JA AirScoops (Not For Sale)

[Rakker]

yeah, at that level of shroud cutting you really may as well just take it off.

For what it's worth, i think the shroud does serve some purpose when it's hot, the car is not moving and the radiator fan is on. there's a bit of space between the fascia and radiator, intercooler, and other bits. To me, the shroud appears to direct outside air through the radiator rather than hotter air trapped there, coming from engine compartment. once you're moving, it should make no difference temp wise. I've been doing some logging on intake temps with the ducts and without, and once you hit 60+, not much difference.

When you say "without ducts" do you mean oem setup or simply just removing yours and not putting the oem contraption back on?

 

[funesto]

yeah, at that level of shroud cutting you really may as well just take it off.

For what it's worth, i think the shroud does serve some purpose when it's hot, the car is not moving and the radiator fan is on. there's a bit of space between the fascia and radiator, intercooler, and other bits. To me, the shroud appears to direct outside air through the radiator rather than hotter air trapped there, coming from engine compartment. once you're moving, it should make no difference temp wise. I've been doing some logging on intake temps with the ducts and without, and once you hit 60+, not much difference.

Definitely interested in a more detailed write-up on this. I love the look of the snorkels, but I'm concerned about the general effects on cooling when the shroud has been removed. Being that I live in a city, I'm stopped or moving under 60 more often than not.

 

[Rakker]

Definitely interested in a more detailed write-up on this. I love the look of the snorkels, but I'm concerned about the general effects on cooling when the shroud has been removed. Being that I live in a city, I'm stopped or moving under 60 more often than not.

I've been looking at my JB4 data and there is no difference in my water temps when the shroud is off and on. As far as being at a stop, in general my water temps are actually lower when I'm at a stop compared to when I'm moving. Here are a couple of JB4 graphs with and without the shroud under similar conditions. Also, the "without" graph have the snorkels install and you can see the IATs are generally lower.

 

[funesto]

Interesting... it looks like the snorkels actually keep temps more stable as well. Thanks for the data!

 

[Thwack]

When you say "without ducts" do you mean oem setup or simply just removing yours and not putting the oem contraption back on?

I just took mine off, I really don't get how the OEM intake can possibly help in any way, it looks like it would suck in hot air from that empty space between fascia and front of car. I'd probably get larger differences if I left that part on.

Definitely interested in a more detailed write-up on this. I love the look of the snorkels, but I'm concerned about the general effects on cooling when the shroud has been removed. Being that I live in a city, I'm stopped or moving under 60 more often than not.

Not much more detailed to get, behind the front fascia, under the headlights, above the radiator, etc, there's several inches of empty dead space. This is where the oem intakes get their air from... problem is that this dead space is cut off from cooler intake air by the radiator shroud, and vice versa, the radiator is cut off from this dead space by the shroud. This dead space seems more open to the engine bay than to outside, so it likely gets warmer . My theory is that if the car idling and the fan kicks on, without the shroud, the radiator fan would suck in some air from this dead space, which is gonna be hotter than outside air, just because it's in more of an enclosed area with lots of heat soaked surfaces. With the shroud, the radiator only sucks in outside air, likely to be cooler. I should qualify this as being a small difference, and really only takes effect when idling for a while, so that dead space has time to heat up, and even then it wouldn't cause an overheat or anything. Once the car is moving, even under 30, you have enough airflow that it shouldn't be noticeable, as you can see from Rakker's graphs. someone would have to datalog while idling with and then without the shroud to know for sure, and I'm not going to that trouble. To be sure, I think the snorkels give a better net cooling effect than the shroud, it's not a bad tradeoff, but it's why I tried to make mine salvage the shroud, to keep best of both worlds.

Rakker, your graphs look similar to what I'm seeing, though I'm trying to analyze mine based on the delta between the intake temp and the ambient temp vs speed. This lets me see at what speeds the snorkels have greater effect, at what point their benefit gets lost in the excess airflow, etc. I take the logs of speed, intake temp and ambient temp, sort and split the data into 10MPH "chunks" then plot all the delta temps in that range, finding averages. This helps rule out outliers due to starting and stopping,and the constantly spiking and diving temps.



I still need to log more data to tighten up my deviation, but I'm basically seeing roughly 4-5 deg cooler intake temps in the 20-50 Mph ranges, decreasing to only about 1 degree cooler above 60. It'd be great to get logs from someone with the OEM intakes to see if that makes a bigger difference.

 

[Rakker]

Updated design with a larger lip on the front so they are more visible behind the grill. I'll try to het some pics of them on in the next day or so.

 

[djerickd]

I'll get pics as well

 

[Gtecko]

Updated design with a larger lip on the front so they are more visible behind the grill. I'll try to het some pics of them on in the next day or so.

View attachment 42238

Great updated design !!
Looking forward to make my future purchase on these

 

[djerickd]

Got them installed! Pretty straightforward. I just used a dremmel to cut around the plastic shround where I needed to fit the duct. I also cut the air temp sensor mount that sticks out in the lower grille. I just remounted the air temp sensor hidden off to the side in another existing hole.

 

[Rakker]

Here are the newer design installed.

 

[djerickd]

My carbon GTS grille isnt as open on the sides as that grille!!

 

[djerickd]

Was that grille modified for more air flow? Look at mine.

 

[Rakker]

Was that grille modified for more air flow? Look at mine.

Nope. It looks like yours has some of those holes filled in. Must be a GTS thing I guess

 

[Rakker]

Was that grille modified for more air flow? Look at mine.

Is that an aftermarket grill?

 

[djerickd]

It's the carbon fiber OEM

 

[Rakker]

It's the carbon fiber OEM

Maybe you could use a dremel and precisely cut holes in those 2 columns?

 

[djerickd]

Yes indeed!

 

[Thwack]

Wow, I thought it was bad that the 1st hexagon on the edges if the stock grille was filled in, but yours are filled in like 4 deep. If it matters enough to you, the grille looks to be removable from the bezel, you can probably swap it for an open one if you can't cut it well.

The stock shroud extends just out to that 1st hexagon, is the GTS shroud smaller?

 

[djerickd]

Yeah that's weird i can dremmel out some holes from behind tho.

 

[Double D]

Finally got a chance to install these. Went on pretty easy. Decided against cutting the shroud and just removed it.