a nice cool nov./dec./jan. night will give better results than what will be obtained during the middle of the day in june/jul./aug.

actually, imo. to get the 'best' results you want a combination of track conditions.

a hot track (better traction).
a cool air temp. and low humidity (better power production).

it sounds like you've got a pretty good handle on your 'method'. esp. if you are able to predict your results within a 'few hundreths', very good, that also tells me you are consistant.

i did notice, however,

i agree, higher pressure up front and lower in rear helps. it basically, changes the angle, applying more pressure to the rear sooner. with higher pressure in the front you have raised the 'nose' of the car a little (albeit a little - but every little bit helps), assisting the weight transfer to the rear tires. as well as allow the rear tires to 'flex' easier/sooner instead of being solid and spinning as soon.

is that on purpose or are you just not getting enough power to the ground ?

agreed, when you spin you aint moving, i'm just curious if you've 'learned' your car well enough that you know how to 'stay on the edge of traction loss' or if you (don't take it personal) aren't 'hitting' it hard enough, or are other things are occuring.

since you are driving an automatic, i'm curious if you've ever tried to 'manually extend you shift point'

here's my explaniation of 'manually extending your shift point'

car in drive.
depress the gas pedal.

the 'automatic' transmission will 'automatically' shift into the next gear when certain thresholds are met. i.e. rpms

if you know when those conditions (when the car will shift) are met you can hold it in the 'lower' gear simply by slowing your addition of throttle just prior to the known shift point.

with each upshift the amount of torque applied to the rear tires is reduced.

let's say your car 'automatically' shifts at 5500k rpms, if you stay in the throttle.

if you slightly lift and hold at 5400k the car will not shift, it will stay in the current gear.

it's similiar in concept to 'peddeling' except instead of 'peddeling', as one would do during traction loss, you are preventing the shift, and thereby delaying the drop in rpms and readjustment of power application.

at a certain point the 'delayed' shift will slow acceleration, once you have detected that you are no longer accelerating, go ahead and bring up the rpms and let it shift into the next gear, but stay in it, don't lift.

btw: i went out the the shed and looked for my data, but it looks like someone rearranged some stuff. i'm gonna continue to look and will let you know when i find it.

 

No Zig I don't really use any real special type launch. I have slowed down the amount of time it takes me to floor it. I do it just slightly slower, but not much. CF member Dennis suggested that and it did seem to help my 60 a little.

On a prepped track my car really just does not spin. To get it to spin I have to power brake fairly hard. Now it will spin on the street on a regular road but not a lot. I had the same experience with my A4/3.15 C5's. For me the runflats were fine for drag racing traction wise. I just did not like burning them up at the track.

I go to two tracks, at one of the tracks it is impossible to stage without going through the water box. So it forces me to spin my tires and clean them off. I did not like doing this with my runflats so I went with DR's.

 

A really hot track will usually result in poor traction, not better. The NHRA telecasts are always talking about this in the summer months. Really cold temps (as in sub-freezing) will also result in poor traction.

Raising the inflation pressures on the front tires does not raise the front of the car even a millimeter, or aid weight transfer. It reduces rolling resistance.

There is a simple reason why the auto tranny C6's do not spin their wheels, and their 60-ft times are consequently so consistent. It's called TM. This would be a good thing if the times weren't so crummy.

Shurite, Next time I'm at the track I'll try rolling onto the throttle a bit at launch. I've read elsewhere that this will offer modest improvements.

 

once the track 'glazes', then yes.

not even one millimeter ??

how high does the car sit when the tires are flat vs. inflated, oh forgot run-flats....hehehehe

yes, higher pressure reduces rolling resistance.

can you explain how tm works in the 'autos' ?

if it (tm) is, an across the board thing, wouldn't that result in a maximum time being able to be obtained and nothing more. you would reach the peak level of performance not be able to exceed it ? all of the best times (corrected) would be the same or within the margin-of-error.

 

You're starting to get the picture --- this is exactly what the A6 drivers have been reporting. My last time at the track, my short times were all within .04 of each other, and the best was a 2.11. That sucks.

(I posted earlier that I had a 2.04 on one pull, but when I looked at the time slip again, I realized it was my opponent --- a C5)

 

i'm not try to start a debate or anything like that i'm just wondering, because apparently i missed the discussion about the times being reported, etc.

60 ft is kinda short .. but how is everyone comparing their times to conclude that they are the same.

is everyone, across the board, regardless of tire pressure, types of tires, traction, altittude, air temp, engine temps, etc. reporting the same best times ?

regardless of 'launch technique' ??

the whole day you stayed within .04 of yourself ? what were the 'conditions', air temp, engine temp, alittude, tire pressure, etc. of your runs ?

how do your best times compare to others with similiar conditions ?

was the c5, you ran against, modded in anyway ?

are you saying, the stock c5 bettered your stock c6 ? were they both automatics ?

 

Lets not get into a "does TM exist again please"

If you have a modern vehicle there is TM in your tuning.

Just do a search on the Internet, lots of info on modern vehicles and how they use TM. Ford, GM, Chrysler all use TM programs.

It really is not a good discussion.

Now back to your regulary scheduled launch thread.

 

 

Zig, you're still not getting it.

My launch technique, tire pressure, type of tire, were exactly the same on every run. DA, temperature, humidity, and wind varied quite a bit from run to run, as the first run was at 10:30 AM, and the last was around 2 PM. However, the short times were always the same!

When you have no wheelspin, traction is not an issue. When the short times are always the same, regardless of atmospheric conditions, then there must be some other constant factor that overrides everything else. That constant is TM. It limits the amount of torque that is delivered to the drivetrain to a maximum limit, and no more. That constant may vary from one car to another, but it sure seems to be consistent for one car on one particular day.

Exactly how it does it, and whether the TQ is measured directly or inferred from other measurements, I do not know. What I do know is that it can be defeated through tuning, and that there are specific variables in the ECM that can be adjusted. Read Chuck's threads from Corvettes of Westchester.

End of story.

 

maybe true, maybe not.

i'm not sure how you can be so adamant about a postion when you say,
maybe, there is an explaniation, who knows, but we will never know if we arent able to eliminate possibilities.

wow.. that is suprising (no offense meant), how great were the variances in temp. humidity, track temp, etc. do the variances fall within the given margin of error for the calculation. i.e. not great enough to make a difference.

why can't use corrected timeslips to compare ?

can you eliminate the possibility that 'traction is not an issue' because there isn't enough power being put to the ground to make traction an issue.

a constant that varies. hmm. cool...

which is what i wouldn't mind figuring out.

yes, there are a lot of items in the ecm that can be tuned to get more power.

i have not heard of ANYONE raising just the TM limits and not changing anything else and reporting major gains.

maybe they have, i just haven't heard.

 

working with knowns. mathmatically we should be able to determine the 'best' time possible, under ideal conditions.

(i stole the following chart from another post, but this way i didn't need to retype it.)
Column 1: A6 (automatic)
Column 2: MN6 (manual)
Column 3: MZ6 (Z51 manual)

Gear ratios
1st gear-----4.02---2.66---2.97
2nd gear----2.36---1.78---2.07
3rd gear----1.53---1.30---1.43
4th gear----1.15---1.00---1.00
5th gear----0.85---0.74---0.71
6th gear----0.67---0.50---0.57
Reverse-----3.06---2.90---3.28
Rear axle--2.56---3.42---3.42

at what gear will you be in at the 60 ft. mark.

how long would it take to move 3500lb (or whatever it is) 60ft using the known gear ratios.

how much hp/trq would it require ?

if you use your known times as the 60ft variable, how much hp/trq does it require ? do you produce that amount, in the time required ?

wouldn't this result be the 'best' one would be able to obtain under ideal conditions ?

how far off are the reported times from the 'ideal' times ?

 

first gear with all

 

As I said, you still don't get it.....

 

then, tell me.

all i hear is wha.. wha... wha...

each time i ask for an explanation all i get is, 'you don't understand, it's beneath me to try to explain.'

please educate me so i will stop asking such silly questions.

are you saying all possible possiblities have been addressed and therefore there isn't any need for a discussion.

what if i told you i had a dyno run show over 1000 hp, no supercharger, no turbo, no nos, no major mod.

fluke, yes, correction factors not entered properly. i can't claim those numbers to 'compare' with anyone.

you cannot use uncorrected numbers and compare them with someone else in another location.

humor me, let's see what type of results we get when we correct the timeslips.

between the hours of 10:30 am and 2 pm. how drastic were the weather changes during your runs.

 

& that is why the 330 & 1000 foot times are so important

 

He is looking at comparing the 60 foot, 330 ft and 1000 ft times.
Correcting for location will not change their relationship to each other.

Why not post some time slips and humor all of us otherwise this discussion is totally useless.

 

Maybe, but do these correction factors take into account traction all the way up the track? Variations in torque converter or clutch slippage as related to various traction or weather conditions? Wind conditions?
It might be the only way but I'm just not sure what comparing times using corrected timeslips really accomplishes/answers, you ran what you ran, period.
When John Force sets a new NHRA record running say a 4.55@323.44 or whatever they don't stop and say "oh wait, in another state that corrects to only a 4.58@322.87, haha it's not a new record" LOL, it is what it is.

 

my point about using 'corrected' timeslips is thus;

it seems that some claim that their best times are as good as they get and therefore TM must be the cause.

what i'm simply asking is let's compare the corrected slips,

if we are able to level the field and have a 'common' base from which we can compare it will be alot easier to prove if the 'best' times are as good as it gets or if there is another cause for ones inability to achieve a better time.

just because one remains consistent on a particular day does not prove TM.

if all things are the same, during the run, what would lead one to believe that something should all of a sudden be different, meaning if you always do such and such and get a particular result why would you all of a sudden expect a new/better result.

if the launch method is the same, the types of tires, tire pressure, traction, power production are all the SAME (run-to-run) then how can one claim that it's TM that is preventing any gains.

correct the timeslips and compare them to someone else's and see how they compare.

if 'corrected' timeslips ALL show the SAME TIMES for the same type of 'untuned' vehicles (z51, mn6, base, auto, etc) you will then be able to claim TM is holding the car back, otherwise you aren't doing a direct comparison.

which location is gonna provide the better times, provided traction is not an issue, alaska or georgia ?

if you're not overpowering your tires (traction) you have not exceed even the most basic 'limit' on the car.

but john isn't claiming that TM is holding his car back.

how can one determine the 'absolute' min. time possible to travel a distance, without any traction issues, tm, etc. etc ?

i'm quite sure the gm engineers did some pretty cool match to figure out approx. ow the car would perform BEFORE they put it together. i really dont think they walked over to the part shelf and said, "hey, let's try this gearset this time, i bet it will do pretty good."

let's see if we can figure out how well the gearsets would work ? are we even close ?

how can we make a 'claim' against gm when we aren't able to prove they are 'limiting or managing' the car by (x) amount.

 

agreed, if he is only comparing his own runs. how can one claim that he has achieved the absolute maximum when he's not able to compare the results from someone else.

 

that being said. here is a copy of the 'uncorrected' results posted in the '1/4 mile challange thread'

i have sorted them by model.

Showroom Stock

automatic transmission.
(sorted by model type)

12.56 @ 112.00 - Orange C6 - 05 Z51 A4
12.71 @ 111.00 - Demented - 05 Z51 A4
13.26 @ 105.30 - Joeking - 05 Z51 A4
13.62 @ 106.18 - Rich28 - 05 Z51 A4

12.70 @ 112.43 - Jelsis - 06 Z51 A6
13.30 @ 107.00 - Shurite44 -06 Z51 A6

12.97 @ 108.00 - Ginny C6 - 05 F55 A4

12.74 @ 108.67 - Shooter 49 - 05 A4 3.15
12.83 @ 109.44 - Tommy D - 05 A4 3.15
12.98 @ 108.00 - Tampa Vet - 05 A4 3.15

12.48 @ 112.11 - LS1LT1- 06 A6
12.61 @ 115.91 - BlownV6 - 06 A6
12.69 @ 112.32 - Silverlx -06 A6
12.72 @ 111.98 - SR0707 - 06 A6
12.85 @ 110.00 - Soldsyclone - 06 A6
12.98 @ 109.86 - JLKing - 06 A6
13.04 @ 109.15 - TMyers - 06 A6
13.35 @ 108.10 - Phatpharmd - 06 A6

Manual transmission - sorted by model (z51, f55, base)

12.23 @ 115.58 - 06C6FVR - 06 Z51 M6
12.42 @ 113.90 - DrRichie - 05 Z51 M6
12.49 @ 114.90 - Jschindler - 05 Z51 M6
12.54 @ 113.24 - NineBall - 05 Z51 M6 - tstat
12.65 @ 111.65 - Zippin Zee - 05 Z51 M6
12.79 @ 112.17 - Jchazr - 05 Z51 M6
12.81 @ 112.83 - Vette-oholic - 05 Z51 M6
12.85 @ 114.53 - Mr Z51 - 06 Z51 M6
12.90 @ 114.83 - Normlunt - 05 Z51 M6 - tstat
12.97 @ 109.98 - Joe G - 05 Z51 M6
12.99 @ 111.70 - C64ME - 05 Z51 M6
13.12 @ 110.40 - JDWK - 05 Z51 M6
13.25 @ 110.60 - C6 Matt - 05 Z51 M6

12.31 @ 114.82 - CYA Vett - 05 F55 M6

12.92 @ 112.92 - Prankster - 06 M6


if one is using 'timeslips' to prove the existance of TM, i wouldn't expect such variances in the times reported for the 'same' models. oh, wait.. these are 'uncorrected'...arrgghhh.. how can we compare ???