N/A stock air box mod

Rotary#10 · 05-10-2010, 01:24 PM

After considering other forums and posting about moding the stock air box. I recieved considerable feedback that the stock air box is restrictive in flow. Would there be anything I could do besides replacing it, that could be done to it? Here is what I did to it. Keep in mind I have 2 stock air boxes.

Whats your take? Folks tell me to dyno the car with the stock box and my moded box or get it benchflowed.

RETed · 05-10-2010, 01:33 PM

I just question why...since you can just slap on a cone filter and call it a day?

-Ted

Rotary#10 · 05-10-2010, 01:42 PM

Quote:

Originally Posted by RETed

I just question why...since you can just slap on a cone filter and call it a day?

-Ted

Too easy plus you'd have to build a box that keeps out the heat. I have a drop in K&N. Im going for a stock look since I live in smog strict state.

vex · 05-10-2010, 02:26 PM

So... basically you got rid of the ribbing. Hopefully that ribbing was 1) not structural, and 2) it wasn't there to keep the flow from being laminar.

Turbulent flow>Laminar flow (velocity wise).

My suggestion would be to get rid of the box entirely and start from scratch. Design a box and ducting that would pull in cool air without issue, and still have better flow characteristics than stock.

Something to consider when modifying the car's stock equipment:
1) Design is dictated by 3 things for a mass market.
a) Cost to produce (Material, Tooling, etc)
b) Reliability/Endurance
c) Performance

Choose wisely which one you choose to modify in order to increase the other two.

I bring that up for a simple reason: What you're doing is removing those ridges for a presumed "better" air flow. The trouble is just by logic it doesn't seem to me that it will based on the above.

Cost to produce: Mazda had to produce that intake box, it had to spend money to produce it. What would cost more? A simple box with internally smooth sides, or a box with ribs spaced throughout the interior? If you answered the internally smooth sides, you'd be right. The molds for such a box would be made (tooling cost) relatively simply, with taking a plate and machining the exterior surface to match perfectly. Consequently the stock box is not like that? Why? Do the engineers that designed it know less than we do today? Probably not. In which case there must be a reason for those ribs.

The long and short of it is this: You have basically taken a golf ball with dimples in it and filed the rises down to create a smooth ball. This animation shows how the dimples work:
http://www.livescience.com/common/me...olfBallScience

(sorry for the dreamy voice the guy has)

Something cool:
http://www.ebaumsworld.com/video/watch/80521365/

Rotary#10 · 05-10-2010, 04:59 PM

I agree. Im getting schooled here but I'll take it since Im learning something too.
The ribing isn't structural. The reason for the ribs... mmm

05-10-2010, 02:26 PM	#4
vex RCC Loves Me Not You Join Date: Jul 2008 Location: Influx. iTrader: (6) Posts: 2,113 Rep Power: 19	So... basically you got rid of the ribbing. Hopefully that ribbing was 1) not structural, and 2) it wasn't there to keep the flow from being laminar. Turbulent flow>Laminar flow (velocity wise). My suggestion would be to get rid of the box entirely and start from scratch. Design a box and ducting that would pull in cool air without issue, and still have better flow characteristics than stock. Something to consider when modifying the car's stock equipment: 1) Design is dictated by 3 things for a mass market. a) Cost to produce (Material, Tooling, etc) b) Reliability/Endurance c) Performance Choose wisely which one you choose to modify in order to increase the other two. I bring that up for a simple reason: What you're doing is removing those ridges for a presumed "better" air flow. The trouble is just by logic it doesn't seem to me that it will based on the above. Cost to produce: Mazda had to produce that intake box, it had to spend money to produce it. What would cost more? A simple box with internally smooth sides, or a box with ribs spaced throughout the interior? If you answered the internally smooth sides, you'd be right. The molds for such a box would be made (tooling cost) relatively simply, with taking a plate and machining the exterior surface to match perfectly. Consequently the stock box is not like that? Why? Do the engineers that designed it know less than we do today? Probably not. In which case there must be a reason for those ribs. The long and short of it is this: You have basically taken a golf ball with dimples in it and filed the rises down to create a smooth ball. This animation shows how the dimples work: http://www.livescience.com/common/me...olfBallScience (sorry for the dreamy voice the guy has) Something cool: http://www.ebaumsworld.com/video/watch/80521365/ __________________ The Official FC Radiator Thread My Project Thread: Cerberus CCVT Virginia Rotary Group Last edited by vex; 05-10-2010 at 02:46 PM..

05-10-2010, 04:59 PM	#5
Rotary#10 Rotorhead Join Date: Sep 2008 Location: "the town " Oakland iTrader: (1) Posts: 219 Rep Power: 17	I agree. Im getting schooled here but I'll take it since Im learning something too. The ribing isn't structural. The reason for the ribs... mmm __________________ Currently running: 90 GTUs converted to S5 TurboII. Track car. 90 N/A GTUs.. Running project car 89 N/A GTUs in Black #2 10/6/18 Blown coolant seal undergoing rebuild and restomod. Last edited by Rotary#10; 05-10-2010 at 05:02 PM..

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05-10-2010, 01:24 PM	#1
Rotary#10 Rotorhead Join Date: Sep 2008 Location: "the town " Oakland iTrader: (1) Posts: 219 Rep Power: 17	N/A stock air box mod After considering other forums and posting about moding the stock air box. I recieved considerable feedback that the stock air box is restrictive in flow. Would there be anything I could do besides replacing it, that could be done to it? Here is what I did to it. Keep in mind I have 2 stock air boxes. Whats your take? Folks tell me to dyno the car with the stock box and my moded box or get it benchflowed. __________________ Currently running: 90 GTUs converted to S5 TurboII. Track car. 90 N/A GTUs.. Running project car 89 N/A GTUs in Black #2 10/6/18 Blown coolant seal undergoing rebuild and restomod.