mooredc

Is a power lag in the 5AT transmission normal?

It feels like when I floor it there is a [very] noticible lag before the HP really kicks in, it is a very good acceleration when it [finally] kicks in. I previously drove an MT so I'm not sure if this is normal for all AT's and it is just an adjustment I need to make to my driving style or if there is a problem with my particular Z's transmission.

Any thoughts / opinions?

hypeiv

iTrader: (2)

when does it happen? low speeds all speeds... from a stop from a roll... I have noticed on an auto car if you roll idle then punch it its a pretty lame jump compared to when you punch it form a dead stop.

mooredc

I notice the lag at any rolling/constant speed.

I normally don't punch it from a dead stop. I just don't want to get the attention of burning rubber ... cops don't like it and it just isn't that safe on the commonly wet FL roads.

Aggro_Al

If you are in auto-mode 4th or 5th and you go to WOT, you might have a slight delay while the transmission downshifts. It shouldn't really be that noticeable because the shift is really fast ~200ms (yes, that's 1/1000 of a second). Just for reference an eye blink is about ~300ms and a professional NASCAR driver can shift in ~0.8s. If you know you are going to floor it ahead of time and you are in a high gear, it is better to manually downshift the car prior to WOT then the transmission won't have to downshift during WOT.

From the dig, it's not a power lag that you are noticing, it's a power surge. Look at a dyno graph of a 5AT in the low to mid end. The 5AT is better at torque management. When the 5AT is un-locked it will torque multiply. If you go to WOT without brake torquing you will get a catapult effect. The transmission will flash straight to the stall speed then as it couples it will gradually trade torque for velocity until it locks or couples.

Aggro_Al

Are you lifting off the throttle when you shift? If you do, you will get a slow shift. I found myself doing this unconsciously out of habit when I first got my car, it took some effort to break myself of that. I don't notice any lag anymore except on the downshifts. The transmission will delay or cancel your downshift command if it ends up putting you way over the rev-limiter.

I had an MT Honda while my car was in the shop and when I got it back I found myself lifting off the throttle again.

Also, are you sharing your Z with someone else? The 5AT is a real-time learning driver adaptable transmission. It doesn't like to be shared. The transmission will learn your particular driving style and change itself so that it almost becomes part of the driver. So, if someone else drives your car for a while it will take time to re-adapt to you.

kinjal

iTrader: (5)

Al, ive read alot of your posts, and its obvious that you know what you are talking about. What mods would you reccomend for the 5at 350z touring? could you list the names of the products that you would reccomend for power gains (intakes, exhausts, plenum, etc.). I have around 1000-1500 i am looking to spend wisely. thanks

Aggro_Al

If you have $1000-$1500 to spend on a NA street 5AT, this would be my mod choices.

High Stall Torque Converter, maybe a mild stall increase around 300 RPMs. There is no real power gain here but it will keep your transmission closer to optimum torque. Only FI will give you faster 0-60 times.
$750-$1000 for part and install

Upgraded Valve Body, no power gain here either but you will get crisper, firmer shifting.
$750-$1000 for part and install

For real power gains you'll need to go FI. Auto transmissions work well with turbochargers because you can launch in boost or modify it to eliminate or reduce turbo lag.

Check in the mod section to see what different people like as far as the torque converter and valve body parts go. Also, check out Stillen, Level 10 and Edge Racing.

Bubble

iTrader: (50)

interesting. This is new for me. Thanks for the info.

Paul350Z

iTrader: (1)

VDC off?

Aggro_Al

Only the 35th Anniversary 5AT has VDC. mooredc has a touring model. If it was TCS his SLIP Light would come on.

mooredc,
You mentioned that you floor your car on the roll. Almost all cars, AT or MT, have a harder time accellerating at speed.

kpiskin

iTrader: (5)

I just got a 2003 5AT Touring model and do not notice any lag, but I am coming from a Chrysler 300M Special that does 0-60 in 7.2-7.4 sec.

hypeiv

iTrader: (2)

what???

200ms = 200/1000

you must have been saying 1ms = 1/1000

Aggro_Al

Yup, you're right. The last time I used 200ms as the shift speed someone used my quote to prove that the 5AT was slow because it took "200 seconds" to complete a shift. Just wanted to make sure people knew that that was in milliseconds and not seconds.

Sensation350Z

ROFL, some people

Nitrouz

iTrader: (27)

tcs off

hypeiv

iTrader: (2)

lol 200 seconds... you could teach someone to drive stick in 200 seconds.

pgh2atl

I have a '03 Touring as well & maybe its just a mental thing, but I've noticed that the lag seems to disappear when I turn off the TCS. When using the shiftage, I do noticed a brief lag when I shift up (even more when shifting down) before the car shifts to the next gear with TCS on. I seems that the car gets to the next gear alot quicker when I turn off the TCS. Maybe because the car doesn't have to take an extra step to make sure the car won't 'slip'....I'm not sure. Does anyone else notice this or can elaborate on this?

mooredc

Thanks for all the great information and tips. I'll see if TCS seems to make any difference for me.

Can anyone point me to more information about the adaptive nature of the Automatic Transmission? I'm curious to know more about how and what it learns about your driving habits.

Teez Zee

So, let me get this straight.

I have 2004.5 SB 5AT touring Roadster.

If I turn off TCS and punch the pedal to the floor while the car is stopped, should It break traction?

If I put my foot on the brake and bring the rpm to 3k and then simultaneoulsy, floor the gas while letting off the brake should it break traction.

My car seems to have plenty of power and acceleration. But, I have never had any hint of tire screech when I take off from a stop.

Is this normal?

Zductive

kinjal

iTrader: (5)

i have never had tire screetch in the auto mode. if you swith to the manual shift mode and do what you said, you should get a bit of tire screech, but nothing insane.