Air Intake on 99on front bumpers.....

[andrewrx7]

Originally posted by iaint
Certainly can\'t hurt too much having the extra vent as long as it doesn\'t give a too-direct route through to the intake system for water (i.e. driving in heavy spray).

If you look at the standard airbox it\'s quite a convoluted route from the intake to the filter box and appears to be designed to not only split the air flow between intercooler and filter but to also prevent water entering the system.

I was looking at various possibilities for getting a cold air feed to aftermarket filters and was considering using the driving light hole on my bumper but that would basically suck up too much moisture at that height.  Havent\' got a decent solution yet that doesn\'t involve a dremmel and the front bumper!

Iain

Very true. On the 92-99 bumpers, the std air scoop takes air up into the intercooler, and the air box draws the air from the same scoop. Its a very direct funnel, so heavy spray will be put directly onto the intercooler (good thing I guess), but the spray will also be directed up into the black air collecter and directly to the air box.
The 99 spec bumpers, have a split the air and intercooler scoops. The black air collecter that sits at the front just behind the bumber, now has 2 openings and pulls air from the cavity behind the bumper, not from the main intercooler scoop. So there is a reasonable air volume to pull from. The scoop I\'ve played with, will direct the air to the cavity in the bumber, it doesnt link directly to the air collecter.
Hopefully I won\'t be driving it too often in heavy rain anyway, so hopefully it\'ll never be a problem!

[scooby_si]

as i had to have my bumper off to sort the feed for the intercooler out as it was sat on top of the main bit of bumper, which gave stupid intake temps of >60 even driving off boost, i was able to easily rig up a nice cold air feed for the induction c/o one deceased vacumum cleaner
Will post pix later if i remember......
Si

[scooby_si]

extension http://www.smileycentral.com/?partner=ZSzeb008\' target=\'_blank\'>http://smileys.smileycentral.com/cat/1053.gif\' border=0> we had to do to standard scoop so it could scoop cold air from under the bumper:

[scooby_si]

& quickly bodged http://www.smileycentral.com/?partner=ZSzeb008\' target=\'_blank\'>http://smileys.smileycentral.com/cat/3/3_2_9.gif\' border=0> cold air feed for induction while bumper was off:

[andrewrx7]

So is the ol\' vacuum cleaner pipe is still there, or was this a temporary fix? Sorted out something else or left as is?

[scooby_si]

well the previous week it was pointed in the intercooler scoop thing as that was sat in warm air land but didn\'t totally fix it so off came bumper to do above extension to scoop & while it was off i noticed i could stick it thru the front panel kinda thing to give the induction a bit of the cold stuff which seemed cunning so did....
Si

[Brett]

This kinda leads me to ask an intake related question:-

 Light cover venting/ducting, does it actually do anything worth while?
:confused:

[andrewrx7]

Not being an expert, but rather thinking logically, then I presume it would depend on (i) the volume of intake air the engine requires,  (ii) the volume of air the extra intake supplies and (iii) the volume of air the cold air is being delivered into (i.e. dilution factor).

Difficult question to answer off hand, without doing alot of measuring! But bottom line would have to be anything is better than nothing, so if like alot of people, you\'ve got big foam filters sat un-heat shielded and potentially drawing hot under-bonnet air, then yes, it may make some difference! I guess the ideal would have to be some kind of heat shielded box, and then good ducting so that the majority of the intake air is cool, i.e. the hot:cold air ratio favours the cold rather than the hot!

[Brett]

I\'d just spent some time looking at the various types available, the only one which seemed to be designed as a scoop was at mariah motorsport.  Dont think I\'m gonna buy a single headlight cover and pay twice as much to ship it though!

[andrewrx7]

Its puzzled me for a while, that people whip out the std air box, which sucks in cold air, and put on big foam filters. If you take the air box out, and look into the gap, what do you see? The backside of the rad for starters! Now I don\'t know how hot the air is that comes out of the rad, but since people say the rotary runs so hot and cooling is a big issue, then I presume it must carry some heat! The filters now sit right in the hot air flow from the rad. Not sure of the relative positive gains here.....std air box + filter which people say can be restrictive (some say not, though) BUT cold air drawn in....vs.....less restrictive filters but using warm/hot air from the rad/engine. Pros + cons with both routes, not sure which is best though.

[sdminus]

i agree with the air box post. why would a mazda or any other company spend thousands of pounds developing an air box if all u need is a foam filter of a certain size. the box shields the intake from hot engine air period. i tried to open mine up to encouage cold air. drilled 20mm holes in the bottom and 20mm holes in the left side to get from wheel arch gaps. verdict. car went much much better but suffered with boost creep. end of experiment got scared.

[Brett]

sdminus,

 did you really drill holes in the air box? In the bottom of the air box!?!  That means you wouls have been suckiing in air without the aid of an air filter!!!

 I\'ve seen a fair few people posting about this, all I can say to you is DONT DO IT!!!  If your going to drill holes in the box (past the filter) then you may as well bin the filter and budget for a rebuild sooner than you\'d wish.....    :rolleyes:

[andrewrx7]

In the std air box, the air is drawn in from the bottom of the box, the filter sits half way up, and the filtered air is taken from the space ABOVE the filter. Drilling venting holes into the base of the box is OK.

Nice little mod can be found here, with the std airbox:

http://www.rx7.org/Robinette/coldair.htm

[Brett]

True, but I\'m sitting here looking at an FC one.  Doh!

 I\'ll just get me coat...         :rollin

[sdminus]

no all the air was filtered. only holes in the base of the box were made. i used the robbinette thing as a guide. once the filter was layed in the box ready for the lid none of the holes could been seen any more. this seems a common thing tohappen. seen may posts form the usa with same things happening. i think it has something to do with the waste gate and lack of fuel. not 100% tho. any ideas