K&N Filtercharger vs. HKS Super Power Flow (B16A)
Zacka Gerald Chan drives an EK-generation Civic VTi-R in Australia. This is
the Australian version of the EK4 Civic SiR but uses the 160ps export version of
the B16A engine. One of the first thing Zacka did to fine-tune his car is to
change the air-filter. Being the simplest and often one of the cheapest to
modify, air-filter mods are perhaps the most popular and usually one of the
first to be done.
Zacka had initially wrote to TOVW's Front-Line some months ago to talk about
his experience using the K&N drop-in replacement filter in his Civic VTi-R.
Having been convinced of the importance of dyno-ing mods, Zacka recently wrote
in again telling me of his recent change from K&N drop-in to a HKS
Super-Power-Flow plus a Dynojet printout on the power gains from these
K&N's Filter-Charger and HKS' Super-Power-Flow
Described in some detail in our K&N article elsewhere on
the TOV, the K&N FilterCharger is a direct replacement of the stock Honda
air-filter. Installing the mod simply means throwing out the stock filter
element and dropping in the K&N in its place. The benefit of K&N as
detailed in the article is the filtering element being of special construction
gives better and more consistent air-flow thus contributing to power gains
though the gains are relatively modest.
The HKS Super-Power-Flow is an open element design and should more
accurately be described as a filter system. Described in detail in our HKS article elsewhere on the TOV, the SPF replaces the entire air-filter box, ie the plastic
assembly in which the stock filter element is located. Installing the HKS
SPF entails removing this box and putting the SPF assembly in its place.
The SPF assembly consists of a foam filter element in a open 'mushroom'
design. SPF comes as a complete kit with specific kits for each of Honda's
model and type. Besides the assembly, the kit also contains all parts
needed for installation and frequently a specially sized pipe to place the
filter in the place originally occupied by the stock filter.
One of the key importance of an open element filter such as the HKS
Super-Power-Flow is the removal of the resonator box. This removes a huge source
of air-intake restriction and will typically give good power gains. This means
an open element air-filter system can be expected to outperform any drop-in
aftermarket air-filters. The downside however is because the resonator box is no
longer part of the air-intake system, the resonator's noise reduction effects
are gone and the engine intake can become very loud. This occurs typically in
the rather unfortunate 4000rpm region. On DOHC VTEC'ed Hondas especially with
the 4.400 ratio final drives, 4000rpm normally equates to around 110 to 120kph
(70 - 75 mph) - smack in the middle of the expressway cruising speed ! The other
effect is the much amplified intake roar when going full-throttle though for
Honda engines and especially those equipped with VTEC, DOHC and SOHC
included, this can be a very pleasant roar indeed.
The Dynojet Results
Zacka supplied a very nice Dynojet chart that illustrates the relative
benefits of both the K&N FilterCharger and the HKS Super-Power-Flow. When
examining the dynoruns, the reader is reminded to bear in mind the benefits to
power gain, of removing the air-resonator box from the air-intake system (plus
the compromises it entails) when comparing the relative effectiveness of the
K&N FilterCharger against that of the HKS Super-Power-Flow. Also, the reader
is recommended to read below about the gains already obtained using the K&N FilterCharger alone in
Zacka's original communication to TOVW, where a gain of 0.4ps was recorded for
peak power while max gain was almost 4ps at 5500rpm with gains reported all
across the rpm range:
"With the paper filter, the best I got out of it was 98.4 kW @ 7600, and 127.7 Nm @ 7000.
A quick changeover to the K&N, and I got the best of 98.7 kW @ 7750, and 128.5 Nm @ 6750.
Doesn't look like much, but when you combine the 2 charts together to check the performance gain,
the difference becomes more apparent. With the K&N element, the power gains are consistent,
from about 2000 rpm to redline, with the most gain at about 5500 ( 2 to 3 kW , and about 5 Nm at
the same rpm). But by looking at the chart, the K&N has also smoothed out some spikes in the
curves, broadened and flattened the torque curve a bit too."
chart supplied by Zacka. The original chart has power units in kW (metric
system) but was converted to PS using a conversion of 1kW equal 1.36PS.
While TOVW do not publish any subjective evaluation of aftermarket mods'
effectiveness, we do want to direct attention to the consistent power gains of
the HKS Super-Power-Flow all across the dynoed rpm range. Power gains across a
wide power gain will not only benefit overall driveability (you gain
improvements no matter which rpm you drive in), it will also have a very
significant cumulative effect when performing full-throttle runs. Thus while
the actual power gain at peak power is already quite large (6.3 ps for the HKS
over the K&N), there is also a consistent 4-6ps gain from 3000rpm till the
8000rpm redline. So full throttle runs will see the HKS equipped car start
gaining right from 3000rpm, and this gain will be accumulating all the way until
8000rpm so the final gain will be quite significant indeed.
The reader is again reminded that the K&N FilterCharger is disadvantaged
by limitations imposed by the resonator box. In return, intake noise levels of
the K&N will be comparatively much lower than that from the HKS system, in
fact quite near the stock levels.TOVW gratefully
acknowledges Zacka Gerald Chan for his great dyno chart which is solely
responsible for the successful publication of this article. Any opinions that
may be implied here are solely TOVW's opinion.
Temple of VTEC World
Dynojet results supplied by TOVW reader
Zacka Gerald Chan.