Tc Off = Loss Of Power?

[555]

I THINK I've read that TC On means a possible loss of acceleration. Anyone know this to be true? Do you turn your TC off in dry weather? Any percentage of power gained with TC off (your estimate)??

Thanks all...

'99 Boxster with only 26k miles, Ocean Blue, Savannah Beige Leather, Tiptronic, Wind-stop, HARD TOP, NAV/PCM, full leather, 18" Pirelli PZeros, TURBO WHEELS, 6 CD Changer, AERO PKG, and for sale!
:-)

[Stryke]

The way TC operates is when it sense that a wheel is slipping or spinning faster than the other one, it will pull power from the wheels to allow it to catch. This means that full engine power is not transfered to the wheels at all times.

When it comes in there is a short lag until full power is restored to make sure you do not slip again so it will slow you down.

If you want to go fast in a straight line then yes, go ahead and turn it off and it may improve your times.

[555]

Thanks for the info! Just wondering because sometimes I see this terrible lag in like 3rd geer. I'lll give it a decent amount of gas and there's this 1.5 - 2 second delay in response.

[Stryke]

I can only think of two reasons for that to happen.

1. The traction control is stopping you from slipping if too much power is going to the wheels, and

2. If you up shift too early you may be in a low RPM range in high gear and therefore the power band may be weak until it catches up.

Maybe others can add to this.

[jfmillr]

I didnt get TC in my 986 for this exact reason. I want full power at the wheels at all times and in all conditions

[Stryke]

But you can switch it off with the push of a button. I feel safer in the rain or winter in general taking corners with the TC on. In the summer I switch it off.

[555]

Hmmm... It's actually a great thing in wet or cold conditions. And... it can be turned off with one touch of a button. So it's great either way.

Why would you want full power to the wheels in rain or ice?

[Adam]

Originally posted by 555
Thanks for the info! Just wondering because sometimes I see this terrible lag in like 3rd geer. I'lll give it a decent amount of gas and there's this 1.5 - 2 second delay in response.

Well its definately not wheel spin if the road is dry. I doubt a 2.5L boxster could break the wheels loose in 3rd. It takes serious power to do that. More power than what the boxster or boxster s has. I give my car all I can, and I get some healthy wheelspin at the 1-2 shift, but never in 3rd gear and my car is sans TC. I think the only way you could get wheelspin in a boxster in 3rd, in dry conditions, is to rev it 7,000 plus rpm and drop the clutch. Even then, the engine will probabbly just bog. Never tried it and I dont plan on it because it's real hard on the driveline. So anyway, I don't see why the TC would kick in if your in 3rd gear. I assume it's something else.

[donv]

My understanding of TC operation is that it doesn't affect the engine output at all - what it does is use the anti-lock system to apply the brakes to even out the car and stop the wheel spin/slip (therefore "fighting" against the engine in a way). I've triggered it in 3rd several times while being a bit too aggressive in fast cornering (dry pavement, on/off ramps), but never on a dry straight. It does feel like a loss of power when it comes on, but much more subtle than hitting the rev limiter.

[Stryke]

I believe you are confusing the TC with the PSM which is the newer system that Porsche uses.

While TC does limit engine power to the wheels, PSM applies independent wheel braking.

[Alienz]

I was testing my Boxster in the parking lot of my appt complex which atleast has 2" of snow. Traction control is amazing! The moment I turned it off I was doing donuts. I don't think you can loose control of the car while TC is on. Unless you are drving insanely fast (at 5th or 6th gear!) snow. THe blizzaks I have are awesome. I'm passing SUVs on the highway. I'm talking EXTREME conditions: heavy snow and unploughed roads. Boxster performs excellent. I wouldnt turn the TC off tho to see what would happen hehe.

[donv]

Thanks for pointing that out... yes, my comment was really about PSM (as was installed on my 2001), instead of TC. Based on the TC description, I'm glad to have the PSM. Other than for the one time on a skid pad at an autocross novice class (wouldn't skid!), it has never got in my way - but produces great assistance when required.

[Stryke]

Aren't you able to turn the PSM off if you wish?

[donv]

Yes, you can (at least mostly...*). The lack of skid was before switching it off - once off, massive sliding/squealing was had, making for much more fun! In normal driving situations, I can do without this form of fun .

*I've seen it represented (I think it was in the PCA magazine) that even though you can turn PSM off, it continues to monitor and can come back on if something really crazy is happening with the car. The example they mentioned was coming unloaded over the top of a rise while cornering at track speeds - the PSM was rumored to come on briefly and then go back off. I doubt I'll ever come to see that myself...