How they were tested
| The filters were tested on the quality of the filtration, simulated by using a vacuum cleaner and millions of microscopic dirt particles. The particles that penetrated the air filter, were collected on a secondary paper filter, so that a fair comparison could be performed, and the results could be compared like for like. As well as the fine particle test, the performance gains were also measured using each of the induction kits in the test. Therefore, in the quest to find the ultimate induction kit, the filters must not only filter the particles out efficiently, but must maximize the amount of clean air flow, through the filter. The winner would be the induction kit that filters the most dirt particles, whilst achieving the maximum power output of the vehicle. |
|
Technical Comparison
Filter
Type
Filtration
Maintenance
BHP
Gains
Blitz
Sus
Dry Metallic Mesh Type Filter
Poor
Zero
Maintenance - Lifetime Use.
13.9
bhp
HKS
Mega Flow
Wet, Foam type filter.
Very Poor
Throw
away. Change Filter every 10,000 Miles. Replacement filters cost around
£25.
13
bhp
Apexi
Power Intake
Dry, Mesh type filter.
Excellent
Zero
Maintenance - Lifetime Use.
14
bhp
K
& N Filtercharger
Wet, Mesh type filter.
Good
Lifetime
Usage - Inspect every 30,000 Miles or 12 Months - Clean and re-oil, if
appropriate.
13
bhp
Conclusion
The comparison clearly shows that
the Apexi Power Intake filter wins the test, not only on filtration but also by
providing the maximum power gains, with K & N, Blitz and HKS coming in
second, third and last, respectively. From a filtration point of view, the
photographic evidence shows that various induction kits had poor filtration
properties, leaving high levels of dirt and carbon on the paper filters. Any
deposits that are allowed through the filters, can potentially cause problems
with the Air Flow Meters on the car, which are attached to the ends of the
induction pipes. It is a fairly common fault with the Skyline, to 'blow' an
A.F.M, and a large amount of carbon can be found coating the sensor in the A.F.M.
It is questionable how accurate the original source of data is, as HKS are
proven to sell more induction kits than any one of the others featured in the
test, and yet there induction kit rates as the worst kit in the test. This
suggests that either HKS rely upon their brand name to sell their 'poorly'
manufactured air filters, or that the original Japanese test was nothing more
than a PR stunt to promote the lesser known equipment. HKS and Blitz continue to
be the best selling induction kits in the UK, and are used by Middlehursts,
Hiteq and Abbey Motorsport as their first choice when the induction kit
modification is carried out.
One thing that does stand out is the fact that all the induction kits seem to
offer similar performance gains, of around 13 - 14 bhp. This would seem
consistant with actual power gains that have been confirmed by using a rolling
road.
So the question still stands, "Which Induction Kit is the best?".
Well, if you can trust the original source of data, then the clear winner is the
Apexi Power Intake. For those of you that are more skeptical, the choice is
probably more to do with the cosmetic looks of the induction kit, as the
performance gains are very much the same.
Important Notes regarding the comparison:
-
Extracts from
www.gtowners.com
website..
- Extracts of this article have been transcribed from a Japanese article
featured in Revspeed Magazine, August 1999.
- The original test was based upon the results found when using filters
specifically made to fit the Toyota Supra. However, the filtration is unlikely
to differ, as all the filtration materials used are the same for every model of
car.
- The cost given for the filters are based on a the kit for an R33 Skyline GTR,
except the K & N kit which only currently exists for a Skyline GTS, and are
inclusive of VAT.
