Hey guys, I need some advice on a cold intake air solution for my FD. I have sourced a 99-spec sir guide, and my car has a non-OEM plateless front 99-spec bumper so this is one option (with some additional work, see below). Another option would be some form of lower airbox modification to open it up for a better cold air supply. I need to maintain the OEM airbox to pass smog check visual, so whatever I do has to include this part.

The pros and cons seem to be:

99-spec airguide Pros:
Maintains OEM function and design, JDM cool factor
Better source of cold intake air, allows more dedicated air to IC,
No big modification needed to airbox

Cons:
99-spec airguide does not fit with stock upper IC bushing and bolt (not enough clearance shaped into the airguide, will require some change to hardware, maybe elimination of rubber bushing),
Seems like it will require some mods to 93-95 bumper support to allow air to move through bumper area to air guide inlet (several hours of work needed here probably)
Seems like the air inlet area is kind of small (particularly compared to the cheap-bastard style airbox mods)

Airbox modification Pros:
Can just use old airguide, no fitment issue
No need to pull bumper and mod the bumper support
Larger area of air inlet

Cons:
Requires substantial modification to airbox
Possibility of water ingestion (mostly a theoretical con in my case, as I don’t really drive in the rain so much)
Increased intake noise (?)

What I am wondering is, if I go to the trouble of pulling my bumper support and modding it to open up the area under the hood release so that the 99-spec airguide can get some fresh air, if that will be sufficient for a lightly modded car – or, is it better to just do the airbox mod and not worry about the 99-spec airguide?

Or maybe do both? Thoughts on this?

 

In my experience, the risk of "possible water ingestion" is pretty low unless you're driving through deep puddles. I had zero issues with my supercharged s2000 through all of the rain in NorCal this last season, and the filter is only around 8-10" from the ground.

I'm personally going the modded airbox route since it's probably just as effective and a pretty cheap modification depending on your level of craftiness.

 

Are you actually talking about cutting an air intake into the bumper? My understanding was that the 99's bumper has an inlet at the plate mount bracket. The revised intake tube draws from that, I think. Can you source the rest of the 99 components (IC duct, etc) and make everything fit nicely like stock?

Seems like lots of people do the stock airbox mod. Why not do both?

 

I've been wondering about how the air gets past the bumper and bumper support - I could be mistaken but it looks pretty obstructed under the hood release mechanism opening which is where the airguide draws its air. I don't have the 99-spec IC duct but I can mod my existing duct to block the 93-95 spec airbox air outlet. My bumper is a plateless 99-spec rep so I'm not sure if the design is the same as the OEM Mazda part.

I agree, low chance.

 

Are you running the plastic block-off plate between the nosecone fibreglass reinforcement and chassis? We did run without that and removed the latching mechanism - and used outboard aerocatches. Volume of air being bounced off the rad and forced up, had the bonnet lifting a good couple of inches and flapping like crazy, so had to install an additional catch up front...you might be surprised how much air gets in there.

 

Well I might be out of luck getting the 99-spec airguide to work with my plateless rep 99-spec bumper. I started looking at the real Mazda 99-spec setup and it looks like the bumper is ducted behind the license plate to feed air to the bumper support and then on to the hood release area. My bumper doesn't have any of these features, obviously. There may be a way to get outside air to the hood release area (as noted noted by billyboy), I will have to take it apart and see what can be done.

 

The Cheap Bastard airbox mod will pass Ca smog, and will supply plenty of cool air for any FD making up to (and likely over) 400rwhp. Sounds like this is what you need.