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Discussion Starter · #1 ·
There's been plenty of debate on which CAI is best, and if a CAI is really any better than the stock airbox because it's likely sucking in hot underwood air, making it a HAI (Hot Air Intake) and possibly negating any potential HP gains. I've seen plenty of claims thrown around here but not a lot of data-based test results.

After having gone to the track yesterday with a terrible DA (2800') and battling hot IATs, my OCD got the better of me and I decided to break out a bluetooth BBQ temp gauge I have and go for a drive to see if I'd be better off going back to the stock airbox.

Before you start telling me this isn't a definitive test . . . Yes, I agree, and I'm not saying it is. It obviously should also be done with the stock airbox and ideally I'd measure the air temp in the same spot next to the filter with and without the JLT heat shield to see the true delta. But I didn't feel like spending that much time today. I may be a nerd, but I also don't have much free time. And another disclaimer - JLT didn't ask me to do this, didn't know I was doing this, and hasn't given me a dime. I paid full price for Jay Tucker's intake. If you like a different brand for some reason, I am not here to debate it with you.

The results are interesting, and (I think) confirm that JLT's heat shield works - the air next to the filter was close to ambient the whole time - parked while idling with the hood closed, at 20 mph, 40 mph and 75 mph. It would seem from this test that any CAI without a shield like JLT's is sucking in air 20° - 30° hotter than ambient. Each pair of temp pics are a screen shot of the BBQ probe temps followed (within a few seconds) by a shot of temps from the Performance Page screen and the outside ambient air temp at that moment.

This test is enough to convince me that the JLT intake isn't causing IATs to be any hotter than the stock airbox would have and seems to support the dyno test he did that showed gains over a competitive CAI.
 

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Thanks for the temp info ……. also have a JLT CAI ….. filled the holes around the lower heat shield section with closed cell foam to block off as much under hood air as possible and then also opened up the top of the factory’s cold air duct to get as much fresh air as possible. About ½ the factory hood vent is open to the cold side of the JLT heat shield too.
 

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Discussion Starter · #4 ·
Thanks for the temp info ……. also have a JLT CAI ….. filled the holes around the lower heat shield section with closed cell foam to block off as much under hood air as possible and then also opened up the top of the factory’s cold air duct to get as much fresh air as possible. About ½ the factory hood vent is open to the cold side of the JLT heat shield too.
Great idea! I can see that helping even more. The most surprising part of this test for me was that the air temps with the JLT were very close to ambient - it's definitely not the cause of high IATs like some have said about CAIs in general - not the JLT anyway. I can't say the way I tested proves this statement - but - it seems that any CAI w/o a full heat shield is feeding air 20-30F higher to start with, at least when it's ~70F ambient.
 

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Good test! Good info!

I know there is no way to really record this (I don't believe), but since our engines are intercooled, I would be interested to see what the delta is between IAT at the filter and ACTs after the intercooler has done its work. IOW, how much of a difference the IAT at the filter makes in the cooled charge after the intercooler.
 
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Good test! Good info!

I know there is no way to really record this (I don't believe), but since our engines are intercooled, I would be interested to see what the delta is between IAT at the filter and ACTs after the intercooler has done its work. IOW, how much of a difference the IAT at the filter makes in the cooled charge after the intercooler.
GREAT question. I thought I had heard from a knowledgable Hellcat tuner that there are like 5 temp sensors along the air charge path, so . . . If HPT or some other logging SW could access them all . . .

At least from what I saw in the this test, it would be pretty easy (with a JLT) to add or subtract a good deal of initial air temp with the heat shield. Someone who knows a lot more about air compression physics might already know how much the initial, uncompressed air temp changes the final temp in a particular compressor. I'm sure it's way more complex than a linear curve.
 
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