Drag Racing: Going straight, really fast.

-A lot of people think drag racing is lame.
-A lot of people think drag racing is the BEST motorsport on the face of the planet.

Let me say this for the first and last time: my Z is NOT a drag car. Drag cars run sub-9 second passes. However, My Z does perform well enough to be considered a fairly fast street car. Some key components to doing well at the drag strip:

  • Limited-slip differential.
  • Rear-wheel drive.
  • Gobs of power.
  • Perfectly timed shifts.
  • Good tires.
  • Lots of practice.

    Personally, I enjoy it.... for about twelve seconds. That's the down side: everything happens really fast, and the key to the whole thing is the launch. Take off from a dead stop in perfect timing with a string of lights. Then you simply accelerate as fast as you can in a straight line, that's the process. That's also all that most people see; like those people who think drag racing is lame. Just like baseball and drift; watching it is kind of lame, while actually doing (and doing it well) it is another can of worms. The truth: It becomes a much more technical motorsport once you get a feel for it. Some tips for newbies: here.

    The progression:

    Car configuration, tires, 60', 1/8 and 1/4 mile E.T. and MPH, speculated RWHP based on MPH and car weight (with driver, at the time the pass was made: varies from 3300 to 3500lbs):

    Summer 99'

    1. Virtually stock 1984 Non-turbo with cone filter, DynoMax cat-back exhaust, worn out Yokohama AVS intermediates.

  • 60' = 2.334
  • 1/8mi = 10.294 @ 67.76mph
  • 1/4mi = 16.117 @ 84.56mph
  • ~150RWHP

    Summer 03'

    2. Converted to turbo over the winter, 11PSI intercooled on stock T3, restrictive muffler, removed A/C, Dunlop SP sport R2 all-season tires.

  • 60' = 2.015
  • 1/8mi = 8.919 @ 77.95
  • 1/4mi = 13.8 @ 101.85mph
  • ~265RWHP

    Subnotes: the car actually did manage 13.4@104 a couple weeks later with some toluene mixed in the gas, but I lost the timeslip, so it's useless to claim something without proof.

    3. Added 90HP wet shot of nitrous to config #2. Added LSD, removed restrictive muffler, Dunlop SP Sport R2 all-season tires.

  • 60' = 1.837 (the best recorded Z31 60' time on all-season tires to date)
  • 1/8mi = 7.945 @ 90.01
  • 1/4mi = 12.299 @ 111.95mph
  • ~367RWHP

    Summer 04'

    4. Added Cams and head work, Full Certified Muffler 3" turbo back exhaust, new turbocharger running 15PSI boost pressure, Cartech FMU, Kumho Ecsta MX tires, BW T5 transmission is now on the fritz (1-2 shift) and the car is having traction problems in first gear, even with a perfect launch, I had to let off when boost hit.

  • 60' = 2.219
  • 1/8mi = 8.919 @ 85.21
  • 1/4mi = 13.465 @ 110.13
  • ~350RWHP (Cool! Almost as much power now without the nitrous as with the nitrous before these modifications.)

    5. Added 100HP shot to configuration number 4, backed out ~4 degrees of timing. Nitrous bottle pressure was ~600PSI; low. Transmission still on the frits, SEVERE traction problems in first and second gear. Got a little sideways in second gear on one run; quite scary. Best trap of the night was 124.4mph. This was my best 60' and ET of the night despite issues:

  • 60' = 1.968
  • 1/8mi = 8.130 @ 95.54
  • 1/4mi = 12.237 @ 122.46mph
  • ~460RWHP ?

    Summer 05'

    6. Replaced engine (100K mile 85NA block from a friend) and 'new' 88T (Nissan FS5R30A) transmission from parts car. Upgraded intercooler from NPR to Bell core with new piping.

    Subnotes: No drag runs on this engine. Broken flywheel on the street and extensive damage forced entirely new engine, clutch, trans to be installed. I installed a spare 88T motor with lots of miles but in good running condition as a temporary deal.

    6. New STOCK 88T engine (260K miles) with none of the above fancy mods, removed Nitrous, still on stock 85T ECU with base timing at ~17btdc. 88T transmission, ACT 6-puck clutch, 3.7 open diff (LSD had pinion bearing failure), Leaning out a little on the top end, so ~10% mix of 110 race gas was added to fuel.

  • 60' = 2.354
  • 1/4mi = 12.912 @ 114.16mph
  • ~380RWHP ?

    Subnotes: Broke driveshaft on second pass, so no opportunity to get the ET down to where the trap indicated it should be. Added upgraded fuel system later in the summer but never ran it at the track. Romulator, 420cc injectors, cobra MAF. Dyno result of 383RWHP/373RWTQ with a little under 18PSI on 93 octane fuel.

    Summer 06'

    7. New modified 86T engine. 7.8:1 stock bottom end with UR pulley, fidanza flywheel. New head work with ferrea valves, JWT springs, 270/262 .440/.420 cams. Same dinky stage 3 turbine and stock internal wastegate probably limits power output somewhat. Fuel system now consists of Romulator and RX-7 550cc injectors, ford mustang cobra MAF. Old tune at 15.8PSI yielded a peak of 418RWHP/386RWTW, built a MAF bypass and ran 20PSI on 93 octane at which point the engine was able to produce 453RWHP/484RWTQ. After some light tuning I cranked the boost to 24PSI with 50/50 race gas mix to go to the dragstrip.The ACT 6-puck clutch started slipping very lightly, as well as the engine developing a slight miss issue at high RPM. Determined the miss was due to the intake valve springs being too light for the amount of boost.

    No dragstrip results before engine failure. I melted a piston while racing an older Suzuki GSX-R 750 on the highway; we ran pretty much even with me in the lead until I decided we were going too fast.

    8. Long story short, I assembled a motor with forged pistons and 8.5:1 compression with otherwise the same configuration as before. Only change besides compression was switching to a DXD clutch instead of the ACT. The DXD Stage 5 is much more managable unit, and restored my ability to lanuch the car that the ACT had taken away. With 14PSI boost on pump gas I managed the following times (I still have to get the exact info off the timeslips, this is from memory):

    12.4@115, 2.0 60ft
    12.5@116, 2.0 60ft
    12.7@116, 2.1 60ft

    Race weight was just shy of 3400lbs (This includes my weight and everything else I left in the car), running on Kumho Ecsta MX street tires not so great for drag racing, 2.0 second 60 foot times were easy. with a 1.6 second time the ET should be into the mid 11's. Can't wait to try with slicks and more boost!

    9. Returned to Mid-Michigan motorplex determined to actually make an attempt at a good pass. My usual 100lbs of junk was removed from the car making race weight about 3300lbs. Boost increased to 24PSI, 110 octane race gas mixed 50/50 with 93 octane, M/T Drag ET 26.0x8.5" drag slicks. Slicks used were rather old so I smoked the snot out of them in the burnout box. They probably did get a bit on the hot side, because they both spun all the way through first with a 4500rpm launch. Also added a new prototype poly differential mount. The rest of the setup was the same as previous except for some small tuning tweaks for the higher boost. Still, the 60' time turned out good despite the wheelspin. Last pass of 2006:

  • 60' = 1.818
  • 1/8mi = 7.89s @ 99.53mph
  • 1/4mi = 11.60s @ 126.61mph
  • ~500RWHP ?

    Plans/dreams for Summer 07'

  • I would like to be in the high 10's @ 130+MPH
  • Methanol Injection
  • Lose weight (My fat self is slowing the car down).