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Oct 19, 2014

IDRC Auto Club Dragway Oct 18th and Clutch Change NISMO R32 Skyline GT-R NISMO R32 GT-R imported under Show or Display

Last weekend we were out at the DSport GT-R Open house, which gave us enough motivation to hit up IDRC this weekend. Thought about running the True Street class, but the time cut was 12.5, and wasn't sure we could make that break on the first time out.  Instead signed up for fun runs. $30 for the day, $60 for two days. With some discounts, was only $20 per day. If you are looking for an in-expensive day at the track, drag racing is a fun time.

However before hitting the drag strip, had to do a clutch change on the car. Last time we had the car out at Buttonwillow, noticed that the clutch just started to slip in 4th gear under high load. The car has still been driveable, but it needed to be changed. Drag racing was enough of a motivation.

The fuse in the driveline of an all wheel drive car like a GT-R is normally the clutch. Once you start to make power, they start to slip pretty easily. Couple good hard launches on a GT-R and they are done.

So I picked up a NISMO Coppermix twin plate clutch to replace the stocker. I really like the NISMO twin plates. They hold up to about 600 horsepower, and drive near stock. Then the fuse isn't the clutch anymore. The next weak link is normally 3rd gear. Since the Coppermix is sprung hub, it helps the transmission to survive. I have Redline Shockproof Heavy and Lite mix in the trans, so that helps a ton. I was going to swap to all Heavy, but ran out of time.  In addition to the clutch, I was going to swap the slave cylinder, and the rubber line, but again time factor. Sucks to live in the real world, where you can't just "Install Parts Now" like Gran Turismo.

Buy USA Legal R32 Skylines at! for Nissan Skyline GT-R and GT-R parts.

The other thing I wanted to see if I could address, when the trans was out, was the boost. The car has only been making about 0.4 kg/cm2 (5.7 psi) to about 0.6 kg/cm2(8.5 psi).  I have trouble shot the problem a couple times, eliminated a real boost leak. Checked the BOV. Checked the solenoid.  Fixed a couple of small leaks, but still was staying at the same low level.  When I had the trans out I checked the lines I could see and touch, and everything seemed OK. At some point someone has replaced the hard lines on the cold side.

I know how it is plumbed, and how it works, but that doesn't stop me from being lazy enough not to really try and fix it.  I did bring everything with me, to work on the boost side.

Stock muffler and resonator

Finally finished the clutch swap late on Saturday night, swapped the wheels and tires over to a set of NISMO option wheels 16 x 8 +30 , with Mickey Thompson ET Street radials. I believe the right tire for the right place. Like a pair of shoes, wear the right ones at the appropriate times. On the road course, it is 18" R34 wheels and R888.

Once I got to the track, some basic prep on the car. Dropped rear tire pressure down to 20 psi. 25 psi in the front.  Poured some gas in the car, and hit the strip for the first pass.

First pass was a 14.4@93 mph.  2.0 60 foot. 9.1 @ 72 mph in the 1/8th.  So that wasn't good. Messed around with the boost lines, went back to the strip, and ripped off a 14.3@92.96 mph pass. 60 foot 1.94. 9.1 @ 74 mph in the 1/8th. Hmmm, That didn't work.

Best thing to do now, is by pass all the stock boost control. Run new lines, see how that goes. Next pass - 14.5@92 mph. 1.97 60 foot. 9.2@73 mph in the 1/8th. That alone didn't fix anything.

Blazing 14.5@92.71 pass
So the next pass, added a vacuum t - 14.0@96 mph. 2.0 60 foot. 8.9@75 mph in the 1/8th. Picked up a little mph. 60 foot sucked. Added another vacuum t bleeder. Next pass. 13.9@99 mph. 60 foot 1.81. 8.9@75 mph in the 1/8th. Ok. That worked. Add another vacuum t.

Three vacuum t's in this picture. Direct from bottom of collector to WG side
13.49@104.92 mph. 2.1 60 foot. Spun a bit off the line. Next pass I would turn the Full Race ATTESA controller up a little. Ran out of vacuum t's, so I put a y in line. added it so that it would give maximum flow.

Launched good, car felt strong. 1.75 60 foot. 8.0@83 mph out to the 1/8th mile. Near 1000 feet I felt the car pop. I didn't look at the boost, but it was up enough to gain some mph. 12.85 @ 91 mph. Yep. That worked, but maybe too good. The top intercooler pipe popped, put that back on, but that wasn't the only one. Limped it back to the pit space. The right lower hose that runs though the fender popped too. So, struggled with that for a bit. First just finding the popped hose, then getting to it.

3:58 pm. More or less the end of the day. Hit the strip one more time. Flipped the vacuum y around, so it wasn't quite flowing as much. 8000 rpm launch - 1.64 60 foot. 8.0 @ 81 mph to the 1/8th. 12.67@106.99 in the quarter. Solid 12 second pass.  Full day, and I was pretty happy with that. From the 14's to the 12's with some vacuum t's. Next its on to replacing the left side axle boot, because it is split. The adjustable wastegate acuators need to go on it.  It needs to go on the dyno, fix the boost control properly, and hit the strip or the track again soon.  11's wont be too much drama. Through the stock airbox. Through the stock muffler.

Last pass of the day. 

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