Well, we finally had some time today to do some pannel filter testing. We started by doing a new baseline on the 2nd factory reflash and the ultimate racing turbo back with mini muffler. Of interest this time is that we hit missfire and breakup in all configurations tested.

Worsk case of missfire was on the factory filter with the 2nd factory reflash. In this case it started missing early, around 5500 rpm. Testing process was as follows:

- Install filter
- let the car idle long enough for fuel trims to become stable
- run the car
- lather rinse and repeat

In each case the runs were started with a coolant temp of 81 - 82 degrees C. Also, all runs were done on the second factory reflash with no tuning. Lets have a look at the results:





I know this is tough to see so I did another series of plots with just the works filter Vs the factory filter:




As you can see the works does indeed beat out the HKS. I'm not real confident in the baseline due to the horrible missing which caused the power to drop out real early. We did not have this problem before installing the turboback with the minimuffler. I'm not sure what to make of it at this point in time, but I have talked with another exhaust vendor who is running into the same issue while testing their exhaust.

Conclusion:
The works does indeed make some power by leaning out the AFR. I'm not sure it's worth $130 or whatever they charge. We did not have a K&N on hand to test, but based on what I have seen in the past, the K&N will have a little less filter element area due to excessive rubber material intrusion into the filter element area. The hks is not washable and reusable, but it can be had for about 1/3 of the price of the works.... if you plan on going to an aftermarket intake in the near future, go ahead and save a few buck and get the HKS. IF you want to stick with the factory airbox for a while.... Works or K&N.

Given the missfire we hit with the turboback and 2nd factory reflash I don't think these results would hold true for a stock exhaust car. I have a feeling the margin of victory for both the Works and the HKS would be much smaller.

I will try to get around to testing the K&N vs the HKS on a customers car in the near future, only if the customer is willing of course and they have a K&N

 

Thanks for the update dyno4mance. I am lucky that my X is not missfireing at all. Looks like the HKS is close to WORKS for the $ In the future I am planing on getting the ARC airbox, so it looks like HKS for me.

 

so how much exactly the Works gain over the HKS?

 

The reason for posting the graphs is so you guys can interpret the results for your self. Peak numbers don't carry much weight with me, I prefer to look at area under the curve. Of course that doesn't help much if for some reason you can't see the graphs

In the case of the plots above, each horizontal line is 12whp. That being the case I would say the works make 5-10 more than the hks through most of the power band.

 

I've never been a fan of the HKS for it's filtering abilities, now there's another reason not to use it.

 

how about the ralliart filter?

 

I am curious about the Ralliart air filter as well.

 

I'm not seeing the misfiring issues that you mentioned. All of the curves look pretty clean, with no dips from misfire or knock. Is there something that I'm not seeing?

 

On the stock map and filter, (the green hp curve), at 5900 rpm's the power starts to fall off. It should be climbing until 6500, the stock peak. The peak power should be at 6500, not 5500. Modding the car changes peak power characteristics so that figure is only good for the stock tune and filter.

 

Is the Works filter cleanable? I just ordered the HKS filter so I'll just use that for 10k then switch over to the Works.

 

While I can appreciate your interest, someone else will have to test the other filters (ralliart, green filters, k&n, etc).

Reason being is that although I have picked up about 80whp over my stock baseline, this X is still 40 whp below where my VIII was and a couple hundred pounds heavier.
I have an upgraded turbo and larger injectors on the way next week so this was the final round factory reflash testing. If I have time I will test the Nisei pipes on the factory flash before swapping out the injectors and turbo.

I certainly don't mind throwing in a couple baseline pulls with various filters and posting the results when someone comes in for a tune though.

 

Yup.

 

Exactly


I should note though that all three configuration still resulted in high rpm (>5500) breakup. The works was the least noticable becasue it resulted in the leanest AFR of the three.

After the works run I added my Nisei hotpipe, touched up my pump gas tune, and bested my previuos pump gas numbers. 300ft/lb 300whp compaired with 300ft/lb 290whp. No breakup, just clean smooth power despite the near 100degree temp in the shop.

 

Just curious,
What order did you run the test in?
Stock, then HKS then WORKS?

-Bill@WORKS

 

Bill, on your drop in air filter, does it require any fuel mixture adjustment? In other words, does the fuel to air mixture stay the same as if the stock air filter were used?