TwinTurbo.NET: Nissan 300ZX forum - Redline Time Attack writeup
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Subject Redline Time Attack writeup
     
Posted by kuah@splparts.com on February 21, 2007 at 5:26 PM
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Message We started out from Austin at 3pm on Wed, drove all night and we were still in Texas, had to stop over Wed night in El Paso:

The next day we drove from El Paso all the way to LA. The truck flat out would hit a max speed of 92mph. Must be the drag from the wing :)

Saturday was practice/DE day. First car we saw when we got to the event, got a real scare. But turned out to be a mostly show car, made to look like a JGTC NSX:

We have never been to California Speedway, Ryan has never driven at this track either. The Z also had some new untested aero mods on it:

1.5" front splitter:

I had originally made a 3" front splitter, but after testing at MSR the weekend before, I found that the car was not balanced. The splitter was trimmed and the rear wing relocated in an effort to bias more downforce to the rear. I had no idea if all that was enough or too much, but I lucked out and it was just right after all the changes.

Pic of undertray and rear diffuser

Pic of interior

GMG showed up with a street modded GT2 as well as a race World Challenge GT3 RSR. The GT2 was in our class, and in the Super Street time attack in December won the limited class. The trailer shows how well heeled the competition is:

Video from the third session on Saturday:

[ http://www.splparts.com/events/redline0207/redline2.mpg ]

We were running very fast laps on the first day, but not without problems. By the third session the car was coming in billowing smoke from both the front and rear Stoptech 14" brakes (equipped with Ferodo DS3000 race pads). We have not had any brake problems before at either TWS or MSR. I was so certain that the 14" brakes were more than adequate I had not bothered to put in ducting, big mistake. Rushed to Home Depot to pick up parts for some homebrew ducting. Front pad was also getting low and we would have to watch it carefully on Sunday.

Next we found that we had broken the shifter bracket/isolater. We placed urgent calls Saturday evening to Greg (Dupree), Seb, and Mark (sipriz). Greg was the first to return our call and happened to have a new bracket at his shop, so we drove across LA to meet Greg at his home and pickup the bracket. Big BIG thanks to Greg, for taking time from his family on Saturday evening to get us the bracket. Thanks as well to Seb and Mark as well for offering to remove the bracket from their cars for us to use. The support from the Z community is incredible...

We got back, quickly installed the bracket and got the car ready for Sunday...

And woke up to rain. When we tried to go out the first and second session, the car fogged up so rapidly that it was not possible to drive. No amount of Rain-X and Fog-X was able to fix it. I wish I never removed the A/C and heater system, the weight savings was really not that significant :( Third session was a little better, and we were able to get the car out on the course. Wing was adjusted for maximum angle, which looked more like an air brake:

Video in the rain:

[ http://www.splparts.com/events/redline0207/redline5.mpg ]

Luckily the weather cooperated and the track started drying out in time for the 2 time attack sessions in the afternoon. After the first time attack session, we were first with a comfortable led in the modified RWD class. Video of that session:

[ http://www.splparts.com/events/redline0207/redline3.mpg ]

Some of the competition in our class:

VRT JWT700BB twinturbo 350Z, piloted by pro driver/drifter Tanner Foust:

Factor X 650whp twinturbo NSX, piloted by Billy Johnson (Speed World Challenge pro driver):

We wanted to try to win the Modified class outright, which was currently lead by the Crawford 550+whp STi on stickier Kumho V700 tires, also piloted by Tanner Foust:

For the final session, I fine tuned the A/F to gain more power, and we swapped to a fresher stickier set of Nitto NT-01 tires. Combined with cooler weather and a dryer track, we were expecting to make up the time on the Crawford car. Unfortunately we were not able to complete a lap before the linkage broke (pic):

Video (Note: profanities in video)

[ http://www.splparts.com/events/redline0207/redline4.mpg ]

If the linkage lasted 2 more minutes we would have gone home with a win in modified RWD and possibly overall win in modified class. On the other hand, we were lucky that the time we set in the first session was good enough to win second place:

The 600hp GMG Porsche GT2 piloted by James Sofronas (Speed World Challenge pro driver) which previously won the Super Street limited class in Dec 06, did not even finish in top 3. Goes to show how tough the competition is getting. On a side note, we actually had a faster time than the 3rd place Unlimited RWD car, which was the Mworkz 350Z piloted by Tarzan Yamada. The other unlimited cars were much faster though, the 700+hp AMS Evo, the 1800lb JIC S15, and the 2400lb $250+K GMG GT3 RSR.

All in all I was happy the car did so well, especially since my Z probably makes in the 450-480whp range (never dynoed), so it was underpowered relative to the competition even in Modified class. The next event I hope (but not definite yet) to attend is Buttonwillow in April, which should favor us as the car is setup for high speed handling (vs. California Speedway = drag + autocross). Hopefully this time we will actually get some media coverage as well...

     
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