Effect of "e-braking" while driving on the transmission and center diff?

[allezgrand]

I've been getting into ice racing recently, and virtually all of the courses have at least a couple hair pin turns which can be attacked much more effectively if you lock up your rear end and swing it around as you enter the turn (sometimes requiring throttle if you don't hit it just right). The last race I was in (with 60 entrants), I won and I utilized this method on every hair pin. I also watched an Evo X win their race class, and they did the same thing on virtually every turn (and have been doing so AND using it as a daily driver for 3 years). But all of this made me wonder, "how much damage am I doing to my transfer case or my transmission?" A buddy of mine who does a lot of rally racing was very wary of doing this with his Impreza as he has been told the center diffs within the transmissions on those are very weak.

I've read the tech articles on LSD's and Types of Differentials, but I'd be curious to hear from those with a solid understanding of DSM drivetrains what effect this type of driving would have on the drivetrain: on ice? on dirt? on asphalt? e-braking while simultaneously on the throttle?

Thanks in advance for your input!

 

[Archer Fabrications]

I'm curious about this too, as when it's cold my ebreak sticks. And i have to drag it to warm it up an pop it off, not exactally the same situation, but similar affected zone. Subscribed.

 

[ricktb]

pretty sure the ebrake was not designed for this and meant for use only while parking, id imagine it would put strain on the entire drivetrain. Couldnt say for sure if or when it would fail. I'd use the e-brake for hairpins on a FWD any day of the week tho.

 

[StarFawkes]

If you're gassing it while the back wheels are locked up then your center diff will not be happy with you.

 

[Archer Fabrications]

Mine doesnt lock up, has similar charistics to break boosting?

 

[hazmat6135]

The best way to do this in an AWD is to clutch in as you e-brake. This takes the stress of the braking against the power off the drivetrain and makes it "kick" alot easier. It takes practice to get the timing down and learn how to throttle over after you let off the ebrake and clutch but it is alot less harsh on the drivetrain and will bring the back end around quicker. I do this daily when it snows in my Impreza which is known for having a weak drivetrain and have not had a problem yet. Good luck and have fun!

 

[gusu]

Another option would be getting REALLY good at feint braking.

The key to any inertia drift is knowing the center of gravity of your car and how much sliding your car will do.

If you don't know or don't feel like googling it. A feint brake drift is where you take the typical racing line however you enter from the opposite side and turn in at the last second causing the suspension to become overloaded which will start the drift. You want to physically be sitting on the racing line with the driver side door being where the front of the car would be. This by itself is a scandinavian flick but when you press the brake right as you start to slide into the drift the brakes it's called feint braking.



As far as how much damage you are going to be doing to your drivetrain, personally I think it would honestly just depend what exactly you are doing. Things like how much gas, how much brake, the surface resistance of the terrain, if you do or don't clutch in, etc. A lot of things that make AWD cars corner fast in hairpins will destroy drivetrain components. Back in the day Colin Mcrae made a video series to help new driver, they are hard as hell to find but they do exist. The most common one you will find is him teaching different forms of inertia drifts, if you find the full length video he actually describes which ones cause more damage and why they are worth the risk if you got the money.

 

[PotatoFlakeSTi]

For whatever reason this seems like a bigger problem on Subaru transfercases.
I've had instructors, and competitors alike sing woes about it.
On ice however, unless the car is on ice tires with 3" studs, I highly doubt it would affect anything negatively as all the wheels would be slowed as soon as grip is lost.

I don't know how big of an issue it would be as occasional occurrence, but I personally don't think you should race any car you aren't willing to write off completely.

I'd suggest picking up a cheap(er) Daily driver, so you can beat the snot out of the DSM without major worries.

Edit; As gusu suggested above, try a Scandinavian flick.

 

[eclipsh]

Your most likely problems will be breaking gear teeth or burning up the viscous coupler (VC) for the center differential. Pushing in the clutch will disengage the engine to reduce harm to the engine and possibly the gears but the front and rear tires will still be connected by the VC and you will still be smacking all the engaged gears pretty hard due to the sudden change in loading. There is always some lash (free play) in gear systems and when you hit the parking brake it is slapping the backs of the gears together quickly instead of the fronts.

The VC is already working hard keeping the front and rear locked together because you are on ice. I'm not sure what that does to the lifespan but a little more abuse through the parking brake seems pretty minor to me.

Since you don't have much grip on the ice locking up three or four tires with the parking brake is putting considerably less force through your gears and drive train than drag launching the car on pavement or even gravel. Given that the stock drivetrain can handle 400 HP I doubt the limited grip of the ice can come close to breaking gears.

In short, you aren't likely to cause much damage. Still, as said above, learning the flick and being prepared to write off the whole car is a good idea.

Wish I had ice racing around here. The best I can do is find a snowy parking lot before the plows hit it.

 

[peypey's ride]

Maybe this will help you guys. Read please.

How to: Scandinavian Flick – Feature – Car and Driver

 

[hazmat6135]

Guys a scandanavien flick is great for a long turn but he's talking about hairpins. The only way to take them with speed is to lockup the backend as your nose is getting close to the peak. Then simply turn in hard and drop the clutch and get back in the gas. It's by far the fastest way to take a hairpin. The "flick" helps with sharp turns at high speeds but not so much here.