At 05:35 PM 9/2/01 -0400, you wrote:
>Well I fineally made it to the track with my truck, and got to make 3 passes.
>
>All runs were done in 75-80 deg temps except the 1st which was about 65 deg.
>First pass I spun the tire a little just to clean it and staged, launched
>from about a 1200 RPM footbrake and cut a .600 light, a small amt of wheel
>spin and I was out of the hole pretty good, I let the truck shift for itself
>which is about 4900 RPM. The truck launched straight ans stayed straight
>even under braking for the very first turn around. Timeslip...
>
>Reaction --- .602
>60 ft --- 2.450
>330 ft --- 7.060
>1/8 mi --- 10.808
>1/8 mi MPH-65.23
>1000 ft --- 14.028
>1/4 mi et-- 16.775 @ 81.94 MPH
>
>I cut a decent light and made an OK pass, the MPH I think is a little low and
>the ET a little slow, but the truck does have 123,000 miles on it and heavy
>31" tires.
>
>The second pass I decided to launch it at about 1800 RPM to try and get a
>better 60' time and pick up a better ET, all this got me was a WHOLE lot of
>wheel spin, I got in and out of the gas about 5 or 6 times in 1st and it just
>wouldn't quit spinning, so since I knew my pass was shot I just stepped into
>it and held it, it shifted second at about the 330' mark and kept spinning to
>about the 1/8 mile... results are as follows...
>
>
>Reaction --- 1.262 yeah I was sleeping, too busy watching the tach
>60 ft --- 3.171
>330 ft --- 8.877
>1/8 mi --- 13.089
>1/8 mi MPH-60.05
>1000 ft --- 16.489
>1/4 mi et-- 19.314 @ 80.20 MPH
>
>For my 3rd pass I decided to try and launch it just like the first time with
>no burnout, just dry hop it 3 or 4 times to clean the tires, it worked and I
>was rewarded with my best pass all day, the only change I made this pass was
>a manual 2-3 upshift at 5150 instead of the shift point of 4900 the past 2
>runs, next time I race I'll try a manual 1-2 shift too and see if I improve
>anymore...
>
>Reaction --- .812 still sleeping
>60 ft --- 2.482
>330 ft --- 7.084
>1/8 mi --- 10.824
>1/8 mi MPH-65.48
>1000 ft --- 14.029
>1/4 mi et-- 16.757 @ 82.70 MPH
>
>Ok so I only went 2/100'th faster, it's still faster and I had more MPH...
>Future mods will be, no fan, short belt (no ac), and dropping some air out of
>the rear tires in search of more traction! Any comments and suggestions are
>welcome!!!
>
>
>Luke
>1996 Black 4x4 Dakota, 16.75 @ 82.7 MPH, SLT CC SB, 318, 3" 2 Chamber
>Flowmaster cat back exhaust, 9" open element Mr. Gasket Air cleaner, 52mm
>Ported TB, 3923 Autolites, A-518 / 46RE, 3.55 geared Peg Leg 8 1/4, 31x10.50
>BFG Mud Terrains, Alpine CD player, Infinity Kappa Speakers.
>If Murphy's Law ever leaves me alone I'll have this installed soon: E-Body 8
>3/4" Rear axle, 3.55 gears, Detroit locker, 10" Brakes, and Moser Engineering
>custom alloy axles!
Luke
The launch techniques that you used on the 1st and 3rd runs seem best for your
truck. Remember, you have a peg leg so launch traction will be a problem.
You may want to try 'rolling' the gas pedal until the tires hook after
launching
(easier said than done because it's not the natural thing to do) and then
slamming
it to the floor.
Unless you can dyno your truck to know the rpms at which peak torque and
peak hp happen, manual shifting is a guessing game. Generally, you want
to shift at about 500 rpms above peak hp rpm. and experiment from there.
Optimal shift points will also depend on what the rpm is when the next gear
starts. That's where knowing what your torque curve looks like becomes
valuable. Also the higher you make your shift points the higher
your trap mph will be but generally often with the result of a higher et.
I think that you did really well. My first three runs with a catback and
K&N replacement drop-in were 16.8, 16.7 and 16.8, and I've got a 4x2
as well.
One suggestion is to replace the 9" open element (interpreting this as
a round cleaner) with a 14".
Bob Tom Burlington, Ont., Canada
'97 CC Dakota, 5.2L, 4x2, 44RE, 3.92SG, 4,275 lb (racing weight)
RW: 231.2 hp 340.0 torque PB: 14.71 93.19 mph
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