 |
| 730 hp Mustang Saleen 302 Black Label - Saleen © |
Most of the non-useful energy left over is turned into heat. That means that your average hot hatch making 200 hp could easily produce around 300 kW (400 hp) of heat as a byproduct of making 200 hp. If you're having trouble wrapping your head around that number, that's enough power to heat a large home improvement store. In Canada. Some of that heat goes out the exhaust (thankfully) but a lot of it has to be dealt with in the engine bay through your radiator, and oil cooler if you have one. Unfortunately, there are limitations to how much air you can get into the engine bay to help you.
The main one is aerodynamics; the more air you suck in, the less air you can persuade to smoothly flow around the car to reduce air drag/resistance. That, in turn, affects your fuel economy. Plus, a large open area increases snow and water ingestion. As a result, manufacturers can't sell cars with huge open grilles (most of the large grilles you see on modern cars are fake; only a small part of the grille is open and flows air). This opens the door for the aftermarket to improve airflow if you prioritize managing heat.
 |
| 2012 Mustang Boss 302 at Atlantic Motorsport Park - Graham MacNeil © |
I do, which is why I bought an aftermarket grille for track day duty in my BOSS 302. For my car, I went with a Saleen S281 grille. Ideally, I would have got the BOSS 302S (race car) grille, but I couldn't justify the extra cost, so I went with Saleen which is no stranger to Mustangs. But to verify whether or not it was money well spent, I decided to put it to the test... three tests, actually.
1st test was going 60 mph (100 kph) in 5th gear until temperatures stabilized. The 2nd test was stopping after that run to see how much temperatures rise while stationary. The 3rd test was going 60 mph again but in 4th gear to bring engine speed up a bit and make more heat. I got someone to record readings for coolant and intake air temperatures through a handheld scanner in real time. I also recorded outside air temperature from the dash readout.
For this write-up, OAT = Outdoor/Outside air temperature (ambient), ECT = Engine Coolant Temp, IAT = Intake Air Temp, and deg = degrees. Here's how the two grilles performed.
STOCK GRILLE - 60 MPH IN 5TH GEAR
OAT: 21 deg C (69 deg F)
ECT: 92.8 deg C (199 deg F)
IAT: 22 deg C (71 deg F)
After I had finished installing the aftermarket grille, outside temperature was much higher at 28 degree C. I could've waited to test in a similar temperature but I thought I'm ready to go, I might as well go out and see how it does. If it can match the stock grille in hotter temperature, then that's a pretty good improvement in its own right. But it didn't match the stock grille...
SALEEN GRILLE - 60 MPH IN 5TH GEAR
OAT: 28 deg C (82 deg F)
ECT: 86.7 deg C (188 deg F)
IAT: 27 deg C (81 deg F)
Yes, it actually beat the factory grille and by a good margin. Coolant temperature was over 6 degree C (11 degree F) COOLER, despite outdoor temperature being 7 degree C (13 degree F) HIGHER. In both cases, the car was going 60 mph in 5th gear (1:1 gearbox ratio in this car) and temperature had stabilized. I was very impressed.
How could IAT be lower than outdoor temperature? Well, Ford actually fitted the Mustang BOSS 302 with what it called a "Cold Induction System". Essentially, it's a cold air intake like an aftermarket kit you'd buy that includes tubing to get air from the lower bumper area; away from the engine bay and its heat. The only difference is that it uses a traditional filter box instead of a conical air filter and plastic tubing.
Chances are, the difference was just down to slightly different readings from the IAT sensor and the OAT sensor providing readout in the dash, in turn resulting in rounding up in the dash and rounding down in the readout, but we can still make a useful conclusion (more on that at end). On a slightly different note, this is a testament to the effectiveness of the 'Cold Induction System' Ford designed.
STOCK GRILLE - STOPPED
OAT: 21 deg C (69 deg F)
ECT: Temperature shot up to 97.8 deg C (208 deg F), then slowly crept to 98.9 deg C (210 deg F)
IAT: 23 deg C (74 deg F)
SALEEN GRILLE - STOPPED
OAT: 28 deg C (82 deg F)
ECT: Temperature crept up to 92.2 deg C (198 deg F )
IAT: 29 deg C (84 deg F)
Once again, despite outside air temperature being several degrees higher, coolant temperature with the aftermarket grille was several degrees LOWER. Moreover, it didn't shoot up initially after a sudden loss of airflow due to stopping.
STOCK GRILLE - 60 MPH IN 4TH GEAR
OAT: 21 deg C (69 deg F)
ECT: 95.0 deg C (203 deg F)
IAT: 22 deg C (71 deg F)
SALEEN GRILLE - 60 MPH IN 4TH GEAR
OAT: 28 deg C (82 deg F)
ECT: 88.3 deg C (191 deg F)
IAT: 28 deg C (82 deg F)
By now, there should be no surprise. Despite being hotter outside, coolant temperature was still several degrees lower with the aftermarket grille than the stock grille**.
WHAT ABOUT INTAKE AIR TEMPERATURES?
Overall, it's difficult to draw a definite conclusion from the IAT readings because it was lower in the first 60 mph test, which could be explained by reading tolerances (aka "rounding error") of the difference sensors. That makes exact calculations rather pointless. However, what is useful to note is the relative difference.
In the first 60 mph test, IAT was 1 deg C HIGHER than OAT with the stock grille but 1 deg LOWER than OAT with the aftermarket grille. While stationary, IAT was 2 deg C HIGHER than OAT with the stock grille but matched OAT with the aftermarket grille. In the final test, IAT was 1 deg C higher than OAT with the stock grille and matched OAT with the aftermarket grille.
If you ignore the exact numbers, you can still conclude a general advantage. IAT was consistently higher than OAT reading from the dash with the stock grille, by either 1 or 2 deg C. With the aftermarket grille, IAT was either lower or matched the dash reading. There is a clear and consistent trend of IAT being improved (relative to outside) with the aftermarket grille, likely due to lower average temperature throughout the engine bay.
NEEDLESS TO SAY...
I was very happy with the results and the grille overall. Of course, not every aftermarket grille will perform this well compared to stock, but it should be a good indication of a well designed option that truly opens the frontal area.
** For thermodynamics nerds: note that the tests were done in the sequence I wrote (for each grille), meaning that the coolant temperature with the stock grille had to cool from 99 deg C after the stationary (2nd) test to 95 deg C in 3rd test. With the aftermarket grille, it had to cool from 92 deg C in the 2nd test to 88 deg C in the 3rd test. Coolant temperature went down the exact same amount with both grilles (nearly 4 deg C), despite a much narrower 'approach' with the aftermarket grille.
Approach is the temperature difference between your 'load' and your 'source'. In this case, the load is the engine coolant - this is what you are trying to cool down - meaning that your load temperature is the coolant temperature. And the car is using outside air for cooling, meaning your 'source' temperature is your outside air temperature.
With the stock grille, OAT (source) was 21 deg C. ECT (load) was 99 deg C at the end of the 2nd test; an approach of 78 deg C. With the aftermarket grille, OAT (source) was 28 deg C and ECT (load) was 92 deg C; an approach of 64 deg C. To achieve the same amount of cooling (i.e. a drop of nearly 4 deg C) with a much narrower approach and no change other than the grille (radiator design, coolant flow, etc. is the same), airflow had to be significantly higher as a result of the grille, which is very impressive!
Comments
Post a Comment