I ask because I recently saw that Hawks now sells a double Cold Air Intake for the TPI. I remember back around circa 2013 when I first got my IROC it seemed either everyone was swaping the TPI for a carb or replacing the airbox with a Cold Air Intake. I remember back then I almost did a CAI but learned about the "free" less restrictive airbox box mod that involves removing the one layer that sat below the air filters and added HVAC pipping to run into them. Later I got the K&N air filters and the airfoil to complete this mod and kind of never looked back until recently.

I kind of forgot about the Cold Air Intake being a thing for TPIs until now. I know from circa 2001-2010 there are a ton of threads on here of people wondering which is better. No conclusive data ever seemed to be given but I feel like from reading the old threads people leaned towards the less restrictive airbox mod being better. If only perhaps because it saved you some money.

 

I'm trying to figure out which type of CAI you're discussing?
The TPI twin filter element and all of it's various modifications I understand. You're probably familiar with Chad Speier's TPI intake upgrade.
https://www.thirdgen.org/forums/fabr...-intake-2.html

In my opinion, and scientifically, anything that has a filter element that's in the engine bay and not shrouded isn't a cold air system. You need an isolated source of outside air for it be effective. Those conical filters hung off a 90° bend putting the filter in the corner (on the opposite side of battery) do little. It's still hot there.
Of course, with a TPI, the option of cowl induction isn't one.
Personally, I think Speier's is probably the best example I've seen. Tested too for CFM as well as baro. He was actually seeing some ram air effect after incorporated ducting to the base of the filters.

What other styles are you thinking of?

 

Every BMW and Toyota (and Pontiac not factory) that I own has a factory port that leads from intake to front of grill somewhere to suck in "cold air". it must work. although in summer cold air is relative. I can notice a performance difference in my BMW when it is cooler out vs a hot day.

 

The cold air I was thinking of, is the basic metal pipe with an air filter in front of the MAF. Really popular on modern MPFI cars. Like these:
https://cdn11.bigcommerce.com/s-ueto...666029.jpg?c=2

Back in the 2000s they were everywhere. I haven't seen them as much in recent years until very recently.

 

As long as that "port" is in front of the grill, as in ahead of the radiator, then that's what you're after. Tucked in the corner, behind the rad support, without no outside air is not.

 

See that cone filter hanging the corner? That is not a cold air intake.
I've seen some with our cars, drill a hole through the battery tray (on the opposite or the battery relocated) and place the filter below that. While not necessarily protected from the elements, it is outside of the engine bay.

 

I think I understand what you are saying, but from a marketing/product name standpoint it sadly is called a Cold Air Intake. If you ask 9 out of 10 people in the US what a cold air intake is, they will say the metal pipe with an air filter at the end that replaces the stock airbox.

That being said, from what I think I understand what you are saying, that's why I am glad I never brought one 12 or so years ago and did the HVAC piping and less restrictive air box mod instead. Since those pipes don't really sound like true cold air intakes.

Just wanted to ask because I've been seeing them a lot again with TPI cars and I know CAI vs the HVAC was a big debate on here back in the day. Wanted to see if any official power numbers were ever proven to which was better. Though it sounds like from what you are saying, those metal pipes really don't draw in cold air and likely don't make great or if any performance gains.

 

3rd Gen SLP cold air intake has an "advertised" number. It was 12 -15 hp at 5000-5500 RPM. Agreed, that intake port needs to be outside of the engine bay where it can get the air flowing

 

Has anyone confirmed any numbers for the HVAC/Less restrictive airbox mod? I know when I did it back in the day, my car felt a bit faster. I did headers, y-pipe and muffler years later and that really felt like it opened the car up.

 

Read through Speiers thread posted above.
He bench flowed his modified TPI intake with and without K&N filters. He went on further to debunk the K&N spec about sq in vs air flow (although it takes some reading between the lines to draw that out.)
My take on it? A modified OEM TPI twin filter arrangement is the way to go. Open up the intake housing by cutting it along the seam and spacing it with 1/2" polystyrene. Enlarge the inlet hose to the TB to 4". Cut out the baffles forward of the filter elements.
For added effect, use the fog light openings to get forward facing outside rammed in.
All air sourced externally and the added volume of the filter back housing takes care of CFM.