? turn signals for some races/bodies...??

just don't look like much frontal radiator air getting in there to me....

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Old 08-23-2008, 11:05 PM
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Those are brake ducts

I think that much air should be plenty if there is no interferences, look how much of an opening nascar has
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Old 08-24-2008, 02:36 AM
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Quote:
Originally Posted by Yellow73SB View Post
I think this car was pretty successful until peter klutt

Knuckle head racing

interesting car there, in that the spoiler looks like something I maybe want to do, and the front grills on both sides are essentially blocked to airflow, looks as if there were lights in there of some sort?? turn signals for some races/bodies...??

just don't look like much frontal radiator air getting in there to me....


he gets away with it because he isn`t ever sitting in traffic, besides he probably has an aluminum radiator.
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Old 08-24-2008, 02:50 AM
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Quote:
Originally Posted by White76 View Post
Quote:
Originally Posted by mrvette View Post
how long on the track and at what ambient temps?? and what speeds???

also what kind of fans you have??? radiator size?? engine??
Well, lets see .....

Track - Road America
Ambient temp - not too bad, I think in the high 70's / low 80's
Time - four 25 minute runs on the 1st day, two 25 minute runs on the 2nd day
Speeds - 70 mph avg with top speeds in the 110-120 mph range (~5500 rpm) in 4th gear

Fan - stock mechanical
Radiator - Griffen aluminum stock replacement
Water pump - Moroso low drag aluminum pump
Engine - 350 ZZ4
Tranny - Richmond 5 speed
Rear gears - 3.08 stock


70 mph average is like (what) a 3:20 lap at R/A?? why would it overheat?
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Old 08-24-2008, 03:54 AM
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Well, that's just it, at 40mph+ I never had a overheat problem even down here, except by maybe 10-`15f with the front plate/holder in place....removing that cured that issue immediately....

it was always that damn off freeway into traffic shit....and I swear that ditching that '87 vette fan in the '72 shroud also helped....less backpressure...

much less it was inadequate for traffic cooling, I would have to kill the a/c sometimes.....not with these Spals....a/c, speed, traffic, 140f temps, no matter, the a/c is cold as at speed, and engine never heats up....

and I admit that i'ts a marginal radiator compared to a DeWitt....for some others...

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Old 08-25-2008, 04:45 PM
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redvetracr,
Well I was just pointing out that even at 5500 rpm, there was no heat management problems blocking off the front grills. It's not the worst case senerio by any means just an example. That's all.

The car also didn't over heat the whole trip, which included 7+ hours each way to and from RA which I'll admit was mostly highway, but it never got hot when I was in traffic traveling through Milwaukee, Bloomington, and going very slowly in major road construction at Rockford.

Now at 90+ temps, who knows how the car would respond. I rarely take it out when its that hot because I don't have A/C and the wife hates the heat.
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Old 08-25-2008, 08:43 PM
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Over the decades of street racing (no Mr. Occifer, ME, street race??) never!!!

but reality is most ALL of use drive quickly in all sorts of vehicles.....

at any rate, even with this shark and the northern installed quickly available at the time F body radiator, the car ran fine at speed....but that damn pesky over hot especially with the off freeway issue tells me there is NO problem with freeway speeds ONCE I REMOVED THE FRONT TAG....

so then the airflow was not from the front of the car as the stock shroud and a '87 vette fan was in place, covering the entire rad core....

finally gave up some years ago, and did a dual spal setup...engine runs the same 180, actually more easily than before with a good 180 state in place in 100f heat on the freeway...get off into traffic and it's good at normal temps with the Spals in there....instant cool down even with a/c on....

I admit the rad is just 'adequate'....

next radiator, and it's a cheep one outta Smut or Jegs...whoever....

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Old 08-25-2008, 10:16 PM
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Quote:
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redvetracr,
Well I was just pointing out that even at 5500 rpm, there was no heat management problems blocking off the front grills. It's not the worst case senerio by any means just an example. That's all.

The car also didn't over heat the whole trip, which included 7+ hours each way to and from RA which I'll admit was mostly highway, but it never got hot when I was in traffic traveling through Milwaukee, Bloomington, and going very slowly in major road construction at Rockford.

Now at 90+ temps, who knows how the car would respond. I rarely take it out when its that hot because I don't have A/C and the wife hates the heat.

my front side grills consist of brake ducts and pieces of aluminum blocking off the remaining grill opening, My car never sees the highway but running 2:26-2:30 at R/A shifting at 7400 rpm on a 90* day my car doesn`t overheat so why should yours?...also my lower valance is blocked where yours is still open. I did the aluminum more to add temp than for aero (I got tired of taping the radiator), although that little factory front plastic spoiler made a world of difference in aero between the kink and corner 12, which is supposed to be the fastest of the three straights at R/A.
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