JBR Tru-3.5 Wide Path "custom" airbox

[AgentWh0]

Since I had installed my BNR S3 and JBR Tru-3.5 Wide Path Aluminum intake I noticed my Boost Air Temps (BAT) were generally about 30 degrees above the ambient air temp outside. With the stock turbo and the Cobb SF intake w/ air box, Turbo Inlet Pipe and Street Unit TMIC the BATs were generally only 20 degrees above ambient air temp. These are cruising around temps, not making hard runs temps. Only running 18 PSI with the BNR S3 (self tune until I get it on a dyno) I believe it shouldn't be adding 10 degrees of heat over the K04 running 18.5. I chalked it up to the TRU-3.5 sucking in hot air from the engine bay. I also noticed that the Intake temp with the JBR Tru-3.5 would rise considerable quicker when at a stand still than I remember with the Cobb setup further enforcing my suspicion of hot air from the engine bay creating higher BATs. This started me on my search for an air box for the JBR Tru-3.5 that would help keep the hot air out.

After searching around and finding nothing online about an air box to help shield the air filter on a JBR Tru-3.5 Wide Path intake I went about creating my own that would be able to be fed colder air from the stock air duct in the grill and from the wheel well/bumper area below the filter. As I grabbed the silicone tube that came with the Cobb SF intake with air box to see if I would be able to reuse this to attach to the air duct in the grill I pulled out the air box for the Cobb intake and noticed that the hole the MAF housing is attached to is about 4" - 5" wide. I removed the filter from the JBR Tru-3.5 intake and placed the Cobb air box around the aluminum MAF housing with some room to spare on the sides. It doesn't make a seal or fit snuggly there but I figure it is going to definitely help keep most of the hot air out of the filter if I can get the air duct connected to it.

Since the air box did not fit snug around the MAF housing it allowed a little play so I was able to turn it this way or that. So I drove over to Autozone and grabbed some plastic flex piping to connect from the air box to the air duct since the Cobb silicone pipe that did this initially was not the right shape for this application. The 3" flex pipe I got ended up working perfectly. The plastic piping came with silicone ends that fit perfectly around the air duct inlet and the Cobb air box inlet while also holding everything firmly in place. It was a little hard getting it in there but it fit (no pun intended). I had to place the flex piping on the air box first with ring clamp for a real secure connection, then to the removable air duct piece before putting the air box around the MAF housing. The top for the Cobb air box will not fit with this setup so this is where it gets a little "ghetto".

Running out of time and daylight I grabbed some cardboard (soon to be replace with heat shielding material)(It's far enough from the engine it wont catch fire) and started cutting it to the correct shape to fashion the new top for the air box. I got it to a good enough shape since it's only temporary. I attached it using the Cobb provided bolts for the original air box top and voilà, I now have an air box that should help keep most of the hot air from getting sucked into the filter. The air box isn't fully enclosed as it has the front and front/bottom open so I do not believe it will be restricting any air flow either, just help not get hot air from above or behind the filter.

I will post some pictures once I have the heat shield material for it.

TL;DR:

If you have or can obtain a Cobb SF intake air box it can be used to create an air box for the JBR Tru-3.5 intake. It does not fit snuggly around the MAF housing but this play is needed to be able to get the air duct connected to the air box for colder air fed through the grill. You will need some 3" plastic flex pipe for the air duct to air box connection and you will have to fashion your own top for the air box.

[MSP6]

Changes in day to day temp, going from a silicon intake with an airbox to metal intake with no airbox.

Why are you surprised to have seen an increase in BAT's exactly? Each one of these things will affect your BAT's let alone all together.

[MS3Shadow]

also, the airbox would barely do any cooling since it'll just get heated up by the turbo anyways.

[anavrinIV]

Originally Posted by MS3Shadow also, the airbox would barely do any cooling since it'll just get heated up by the turbo anyways.

Not necessarily. If the air box pulls air from, say, the bumper well and isolates the hot engine bay air from reaching the filter to a reasonable degree its possible.

That said I don't see much value in it. Your biggest concern should be high load BATs moreso than cruise BATs. Do you see a difference there?

[AgentWh0]

Thanks for the replies. I just added the air box yesterday and have only driven the car in the cold this morning so I haven't been able to compare

I'm going to gather some logs day to day with and without the air box when the air temp is higher and the engine is heated up to see if it is indeed helping.

Just wanted to post this since I couldn't find anything about an air box to try and accomplish what I am trying to do. From theory it should help with the IAT since it's being fed air more from the air duct and from below instead of just all around. We'll see though, I'll post logs when I get enough of them.