When you have a timeline and schedule set up for a project, you can bet your sweet ass that everything isn't going to end up according to plan. Luckily for us, the Skunk2 RR strayed off its path for good reason: the Hotchkis On Track Day. You can read more about this event elsewhere in the issue provided that Nads finishes the story. (Uh, about that...stay tuned for next month's report! --JN)
Although we were more than impressed with the 177 hp the Civic RR was putting to the wheels, Dave Hsu of Skunk2 knew the K20 motor had way more potential. By swapping the Type R header for a prototype Skunk2 piece, they managed to squeeze out an extra 7 hp to the wheels. Still not content with the power, David and his crew decided to work on the internals of the motor. The flaws--if you can really call them flaws--in the original motor setup were the use of the Civic Si pistons and injectors, which limits the compression ratio to 9:1 and fuel flow as well. In order to bump the power up, Integra Type R pistons and injectors from Japan were used. Actually, that's not entirely correct. The Type R pistons on their own would raise the compression ratio to an astronomical 11.5:1, which isn't too friendly on pump gas, so many hours of testing and measuring were done in order to get closer to the 11:1 compression ratio goal. After several different variations in the combustion chamber and the use of two head gaskets, the final result was 10.8:1.
After playing with the compression ratio, the crew spent its time on the top end. In most cases, tons of power can be extracted with a proper head port and polish job. This theory isn't entirely true when it comes to newer motor designs such as the K20. Dave tells us that the intake ports were already very well designed and only a little bit of clean up work was needed to gain an extra 5 percent of airflow. The exhaust ports, on the other hand, were in desperate need of some help. After some serious porting and polishing, airflow was increased by an astounding 15 percent. It's hours of R&D that allowed Skunk2 to finish this stage at 210 hp to the wheels. The crew seems satisfied for the most part, probably because it's planning on yanking out the K20 and dropping a K24 engine anyway. This time around, a pair of prototype cams were used. It turned out that using stock Type R cams would have been more beneficial, so expect to see those when the new motor goes in. And to think, we're only on Stage IV.
We don't even know when Skunk2 plans on stopping.
Although the prototype cams did manage to make more power compared with the stock Si cams, look for OEM Integra Type R bumpsticks in the near future. |
The Hasport engine mount kit keeps the car feeling solid, but for street use, it might be a little too unforgiving. |
After an intense regimen of porting and polishing, flow was increased by 5 percent on the intake side and 15 percent on the exhaust side. |
Don't get too attached to this K20. The bigger and badder K24 will be taking its place very soon. Maybe you can hang around Skunk2 afterhours and score some parts out of its dumpster. |
Park your car overnight in our garage and it might end up looking like this. |
Using the prototype header, Skunk2 was able to gain another 7 hp at the wheels. This piece should be available by the time you read this issue. |
The Civic Si pistons made the compression too low at 9:1, so they were yanked out and replaced with a set of high-compression pistons from an Integra Type R. |
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A series of volume tests were performed to determine the compression ratio. The goal was to be somewhere around the vicinity of 11:1. With the new Type R pistons in place, the compression ratio was raised to 11.5:1., which wouldn't be so bad, but pump gas sucks around these parts of the nation, and race gas gets very pricey if you're filling up every couple of days. After some serious reworking of the combustion chambers and using two head gaskets, it was finally brought down to 10.8:1. (See Preceding and Following Images As Well) |
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