Improving Regal aerodynamics

[Clone TIE Pilot]

While there is only so much that probably can be done to improving the aerodynamics of Regals. It is still a good topic to discuss and seems to be overlooked. Reading about car aerodynamics online, it seems the worst air drag for most cars stems from air flowing under the car causing lift. The wheel wells causing lots of turbulence, and of course the wake at the rear which causes a vortex that pulls backwards on the car. Of course the steep rear windshield is a major problem, which is why Chevy made the rare aerocoup Monte Carlos to resolve that issue. Airflow though the grill is also a major source of drag.

As far as simple bolt ons go, the first choice are those aftermarket headlight covers to reduce the drag from the buckets. While the turbo Regals already have grill airdams to direct all the incoming air though the radiator and reduce drag, plain Jane Regals lack them. Front airdams below the bumper really help out reducing drag and there are plenty of different aftermarket airdams to choose from.

Any more ideas? There is always deleting trim, and building rear fender skirts.

That last one is pretty tacky looking.

 

[oxide80]

Aerocoupe GN... neat build.

 

[pontiacgp]

Interesting topic, if you put a diffuser in front of the front wheel and rear wheel that will help with deflect the air from hitting the tire...you will see diffusers on most vehicle these days.

 

[lilbowtie]

Kinda hard to make a brick aerodynamic - I've done what you mentioned, have to watch for other ideas.

 

[UNGN]

The stock GN's actually suffered from pretty bad front end lift at high speed. Like goggles, the "airdams do nothing!"

The problem is while the airdams help a little, the big scoop pressurizing the air under the hood hurts A LOT. Even a tiny pressure differential over a large area like a hood can make a lot of lift. Not only does the intercooler scoop make lift, it promotes high speed overheating because its pressurizing the wrong side of the radiator.

If you don't have a stock location intercooler, put a deep core support airdam as close to ground as you can live with given the streets in your area. Remove any stupid "pressurization kit" baffling that blocks airflow from coming up to the radiator from under the bumper, then completely block off the grill opening from behind (or at least the top 3/4 of the grill opening).

Headlight covers might help a little. Lowering the car and giving a slight nose down rake helps more. Hood vents work great, too. On our Aerocoupe at speed, you can literally see the hot air coming out of the hood vents. Under the bumper airdams helps reduce lift, but blocking the grille helps more so if I had to pick between the two where to get air for the radiator, I would pick under the bumper and block the grille.

Most modern performance cars are bottom feeders for radiator airflow. The actual grill opening on the #11 Mountain dew car above was probably a couple inches by a couple inches blowing directly on an oil cooler with the rest of the grille blocked off. The actual air for the radiator came in under the bumper. That is the key for going faster than about 145 mph. Once the front end starts to lift, if you have the HP's to keep accelerating, it won't come down until you top out the shocks and eventually crash. Seen it happen more than once. The all over the road skidmarks the guy leaves are pretty cool. When it happens, most people don't realize they have no more suspension travel and the front tires are coming off the road on even small bumps.

 

[motorheadmike]

Good to 200mph.

https://www.turbobuick.com/threads/...complete-turbo-mag-write-up-and-video.257874/

 

[UNGN]

Good to 200mph.

https://www.turbobuick.com/threads/...complete-turbo-mag-write-up-and-video.257874/

Until the tire blew and it crashed. The wreck in the Japanese 350Z video is my buddy Charlie Friends 1965 corvair and not the Buick. He has walked away from high speed desert crashes more times than anyone can count, which is what you would expect from a 75+ year old ex-fighter pilot. He was the last guy still rated to fly the F100 Super Saber when the Obama Admin grounded them.

With basically the same drive train as the Buick, a Turbo T/A went 299. If you don't have an intercooler, its better to block more of the grille. The "worlds fastest production car with an unmodified body" TTA went 299 because it had 1,000lbs of Ice in the rear hatch area keeping the rear of the car down and cooling the turbo air (instead of an intercooler).

 

[Clone TIE Pilot]

Those factory GN airdams are pretty small, but its more than what n/a Regals got. I was mainly thinking of street applications and saving gas with starting this topic, but racing and drag strip discussions are important too. Since I have a n/a V8, I don't have to worry about intercooler scoops.

I can see how the bottom air baffle from the bumper to the rad can block airflow from below the bumper. What about the side baffles? I heard the side ones channel air through the rad instead of going around it behind the headlights and pressurizing the header panel? The n/a Regals did not get any airbox baffles.

 

[L67ss]

I second the hoodvent thing. Under hood pressure is a hindrance to aero. I figured that out on both my 86 cutlass and my 97 Monte. On the cutlass with the hood on around 55-60 itd start this slight slow bounce. Like the whole car would sway up and down. Without the hood it wouldn't even try to start doing that till 95-100. On the Monte it wasn't so noticeable. On it I had cut holes in the hood and installed functional 95 gtp hoodvents. Where I noticed the lower restriction on it was when I'd go across flooded low water bridges. Water would literally rocket out of the holes

 

[UNGN]

Those factory GN airdams are pretty small, but its more than what n/a Regals got. I was mainly thinking of street applications and saving gas with starting this topic, but racing and drag strip discussions are important too. Since I have a n/a V8, I don't have to worry about intercooler scoops.

I can see how the bottom air baffle from the bumper to the rad can block airflow from below the bumper. What about the side baffles? I heard the side ones channel air through the rad instead of going around it behind the headlights and pressurizing the header panel? The n/a Regals did not get any airbox baffles.

Yes, get rid of the bottom baffle at the bumper and you don't need side baffles if you block the grille from behind. All of the baffling sold to turbo guys was a turbo specific solution to a problem that would have been better solved by dual electric fans. It definitely didn't do anything for front end lift, which is where most higher speed drag comes from.

You want to make the the air going through the radiator as efficient as possible because air going through the radiator and not over the car is drag. Hood vents, a deep core support airdam, a high cfm electric fan... and then start blocking the airflow to the radiator (starting high first, then going down). This is why NASCAR guys tape the grille for qualifying. the actual openings in the grille are already just a small fraction of the painted grille, and they tape off some of that, too.

you can use the openings on the side of the core support for intake air, or block them with some sheet plastic or rubber. You don't want the motor to eat straight radiator air so using the non battery side for intake air is good and cover the battery side. this also helps make the radiator more efficient.