To evaluate the true power potential of the K20A engine on this 2.0l Civic, I sent it for a dyno-check on a reference level Dynojet chassis dynamometer. This dyno-check was made possible by TOVA's main sponsor Afterburn whose manufacturer Aerotech also operates Dyuojet Far East for the marketing and servicing of Dynojets in this region. The dyno-check was part of a 'payment-in-kind' package for their advertisement here on TOVA.
The Dynojet measures power at the wheels which is the resultant power after losses incurred from engine ancillaries (like the air-cond compressor) and the gearbox. In this case, there are 3 main factors to note when looking at the result of the dyno-check. Firstly would be the rated max power of the K20A engine. This is spec'ed at 155ps as we already know. In terms of parastic power losses due to engine ancillaries, the EPS used on the 2.0l Civic is an advantage here because it does not require a hydraulic power steering pump to be driven by the engine. So instead of the usual 3, there are now only 2 devices attached to the engine - the alternator and the air-cond compressor. Then finally the 2.0l Civic only comes with a 5-speed GLC automatic gearbox which loses quite a bit of power when compared to the standard 5-speed manual gearbox or even the CVT as used on the Jazz and City.
First hand experience with non GLC equipped 4ATs used on older Hondas ranging from SOHC to full blown DOHC VTEC models have shown a good correlation for a general figure of around 30% power loss. I.e. dyno'ed power at the wheels on a Dynojet quite consistently comes out at 70% of that of the rated engine power for stock and almost stock examples. For more recent Honda models, those with auto gearboxes equipped with Grades Logic Control (GLC), the dyno-charts I have seen suggests a generally lower power loss. The new generation of Honda autoboxes seems to be more efficient and the figure is now generally around 25% or so. These figures however are for cars that are equipped with the usual ancillaries; alternator, power steering pump, and air-cond compressor. As noted, the 2.0l Civic uses an EPS and so has 1 less ancillary for the engine to power. Though I have not seen actual dyno-charts, I have been told by reliable enthusiasts that removal of the PS belt generally delivers around 2 to 3% higher power on the dyno. So I would think that this 'gain' will apply for the 2.0l Civic as well.
Finally there is the issue of the running-in of the engine. From extensive experience with a wide variety of Honda engines in the past, it seems that Honda engines needs a unusually large amount of time/mileage to run-in properly. The generally accepted run-in mileage for a new engine is 1,000km and indeed this figure was even quoted to me by a Honda R&D engineer. However, running-in is one thing but running-in till the engine delivers its rated power or better seems to require a much longer mileage for the case of Honda engines. My personal experience is that at least 5,000km of mileage is required before a Honda engine starts to deliver its spec'ed power rating and indeed many Honda engines seems to deliver their best only after 10,000km. In this sense, for a car magazine or web-site, there is a huge conflict between fighting to be 'first on the block' to get a full review of a new car out to the responsibility of the reviewer to ensure that any car reviewed must be given the best chances to show it's full potential. Fortunately for TOVA, the lack of advertiser considerations so far means that I can take my time and wait until the media cars rake up the proper amount of mileage before requesting for a loan. This however was not the case with this K20A Civic as I was eager to get an early review done due to its importance to us enthusiasts. Consequently, the test-car's mileage was barely over 2,700km when I took it for testing and when reading this review, readers would do well to bear this in mind constantly, i.e. whatever the results, chances are they will improve further once the car builds up more mileage.
Nevertheless, regardless of the mileage consideration, as far as expectations are concerned I was looking forward to the K20A Civic coming out with around 70+%, near 80% of the rated engine power on the Dynojet.The dyno-chart for the K20A Civic is published on the left. The most important figure would be the max-power and this comes out to around 120ps at the wheels or around 77.5% of the rated engine power. Amazingly this tallies very well to what was worked out above despite the car's relatively low mileage !
Taking a closer look at the dyno-chart, a most satisfying feature of the power curve is that it brings back the very familiar shape that is typical of the great DOHC-VTEC engines of old, especially the legendary 'B-series' engines. There is a very clear 'power hump' that starts at around 4800rpm, the 'VTEC changeover' point. This should give a clear 'VTEC rush' when VTEC activates the high cam profiles and is something Honda enthusiasts have grown to love and expect from Honda's performance models. Another much loved characteristic is the power curve hardly drops after peaking at the max-power point. The power curve clearly shows that the K20A engine will pull all the way to its redline and beyond, with a nice 'VTEC kick' after 4800rpm when the wild (intake) cams kicks in.
The welcome 'return back to basics' also applies to the engine note as well and the K20A screams nicely at WOT once VTEC opens the wild cams after 4800rpm. So what Kinoshita-san, the Honda R&D engineer told me about how this K20A engine regains the famous 'VTEC Roar' of the much-loved B-series engine is true after all. Of course nothing beats actually hearing the engine note itself and as usual, a video clip, now in WMV (Windows Media Video) format can be downloaded by clicking on the photo of the Civic on the right. So crank the volume of your multimedia speaker all the way up to listen to how the 2.0l Civic sounds when doing a WOT run on the Dynojet !
In terms of consistency, the K20A engine falls back a little. After the initial run shown here which delivered 120ps atw, the following 2 runs delivered around 119ps atw - dropping 1ps. And when we continued the dyno-runs after that, power started to drop even more. The 4th run delivered 118ps atw and subsequent runs after that sees further drop in the power curve. In this sense, the K20A engine does not seem to have the 'stamina' to generate consistently high power during prolonged runs. The logical conclusion would be that the engine overheats mildly when doing multiple consecutive runs and to test this out, we let the engine cool down for around 10 minutes and repeat the dyno-run again. We did this twice, doing more than 20 dyno-runs in total. Almost exactly the same results were repeated, the first run generating 120ps atw with the 2nd and 3rd runs at around 119ps atw and then subsequent runs seeing steady power drops. Recall that in the previous section I noted the Honda engineers did not upgrade the Civic's cooling system and that it is basically the same system for both the 1.7l and 2.0l variant. So it would seem quite clear here that the engine overheats mildly over prolonged WOT runs and this affects the max power output. As correlation, during the dyno-runs the radiator fan keeps cutting in very frequently and runs for long periods of time. So in this aspect, one of the first mods the enthusiast should consider for the 2.0l Civic would be to upgrade the radiator to a more efficient one or better still to consider the addition of a good quality oil cooler.
The other important observation from the dyno-check would be the general air-fuel ratio the K20A runs at. The AF chart is plotted below the power chart and it shows that the K20A runs mildly rich at WOT, with an AF of generally around 12 : 1. I think this is a result of the Honda engineers intentionally tuning the K20A to cater for general conditions around ASEAN, and especially for low grade fuel (down to RON91). From experience, Honda's DOHC VTEC and by inference the K20A DOHC i-VTEC engines generates most power with an AF nearer 13 : 1. So for Malaysia, where fairly high grade RON97 petrol is available all across the country, there is clearly more power to be squeezed from the K20A engine by tuning the AF ratio.
In absolute terms, 120ps atw is a very good figure for an auto
gearboxed engine rated at 155ps. In comparisons with past Honda DOHC VTEC models, the
EG9/EK4 B16A SiR autos which are rated at the same max power typically dyno's at
110-113ps atw. Indeed, even the DC2/DB8 B18C DOHC VTEC Integra SiR autos, which are rated
at a much higher 170ps still delivered around 119ps or so atw on a Dynojet. In terms of
comparison with non-Hondas, the very popular Proton Putra coupes and Satria GTi
hot-hatches uses a 1.8l DOHC EFi engine rated at 140ps. Running with 5speed manual gearboxes
even they too typically dyno's at ~115ps atw. So in comparison, it can be seen that
the 2.0l Civic's dyno'ed power compares very well with competing performance models !
Since the dyno-runs are sponsored by Afterburn, I also requested a second set of dyno-runs for the 2.0l Civic with the proper amount of Afterburn added to the fuel tank. This is around 10% mixture ratio or 450ml of Afterburn to a full tank (45litres). While Afterburn works on both stock standard and modified cars, the one thing I have seen consistently is that it tends to deliver best results on engines that generally have 'high tuning potential'. In this sense, an engine that responds well to Afterburn will generally respond well to modifications as well. So this 2nd dyno-check will not only check the effectiveness of using Afterburn on the K20A Civic, it should also give us a good indicator to how 'tune-able' the K20A itself is.
The chart for this 2nd run is published on the left and the result is actually quite astonishing. With just a simple fuel additive added, the 2.0l Civic now generates almost 125ps atw, 5ps or 4% more power ! More impressive was how the extra power was generated all across the rpm range, and that the general profile of the power curve was preserved. Effectively, the entire power curve was moved up a few horses ! So Afterburn was very effective on the K20A engine and personally I think it also indicates the high tuning potential of the K20A as well. In terms of driving feel, addition of Afterburn really improved the throttle response of the engine, especially for partial throttle. There was a urge from the engine to surge forward even with light stabs at the throttle.