I went out tonight and G-teched my open 12" conical filter w/90 mm sensor vs. the stock 01 airbox w/panel K&N. Here are the results. First #'s are 0-60 and second #'s are 1/4 miles ET

Open 12" filter
5.05 13.52
5.15 13.53
5.15 13.54
5.17 13.55

Stock 01 airbox
4.93 13.39
4.97 13.42
5.03 13.47
4.91 13.39 (personal best)


I am now a believer that its QUALITY, not quantity of air!

 

My track results indicate the exact opposite:

2 weeks ago at FFW:

Stock air box best: 12.73 @ 105.00

JDM Open Filter 12.61 @107.46

I'll stick with lots of hot under hood air

 

I think I can explain the results, Both people can be correct in there observations.

In testing (with an OBD-2 tap) I found that the temp within the engine compartment would start rising about 4 min after startup and peak about 10 min after startup or in traffic. This makes sence if you take into account how long it takes for the cooling system to open the thermostat. In drag racing with all the stoping, sitting, pushing... I bet that the engine compartment air is still real close to outside temp. When testing with a G-Tech you have to drive somewhere to test. By that time, the engine compartment is running about 140 deg and your hp drops like a rock.

You guys may not know that in pro drag racing with snowmobile drag sleds the motors are set up to launch at 30 deg water tempreture. In the summer events they use self-contained air conditioners to lower the water temp to below outside temp to keep the block from warming up the air in the next 9 sec. When I race my car we launch with about 90 deg water temp and the temp goes up about 1 deg per sec during the run.

Hope this helps

 

This is a direct apples-to-apples comparison. Same outside temp, same road, etc. The distance to the road from my home is the same so the engine was at normal operating temp both times.

 

awhittle,

Thanks for clearing this up, your explanation makes sense to me

On most of my runs at the track I usually have at least 45 min to cool it between runs, where on the street you unfortunately don't have that luxury.

 

Totaled

What was the surface like Concrete/Asphalt... and what was the air temp?

AW

 

I will be putting in my JDM widemouth filter this weekend. I too have a G-Tech but I don't have a K&N panel filter. It will be hot this weekend here in Dallas. I'll run some G-Tech tests of the stock airbox and filter against the JDM at normal engine operating temps and post the results on Monday if anyone is interested.

 

awhittle: not to dispute your theory, but MRBBQMAN posted a link to an old thread of his a few days ago where he actually measured the underhood temps on his L in various conditions and found that when moving the underhood temp was VERY close to outside temps (less than 5 degrees I believe). Even when stopped for a relatively short time, the underhood temps didn't rise all that much. Personally, I like my open filter (and would probably be willing to sacrifice the ~1 tenth of a second difference just to hear that supercharger whine). later...

 

AW,

The surface was asphalt and the air temp was mid 90's.

 

Red2k

Interesting, where did you get the 01 stock air box? Dealer? How much?

Thanks

 

Hilander,

Yeah a friend of mine at the dealer ordered it for me at cost. Got the box, filter and sensor for $185.

 

red2k#1554, thanks for providing your results.

Here's my theory: Was your launching result the same in your comparison? Is it possible that with the open 12” filter you were making more power off the line and it actually hurt your times? The launch pad at a dragstrip typically provides better traction than the street, therefore the additional power resulting from the Open filter can be utilized. Did you also record the MPH’s for each run? Since MPH is a more direct relation to HP, how do these numbers compare?

Looking forward to your response.

 

I launched as closely as possible to the same as I could. About 75% throttle, then hammered it. Got a little chirp each. Helps to have 3 day old F1's on the back. As for MPH, the G-techs run high (5-6 mph). Running 107.5 with the cone and 108.2 with the stock box.

 

Hmmmm.

I do appreciate the MPH is not accurate, but at least they would be consistent. Is your cone filter the kind with the inverted cone end cap (sometimes called a PowerStack or an AutoPhysics http://www.autophysics.com )? AutoPhysics claims their end cap results in a smoother flow path.

Which test did you run first? Did you make passes both directions on the same stretch to cancel road and wind variations? I know you said the temps were the same. How much time passed between configurations?

BTW, I’m not trying to hassle you as I think this is a great technical discussion. The differences are slight. I’m just trying to understand the test variables.

Joel......

 

Jim just do your test at the track tonight. Jeff