So for my engine swap impressions.. it is quite a bit of work to turn the front-wheel drive setup to rear-drive, and mostly makes sense for horsepower or dollar limited series of racing. For the money it's a decent upgrade, but having a 400whp V8 240sx, I was slightly underwhelmed by the 190-200whp car. It's certainly smoother than before, and the power pulls all the way to redline with no noticeable dropoff in torque towards redline. The KA24DE drops off hard enough that it was pointless to run to redline.
We sadly never did put this engine on the dyno, as I was a little depressed by some of the lack of gains. This dyno below is NOT our car, but the same engine type to show the general powerband. In this example you can see between 5000rpm and redline, it only drops about 20 ft-lbs of torque. At redline it's still making more torque than our KA24DE ever did. Our KA24DE drops roughly 50 ft-lbs in the same span, giving a very noticeable lack of pull up top.
Our old KA24DE dyno (note the torque dropoff, power peaks at 5500rpm):
VQ30DEK dyno (NOT our car, just an example, but power peaks at redline):
We decided to experiment with running no manual steering. It saved some time and a little weight, and we figured it was worth experimenting with. While obviously the steering was heavier, it wasn't too bad catching a slide.
One of the most striking things I noticed up front, is that with the combination of the new trans and stock differential, the gearing is much shorter. So now everything was a gear higher. Definitely a little mental gymnastics.. only downshifting into 4th for the chicane feels very weird! I am also used to being able to shift by sound and feel, and with this engine I can't feel the drop off in torque to know when to shift, and I'm not used to the sound. So occasionally I bump the rev limiter, which hits pretty hard since it's still pulling at redline.
Another thing I noticed was that once I was in 6th gear, there was quite a bit of driveline vibration. The driveline is going pretty significantly fast at this point, but this was not expected. We tried doing various tricks on the lift like using a band clamp rotated to different positions to see if we could affect it, but we only seemed to be able to make it worse. Eventually we shipped back the driveline to be checked out, and they sent us another one. This one still did it, although not quite as much. Oh well, hopefully it doesn't wipe out any bearings.
Unfortunately my GPS to speedo connection did not work out. Once I had the Arduino reading and translating all the information from the datalogger, it wasn't fast enough to still do the pulsing for the speedometer.
Here's some of my first laps from the track day getting a feel for the car:
To compare my fastest laps with the 4-cylinder and 6-cylinder, I was hitting just 3mph faster on both the front and back straights. Lap time difference was a 1:31.61 versus my old fastest of a 1:31.98. The car made cooler noises and felt better, but it was certainly not nearly the bump up we thought it was going to be when we had such a freak 4-cylinder to begin with.
So after all this work, we are *slightly* faster. The real kick in the gut is that while we've been working on getting this engine in, ChumpCar pulls out of the West Coast. So the race series that got us to consider doing this engine instead of the 350Z engine is now out of the picture. Oops. Would I do it again? Only for certain rules/reasons. The VQ30 in a street car would work out really well, it's bulletproof and gets mileage as good as the KA24DE while making more power and sounding better.
One thing with our old KAs, is that our first three engines burned oil. We were used to having to add oil at every pit stop, and only our last engine did not burn oil. We also got 37 hours, 50 hours, and 49.5 hours out of the first three engines (this one pulled due to burning too much oil even after rebuilding the head). Our last engine was the best and still going strong when we pulled it out at 83 hours. Our VQ has fantastic compression and doesn't burn any oil, so hopefully we get a lot of hours out of this one!