TSI questions!

[Imontalto]

So I have read in several places that TSI's actually do nothing to reduce the under hood temperatures, and in fact take air away from the radiator.

1: Is there any truth to this?

2 & 3: Has anyone tried taping up the back of the one that does not go into the cold air intake? Would that help relocate some of the air back to the radiator?

4: if none of this works, why do they exist?

Thank you in advance!

[Golden Stallion]

To sum up your questions. Someone actually didn't legit testing and found no effect temperature wise. They exist because people like the way they look. I guess it is a thing where it doesn't hurt to try. They like the look and it might help. Sorry I can answer 2 as I don't have tsi's

[RotorNutFD3S]

They can help reduce underhood temps, but only when you have something like the old school FM extraction hood that pulled air from all over the front bumper and extracted it out from the inner, rear area of the hood.

On my '95 I had a sealed intake airbox for the turbo right behind the driver's side headlight, that TSI may or may not have helped allow cooler air in (never did pressure test it like I wanted), but I blocked the other one off. I did that because they do interfere with airflow through the radiator if no other airflow mods are done. Is it by a lot? Probably not, otherwise you'd see a lot of people with TSIs overheating their cars but it's not an optimal design. They pretty much are for aesthetics unless you have supporting mods for them.

[Imontalto]

Gotcha! I love the way they look, but I was worried about overheating my car as it does get pretty hot around here. I intend on maybe sealing off an intake box behind one, but want to make sure that my radiator is getting as much air as possible. I found a good deal on some, so I kinda wanted to learn more before I bought them. Thanks for your help!!

[revlimiter]

My passenger side one is basically blocked and ducted. "All" of the air is pointed at the top portion of the radiator and the bodywork is sealed up so it doesn't enter the engine bay. Not a ton really flows, but at least it's not pressurizing the engine bay and taking away from radiator efficiency.

My driver's side one is a small supporting inlet to my headlight lid naca duct. Both feed a sealed airbox that my turbo breathes from.

Ducting is awesome, even in the tiny turn signal intake variety. But air is lazy. You have to force it to go where you want.

[BoBo]

They look good, there's a possibility that it might cool the engine bay combined with other stuff, but your better off getting one of those headlight NACA ducts, if cooling the engine bay is your priority. I like it for what it is, it makes the miata look better. OP don't worry about overheating. I had TSI on a few of my old miatas and I had no issues.