jeremy

iTrader: (1)

has anyone done any dyno testing to see if a cone, say K&N, blocked off from engine heat really has any gain in power over the stock box with it's cold air snorkel and a K&N drop-in?

sonorous7

can't say that I've seen any dynos but you can pretty much assume it would be good for a few hp, as the stock box is pretty restrictive.. so I've read. Just have to make sure it's enclosed, otherwise:

https://www.rx7club.com/showthread.p...=cone+box+dyno

NZConvertible

Don't waste money on a drop-in filter. The pressure drop through the stock filter is so small that even removing it entirely won't make a noticable difference to performance.

jeremy

iTrader: (1)

i bought one years ago. now i have a cone. i'm looking to see if anyone has numbers to back up any claims such as that.

SpooledupRacing

now see when I bought my car everyone advised me to get a drop in and leave the stock air box saying that the snorkle etc was VERY functional..

I think u should take the stock box lid off and grind off all the ribs on the undersie of the lid then it would flow a touch better. and remove any silencers etc.

I think this winter I will remove the whole setup and sell it with a brand new K&N and go with a custom cai setup to my liking!

ra ra rotory

Iv run both, and a cone is the way to go, a noticable amount of power. Although, before I got a cone, I cut the big 'Mazda' logo out of the lid of an extra airbox, leaving the snorkle.. That seemed to open up some pony's. The stock box is just.. restrictive.

sintri

there's a thread by a guy a while back that did start it, but don't think he ever finished. But as long as you have a box or move the filter somewhere on in the engine bay, it generally should improve it by maybe 0-5.

sniperstevedave

I just thought I would add my voice to jeremy's: Does anyone have real evidence of improvement from mods? I mean numbers, not opinions or seat of the pants observations. I have seen alot of advice posted that is either flat out bad or very questionable.

If I wasn't a poor college student (could be worse) I would get a dyno test with the stock setup I have now, and then retest for every modification I made, only making one mod at a time. Maybe I am being an engineering snob, or maybe I am just a geek, but if anyone has gone at it like this, please let me know what you found out.

Apathy

I know that intake and exhaust upgrades drastically increase flow which allows higher hp numbers to be reached when used on a turbo vehicle. On an NA vehicle its not going to be very noticable unless you have more mods to complement it.

InsomniacFC

iTrader: (4)

http://fc3spro.com/TECH/MODS/IN/airfilter.htm

I know it's not dyno sheets but good info none the less.

NZConvertible

If you're considering wasting money on a drop-in, read this...

http://autospeed.drive.com.au/cms/A_2232/article.html

sniperstevedave

Okay, so I am going to replace the air filter, just because I like things to be clean and squeaky new. The consensus seems to be that the stock air box works well enough, and that any power gains from a cold air induction system will be so small as to be undetectable. Fair enough, it makes plenty of sense to me, and I don't want to frankenstein my precious anyway.

ra ra rotory

I doubt that a 'cold air' setup actually has an effect on hp. yes, I understand, cold air's more dense and whatnot. But, for our mildly modded cars, the most noticable effect comes from removeing the restrictive stock airbox.

sonorous7

wow, polar opposites This thread really makes me wonder whether I should keep my "unboxed" bonez intake or just put the stock airbox back in...


or.. maybe I should do something like this:

SpooledupRacing

I think I will be doing the above!

jeremy

iTrader: (1)

and yet again, i see no numbers but an amazing amount of people jumping in to share their idea of what's right.

NZConvertible

That's absolutely wrong on both counts. It's been proven that the FC's stock airbox is restritive, and most people here understand the benefits of a functional cold air intake. The colder the air engering the engine is, the more power you will make. Simple physics.

And you'd be completely wrong. There's so much proof of this it's truly amazing that people still doubt it.

Hacking up the stock airbox won't make it flow as well as a pod filter but it will make it suck hot underbonnet air.

jeremy

iTrader: (1)

1, 2, 3, 4, 5, 6, 7, 8, 9, 10...........

ra ra rotory

That is what I said... And I still believe THE MOST NOTICABLE EFFECT COMES FROM REMOVING THE RESTRICTIVE STOCK AIRBOX.

But.. than again, im just some guy blabbing on the internet without some dyno sheets.. right?

jeremy

iTrader: (1)

yes.

or fluid dynamics charts on vertices cuased by the ribs/orifices and it's effect on air passing from the snorkel to the afm.

fstrnyou

i don't really care to go back a look to see if we're talking about an N/A or turbo car, but....

with my stock air box with stock filter, my boost ran normal. took the filter out entirely and boost still remained the same. installed a 3" inlet duct with cheap advance APC filter, and boost ran all the way up to fuel cut. dead on proof that the stock air box is too restrictive.

if you install a cold air intake, your gains will come only from the better air flow not because it's cold air. the stock box gets cold air already. doesn't really matter if it's N/A or turbo, better air flow makes more HP.

Sideways7

iTrader: (7)

I personally think that the verdict is still out as far as an open cone filter vs. stock airbox on NA cars. On turbos, however, I think that there is no question that increase in flow from a cone filter will definately offset any losses from hot engine bay air.

fstrnyou

my original intention of my post was to point out that no filter at all isn't any better than the stock filter, which aught to mean that a K&N is a waste of money in a stock airbox

sniperstevedave

I like that suggestion, it is rather elegant. And elegant solutions go really well with rotaries, 'cause they are as elegant as you can get.

sniperstevedave

Wups, just noticed there are two pages now. Meant that the extra holes in air box was a new suggestion. Still don't know that it would work though.

Please believe me, I do understand that cooler air+less flow restriction=better. This is basic theory. But theory often doesn't jive with practice. We have seen some evidence that the filter element itself makes very little difference, but we have been unable to seperate the effects from colder air intake from that of less restriction on flow. And we still don't have any quantitative evidence for the performance gains they are claimed to give. It is possible that the gain is so small as to not be worth the cost of the extra component and the time it takes to install them. Does this make since or am I just being confusing? Let me know and I will clarify.