Launch Technique BF 290 ZF Auto

[JG3282]

No wheelspin... I will locate as many timeslips as I can, although I'm sure there was a thread in this section at some stage that had them posted in it

[JG3282]

the break down of the best 6 runs (by full ET) is as follows:

R/Time: 0.4253
60ft Time: 2.1232
Half Track Time: 9.0880
Half Track MPH: 78.36
ET: 14.0004
MPH: 104.26

R/Time: 0.4439
60ft Time: 2.0150
Half Track Time: 9.0950
Half Track MPH: 78.04
ET: 14.0321
MPH: 102.55

R/Time: 0.4699
60ft Time: 2.0049
Half Track Time: 9.1335
Half Track MPH: 78.64
ET: 14.0401
MPH: 102.18

R/Time: 0.4115
60ft Time: 2.0866
Half Track Time: 9.1183
Half Track MPH: 78.04
ET: 14.0435
MPH: 102.76

R/Time: 0.4139
60ft Time: 2.0324
Half Track Time: 9.1029
Half Track MPH: 78.07
ET: 14.0477
MPH: 103.40

R/Time: 0.5041
60ft Time: 1.9730
Half Track Time: 9.1337
Half Track MPH: 78.15
ET: 14.0537
MPH: 103.35

There was that 8.9/81 half tracker which resulted in a slower ET at the end of the strip due to driver error and also the 105 mph which was done with a passenger... As can be seen by the R/T's and sixty foots, the driver had no problems launching the car except on the quickest run of the day where a slight chirp of the tyres saw the driver back off at the sixty foot mark.

Interesting to note the car did 103-105 mph with passengers on board and also ran consistently two tenths slower without the air filter. The quickest runs were recorded in 100% "as driven on the road" trim, including auto shift.

In all honesty I think that the 1.97 sixty foot is ok, but knowing that the car was not hammered out of the hole, perhaps it has about 5/100ths in it, maybe enough for a 1.89 sixty.

[XA-Coupe]

how about a scan of the slips ?? I wouildnt mind seeing the conditions at the time.

[xd5.8l]

Out of my territory I know but I would like to just tip in my 50 cents worth on conditions. A temp differential of 20 degrees can make up to a second difference in time.

Heathcote I ran 15.5 when it was 35 degrees

Last saturday was different story. Although I was more Commited.

[XA-Coupe]

Originally Posted by xd5.8l

Out of my territory I know but I would like to just tip in my 50 cents worth on conditions. A temp differential of 20 degrees can make up to a second difference in time.

Heathcote I ran 15.5 when it was 35 degrees

Last saturday was different story. Although I was more Commited.

You are 100% correct.. but the times and MPH reflect the conditions .. not have a great 60 footer and great mph and dodgy ET.. The ET and MPH will suffer.. not just one.

[Quadcams]

Roughly about 1.5 tenths for every 1000ft RA so for a temp of 37c would roughly be around 3000/3500 RA total crap air (tepending on track altitude) take that down to say 20c with a 1000ft RA should gain at least 3/3.5 tenths minimum. Of corse humidity,barometric pressure also come into the equation where air temp is the biggest factor to good air close behind is the humidity.

[XA-Coupe]

Originally Posted by Lowride260

Roughly about 1.5 tenths for every 1000ft RA so for a temp of 37c would roughly be around 3000/3500 RA total crap air (tepending on track altitude) take that down to say 20c with a 1000ft RA should gain at least 3/3.5 tenths minimum. Of corse humidity,barometric pressure also come into the equation where air temp is the biggest factor to good air close behind is the humidity.

Yep.. everything suffers.. not just one part of the equation.

[xd5.8l]

1000 ft RA? Enlighten me, has it really been that long since ive left school? I took a spin in a 12 second 180sx running 20 pounds boost. Man you get a headspin from the 'G' forces these things pull. The ego was a bit deflated after that little outing. TURBO is the way to go as much as I hate to admit it.

[Quadcams]

Originally Posted by XA-Coupe

Yep.. everything suffers.. not just one part of the equation.

You bet ya it does!

Does seem a bit strange you would think in those temps the mph would be down around the 100mph mark. Myself in 37c only run around 102/103mph to 20c run around 105/106mph

[Quadcams]

Originally Posted by xd5.8l

1000 ft RA? Enlighten me, has it really been that long since ive left school? .

RA= relative altitude

Check this out!http://wahiduddin.net/calc/calc_da_rh.htm

[Walkinshaw]

Originally Posted by XA-Coupe

Call me dumb but I still don't see the issue addressed.
How can a car that runs the same 60 footer and better mph not be closer in ET?
Post a copies of the time slips.. maybe there will be a clue in them. I am willing to be educated.

Indeed. nailed the 60' decent mph (it is making the power regardless of air temp) and only a 14.0.. Similar car here ran 2.2 60' 101mph and 13.8's

[JG3282]

Air was at 982, humidity 32% + and temperature ranged from 23 at 10 am to 37 by 4pm

On the Bluepower dyno two days later with air at 985, temp in the mid 20's and humidity at 30% it made 248 kW at the wheels

[XA-Coupe]

Originally Posted by JG3282

Air was at 982, humidity 32% + and temperature ranged from 23 at 10 am to 37 by 4pm

On the Bluepower dyno two days later with air at 985, temp in the mid 20's and humidity at 30% it made 248 kW at the wheels

Let's see the scans.

[Quadcams]

Originally Posted by JG3282

Air was at 982, humidity 32% + and temperature ranged from 23 at 10 am to 37 by 4pm

On the Bluepower dyno two days later with air at 985, temp in the mid 20's and humidity at 30% it made 248 kW at the wheels

982 RA thats ok air, there was a stock MKII manual GT the other week at WSID that did a 14.005@102.7 2.2 60' with 1600ft RA.