Project: Modifying the 1590cc SOHC PGM-Fi
For a number of years, the 1590cc SOHC PGM-Fi engine has been powering the
top Civic models in Malaysia. This engine produces 120ps at 6400rpm and was the
powerplant for the 1.6EXi Civic models (4-door sedan and 3-door hatchback) in
the 1992-1995 generation EG-bodied Civics. In the current EK-bodied Civics, this
engine still powers a Civic EXi model even though the top of the range Civic VTi
now uses a power oriented SOHC VTEC version of this engine. In many other
countries in Asia, especially ASEAN countries, this engine still remains in use.
So the 1.6l SOHC PGM-Fi engine has became very common in ASEAN Hondas and
consequently souping up the engine would be of considerable interest.
Recently Aerotech, HKS representative for Malaysia, asked me an interesting
question: what would be a typical Civic 1.6 owner's budget for an initial
modification package ? My reply was to work with a budget of around M$2k
or less, and that the package will need to be cost-effective, giving good power
gains for the money and preferably of a reputable brand (HKS would be
perfect of course !) Having a Dynojet in the shop-floor, I also ask for the
power gains to be quantified.
Given this M$2k limit, Aerotech then proposed a package comprising HKS AFR
paired with either HKS Super-Filter (a stock drop-in replacement) or a HKS Super
Power Flow. They also propose cleaning the fuel injectors because stock
new injectors contain wax which will interfere with their operations.
Either the AFR and Super-Filter or the AFR and Super-Power-Flow combination will
still allow enough in the budget for cleaning the injectors.
Aerotech used a Honda Civic EXi that they own as a test-bed to
demonstrate how they would answer my requirements. This is a 1998 Civic
EXi which uses the 1.6l SOHC PGM-Fi (non-VTEC) engine and was bought new
with an automatic transmission for some special project. Being new, the
car was first properly run-in by putting in 1000km, after which the 1st
service was performed. Dyno sessions were also done to establish the base
power as the reference for comparisons.
Mods and Power Gains
Stock Honda transmissions typically causes a 15% power loss for manual and
30% power loss for automatic. As a result, with a base of 120ps, a stock
automatic Civic EXi would be expected to deliver 70% of 120ps or 84ps at the
The actual max power at the wheels for Aerotech's stock and brand new Civic
EXi before the 1st service was in fact 84.1ps ! After the service, the
max power increased to 85.2ps, the power curve showing small improvements in the
high-rpms. This clearly shows the importance of maintaining a regular service
interval ! A HKS super-filter, a direct replacement for the stock filter was
then put in and subsequently the car dynoed at 86.0ps, about 1ps increase in
max power but also with some good gains in the mid rpm range, delivering almost
consistently around 2ps more in the 4000rpm to 5000rpm band.
Starting with this stock engine plus a HKS Super-Filter as base, a HKS AFR
was next added in. The AFR mod requires a dyno-tuning session in order to
determine the setting which will deliver the highest power gain. Because of
this, Aerotech offers an AFR package which includes the AFR device, labor
and a tuning session and which still fits into the M$2k budget. On
Aerotech's Civic EXi, the addition of a properly set AFR enabled it to dyno at
88.6ps at the wheels. Although this represents a gain of 2.6ps of max power, the
result does not really show the true benefit of the AFR as actual power gains
from 5000rpm onwards can peak as high as 4ps in the higher RPMs.
Next, the fuel injectors were examined and then cleaned using a special
injector cleaning machine. The cleaning was done by immersing the injectors into
a liquid ultrasound bath. The result of cleaning the injectors allows them to
flow better and more consistently allowing the Civic to deliver 89.4ps at the
wheels. The Super-Filter and AFR combination together with cleaning the fuel
injectors clearly shows power gains over the stock power curve (both before and
after service) all across the dynoed rpm range, almost consistently 4ps or more
from 5000rpm till the redline of 6800rpm with maximum power gaining more than
The best package proposed by Aerotech however involves the use of an
open-element HKS Super-Power-Flow filter instead of retaining the stock air-box
with a Super-Filter. Substituting the Super-Power-Flow into the Civic allowed
the Civic EXi to finally dyno at 93.2ps. This is a 9ps gain over the base
reference or 8ps over the base Civic after the 1st service ! For M$2k, Aerotech
feels this package of HKS Super-Power-Flow, HKS AFR, and fuel injector cleaning
will offer the best power gains for the price, with dyno results showing a gain
in power at the wheels from 84-85ps to 93ps or a 10% increase ! At the engine,
this will work backwards to a high 133ps at the engine, up 13ps from the 120ps
Aerotech feels this package will also work very well with the 1.6l SOHC VTEC
engine of the Malaysian Civic VTi, also a very common and popular engine in
ASEAN markets. Being tuned for better high-end power, the gains using this
package with the VTEC engine has the potential to be even higher.
However, Rennie Khoo was also quick to also bring to my attention that actual
results will vary according to individual cars. A lot of factors will influence
the final power gains from the package and these will include general state of
health of the engine as well as age and mileage. Obviously a 10 year old engine
or one that has done 150,000 kms will not be likely to see this kind of power
gains. Nor would a relatively new engine that has undergone heavy usage but
without getting proper care. Even for a brand new engine, tolerances in the
manufacturing process will still introduce variables that might influence the
power gains either way. It is always important to keep this in mind when
attempting to modify our engines to get more power.
Civic or Honda owners using the 1590cc SOHC PGM-Fi engine (the JDM DA and DC
series Integra ZXi also uses the same engine) who are interested in this package
can contact Aerotech at 60-3-7556112. If you have taken this package, be sure to
write in to TOVW to tell us your experience !
Copyright 2002, Temple of VTEC