Alas, what could have been. Day 3 dawned hazy but dry in Atlanta and our spirits were up because this was the day we were to hit the drag strip. While I personally prefer road racing, we weren't able to take the Accord V6 6MT coupe and TSX to a real racetrack. And while the Tail of the Dragon is huge fun, we can't push the cars to the limit safely there. The dragstrip, on the other hand, allows us to perfect our launches and find the limits of acceleration for the test cars in the relative safety of a dedicated facility.
But before we went to the strip, we hit the dyno to get the objective numbers on engine output. Our dyno facility of choice in Atlanta (and the south in general) is Dynolab in Marietta, Georgia (http://www.dynolab.net). We arrived in late morning and were graciously greeted by Arthur, the owner of the shop. As a fellow dyno owner, I'll tell you right now, Arthur is a great guy to work with and was efficient and helpful in response to all our unusual requests.
The TSX was up first and it laid down a pretty solid pass of 169.9 hp and backed it up within 1 horsepower on a subsequent run. Torque was 152.2 lbs-ft. Once again, Honda underrates a K-series, although in this case not nearly as bad as they did with the K24 Accords. We estimate the real flywheel output of this engine to be somewhere in the vicinity of 210 hp and 175-180 lbs-ft. Check out how flat the torque curve is as well despite using a single runner intake manifold. i-VTEC scores again. Also note how high the VTEC transition is at 6000 rpm. That's the same rpm the K20A2 in the RSX-S switches. And we already know that the RSX responds even better to a 5200 rpm VTEC point. Could there be another big swell of torque in the midrange with some Hondata hacking? Don't bet against it.
The Accord went second and performed like we thought it would after hammering the throttle for a couple of days. No shy, retiring commuter engine, the J30A4 is a beast. It belted out 217 hp and 195 lbs-ft of torque at the wheels. And this engine is only rated at 240 hp/212 lbs-ft at the flywheel! Of course, we did use premium gas to extract the most possible power and the J30A4 rewarded us with a surplus. By comparison, last year's CL-S 6-spd pumped out 218 hp and 201 lbs-ft (also on a Dynojet) from its J32A2 engine. We felt that the J32A2 was pretty accurately rated at 260 hp/232 lbs-ft at the flywheel. If this is the case, that would make the Accord a 260 hp/225-230 lbs-ft engine. Not bad for 3 liters, SOHC and the "economy" form of VTEC. Note how ruler flat the torque curve is. From 1500 to 6500 the engine produces 90% or more of its peak torque. The little blip at 4000 rpm appears to be the VTEC transition, while at 5000 rpm the intake manifold butterfly valves open. Sweet. If we had any complaint about this engine it was that it wanted more revs - yep, that's about the only complaint.
We used some OBDII logging software to ensure that intake and coolant temps were consistent across all runs. The TSX was far easier to keep cooler as it shares a similar cooling system with the Accord, but produces far less output to tax the radiator with. We also checked tire pressures (37 psi hot on both cars) to further ensure that we controlled as many variables as we could.
After doing our baseline runs, both cars were also subjected to our traditional intake mod test, whereby we tweak the stock airboxes (or remove them) to see if there is any power lurking in the intake. The answer? A resounding yes. The TSX gained about 5 hp while the Accord picked up nearly 7. Imagine what a proper cold air intake will do!
Once the dynos were finished, we did an undercar video of each car, highlighting the critical elements and differences. You'll have to wait for the pictures and the videos, but suffice it to say the most noticeable difference between the two cars which share a platform was the aero trim on the TSX. Acura really went all out on this car and it pays off in great gas mileage and low wind noise - oh yeah, and great stability at high speed.
After the dyno runs we took a break and headed out to Montgomery, AL to hit the dragstrip. We encountered a real frog strangler of a storm on the way that required us to slow down to 30-40 mph on the Interstate because visibility was so bad. A little worried about the rain, we called base camp to check the weather in Montgomery and were told that the storm had passed. A call to the track confirmed they planned to open. Imagine our disappointment then when we arrived to be told that they would not be racing that night. Never mind that a tractor was dragging the track (to put rubber down) and the sky was clear. They were worried about another storm system on its way - yeah, so why not race and then stop when the rain hits? I confess that maybe I just didn't understand Southern sensibilities in this case.
Regardless, we did manage to get some good data for you. Stay tuned for a more in-depth engine analysis and technology review.