I searched, but did not come up with anything meaningful.

I see that a lot of people remove the stock air box and replace it with a cone filter.

My question is, has anyone ever done a before\after dyno to prove how restrictive the stock air box is, or is it just assumed that it is a restriction.

I would like to keep my car as stock as possible, however, if the cone filter is going to give me 10+ HP then it may be worth it.

My set up
88 TII
6 port keg(streetport, NA rotors)
Hybrid turbo @ 8 psi
no cats
CorkSport cat back w\ unknown pre-silencer

 

the stock air box is going to be fine

i ran it... RB exhaust and just ECU.... and did 13.3@103mph...
and it doesnt look like a ******* mickeymouse crap with a homemade tid and all that bullshit either.

took the TID off (on standalone so the afm just sits there) and ran it open turn

did the exact same time >.>

 

Haven't come across any independent numbers (i.e. not people trying to push products). If you could document before and after, you'd be doing a service to the list, IMHO.

I've seen intakes much worse than our stock one, FWIW.

The problem with cone filters is most people don't gain anything, and even loose out, because they don't correct for the fact that their newly installed cone filter is getting heat from the engine bay. You have to build a box to keep the heat out from the filter. I have seen some good intake 'boxes' here or in the archives. Try searching "cold intake box". The other thing is you don't want the cone filter where it'll get water and crap.

I got a bit off topic, but oh well.

 

I kept the stock airbox until I could make a nice TID and custom airbox. But the gains I saw with the TID surprised me. I'm seeing faster boost response, more boost in low gears & the turbo is able to hold peak boost longer. It's well worth it, if you do it the right way, and have a ported wastegate. If your wastegate is stock, you can expect to start seeing some boost creep issues, just like you'll get with an open exhaust.

Pictures and info here in my airbox thread: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/diy-cold-air-box-830116/

 

of course you didnt see a difference, your probably still rocking the same rubber intake hose on that with teh airbox and with cone filter. you gotta change everything out.

 

Hypertek, when you gonna write a DIY for a nice TID mod lol?

 

would i see any gains by replacing the stock TID, but keeping the air box?

 

I have an S5 turbo with ported wastegate and no boost creep. It holds 8 psi to 7K rpm.

I checked that link you posted, nice work. I may do something like that in the future. Thank you

 

I think banzai racing made a tid that fit the stock airbox. I ran one on my s4 and the difference seemed like a extra psi of boost.

on my fd i installed ebay hardpipes, cut a small rectangular hole in the bottom of the airbox, then ordered a metal "duct" from a dude on the forum, that took air from between the side of the radiator and frame. it made a huge difference. so maybe something like that could be fabbed for FCs?

the only restriction I see is the snorkel, but at least that sees cool air.

 

One weekend I decided to try the Apexi intake that was growing cobwebs sitting in the garage. Timed it with the stock air box, 40-70 then again with the Apexi, and both showed 11.5 lbs boost and almost the identical times, but just a lot more noise with the Apexi. Took it off, put the stock box back on, and the Apexi has been sitting in the garage even since, maybe 4 years or more.

 

The stock airbox, TID and snorkel have six 90* bends altogether. Three of those are in the stock TID. But a custom TID has just one 45* bend. Clearly, the flow characteristics will be better with the custom setup. This is all great, but unless there is a box of some kind to block out hot radiator air, the increased intake temps will negate any gain that can be had by improving the flow.

So to turbonut and slpin, did the non-stock setups you tried have any sort of box to ensure cooler air was pulled in? If not, then I can completely understand seeing no difference between the two.

I actually didn't expect to see much of any change with my custom setup. I was mostly looking to get rid of the stock rubber TID, which as usual, was ripping at the turbo inlet. So, when I drove the car for the first time with the custom TID/box, and my boost gauge showed 14 psi loaded up in 3rd gear, I was caught off guard. I had to adjust the MBC to get it back to the ~11 psi I normally run.

 

are you an idiot?
i literally took the air box out, the AFM that doesnt do anything with my setup and is only there to keep the **** police happy here in california, the stock rubber TID, and everything

the turbo didnt even have an air filter on it - it was just OPEN - which is basically the same deal as all these idiots running TID thinking theres actually a gain on it.

the wheel is completely exposed - i mean, knowing your ***, your small *** ***** could just fly in there and get chopped up... thats how open that ************ was....

i trapped 103 before, i trapped 103 doing that... plus, i was stupid enough to get a hot chick to stand outside the car to watch me run that i thought i was going to get a better time

there really isnt anything wrong with the mazda filter setup on a stock turbo... i mean if you want real gain, you are going to have to do more than what mazda enginners did.... home depot and PVC pipes are just pathetic... i mean... yeah instead of 12 psi you see 14 now - but that air is hotter than your cousin that i banged last week at a frat house... doesnt mean **** if your top mount doesnt do **** about it....

If you somehow manage to mount it so it is getting cooler air - there *might* be an improvement.... but I do not believe you will see any REAL improvement until you upgrade the intercooler....

which is why - i said, the stock air box isnt an issue in a T2.... the time comes for it to be an issue - it will physically be in your way of your turbo or intercooler pipings.

 

^ lol you made my night. your jaded posts are so damn funny.

back to the topic. I had a couple n/a's at one point. once with a k&n and the other with a drop in. the one with the drop in would feel a hell of a lot peppier on a hot summer day than the cone filter. the one with the cone would always feel like it was a quart low on oil after a hard run. (HOT!!)