Blocking off portions of the front grill for improved downforce and reduced drag

[mavisky]

I just added Race Louvers to my 2019 GT350. No mods to the factory radiator enclosure. I’m going to run Road Atlanta late June and see how it does. Not that excited about removing the front of the car to box in the radiator….

What can I realistically expect in terms of lift reduction and potential cooling benefit?

The radiator is pretty well boxed in from the factory above and below the crash bar. I'm sure it could be improved upon, but not sure how much you'd really gain for the effort.

20230117_183455 by Kyle Mavis, on Flickr

 

[ShadesOfBloo]

I've got this picture of a 2016 GT350 grill:


This picture of a 2019 GT350 grill:


Even the GT500s upper grill looks about 40% blocked off.


My 2020 GT has a completely open upper grill, and it looks dumb and cheap to me.
Like, they didn't block it at all because the plastic would have cost money (but by God we'll chrome that horse!)


Are the GT and GT350 grills interchangeable? They kinda look like it, but I don't take it for granted that the outline or the attachment points are the same.

 

[mavisky]

I couldn't imagine that the clips will line up in the right spots. Would be much easier to just get some black ABS, trim to fit, and then adhere it from the backside with some hidden fasteners and zipties.

 

[Bill Pemberton]

Really interesting thread and considering the years and years of folks concerned about their cars running too hot ( especially at high altitude tracks ) I think the logical move would be to first get a Tiger Hood ( chicane23.com is the Distributor for everyone though the name is not used ) or something similar from Anderson Composites. Two examples to implement, along with the hood vent kits, and once those things are completed then maybe try blocking off part of the front end. Since in hot weather I have still seen drivers complaining about their Mustangs running hot , I have to address the fact that neither my Boss 302S or my current Mach 1 run hot at all. Both have CF hoods and they pull air from under the hood fantastically.

The info here sure gives on a lot of data to block off more air, but taking Nascar into play, they often discuss blocking off air at high speed tracks and one wonders if there is really a big advantage at the bulk of tracks where speeds seldom hit more than 120-130mph.

Worth experimenting for some, since we all look for every little advantage, but I would sure work on running cool first, and blocking airflow second.

 

[ShadesOfBloo]

...one wonders if there is really a big advantage at the bulk of tracks where speeds seldom hit more than 120-130mph.

The last few years they sold the Ford Fusion, didn't that have automatic grill shutters to try and reduce drag at highway speed? I thought I saw one source say the shutters closed at 55mph.

If my GT ever runs hot, my first move to address that is to remove the plastic engine cover, and the drip trays under my factory vents. Even if I left the engine cover on, I'm under the impression my differential will run hot before my engine.

 

[SMGDHG]

The last few years they sold the Ford Fusion, didn't that have automatic grill shutters to try and reduce drag at highway speed? I thought I saw one source say the shutters closed at 55mph.

If my GT ever runs hot, my first move to address that is to remove the plastic engine cover, and the drip trays under my factory vents. Even if I left the engine cover on, I'm under the impression my differential will run hot before my engine.

This surprised me, but the shutters serve multiple purposes, drag being one of them.

1.) Decreased warm up time for cold climates
2.) retain engine heat while in cold climates

I used to work in Denver for about a year. I was absolutely baffled by the fact that my rental car couldn't get up to temperature in the winter while driving on the freeway. I'd start the car, scrape the snow off, wait 5-10 mins and car would be close to operating temperature. Say, just under the "NORMAL" reading on the dash. I'd get in the car, get on the freeway, and bam. Minutes later heater would lose heat and the coolant temperature gauge would be back in the COLD zone. As a person who never spent time in anything other than California weather, this was a huge surprise to me. I gained a newfound appreciation for grill shutters after that.

 

[xr7]

This surprised me, but the shutters serve multiple purposes, drag being one of them.

1.) Decreased warm up time for cold climates
2.) retain engine heat while in cold climates

I used to work in Denver for about a year. I was absolutely baffled by the fact that my rental car couldn't get up to temperature in the winter while driving on the freeway. I'd start the car, scrape the snow off, wait 5-10 mins and car would be close to operating temperature. Say, just under the "NORMAL" reading on the dash. I'd get in the car, get on the freeway, and bam. Minutes later heater would lose heat and the coolant temperature gauge would be back in the COLD zone. As a person who never spent time in anything other than California weather, this was a huge surprise to me. I gained a newfound appreciation for grill shutters after that.

Bad thermostat or crappy design, been driving in extremely cold Minnesota weather all my life and heat was rarely an issue. Even my Pinto had heat. Worst was my 2008 GTI, apparently the Germans can build a solid car but have trouble with thermostats. My GTI took forever to warm up once it dropped below 10 degrees, massive crud under valve cover. VW wouldn't warranty it, told me my drive to work was too short, ten miles one way, told me I should take it on a long drive once a week. I put a new stat from NAPA in it and all was good. A friend of mine had same GTI and same experience, pull the oil fill cap and plenty of condensation crud.

 

[SMGDHG]

Bad thermostat or crappy design, been driving in extremely cold Minnesota weather all my life and heat was rarely an issue. Even my Pinto had heat. Worst was my 2008 GTI, apparently the Germans can build a solid car but have trouble with thermostats. My GTI took forever to warm up once it dropped below 10 degrees, massive crud under valve cover. VW wouldn't warranty it, told me my drive to work was too short, ten miles one way, told me I should take it on a long drive once a week. I put a new stat from NAPA in it and all was good. A friend of mine had same GTI and same experience, pull the oil fill cap and plenty of condensation crud.

For me, this was not just one car, as nearly every rental car I had while in Denver showed the same issue. Toyota, kia/hyundai, jeep, etc. Was working in Denver for a year, had a different rental car every week. All new cars with under 30k miles. Nearly all of them would need to close the thermostat once on the highway to keep coolant from going to the radiator.

I highly doubt the thermostats were bad in every single one of them.

 

[xr7]

For me, this was not just one car, as nearly every rental car I had while in Denver showed the same issue. Toyota, kia/hyundai, jeep, etc. Was working in Denver for a year, had a different rental car every week. All new cars with under 30k miles. Nearly all of them would need to close the thermostat once on the highway to keep coolant from going to the radiator.

I highly doubt the thermostats were bad in every single one of them.

That's odd, altitude? All the vehicles I've owned and fleet vehicles I dealt with never had much problems with heat, I'd assume that Minnesota has to be at least as cold as Denver. Best heater, 68 Cougar w 428, 20 below zero and you could wear a t-shirt. The other trick in olden days was cardboard in front of the radiator, just better remember its there when the temps warm up. Another nice thing about below zero weather back in the day, light traffic, seemed like half the peoples cars wouldn't start.

 

[ShadesOfBloo]

That's odd, altitude? All the vehicles I've owned and fleet vehicles I dealt with never had much problems with heat, I'd assume that Minnesota has to be at least as cold as Denver. Best heater, '68 Cougar w 428, 20 below zero and you could wear a t-shirt. The other trick in olden days was cardboard in front of the radiator. ...just better remember its there when the temps warm up.
Another nice thing about below-zero weather back in the day; light traffic. seemed like half the peoples cars wouldn't start.

I would have guessed the thinner air was worse at cooling a radiator. I suspect the altitude alone is not to blame, and I have one idea...

When I lived in New Mexico, and went into the mountains - up to 9000 ft above sea level - my cars ran fine most of the time. Uphill, I had all the heat I wanted.
It was going downhill that messed things up. The engine didn't have anything to do, so there was no heat, but the air still blew over the radiator. Any time but summer.
Descending from Cloudcroft to Alamogordo, that was probably about 20 minutes of freezing my butt off.

 

[theamsoilguy]

I will be completely blocking off the grill opening on the top portion of the bumper between the lights. I have ducted the lower opening to the rad. I also have lots and lots of hood vents. I have not found a spot ( 3 valve ) to install my aftermarket water temp sensor yet but I should hve something for that before I track the car to keep a eye on temps just in case. Once I know my temps are ok I will extend the splitter to the engine crossmember ( that caused me some temp issues on another car ).

 

[twistedneck]

I have since taped off the top bar of the grill with the plastic and gaffer tape kit you get from Race Louvers. In addition, i put thick foam under the hood to seal off the huge air gap. My goal is to keep as much of the air as possible out of the radiator starting from the top and moving down - so far its fine on temps.. lets see this summer, if its good i'll tape off the middle one.. then finally the whole damn thing if it doesn't overheat. The Corn fuel and that 72 row setrab is going to keep my gen 1 cool.. Too bad the damn AC condenser is blocking the entire radiator.