XS GT-R Time Attack – Super Lap Battle 2007 @ Buttonwillow

 

Last week on November 7th was the Super Street Super Lap Battle. Otherwise known as Time Attack, but they had to get all JDM on the name. So for a couple weeks before SEMA and the days following SEMA, I spent a good part of my time preparing the XS BNR32 GT-R for the event after work. While I was at SEMA, Koji and Peter at XS took over and put the car together. As usual, Koji and Pete did an excellent job as the car was mechanically 100% reliable. There was a lot to do to get the car running, but we did it. We didn’t quite do as well as we wanted though. I think we finished 4th in class and like 6th or 7th overall. In fact, the car went over second slower than last year. If we just ran our last year’s time, we would have finished 3rd overall and 3rd in class. In the first two sessions, we had Mr. Kobayashi from MCR Japan (Matchless Crowd Racing) driving to help us dial in the suspension. His experience with GT-Rs was invaluable. Kobayashi was over here driving for Tein, but Tein was cool enough to let him drive our car which has KWs on it. By the third session we gave up trying to win so we put Tanner Foust in the car. He was also driving it for part of the Redline TV show on the Speed Channel. He ran the 1:50.3 the absolute first time in the car. Tanner is definitely talented. Oh well….maybe next time we’ll get Tanner in the car again and smoke everybody (but HKS). That’s what we get for going out to the event with a new suspension and no track time. This is only the 3rd time the car has every been on the track, but the first time we set a time attack track record at Fontana which still stands today by 1.5 seconds and the second time we finished 2nd overall and 1st in class. I guess we got a bit dependent on good luck. Lesson learned.

 

Before I left for SEMA, I finished up the dry sump oil system. I got a lot of tips from some of the guys at Cosworth (Skip, Larry, and Lew). Since I knew absolutely nothing about dry sumps (other than how to plumb them), these guys told me about the little details to setting a dry sump system up properly – things like vacuum in the head, vacuum in the crankcase, how to seal the head from the block, pump vs. crank RPM, and even the oil level in the tank. There was some adjustment to the vacuum levels on the dyno, but otherwise the dry sump pump worked on the first try thanks to Skip, Larry, and Lew. These guys definitely know their shit! I’m glad I had these guys to bother for advice.

 

While the car was over at M-Workz for corner weighting and alignment on 11/4, it took Steve Mitchell almost 7 hours to set the damn car up. There are no bushings on the car’s suspension and every connection is a spherical bearing. This would ordinarily make it even easier to set up, but it was just way off to begin with. The corner weighting was done for a 175 pound driver with sandbags in the driver’s seat.

 

I previously built the engine earliier this year in April. I optimized the cam timing on the dyno the Saturday night I got back from SEMA on (11/3) and picked up a ton of mid-range power compared to the previous engine. Koji did most of the engine mapping on Monday night (11/5). This new engine is absolutely perfect with a wider powerband, more torque, and the same peak horsepower as the old engine. The torque curve is relatively flat from 5500-9500rpm. Props to the new Tomei camshafts, Cosworth valve springs, and WPC Treatment throughout the entire engine. The rest of the engine is also a mix and match of parts that I chose: Tomei 77.7mm stroke crankshaft, HKS step 2 87mm pistons, HKS step 2 con rods, XS big port head, HKS retainers, Cosworth main and rod bearings, and Tomei head gasket. BTW, Steve at Cosworth did a bitchin job on the machine work on the head. I mixed and matched what I thought would work together and what we had already in the previous engine. It worked extremely well together for a final power output of 785whp (HKS GT2835 turbos x 2 max out at 800) on the XS DTS chassis dyno. This is approximately 840whp on a 2wd Dynojet. We never exceeded 20psi of boost which yields approximately 730whp at the track that day since we didn’t get the chassis and suspension sorted out entirely. Mr. Kobayashi from MCR kept on saying how great the engine and power delivery was. It was his first experience driving an American built RB26 and he liked it A LOT. Of course I told him that not all American built RB26’s are like this – only the one’s from XS. Even Tanner was surprised at how linear the power delivery was in respect to throttle input. Many small displacement turbo engines are like an off/on switch, but not this one.

 

We’ll be making dampener adjustments with the KW suspension with the help of Mike Kojima’s advice. We’ll also have to make some aero modifications with the help of Johnny Mac. I’d like to thank everybody involved who helped us out along the way. There’s more to come in 2008!

 

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At M-Workz getting weighted and aligned.

 

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The new engine and hand fabricated valve covers.

 

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NASCAR oil pump with 5 stages of fury.

 

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Here’s the 6 quart tank. With the lines and coolers, capacity is 13 quarts.

 

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Here’s shot of the ATL fuel cell and battery.

 

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There’s Steve getting crazy on the alignment.

 

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There’s Steve getting crazy on the toe.

 

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I love those CCW wheels. 18×11.5’s all around with the deep lip is dope.

 

There’s a possibility this car is going for sale. It looks like we’ll be building something new for the later part of 2008. Shoot me an email if anybody’s interested at eric_jdminsider@socal.rr.com.

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