At VTEC.net, we're thorough when it comes to a road test. Here's a little preview of just some of the data we've collected on the 2002 Civic Si.
Dyno testing is a great way to get a handle on how much power your car makes and where it makes it. Getting this data allows you to optimize shift points and judge the benefits of modifications.
Past B16 Civic Sis put down around 130-135 hp to the wheels. A 25 hp loss is pretty normal for a FWD Honda, so that's about what we expected to see from our preproduction test car. So, imagine how surprised we were when our first test only put down 128 hp! That was a bit lower than we expected. Then we realized part of the problem. Not having a service manual, and looking at the 9.8:1 compression ratio, we assumed 89 octane gas would be fine. However, it appears the engine really likes premium (If you can call California's 91 octane "premium"). After refilling with premium we found a gain of more than 2 hp and 3 lbs-ft of torque. Not bad, but not quite as good as some of the 135-136 hp numbers we'd heard about for the new Civic's K20A3. However, a few hp variance is not unheard of. Note: The official specification calls for 87 Octane
Overall, the curve is really quite nice. The torque curve is nice and flat, producing about 90% of peak torque from 2000 to 6400 rpm. That's a full curve. There is a slight midrange dip, found on all Honda engines equipped with single runner intake manifolds. Imagine what the curve must look like on the dual runner base RSX version of this engine! The torque signs off very gradually on the top end, lending credence to our complaints about the rev limiter coming on too soon at 6900 rpm. This engine/tranny combo is just begging for another 500 rpm and knowing Honda, it can certainly handle it. Acceleration times should improve nicely.
Next, we decided to see what would happen if we removed the rather restrictive looking stock airbox. We performed this test before filling up with 91 octane, so we've compared it to our best run with the airbox and 89 octane juice. Note the massive improvement in power!
We gained nearly 7 hp and 3 lbs-ft of torque at the peaks while maximum torque gains were nearly 13 lbs-ft down low! That's torque you can really feel. Looking at the specs on this engine, and examining the actual equipment, we suspected that it was a bit corked up from the factory (emissions? noise? didn't want to cramp the RSX's style?). The result of our simple intake test helps confirm our suspicions. With a proper cold air intake and a good exhaust system, we believe this engine could easily produce 145-150 hp at the wheels and about 125 lbs-ft of torque - and that's only the beginning, in our opinion.
Finally we decided to make a full throttle pass through the gears. It seems this engine liked spending time on the dyno, as it performed even better as we made more passes. Power peaked at 132.6 hp (with the airbox back in place), close enough to our expectations that we were finally satisfied. Note the slight variations in 5th gear. Mark, the dyno technician at Jackson Racing was easing back on the throttle a bit to avoid running into the limiter, which we found at around 125 mph. The car can certainly run that fast on the road, so slightly taller tires might allow more top speed if that's your thing.
Overall, we were very satisfied with the Civic Si engine. It has the peak power of the old B16A, but with a heck of lot more torque, not just at the peak, but down low where you can use it (and that helps on launch, believe us). Its unbelievably smooth and comes with the potential for a lot more power with minimal mods (the B16A required a little effort to extract another 20-30 hp, we think the K20A3 in the Si will be a bit easier). Our only complaint is that disappointingly low rev limiter. As soon as someone figures out how to bump that up, the car will get faster, even without any actual hp improvements.
Stay tuned for videos/photos of our dyno test and the rest of our test drive!