Two questions:
Can someone explain to me how and why the intake air flow is set up how it is on the GE Fits? As far as I can tell, air is routed through an under-hood scoop, dumped against a flat piece of "blocker" plastic that has no visible function, then optimistically sucked in by the hole in the actual intake box that's placed behind the flat "blocker" box.

This has been a consistent puzzle to me.

Second, is anyone familiar enough with airflow theory to educate me what will improve low-end torque (at the expense, I'm certain, of high-rpm power?)

The recipe for high-end power goes something like this: shorten the intake path, feed it cooler air, and widen the throttle body (impossible on the GE afaik). And that recipe is usually at the expense of low-end power to a small extent. So ... do you reverse that? Somehow I can't imagine that restricting air flow is good for any aspect of operation, but ... I would find a little more grunt at the low end to be welcome day to day, and would be willing to experiment with a (small!) sacrifice in power in the upper ranges.

 

I'm guessing it took a lot of time for engineers to come up with the intake design for GE8. Pretty much any CAI on the market will loose low end power on the Fit and gain 1-3HP up top. These chambers you see in the intake create "pressure"

You can widen throttle body on the GE8. I have one from Spoon, expensive as hell but worth it when I use it with Ktuner. Even Spoon uses Venturi effect on their TB to increase the air volume and efficiency to the engine. I kept my intake stock, just dropped high flow filter and the low end response and power is impressive.

 

Wow ... $1000! Your description of the cost is accurate.

Soooo ... if I restrict airflow, will I gain low-end torque?

Since no one knows. Only one way to find out. :P

 

You won't gain low end torque by simply restricting airflow. Thats not how it works.

 

RESULTS ARE IN and ommegga is absolutely right. Restricting airflow just makes the car entirely rubbish as in slow .. which is what one's intuition would tell you. So yeah. Experiment over and I still have no idea how to make the car a bit torquier in the 1000-2500 rpm range where I mostly use it.

Having determined a lower-flow filter makes the car rubbish, I've ordered a AEM Dryflow filter. It's hard to find good test data but what I could find suggested this lets through no more particulates than the stock filter, while maintaining a faster flow rate. I had pulled out my filter today and was starting to get a bit dirty (1 year old single use filter), so it was about time and the AEM will last long enough to be price competitive over time.

 

Unless you spend some serious cash, any torque/hp gain won't be noticable. Your best bang for the buck is Ktuner + eTune which will set you $750. That will gain you probably around 10whp on a stock motor. Low end all the way to redline will be improved.

Install colder range spark plugs. I have them and according to some test, they will net you solid couple of hp. Don't know if its true but it won't hurt to try.