[hotrod182]

I wanted to test short shifting at 6300 rpm instead of redline, and the effects it has on ¼ mile performance. I made four runs alternating between short shifting, and letting the car shift at redline.

Conditions: 50F, Sea Level, 265/30/`19” General Exclaims. 91 Octane Shell
JB3 Map #6.

Run#1, Short Shifting:
¼ mile: 12.8 sec at 113.7mph
1/8 mile: 8.4 sec at 91.1 mph
0-60mph: 4.4 sec
60 ft time: 2.1 sec

Run#2, Redline Shift:
¼ mile: 12.7 sec at 113.3 mph
1/8 mile: 8.3 sec at 90.9 mph
0-60 mph: 4.3 sec
60ft time: 2.1 sec

Run#3, Short Shift:
¼ mile: 12.7 sec at 113.6mph
1/8 mile: 8.3 sec at 90.9 mph
0-60 mph: 4.3 sec
60 ft time: 2.1 sec

Run#4, Redline Shift:
¼ mile: 12.7 sec at 113.2 mph
1/8 mile: 8.3 sec at 90.6 mph
0-60mph: 4.4 sec
60 ft time: 2.1 sec



So it appears that short shifting can net you about .40 mph in the ¼ mile. Too bad I didn’t do that on my record run, as I would have been trapping around 118.3mph! (Map #7)

Also, bring that 2.1 sec 60’ time down to a 1.80 sec 60’ time and you should be able to get a 12.1-12.2 second ET. Not to shabby for map #6, all on 91 octane!

I just got done doing some canyons runs. Before I went, I added 3 gallons of 100 octane to 4 gallons of 91 octane. Hopefully I will get a chance to see what a couple pts of octane will do to the 1/4 mile traps on map #6

[luca335i]

Did you use DS or M mode for the redline runs. I find my car faster with DS than m mode.

[hotrod182]

Originally Posted by luca335i

Did you use DS or M mode for the redline runs. I find my car faster with DS than m mode.

Thats interesting, because I just leave it in M1 mode now, for fear of it short shifting into 2nd gear and then back to 1st gear on its own when the tires stop spinning.

[AlpineG05]

Have you seen any difference between map4 & map6 on 91 octane?

[hotrod182]

Originally Posted by Alpine 335i

Have you seen any difference between map4 & map6 on 91 octane?

Here is the difference between map#6 and map#4. Not too much difference, but the highest mph on map #6 beats the highest mph on map#4 in this particular test. As you can see with 50F testing this morning, and lots of adaptation, car was runniing good traps this morning.

Here are the previous tests at 57F:
Note: These tests were done with redline shifts.

91 Octane. 19” Generals. Map#6 57F.
13.1 sec at 111.2 mph, 2.3 sec 60ft
12.9 sec at 111.5 mph 2.1 sec 60ft
12.8 sec at 112.2 mph 2.1 sec 60ft (2nd gear launch)
12.8 sec at 112.3 mph 2.1 sec 60ft (2nd gear launch)

Runs same as above but on map #4
12.8 sec at 112.0 mph, 2.2 sec 60ft (2nd gear launch)
12.9 sec at 111.3 mph, 2.2 sec 60ft (2nd gear launch)
12.8 sec at 112.2 mph, 2.2 sec 60ft (2nd gear launch)
12.8 sec at 112.5 mph, 2.2 sec 60ft (2nd gear launch)

Runs same as above but switched back to map #6
12.8 sec at 112.5 mph, 2.1 sec 60ft (2nd gear launch)
12.7 sec at 113.3 mph, 2.1 sec 60ft (2nd gear launch)
12.8 sec at 112.8 mph, 2.2 sec 60ft (2nd gear launch)
12.7 sec at 112.9 mph, 2.1 sec 60ft (2nd gear launch)

[darkphantom]

^if you modulate the throttle, 1st gear launches can be pretty good

[hotrod182]

Originally Posted by darkphantom

^if you modulate the throttle, 1st gear launches can be pretty good

The more power you have, the more difficult it is with the steptronic. Sudden wheel spin will often result in an automatic down shift, and then when it regains traction, often full throttle will cause it to down shift to 1st gear and over rev.

[darkphantom]

hmm, quick question, when you have the throttle pressed after the resistance point, can you still manually upshift or does it redline?

[dlbrooks18]

Hotrod, we appreciate all the research and testing you do!

[hotrod182]

Originally Posted by darkphantom

hmm, quick question, when you have the throttle pressed after the resistance point, can you still manually upshift or does it redline?

It seems to upshift when you want it to at the top of 2nd or 3rd gear during and acceleration run. But if you let off the throttle and stomp on it again, it will sometimes downshift when you don't want it to.

[AlpineG05]

So you can run map 6 on 91? Interesting.

[brianhn1]

I've said this before: Someone needs to come out with a ECU/TCU update to get rid of the automatic upshifting in manual mode, like MB AMG's manual mode.

[midlife]

Originally Posted by brianhn1

I've said this before: Someone needs to come out with a ECU/TCU update to get rid of the automatic upshifting in manual mode, like MB AMG's manual mode.

someone is already working on it right now...
i think it is one of the flash tuners, but i cannot remember who.
IMHO, it would be a great idea for our 6AT

[brusso]

Hey something Shiv and hotrod agree on . ..... Shiv mentioned short shifting at about 6200-6400 as well to keep the car in peek hp numbers.

[hotrod182]

Originally Posted by Alpine 335i

So you can run map 6 on 91? Interesting.

Not really recommended. But I think in colder weather, it probably isn't too bad. The other day, it was 82F, no problems detected. Although I wouldn't be doing full 1/4 mile runs in hot temps. Perhaps in the summer I will switch to map #4? I will get some readouts to make sure the is happy too.

Originally Posted by brusso

Hey something Shiv and hotrod agree on . ..... Shiv mentioned short shifting at about 6200-6400 as well to keep the car in peek hp numbers.

If only I would have remembered to do this at the track! Short shifting is something I have only tried doing recently.

[GAaaAR]

So these are all second gear launches and mash on the throttle? And braking to 2K RPM?

[hotrod182]

Originally Posted by GAaaAR

So these are all second gear launches and mash on the throttle? And braking to 2K RPM?

No, these are all 1st gear launches.
I just got back testing after putting a little 100 octane in the tank. Not very conclusive. The first run was definitely the fastest trap. But the next 2 runs short shifting showed no improvement whatsover. I think the results are skewed though because 1st gear wheel spin is not very manageable with these tires and the higher octane fuel.

Run #1 Redline
¼ mile: 12.9 at 114.2 mph
1/8 mile: 8.6 sec at 91.3 mph
0-60mph: 4.6 sec
60ft time: 2.3 seconds

Run #2 Shifting at 6300 rpm
¼ mile: 12.8 sec at 113.7 mph
1/8 mile: 8.4 sec at 90.6 mph
0-60mph: 4.4 sec
60ft time: 2.1 sec

Run#3 Shifting at 6300 rpm
¼ mile: 13.0 sec at 113.5 mph
1/8 mile: 8.6 sec at 90.4 mph
0-60mph: 4.6 sec
60ft: 2.2 seconds

[NYBMW335]

If you fart as you launching it might get you another .10 mph. LMAO. All jokes aside, You definitely do a lot of 1/4 mile testing. I am really impressed. And thanks for all the info you provide.

[hotrod182]

Originally Posted by NYBMW335

If you fart as you launching it might get you another .10 mph. LMAO. All jokes aside, You definitely do a lot of 1/4 mile testing. I am really impressed. And thanks for all the info you provide.

No prob. I think the next step will be I will try again, and see if the mph goes up. It always seems to do better a day or two later for some reason after a major change (octane, etc). But as far as the traction issue. Perhaps I will bolt on my slicks to show exactly how much difference traction makes, and how it affects trap speeds.

[hotrod182]

Okay,I really didn't feel like doing it tonight, but I promised I would do some more testing, so here it is. Didn't want to change too much, so I tested on the same tires. As usual, a day later, and better times. Same tank of gas. However, about 10 degrees cooler temps, and a slight tail wind. So about the most ideal conditions one could expect. Probably about 94 octane? But with a 1.8 sec 60Ft time, these would be 12.0-12.1 sec qtr mile times, on map #6! Tires pretty much start spinning in 1st gear right off the line, so you have to be very gentle in easing into the throttle. In fact, run#4 was run in the regular DS mode, and I was so easy on the throttle the thing short shifted into 2nd gear at around 5500 rpm. Run #5 I accidentally shifted 2x, so it went into 3rd and then immediately into 4th. Still trapped at 114mph, so it just goes to show you the great torque/powerband that our cars have. So what is better, short shifting, or letting the trans shift by itself at redline? I think it is really hard to tell at this point, and complicated more by the fact that the launch traction is so restricted.

Conditions: 43F, 6mph tail wind. Map #6
3gallons of 100: 4 gallons of 91 octane. 19” Generals

Run#1 Shifting at 6300 rpm
¼ mile: 12.7 sec at 115.5 mph
1/8 mile: 8.4 sec at 91.6 mph
0-60 mph: 4.5 seconds
60ft: 2.2 seconds

Run#2: Shifting at redline
¼ mile: 12.6 sec at 114.9 mph
1/8 mile: 8.3 sec at 91.9 mph
0-60mph: 4.3 seconds
60 ft: 2.1 seconds

Run#3: Shifting at 6300 rpm
¼ mile: 12.8 sec at 114.5 mph
1/8 mile: 8.4 sec at 91.2 mph
0-60mph: 4.4 sec
60ft: 2.2 sec

Run#4:Shifting at redline
¼ mile: 12.6 sec at 115.1 mph
1/8 mile: 8.3 sec at 92,2 mph
0-60 mph: 4.3 sec
60ft: 2.1 sec

Run#5 Shifting at 6300 rpm.
¼ mile: 12.8 sec at 114.0 mph (shifting into 4th accidentally right after 3rd)
1/8 mile: 8.4 sec at 89.2 mph
0-60 mph: 4.4 sec
60ft: 2.1 sec

Run#6: Shifting at 6300 RPM
¼ mile: 12.6 sec at 115.0 mph
1/8 mile: 8.3 sec at 91.6 mph
0-60mph: 4.3 sec
60ft: 2.1 sec

You can see that shifting basically from 2nd gear to 4th gear killed my 1/8 mile traps by about 2mph, but the 1/4 mile by only 1mph. As I said before, any 1/4 mile trap advantage the steptronic has over the manual due to gearing is probably pretty small considering the huge gearing disadvantage of going from 2nd gear to 4th only resulted in a 1mph trap reduction.