What broke at the track day?

LaCross · 06-22-2015, 08:17 AM

Lets get a little guide set up. Do you track your car? Did something break? Tell us what broke!

1Spec · 06-22-2015, 08:32 AM

Things don't typically break when you track your car. When you're at the dragstrip and you launch hard is when axels usually give out, especially if you have wheel hop.

88atlas07 · 06-22-2015, 09:19 AM

First ever track day yesterday and nothing broke, and I ran her pretty hard. Oil temps held steady at 250F and no limp of any sorts. Brakes were smoking when I came off but that's to be expected. Took the beating like a champ!

LaCross · 06-22-2015, 09:25 AM

These things actually break axles? Those damn axles are beefy

Zombie1 · 06-22-2015, 09:28 AM

Quote:

Originally Posted by LaCross

These things actually break axles? Those damn axles are beefy

they are hollow..

matthewo · 06-22-2015, 10:43 AM

I broke everything, had to buy a new car

Antetokounmpo · 06-22-2015, 12:01 PM

Quote:

Originally Posted by Zombie1

they are hollow..

The torsional rigidity of a hollow shaft is almost always greater than that of a solid one. Meaning a hollow drive shaft can handle a greater shear stress than a solid one. Meaning, a hollow drive shaft is actually stronger than a solid one. This is mainly because the shear stress near the middle of the shaft is negligible.

Zombie1 · 06-22-2015, 01:03 PM

Quote:

Originally Posted by bk335

The torsional rigidity of a hollow shaft is almost always greater than that of a solid one. Meaning a hollow drive shaft can handle a greater shear stress than a solid one. Meaning, a hollow drive shaft is actually stronger than a solid one. This is mainly because the shear stress near the middle of the shaft is negligible.

Thats interesting because all the upgraded shafts are solid ones?

csu87 · 06-22-2015, 01:07 PM

Quote:

Originally Posted by bk335

The torsional rigidity of a hollow shaft is almost always greater than that of a solid one. Meaning a hollow drive shaft can handle a greater shear stress than a solid one. Meaning, a hollow drive shaft is actually stronger than a solid one. This is mainly because the shear stress near the middle of the shaft is negligible.

Quote:

Originally Posted by Zombie1

Thats interesting because all the upgraded shafts are solid ones?

Depends on materials and diameters of the shafts.

Generally speaking, the same materials, same diameter, a solid shaft is stronger. The benefit to the hollow shaft is it is lighter even if it has a bigger diameter. Usually, a hollow shaft is made slightly bigger than its sold shaft counterpart, but still comes out lighter overall.

There are lots of theories and testing on this though and it seems that there are several trains of thought with differing opinions.

Antetokounmpo · 06-22-2015, 01:43 PM

Quote:

Originally Posted by csu87

Depends on materials and diameters of the shafts.

Generally speaking, the same materials, same diameter, a solid shaft is stronger. The benefit to the hollow shaft is it is lighter even if it has a bigger diameter. Usually, a hollow shaft is made slightly bigger than its sold shaft counterpart, but still comes out lighter overall.

There are lots of theories and testing on this though and it seems that there are several trains of thought with differing opinions.

Correct, I guess I should've specified, per unit mass, the hollow shaft will be able to withstand a greater twisting moment, due to the polar of inertia being affected little by a hollow shaft.

Give_Em_The_DD · 06-22-2015, 02:07 PM

Drag strip-

Front diff
Passenger front axel
Halfshaft

LaCross · 06-22-2015, 02:18 PM

Lol have you ran a 10 yet?

mike@x-ph.com · 06-22-2015, 02:42 PM

Most of the times nothing breaks but this is a list of what broke with me (separate occasions)
1- Coolant line
2- Coolant reservoir tank ( not at the track, the day after)
3- HPFP
4- LPFP
5- Transmission slippage

Quote:

Originally Posted by matthewo

I broke everything, had to buy a new car

Sorry about that

matthewo · 06-22-2015, 03:41 PM

Quote:

Originally Posted by mike@x-ph.com

Most of the times nothing breaks but this is a list of what broke with me (separate occasions)
1- Coolant line
2- Coolant reservoir tank ( not at the track, the day after)
3- HPFP
4- LPFP
5- Transmission slippage

Sorry about that

LOL sorry I just had to

mike@x-ph.com · 06-22-2015, 03:42 PM

Quote:

Originally Posted by matthewo

LOL sorry I just had to

LOL

brecken · 06-22-2015, 09:47 PM

If you want the engineering terms behind this 15/16 of the torsional rigidity in a pipe are at the outer radius meaning most driveshafts and axles are hollow and can withstand almost the same torque

Give_Em_The_DD · 06-22-2015, 11:50 PM

Quote:

Originally Posted by LaCross

Lol have you ran a 10 yet?

Negative : /

musc · 06-23-2015, 08:58 AM

Quote:

Originally Posted by LaCross

Lets get a little guide set up. Do you track your car? Did something break? Tell us what broke!

What broke? my heart....when I saw my 60 ft time. lol

Mike@N54Tuning.com · 06-23-2015, 10:00 AM

I think you should also break this thread down or edit the title to separate road track and 1/4 Mile track. These are complete different things and different stresses depending on which one you are talking about.

Mike

Miller335 · 06-23-2015, 09:36 PM

Quote:

Originally Posted by musc

What broke? my heart....when I saw my 60 ft time. lol

I LOL'd.

vasillalov · 06-24-2015, 07:28 AM

My worst nightmare so far was an injector bracket bolt shearing off mid track session. Basically a $2.00 bolt that holds the bracket for injectors #3 and #4 sheared off from the head, the two injectors popped out and the engine lost all compression on those cylinders.

I had to call a buddy of mine with a trailer to come and get me one state over. This little adventure cost me close to $1000.00 in repairs.

06-22-2015, 08:17 AM	#1
LaCross Second Lieutenant 65 Rep 243 Posts Drives: e90 335xi Join Date: Aug 2014 Location: United States iTrader: (0)	What broke at the track day? Lets get a little guide set up. Do you track your car? Did something break? Tell us what broke!
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06-22-2015, 08:32 AM	#2
1Spec Private First Class 12 Rep 137 Posts Drives: N54 Join Date: Apr 2015 Location: Toronto iTrader: (0)	Things don't typically break when you track your car. When you're at the dragstrip and you launch hard is when axels usually give out, especially if you have wheel hop.
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06-22-2015, 10:43 AM	#6
matthewo First Lieutenant 58 Rep 319 Posts Drives: 335i Join Date: Mar 2015 Location: SC iTrader: (2)	I broke everything, had to buy a new car
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06-22-2015, 02:07 PM	#11
Give_Em_The_DD Banned 258 Rep 1,084 Posts Drives: 2010 black 335xi coupe Join Date: Sep 2013 Location: IL iTrader: (2)	Drag strip- Front diff Passenger front axel Halfshaft
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06-22-2015, 02:18 PM	#12
LaCross Second Lieutenant 65 Rep 243 Posts Drives: e90 335xi Join Date: Aug 2014 Location: United States iTrader: (0)	Lol have you ran a 10 yet?
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06-22-2015, 09:19 AM	#3
88atlas07 Private First Class 47 Rep 194 Posts Drives: 2014 535i Join Date: Aug 2013 Location: Fort Worth, TX iTrader: (0)	First ever track day yesterday and nothing broke, and I ran her pretty hard. Oil temps held steady at 250F and no limp of any sorts. Brakes were smoking when I came off but that's to be expected. Took the beating like a champ!
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06-22-2015, 09:25 AM	#4
LaCross Second Lieutenant 65 Rep 243 Posts Drives: e90 335xi Join Date: Aug 2014 Location: United States iTrader: (0)	These things actually break axles? Those damn axles are beefy
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06-22-2015, 09:47 PM	#16
brecken First Lieutenant 24 Rep 372 Posts Drives: 335i Join Date: May 2013 Location: Tampa and Melbourne iTrader: (0)	If you want the engineering terms behind this 15/16 of the torsional rigidity in a pipe are at the outer radius meaning most driveshafts and axles are hollow and can withstand almost the same torque __________________ Thought I joined a car forum but all we ever talk about is alcohol, meth, and LSD
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06-23-2015, 10:00 AM	#19
Mike@N54Tuning.com Joint Chiefs of Staff 4920 Rep 115,999 Posts Drives: 2007 335i, 2015 M3 Join Date: Dec 2008 Location: N54tuning.com iTrader: (89)	I think you should also break this thread down or edit the title to separate road track and 1/4 Mile track. These are complete different things and different stresses depending on which one you are talking about. Mike
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06-24-2015, 07:28 AM	#21
vasillalov Mad Linux Guru On The Loose 1121 Rep 5,397 Posts Drives: 2008 335i Sedan, 2023 M3 Join Date: Aug 2009 Location: Chicago, IL iTrader: (5) Garage List 2023 BMW M3 [0.00] 2008 335i E90 [8.00]	My worst nightmare so far was an injector bracket bolt shearing off mid track session. Basically a $2.00 bolt that holds the bracket for injectors #3 and #4 sheared off from the head, the two injectors popped out and the engine lost all compression on those cylinders. I had to call a buddy of mine with a trailer to come and get me one state over. This little adventure cost me close to $1000.00 in repairs. __________________
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