ohhh....ok i get it...
awsome..thanx... and u sed that was the hks rs intake hardware with the k&n filters..?

 

Thanks guys

 

The airbox height was a point mentioned to me by Dave @ Rick's Rotary. IIRC, it was designed that way to clear aftermarket hoods. It's only marginally lower so I doubt you could tell a difference by looking at the picture.

This airbox is probably of similar if not the same design as the Rotary Extreme unit. AFAIK, RX-7 Fashion was Chuck Huang's venture before he sold it to Rick's Rotary.

 

hmm, I thought apexi would have been a good choice, I know for the mr2, they make a heat shield for it, I wonder if they have that for the rx7. But heat shields are not difficult to make.

 

What about Injen? They're known for their intakes and it works awesome on my friend's Eclipse GSX

 

Someone on the list a while back dynoed their car with the M2 intake both with the top filter cover on and off and found no difference at all in power. This indicates that the cold air opening of the M2 intake along the frame rail is not restrictive and that the cold air box flows just as well as having an open filter element.

The dyno was of course run at a standstill with the hood open so I don't think you can make any assumptions about intake air temps with the M2 lid on or off.

I am a big believer is not sucking up super heated air from under the hood. I would never run an open filter element under the hood especially on a turbocharged rotary vehicle.

 

As always, the temp data on Steve Ciriani's site should be brought up (thanks to Dave Disney for the measurements)....

Cold Air Intake Review

The products tested in this review are:

Stock FD3S Intake
Mostly Mazda Intake (M2)
Pettit Intake


I wish I could have tested one of the PFS intakes - just couldn't afford to buy a third unit just for testing. Anyone know how it is designed or where it gets its air from?

I'm assuming that the Pettit/N-Tech units are similar as well as the M2/Rx7Fashion intakes. If there are significant differences between them let me know.

Here is how the tests were performed. The car was driven through two areas. The first area was a rural highway where the air temperature was 75 degrees F. The second area was a cool valley area where the air temperature was 68 degrees F. Data was taken in both areas at 60 mph. Additionally, upon finishing the road tests, the car was allowed to sit at idle until the temperature readings stabilized. This was done to see the effect of the airbox while sitting in traffic.

The car was brought up to operating temperature and then shut off for several minutes before leaving for measurements. This was done to allow everything in the engine compartment to heat soak so that it would be nice and warm and the effect of fresh incoming air could be seen. I used a thermistor placed about one inch away from the filter element for temperature readings. On the aftermarket intakes, the sensor was placed between the dual cone filters (above one and below the other).

I did my best to drive the car in a similar fashion in all three runs trying the same speeds/throttle usage at the same points on the roads.

Here is a table of my findings, with comments below:

Temperatures are in degrees F.

STOCK M2 PETTIT
IDLE 147.4 137.5 162.3
HIGHWAY 97.7 112.5 124.2
VALLEY 90.8 104.2 122.9

As you can see, the stock airbox performs best with regards to intake temperature with exception of idle temps. I believe the thick plastic of the stock box heat soaks pretty badly.

The Pettit intake's temperature did not drop much when going from the highway to valley area. This tells me that most of its air is being sucked from the engine bay. Also, any speed above 30 mph didn't cause significant changes in the temperature. It got really hot when the car wasn't moving.

The M2 intake's temp did drop when going from the highway to valley area, which would indicate that it is getting fresh air (though not as fresh as the stock box). I could also tell a difference in intake air temp based on speed. The faster I went, the cooler the intake air (dropped by about 5 degrees from 60mpg to 80mph, went back up 5 degrees from 80mph to 60mph). Also, the temperatures in the M2 box dropped/stabilized very quickly at idle and when the car was shut off. I didn't take readings of how long it took the temp to stabilize, but it seems to bleed off heat much better that either the stock or Pettit units.