|Taking the B20Z to the track
Buttonwillow Raceway, Jan 20th, 2001.
First time on race tires for me, and the EG was awesome. But the tranny was not right for this track. With Kumhos, I was in 3rd and 4th gear all the time. Only time I saw second was after braking too hard or after screwing up the Off-ramp by coming in too hot and scrubbing off speed by plowing. Fourth gear tops out at 100mph at 7000 rpm, and when i shifted to 5th, I would lose more speed shifting than I could make up in the distance to braking point. The LS 5th gear is just too low for a fast track like Buttonwillow. A GSR tranny would have been a better choice for this track, or perhaps I'll make a new hybrid tranny.
The other problem is my on-going issues with my O2 sensor. It's operating range seems to drop down when the headlights or heater fan is on, due to some yet undiscovered grounding problem. But when it seems normal, if I can beleive it, the B20 is running lean on the LS ecu at WOT (DUH!). I tried adding some resistance to the air temperature sensor, IAT (TA on the OBD0 cars), to trick the ecu into adding more fuel. It certainly adds a bit more fuel, but only in the midrange, where the injectors are operating within their range. At WOT, it remained several light bars from full rich. Pulling the plugs also confirmed the lean mix.
I did buy a FPR for the event, but the event planning kept me from installing it. I had hoped to get the fuel and cam gears dialed in before the event. So even without, the B20 rocked my world. Pulling out of corners in 3rd gear was awesome anywhere from 4000 rpm up. Frequently I could just slightly spin the inside Kumho on corner exit, so there was no reason to downshift to second. On the dyno, the power falls off starting at 5700, but I frequently found myself pulling out to 7k before shifting. I guess I was too busy braking and pointing at the next corner to feel the power fall off. 4th gear suffers from shifting so late, but it would still top out 4th very quickly. Through Riverside, and the Club Corner, I would be flat out, either holding it just below or bouncing off the rev limiter. When I took the correct line out of Sunrise, I would top out 4th gear before the start-finish. A quick shift to the too tall 5th would only net 2 more mph.
So I don't think I need the super short gears of the Y21. If I had the correct Y21 5th gear, (same as the ITR) I would have shifted from 4th to 5th at about 6000 rpm, dropping to 4800. That's right in the thick of the torque band, so it should be able to pull to at least 6000 rpm in 5th. So what is 6000 rpm in 5th? 108 mph. Oh yeah, the B20Z would have easily seen that on the main straight.
Next time: more power, taller gears.
B20B driving impressions...
On the freeway:
But the B20 has enough torque from 2000-5000 to pull the LS 5th gear even up hills. At 60 mph all you have to do is press harder and it will accelerate without bogging or pinging. With 87 octane too. It takes a couple seconds to get from 60 to 65, but then the speeds increase faster as the B20 picks pulls out of the torque hole.
I love how the engine is like a stealth powerplant. Since it makes so much power at low revs, there is little noise. No buzz. Quiet. Low revs equals stealth power.
So lets talk about shift points. Shifting by feel:
Keep in mind this is basically a stock engine. And its the lower compression B20.
Streets of Willow:
However, when going up the main straight, it was clear that it needs more top end. Especially with the LS 5th gear, it needs more rev range in 4th gear. The original y21 5th would have been nice. Oh well.
What others have to say
Jeff Ho-See, MR2 Turbo, 241 ft-lbs:
Jeff Sloan, B18C1 EG HB:
Kit Wetzler, S2000:
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