Which is it OD or D?

What the hell happened here? I always run in Drive. Last time at the track I inadvertently ran once in OD and picked up 0.71 mph from the previous run. On the subsequent run I put it back in D and lost 0.53 mph from the OD run. Here's the ETs and MPH for the 4 runs I had. Initial track temp was about 98 cooling to about 85 by the last run so I expected to pick up mph on every run.
1. 2.199/13.739@101.77 D
2. 2.278/13.771@102.17 D
3. 2.436/13.899@102.88 OD
4. 2.331/13.887@102.35 D
I thought 4th gear wasn't needed in the 1/4 for an A4. Is it something else? The only other things I can think of is that the staging lanes took a little bit longer on the last run and the car was now at an 1/8 tank (in case that timing retardation with low fuel level rumor is true). Can someone set me straight here? At what mph does fourth kick in at WOT (I thought it was 110)? Is there any difference between racing in D vs. OD at the strip? Any info would be much appreciated. Thanks.

You want be in 4th at the end of the 1/4 with your current setup.
It really does not matter if you leave it in D or OD, it won't affect performance at all.
Typically when you spin alot at the starting line you will trap higher MPH than ET. By the look of your 60' times, you are have major traction issues, either go softer at the launch or invest into some stickier tires.

If you have 3.23 gears you won't hit 4th 'till 130 at WOT. You're not anywhere near that in the 1/4.
If you really want to quantify any differences in leaving it in D or OD then you'll have to make several runs each way in the same lane. I really don't think that it makes any difference.
I leave mine in D to use the engine breaking at the end of the run.

From what I've been told, the shift points should be higher if left in D but since I don't have an OD tranny I can't confirm it.

Originally posted by Stephen 87 IROC
From what I've been told, the shift points should be higher if left in D but since I don't have an OD tranny I can't confirm it.

That was rumored with the LT1 cars but never proven.
His is an LS1 car and I have noticed no difference at all with mine.

forget OD and D... i dont care what anyone tells u if u watch ur tach u shift early at WOT. (~5800 RPM) redline on these cars is 6000. i shift my car out of first manually and it will USUALLY give u a tenth or two. shift it at about 5700 and the tranny should delay and shift at around 6000. get it right and it FEELS stronger too. IT ISNT GOOD ON THE TRANNY but for a couple tries at a best ET, it wont hurt anything. plus its more fun then pointing and shooting lol.

Originally posted by Ken95Z28
Typically when you spin alot at the starting line you will trap higher MPH than ET. By the look of your 60' times, you are have major traction issues, either go softer at the launch or invest into some stickier tires.

Thanks for the info Ken. I didn't know spinning of the line had that affect on MPH. On the third run I overshot the staging markers then put it in Reverse and deep staged. I was still inching backwards when they started the tree on me:mad:. I then shifted into OD as quickly as I could and mashed it, got zero traction for what seemed like forever. Fortunately I was running an 02 Accord. He ran a 16.444@84.60 with a 2.583 60' and a 0.940 R/T. I ran a 13.899@102.88 with a 2.436 60' and a 1.634 R/T. Sad thing is I still beat him by 1.8517 sec.

Originally posted by 94ZRiCeKiLr
forget OD and D... i dont care what anyone tells u if u watch ur tach u shift early at WOT. (~5800 RPM) redline on these cars is 6000. i shift my car out of first manually and it will USUALLY give u a tenth or two. shift it at about 5700 and the tranny should delay and shift at around 6000. get it right and it FEELS stronger too. IT ISNT GOOD ON THE TRANNY but for a couple tries at a best ET, it wont hurt anything. plus its more fun then pointing and shooting lol.

Forget that just get a programmer and set it to shift exactly where you want it to. You'll be a lot more consistant.

Originally posted by Ken95Z28
You want be in 4th at the end of the 1/4 with your current setup.
It really does not matter if you leave it in D or OD, it won't affect performance at all.
Typically when you spin alot at the starting line you will trap higher MPH than ET. By the look of your 60' times, you are have major traction issues, either go softer at the launch or invest into some stickier tires.

Exactly what I was thinking. The 60' times are all over the place. If you look closer, your MPH is higher but your ET is slower. It's all in the 60'...

;)

You can try to shift the tranny manually but you won't gain anything. The computer controls the shifting. If anything it will bump off the rev limiter a few times than it will shift it for you (computer that is). Now if you have a TransGo shift kit it will allow you to hold any gear at any RPM.

Danno02SS - At least you won against the Accord :D
Just keep practicing on the launch. I know when I had some 275's BFG T/A's on the rear the best 60' I got was in the 2.0's.

Unless you can run near identical slips back to back with an identical set-up, you are fooling yourself if you think you can discern fractional gains when you make a minor change.


Other than that, on a non-electronic 700r4 / 4L60, keeping the tranny in D will generate higher line pressures than OD. This will give you slightly harder / later shifts. Stock trannies it doesn't make a big difference at max line pressure is still low. With a well-built tranny though, if you leave it in D you can tell a difference. If i leae my car in D driving around town my trans will beat the hell out of me because every up AND down shift becomes ultra-positive and crisp. In OD it's almost a cadillac.

I don't know if the 4L60E is programmed to similarly give more line pressure or different shifts based on shfter position. I'd venture not, unless you specifically programmed it to do so.

Originally posted by notgetleft


I don't know if the 4L60E is programmed to similarly give more line pressure or different shifts based on shfter position. I'd venture not, unless you specifically programmed it to do so.

The E on the 4L60e is the key. The PCM controls the line pressure based on MAF readings, current gear, TPS voltage, current RPM. There is no correlation between the 4L60/700r4 and the 4L60e except for the hard parts.

I leave mine in D when I run.

i dont think it matters at WOT on the 1/4 mile. Ive tried testing it. i do have a transgo shift kit installed too. but when goign from a roll, D is alot better since u alread are 1 gear below what ud be in od. all od is there for is too shift early to get better gas mileage under NORMAL DRIVING CONDITIONS, NOT RACING

Originally posted by AL SS590 M6
The E on the 4L60e is the key. The PCM controls the line pressure based on MAF readings, current gear, TPS voltage, current RPM. There is no correlation between the 4L60/700r4 and the 4L60e except for the hard parts.

The non-e trannies do more than just increase line pressure when you're in 1-2-D compared to D. Besides increased line pressure, it also locks the sprag to allow engine braking. I just figured that the later pcm also looked at shifter position to do stuff like that as well. And when you're engine braking, you want good line pressure.

But then again, maybe not.

I never thought it made a difference whether the tranny was in D or OD?:think: I thought the only difference was it won't shift into 4th if kept in OD?!:confused: (I've never heard that the line pressure applied on each shift would increase if the shifter was kept in D?).

Your times all look pretty close together, so I don't think it has anything to do with the shifter position..........it's all to do with your launch (mostly). Your times are between 13.7 - 13.9, @ 101 - 102 mph...................I've had times from 13.4 upto 14.1 on the same night, with speeds from 100 upto 106:rolleyes: (all based on my 60' time, which relates back to traction;)).