R1ck

Hi everyone,

I have an Acura TL 06 automatic and I was wondering about something:

If i'am on the highway at 100 km/h and I switch to the SportShift mode and then downshift to the 2nd gear (from 5), can this damage the engine and/or something else?

I tough that the computer would block any action that could damage the engine but it let me downshift 5-4-3-2 (RPM goes from 2500 to 6500+) on the highway at high speed (100 km/h). It let me down shift to the 2nd gear at 100km/h!

Thank you

stock to the bone

Canadians and their metric system.....j/k. Yes, doing things like that would shorten the life of your transmission. IIRC, the ECU wont let you do that if downshifting revs pass the redlight.

Bearcat94

Owners Manual shows max speed to allow downshift. Above that speed the gear indicator light will flash the gear number you wanted, then display the gear the car is in.

For 3 --> 2 downshift, max speed is 56mph/90kph for the TL or 61mph/98kph for the TL-S.

My guess is that you weren't doing 100 kph when the shift actually occured. From the time you request the shift for (iirc) 5 seconds after, your speed falls within the paratmeter, the shift will occur.

R1ck

Could it actually be damaged if I done this twice?

Bearcat94

Possible. However, may bot be likely. It depends on whether you did in fact over-rev and by how much. There should be a little wiggle room.

The probelm with an over-rev is that you can "float" the valves and damage them. Typically this occurs in the MT with a mis-shift. Where you plan to grab 4th, but mistakenly grab 2nd --> zoom, rpms hit maybe 8k or so.

There SHOULD be no way to over-rev the AT. If there is, it's a defect and that means it's a warranty issue.

The way to test for damage is a compression leak-down test. If the cylinders hold pressure, the valves are seating properly.

R1ck

In fact, The RPM never went over the redline; it went 6500-6000...

is that kind of down shifting (with AT using Sportshift) bad for the engine?

Thanks!

Doridori

I'd like to know this as well.
I thought ATs blipped the revs so it would be easier on the tranny... not sure.

I hate cars

You can't hurt the engine or trans by downshifting. The sport shift mode is just a switch. It sends a signal to the computer and the computer decides to execute the command to the trans or not.

I don't recommend downshifting from 5th to 6,500rpm in 2nd over and over, it will cause more wear but won't hurt anything right away. If you're driving on a course and already have the rpms at 4,500 and you downshift to 6,000 it's not a big deal. It hurts more when there's a large differential say from 1,200rpm to 6,500rpm.

I hate cars

'07-'08 models do this. Much less shock on the drivetrain.

Bearcat94

Sorry, I misread your post. For some reason I thought it allowed you to downshift into an over-rev.

IHC's post is more relavent to your sitiuation.

Regardless, the car should not allow a downshift into 2nd at 100 kph.

01tl4tl

98-100 to your eyes its the same thing~

the ecu wont allow a downshift that would cause a redline-over rev condition
The PROBLEM with 5 to 2 gear downshift is the 2nd and 3rd gear clutchpacks are weak, and not well oiled or well cooled by the oil
As a result, frequent extreme use will put the hurt on them

A few times is no sweat, only if you are doing it over and over will you be damaging things, wearing out the clutches- yes the auto trans has clutch disc- similar to a motorcycle, not a dry system like MT cars

SS is good for backroads fun-when you want to be in 2nd and 3rd most of the time
It doesnt make you pass anyone faster on the freeway than stomping the throttle- the computer still has to make several things happen in a row to downshift and accellerate

Use the BRAKES to slow the car- they are relatively cheap versus a trans replacement at 4000$++

Doridori

Hi,
then is it better to step on the gas instead of down shifting in sport mode for quick acceleration?

R1ck

Id like to know this as well: Is it better (overall) to put the paddle all the way down to accelerate or do a downshift + paddle?

01tl4tl

for pure accelleration on demand just stand on the gas pedal in D5

the purpose of SS mode is to allow a sporty feel when you play in the backroads
You can do the same thing by using d3 d2 but its much more race driver to have a flick stick

swoosh

iTrader: (5)

i would not downshift to slow my car on a downhill slope or before a stop sign....but yeah you can downshift if your in a hurry and need to get some speed from lower gears at higher rpms !!!

say your doing 80mph (120kmph) on 5th and you downshift to 3rd !!! by mistake you tap is 3 times and the car is downshifting to 2nd....the ECU will not allow this since you will be wayyyyy into redline doing 80mph/120kmph on 2nd....so '2' will blink (in the dash) and the car will stay in 3rd....

the threshold for up-shifting is:
3rd to 4th you should be more than 30kmph or 18mph....
4th to 5th you should be more than 60kmph or 38mph....

similarly downshifting thresholds !!!

AckRite5TL

Is it me or is anyone wondering why he is doing this more than once? I use the SS to downshift and hit the gas to gain speed more quickly in a lower gear. Why on earth are you trying to shift from 5 down to 2 on more than one occasion?

Couldn't you have answered your own question?

swoosh

iTrader: (5)

^^^ he couldve !!! unless you were talking about me LOL !!!

OP again when you shift from 5th to 2nd the tranny is taking a major thrashing....the car will shift if your at 40-50 mph (60-80kmph) since you will be redlining on 2nd @ ~55mph (~80kmph)....any more and your car will not down shift anymore than 3rd !!!

R1ck

I was curious!! I thought that it went in the 2nd gear but looks like it went on the 3rd only and refused to go on the 2nd because the RPM only went to 6500 and never redlined.

Thanks!

csmeance

The stock automatic transmission software will not allow the car to over-rev what-so-ever. If you drop it into second gear going about 60 and the car allows it, it will be fine. The only thing you have to worry about at that point is not scaring your passengers. Also FYI the stock RPM guage has an error in about 200 RPMS near redline from what I have seen with dyno's here.

hp1kw

Hehe do not do this. 2nd Gear is very fragile. I've hit the rev limiter and I'd rather do that than downshift 5-2.