Hey guys,

I plan on dynoing my 03 5AT soon, but I am not sure what to expect. Im not talking about the numbers, but the ability for the tiptronic to hold a gear. On my model, if I put it in manumatic and into second at around 20mph the car will downshift into first when I floor it. This happens at every speed when there is the option for the transmission to downshift to a lower gear for faster acceleration.

On the dyno, when I want it to stay in fourth, I am afraid that it will just downshift back into first once the pedal goes down.

How do members with 03's dyno their cars? Is there a way to avoid this, or is this a non-issue?

Thanks for the help

 

Just put it in manual mode ones on the dyno and then slowly accelerate until you get into 4th gear and put it to the floor after that.

-Sean

 

thanks, ill give it a try, but i dont know how well that'll work on a dynapack (my local dyno)

 

Dyno in 3rd, not 4th. Although 4th is technically the 1:1 gear, the torque converter apparently operates differently in 3rd vs 4th gears.

 

will do, i just read that on another site about a g35 dyno day

 

OK -

4th gear is the right gear to do it in. Your numbers will be off doing it in 3rd gear, as ratios are different. As long as the tuner configured your RPM adjustments properly, and enters the right stall info, you'll be fine.

When you hit 4th, take your RPM's up to 3000 and hold it for 1-2 seconds, and smash it to the floor. Lift when your at the desired RPM for the reading.

Do this in Manumatic mode with VDC off.

Rick

 

+1

Torque converter is in full lockup in 4th and 5th...you don't want to dyno in 3rd

 

It will lock up in 3rd as well, but the trans ratios will through off torque numbers and power band measurements, as you will actually go through the band faster.

I've done comparisons of this, in both gears, and when the dyno is adjusted to compensate properly, there is no measurable difference.

As long your tuner knows REALLY what he is doing, and you make sure he knows your 1:1 gear is 4th, you're stall is 2800 - you should be set. Many set the stall to 3000 - as after several runs, and heat build-up, it tends to fluctuate.

Rick

 

He may have trouble with an old sedan unless he gets new tranny firmware update from the dealer. The 03 sedan tranny manumatic mode was more of a top gear selection, not a true gear selector... I do believe the firmware update fixes this to behave more like the coupe.

 

+1....I'm not a pro on the early years...so yea, make sure you address this...

 

I've always dyno'd in 3rd... Church's several times Stillen and couple of times and Motodyne once... all pretty experienced people.

(actually I've dyno'd in 4th too, but it's always mucked).

 

A lot of this depends on the dyno being used; a dynojet offers no such adjustment afterall.

On a dynojet, 3rd is the correct gear. Dynojets attempt to automatically adjust for gear ratios. It's not entirely accurate, but it's damned close. And it's not that hard; the dynojet software knows how fast the roller is spinner, and monitors the car's rpms via the spark pickup. With these two values, it is rather simple to derive a cumulative to-the-roller ratio, that includes FD, selected gear, and tire height. As a result, two successive runs in different gears should produce numbers that are within +/- 3 per cent of each other.

Back in early July I had a friend dyno his bone stock 2005 5AT coupe. First two pulls were in 3rd gear, and the last pull was in 4th gear. Here are the numbers:

1st pull(3rd gear): 227/215
2nd pull(3rd gear): 229/217
3rd pull(4th gear): 223/223

His peak hp increased by 0.9% from the first to second pull, and peak torque increased by 1%.

When the last pull was performed, his peak power went down by 2.6%, and peak torque increased by 2.7%. And he didn't lose heatsoak. I have seen several VQ's on this same dyno continue to make more power until the 5th pull. Additionally, if it were heatsoak, his peak torque would not have increased.

But if you look at the numbers, -2.6% and +2.7%, both are within the +/- 3% range I established earlier, which is fairly accurate. And again, this is on a dynojet, which offers no gear ratio nor stall customization.

 

Absolutely and great points. Although you can't manually adjust the dyno that way, it will do it automatically, which is really just as good.

For me..I want to know that my dyno is as accurate as possible. The 1:1 gear dyno, for me, does that. The +/- 3% difference is meaningless to me, which is why I choose the 1:1 gear every time.

Rick

 

for tuning purposes we always dyno in a gear that is a 1:1 ratio.


on the 6 speeds, the higher the gear usually puts down more power. the 5ATs actually make more in a lower gear due to the running through the gear faster..