High Idle IAT's

[Cobrakit]

I tried searching, but i apparently don't get along with search engines. Installed FRPP performance package on 2019. IAT's go up fast at idle. Nominally 5deg higher than ambient when moving. I have already sealed air horn at grill and even added rubber pipe insulation on lip of cai to ensure good hood seal. So next step would be to insulate inlet tube going to intake and possibly sides if airbox. Any thoughts?

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[FreePenguin]

stock intake box provides best heat fighting ability. Atleast that’s what I read

Toss it on and compare

 

[Dfeeds]

Not really worth the headache honestly. It's something all of us with the gt350/bullitt/frpp air box deal with. If your temps didn't drop to 5 or less, above ambient, then I'd be worried. Unless you're chasing a certain 1/4 time, where every ounce of timing matters, then the high IATs are more visually distressing than anything else.

I think the lid of the gt500 box works if you can snag one. It was discussed in one of the 2018+ frpp threads and in the bullitt forum. I'd take that route over trying to Frankenstein something together. There's a whole thread on that, too, and the thread starter just ended up getting a different CAI and scrapping all of his effort.


EDIT: Be cautious about plugging up every hole on the box. Some are there to vent the hotter air as the cool air comes rushing in. I tried it and had better IATs but my cruising temps were also much higher.

 

[AZ18yote]

Very common with open element cai. Stock box keeps it down. Closed box with a drop in and call it a day.

 

[TX5OH]

I have a JLT CAI, it was doing the same thing. So I insulated the interior wall on the side closest to the engine and cut me a thin sheet metal piece that rests on the rubber seal. When the hood is closed it pushes the sheet metal down to help it seal. It helps keep it from sucking in the air in the engine compartment. The temps will rise at idle but it rises orders of magnitude slower. It also cools like a rock once moving.

All I did sheet metal because it was cheap and easy. It’s the engine compartment air that is the issue being sucked in. The rise in temps some the heat of the inlet tubes is very minimal. Sheet metal is actually good at lowering radiant heat.

 

[Cobrakit]

So i assumed that since the cai makes contact with the hood insulation, that no hot air was getting in. And maybe the airbox and intake tube where getting hot. So i might try temporarily sealing top of airbox to confirm that its the source. I was stuck with engine running at idle for about 30min one time and saw iat of over 50deg above ambient.

 

[Shifting_Gears]

So i assumed that since the cai makes contact with the hood insulation, that no hot air was getting in. And maybe the airbox and intake tube where getting hot. So i might try temporarily sealing top of airbox to confirm that its the source. I was stuck with engine running at idle for about 30min one time and saw iat of over 50deg above ambient.

Unfortunately, there’s no escaping it with an open element setup. The factory box is thicker, more heat resistant and truly is “sealed” except for the air inlet, which draws outside of the engine bay.

 

[schmeky]

The inlet assembly on the FRPP sucks. Plan and simple. It allows hot under-hood air to enter all around the "performance" version supplied by Ford.

In my region of the country my inlet temps rose about 10 degrees per minute of idling. 4 minutes in slogging in stop and short go I would see 40+ degrees in rise.

Reinstalled the stock inlet box and installed a hi-flow element and I could not tell any performance difference.

My inlet temps very low with the stock hi-flow box and hi-flow filter.

 

[AZ18yote]

The inlet assembly on the FRPP sucks. Plan and simple. It allows hot under-hood air to enter all around the "performance" version supplied by Ford.

In my region of the country my inlet temps rose about 10 degrees per minute of idling. 4 minutes in slogging in stop and short go I would see 40+ degrees in rise.

Reinstalled the stock inlet box and installed a hi-flow element and I could not tell any performance difference.

My inlet temps very low with the stock hi-flow box and hi-flow filter.

Agreed stock box with drop in gets the iats under control and flows great.

 

[GregO]

IAT’s as measured at the MAF sensor VS. IAT’s / Fuel Temp. as measured at the intake valve head.
That delta isn’t linear, don’t be fooled.
Installing a 170 deg thermostat will do more for the air temperature entering the cylinder then losing sleep over MAF sensor IAT’s.
There’s a reason why PMAS & JLT focus on using a 120mm MAF housing VS. mitigating heat at the location of the filter element.

Just one man’s opinion.

 

[Elp_jc]

Unfortunately, there’s no escaping it with an open element setup.

Bullitts have an 'open element'... but it's only open when you open the hood. It seals really well against the thick hood insulator when hood is closed, so it's basically at least as good as the stock closed box. But it has a larger (effective area) filter. Both get air from the front of the engine, AFAIK. If it was worse (or even the same) than a stock box, Ford wouldn't have used it in the Bullitt, Mach1, and GT350.

 

[Shifting_Gears]

Bullitts have an 'open element'... but it's only open when you open the hood. It seals really well against the thick hood insulator when hood is closed, so it's basically at least as good as the stock closed box. But it has a larger (effective area) filter. Both get air from the front of the engine, AFAIK. If it was worse (or even the same) than a stock box, Ford wouldn't have used it in the Bullitt, Mach1, and GT350.

Very true. Seems like the aftermarket ones just don’t seal the same, or maybe the materials are less heat resistant.

I have a Steeda intake. It’s great, well constructed and fits perfect but the IAT creep is definitely there.

 

[Shifting_Gears]

IAT’s measured at the MAF sensor VS. IAT’s measured at the intake valve head.
That delta isn’t linear, don’t be fooled.
Installing a 170 deg thermostat will do more for the air temperature entering the cylinder than losing sleep over MAF sensor IAT’s.
There’s a reason why PMAS & JLT focus on using a 120mm MAF housing VS. mitigating heat at the location of the filter element.

Just one man’s opinion.

True, but I am pretty positive the computer does pull timing when intake IAT’s rise. Although the air is heating as it gets sucked into the engine anyway, the hotter it is coming in, the hotter the charge is going to be going into the engine at the valve.

 

[GregO]

I am pretty positive the computer does pull timing when intake IAT’s rise.

Timing isn’t pulled until MAF sensor IAT’s reach 150 deg F.

 

[WildHorse]

Where there's a will, there's a way. My PMAS cruising IAT anywhere from 1-5 degrees above ambient. Idle IAT takes a some long time to reach 81F. Once cruising, drops quickly. @GregO is right, doesn't pull timing till the IAT is stupid high. Not the prettiest to look at, but I'll take function over form 24/7/365. Key here is DO NOT completely seal to the hood. I did before, live n learn.

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