8Gen Honda Accord 2.0 Dyno Check

The new 8th generation Accord for Asia comprises a 3-variant line-up made up of the base 2.0 VTi, the 2.4 VTi-L, and the 3.5 V6. These models are powered respectively by the 2.0l R20A, 2.4l K24A, and 3.5 J35A. Recognising the excitement and hunger for information that comes with a new model launch, I have decided to stop my customary arrangement of waiting for the cars to run in and have decided to try my best to review the cars as early as possible after their launch. Consequently, I am happy to report that I have just returned the base-variant, the Accord 2.0 VTi, to Honda Malaysia after a slightly extended review period lasting 5 days from May 16th to 20th. I plan to complete the reviews for this car over the next couple of weeks and this is the first report. As usual, my first report is about the results of its dyno-check.

An SOHC Accord Again

Reactions to this new Accord have so far been mixed, ranging from rave reception to complaints about its supposedly bland looks - and similarity to a particular Hyundai model ! However, there seems to be one reaction that have been very consistent as far as this Accord 2.0 VTi is concerned and that is the standard exclaimation made whenever an enthusiast checks out the engine bay - 'they put in a single-cam engine again !'.

As is well known by now, for the base variant Accord 2.0 VTi, Honda has replaced the K20A with the R20A. Coded R20A3, this engine displaces 1997c.c. and is an undersquare design with bore and stroke of 81.0mm x 96.9mm and SOHC in configuration fitted with a variation of i-VTEC that is designed for maximum fuel economy. This engine is of course a variant of the R20A that powers the base CR-V as well as the JDM-only 2.0l Stream. The engine is rated for a max power of 156ps (115kW) at 6,300rpm, with a max torque of 189Nm (19.3kgm) at 4,300rpm. Thus eventhough it is now one camshaft less, the R20A actually delivers 6ps more than the outgoing K20A (which was rated at 150ps max power). The new Accord 2.0 VTi weighs in at 1,475kg, just a bit heavier than the outgoing 7Gen 2.0l.

Prior to the outgoing (7Gen), the Honda Accord have always been using only 'single-cam' (SOHC) engines for its entire line-up. When the previous (7th Gen) Accord was launched, I made a big fuss out of the fact that Honda had at last fitted 'Twin-Cam-VTEC engines' to the Accord - both the base variant 2.0 VTi and the main variant the 2.4 VTi-S being fitted with the K-Series DOHC i-VTEC engine. Such was my enthusiasm proclaiming that the Accord finally gets 'proper engines' at last, that one reader wrote in to ask me whether the original SOHC engines are really that bad. They were actually quite good engines of course, just that I got carried away from finally seeing DOHC i-VTEC engines on the Accord after so many years. But now, Honda has reverted back to an SOHC engine for the base variant Accord 2.0 VTi again. What was Honda R&D's rationale for replacing the well received K20A with the R20A for this variant ?

Honda's response was simply to point out that the Accord 2.0 VTi is indeed the base variant in the line-up. They highlighted that the 2.4 VTi-S continues to use the K24A DOHC i-VTEC engine which has been very well received by enthusiasts. That is the variant which they made sure is suitably sporty and well equipped enough to satisfy enthusiasts demands (eventhough they admit the overall design is more towards a big luxury style). But for the base variant, a more well-rounded engine is more desirable. The R20A engine is more compact than the K20A and being undersquare in configuration offers stronger mid-range. It is also more economical in fuel consumption, thanks to the special i-VTEC mechanism for a unique economy hi-cam operation (read our RSeries technical feature for an explanation of this i-VTEC mechanism.) So for the target market segment that the base variant is designed for, Honda R&D believes the more rounded R20A engine is more suitable.

At the risk of being labelled a hypocrite, I have to say I do see Honda R&D's point of view. Of course not all enthusiasts will able to afford the Accord 2.4 VTi-S, given its significantly higher price. But the truth is the bulk of the buyers for the base Accord 2.0 VTi really are not bothered about whether it has a single-cam or a twin-cam engine. While Honda R&D do want to cater for the enthusiasts desires in this new Accord, the realities of doing business also do mean that they need to cater for the mass market as well because that's where the bulk of the sales are generated - they are running a business after all. So by using the base 2.0 VTi to cater for the mass market while the 2.4 VTi-S handles the job of catering for the enthusiast, Honda R&D feels they have suitably catered to both. Furthermore, even for the base 2.0 VTi, Honda R&D puts forward a pretty convincing case for the R20A when they say it actually has more power, is more economical and produces less emissions compared to the K20A on the 7Gen Accord 2.0 VTi. The gist is that the R20A out-performs the K20A. So in this sense, we must not put down the Accord 2.0 VTi just purely based on the fact that it has an SOHC engine but rather should judge it based on its abilities.

And finally, I must also point out that in the past the JDM Accord line-up has always had a mix of SOHC and DOHC engines. Take the CF-Acccord for e.g., what technically is the 6th generation for the JDM. There were three main variants, the CF3 1.8VTS and CF4 2.0VTS which uses 1.8l F18B and 2.0l F20B engines respectively both SOHC VTEC, and the CF4 SiR/SiR-T which uses the 2.0l F20B DOHC VTEC engine. This CF generation is of course the one just before the last 7Gen (CL in Japan, CM in Asia). So seen from this context, what Honda has done is really just reverting back to the mix of engines they have always been offering with the Accord line-up all the while (before the 7th gen).

Dyno Power Check Result

Enough of talk then. It's time for the new 8Gen Accord 2.0 VTi to deliver. The unit that I took for review had accumulate mileage of just over 2,600km. While this mileage is over the 1,000km run-in threshold, it is still a very low mileage and suggests that the engine will not be delivering its optimum power (usually after at least 5,000km). This is of course one of the pitfalls of going for early review - the cars are almost always low-mileage units and so it can sometimes affect the dyno power-check result. But we will have to work with this constraint.

On the Dynojet, the new 8Gen base variant Honda Accord 2.0 VTi delivered almost 122ps at the wheels. The power chart shows a very nice fat midrange with power output flattening (not even dropping, just flattening) in the high-rpms after 6,000rpm. This is actually quite a good showing from an SOHC engine. From the stock specification of 156ps, 122ps works out to 78% which indicates a 22% power loss from ancilliaries like alternator and also power loss from the new automatic gearbox. The torque curve is particularly nice. It is completely flat from just after 4,000 rpm all the way to 6,000rpm, a crucial rpm range for an automatic car. This will give the Accord 2.0 VTi a good preppy midrange pull during acceleration runs like during overtaking. Like all modern Hondas, the R20A runs a bit rich in stock settings, hovering around the 12:5 AF ratio though leaning out in the high-rpms.

So on the dyno, the Accord 2.0 VTI's R20A3 delivers quite well indeed, with the benefit of the dual runner intake manifold quite obvious from the very good midrange.

Accord 2.0 - New versus Old

So, R20A3 delivers pretty well on the dyno. But now its time for the acid test. Just how well does the R20A stack up against the old K20A from the 7Gen Accord 2.0 VTi on the dyno ?

According to Honda's data, the R20A outperforms the old K20A in all three crucial areas of power, economy and emissions. In terms of max-power rating, the R20A delivers 156ps versus only 150ps from the old K20A - that 6ps is nothing to sneeze at. In terms of max-torque, the R20A delivers 19.3kgm or 0.3kgm more than the old K20A (which is rated at 19.0kgm). Again this 0.3kgm is quite significant. Added to this, Honda says the R20A has 7% better fuel economy while also meeting the stringent EURO-4 emissions regulations from Europe.

The power+torque comparison chart on the right is extracted from photos of the technical presentation given by the Honda R&D engineers during the media launch event. This chart is a direct comparison of the power and torque delivery curves for the R20A and the K20A. It shows that the power delivery of the R20A is quite significantly better than the old K20A as it delivers more power/torque across the whole rpm range. The midrange of the R20A is especially superior to the K20A, thanks to the dual-runner intake manifold. Then overturning the traditional relationship between an SOHC and a DOHC engine, the R20A also delivers significantly more power than the old K20A in the top-end, from just after 5,000rpm till the redline (which remains the same at 6,800rpm).

Can the R20A deliver this on the dyno as well, where it matters ? To answer this question, of course we need to compare the dyno chart for the old 7Gen Accord 2.0 VTi with the new one. Now, I have never properly reviewed the 7Gen Accord 2.0 VTi. Unfortunately the sole unit that Honda Malaysia allocated for review was crashed before I could arrange to borrow it. As a result, my only experience with that car was a couple of brief test-drives at Honda dealers. And of course it also means I have never dyno'ed it as well.

So in my best effort to compare the dyno power of both cars, I sourced for dyno charts for the 7Gen Accord 2.0 from owners who have dyno'ed their personal units. Now, while I conduct dyno power-checks on completely stock Hondas as part of my reviews here on TOVA, few owners will actually dyno their car when it's completely stock (though there's actually a lot of sense to dyno your completely stock Honda, to confirm that the engine is delivering its specifications for e.g.) So the dyno-charts I got (there were two of them) were not for completely stock cars. Nevertheless, both of them only had mild modifications and both dyno results turned out to be very similar as well. So I chose one of them for the comparison here. While I am not sure exactly what other modifications this 7Gen Accord 2.0 VTi has, I can confirm that it has at least a Greddy e-Manage (ECU) piggy-back as the dyno-chart was from tuning the e-Manage on the dyno(jet). So in a sense, the new 8Gen Accord 2.0 VTi is quite a bit disadvantaged in this comparison as the whole car is truly completely stock. Which makes the actual comparison results below all the more impressive/shocking.

On a Dynojet chassis dynamometer, the new 8Gen Accord significantly outperforms the old 7Gen Accord 2.0 VTi ! Honda's own comparison really does not do the R20A justice though in their defence, their comparison chart (above) was for power at the flywheel whereas here we are looking at power at the wheels, which includes the influence of the newer and presumeably more efficient gearbox the new 8Gen Accord 2.0 VTi is equipped with.

Still, personally I was quite shocked at how much more power the R20A delivers over the old K20A. More importantly, it could deliver this extra power more or less consistently across the entire (dyno'ed) rpm range. The profile (i.e. shape) of the power and torque curves of both engines are very similar actually. In addition, the R20A actually sustains power into the high rpms better than the 'twin-cam' K20A ! When we take into consideration the fact that the R20A is still quite raw with only 2,600km accumulated mileage while the K20A has modifications, the results are actually quite impressive indeed.

Counterpoint - Accord R20A versus FD-Civic K20Z

In a way, one can argue that the K20A on the 7Gen Accord 2.0 VTi is a 6-years old design. It was developed for the 2.0 VTi back in 2002 when the 7Gen Accord was launch here in Asia and it remained exactly the same during the mid-life MMC back in 2006 (though the K24A had some updates). So we can say that the R20A vs K20A comparison above was a brand new design versus a 6-years old one. So, a valid question to ask would be how the R20A3 compares to a more modern K20 engine ? To answer this question, we first need to find a proper 'up-to-date' K20 engine to compare with. The closest I can come up with for this comparison is the K20Z engine from the FD2 Civic 2.0S. This engine is of course tuned for the Civic which is quite a different car from the Accord, especially in terms of bodyweight, but it remains the closest match we have. The K20Z of the FD2 Civic 2.0S is spec'ed for almost the same power - 155ps vs 156ps - as the R20A. Plus being the most current implementation of the K20 DOHC i-VTEC engine, it comes complete with balancer-shafts and variable intake manifold like the R20A and also a DBW system, like the R20A.

The K20Z has the advantage of i-VTEC and a variable intake manifold to maximize power and torque across the rpm range. i-VTEC on the R20A on the other hand has been re-deployed to maximize fuel economy instead and Honda depends solely on the variable intake manifold to optimize power and torque for this engine. However, the R20A is an undersquare configuration, which delivers superior low and mid-range power/torque compared to the square configuration of the K20Z which is more suited for high revving, eventhough Honda did not exploit this on the K20Z as it has the same redline (6800rpm) as the R20A.

For an example of the dyno result from the K20Z of the FD2 Civic 2.0S, I use the dyno power check result I did for the Honda Malaysia media review unit back in 2006. That engine was well run-in though, with over 13,000km on the odometer when I put it on the dyno. But the main rationale for choosing it is so that we are comparing engines which had similar usage, both being media test units.

The comparison is intriguing. Despite the rated specifications on-paper, it is the K20Z which delivers a higher max-power than the R20A. However, we must bear in mind the very low accumulated mileage of the R20A - 2,600km. So there is every possibility the R20A power will increase as more mileage is put into the engine. Unfortunately at this point, we won't be able to confirm if the R20A will deliver more power after say 10,000km has been put in. Nevertheless, there are other surprises from the comparison. The R20A delivers a much fatter midrange than the K20Z, not surprising as it is expected from its undersquare configuration. Rather more surprising is that the K20Z actually delivers more low-end power than the R20A. So in this case, the benefit of VTC from i-VTEC is actually very clear.

In the end, I think the R20A fared pretty well even against the K20Z. This really shows that one mustn't judge something from the covers only. The R20A might have 1 camshaft less and no performance benefit from its i-VTEC mechanism, but it certainly does a very good job even in outright power.

Conclusion

The issue of 'Single-cam' versus 'Twin-cam' aside, the new 8Gen Accord 2.0 VTi actually delivers the goods on the dyno, argueably the place where it matters more. Delivering quite a bit more power to the driving wheels will directly mean that the car is faster on the road, especially given the relatively modest increase in bodyweight over the 7Gen. This can be a significant point because the old 7Gen Accord 2.0 VTi has often received complaints of being lacking in power (and 'go'), even from casual (non-enthusiast) buyers.

So where it matters, the new R20A3 engine really do deliver more than the 'old' K20A engine eventhough it works with a camshaft less and has the economy version of i-VTEC. It is more powerful on paper and on the dyno plus it offers better fuel economy and lower emissions to boot. Put it another, more blunt way. Even if Honda had retained the K20A engine for this variant, and have suitably updated it, it still would not have delivered more power than this R20A. Plus it will definitely deliver worst fuel economy as well. Having explained Honda's rationale in equiping what is basically the base variant of the Accord with the R20A, and given that the R20A is one of Honda's current 'state-of-the-art' SOHC engine designs, the most appropriate conclusion from here must surely be that for those who are considering the new Accord 2.0 VTi, the R20A being an SOHC engine should not be of any concern. It has proven that it can deliver.

The next thing to do would of course be to test the Accord 2.0 VTI's actual performance on the road. And this is the topic of the next review on this car.