Nascar question

Tech questions that don't fit above forums

Moderator: Team

Post Reply
DavidM
New Member
New Member
Posts: 23
Joined: Tue Aug 04, 2009 6:59 pm

Nascar question

Post by DavidM » Mon Nov 25, 2013 3:56 am

I know this isn't in the right section, but I think it might get the best answer here.

What could have caused that explosion on Paul Menard's car at Homestead? It blew the floorboard loose and curled up the hood even with the hood flaps. It also blew the entire hub, brake rotor, axle and wheel off. The tire changer said he would have been killed if he hadn't hesitated.

https://www.youtube.com/watch?v=NpEObbJ-hhQ
explosion.png

User avatar
John Wallace
Guru
Guru
Posts: 1352
Joined: Tue Jan 04, 2005 10:20 am
Location: was Central Illinois - Now in Sunny Florida!
Contact:

Re: Nascar question

Post by John Wallace » Mon Nov 25, 2013 5:51 pm

Tire got hot and blew?

Then possibly with the fire under the rear of car from the rubber, it caught the fuel on fire?

:?:
John Wallace
Pontiac Power RULES !
www.wallaceracing.com

DavidM
New Member
New Member
Posts: 23
Joined: Tue Aug 04, 2009 6:59 pm

Re: Nascar question

Post by DavidM » Tue Nov 26, 2013 1:35 am

The tire itself did not blow up, it was blown off. A shockwave appears (to me) to come out of the axle housing and is reflected out of the wheel well on the driver's side. So far, no one has said anything about a fuel fire that I am aware of.

4banger
Pro
Pro
Posts: 233
Joined: Mon Mar 04, 2013 10:44 pm
Location: Rocky Mount North Carolina 27801

Re: Nascar question

Post by 4banger » Sat Mar 08, 2014 10:48 pm

Gear oil !! There is a pump to pump oil in the rear end to keep it cool. His rotor came apart and tore off brake line then probably caught brake fluid on fire, He was losing parts from that side all around the track. Axle got hot enough to burn out seal and pump pushed out hot oil fueling fire til tire blew.
I thought I was wrong once but I was mistaken...

6250
New Member
New Member
Posts: 10
Joined: Fri Nov 29, 2013 7:44 pm

Re: Nascar question

Post by 6250 » Sun Jan 14, 2018 1:31 pm

Way too much pressure to just be gear oil fire. First guess a high pressure chamber built into the rear end housing. For what ?
Mike Caruso
Do It Like You Mean It .....or Don't Bother!
Retired 2015
Engine Professional Magazine Free To All
http://www.aera.org/ep/index.html Engine Professional Magazine

peejay
Guru
Guru
Posts: 1434
Joined: Tue Aug 10, 2010 9:16 pm

Re: Nascar question

Post by peejay » Sun Jan 14, 2018 3:17 pm

Classic tire explosion.

Look at it at 1:50 or so, you can see that it is massively overpressured from heat.

The mechanism is, the heat from the fire made rubber inside the tire start to smolder. I was under the impression that they ran nitrogen in the tires, but even without oxygen present for a flame the outgassing would still raise pressures considerably, which raises heat, in a positive feedback loop.

Here's an interesting video with pressure and temperature gauges attached.

https://www.youtube.com/watch?v=uScd7nFzfQE

And an OSHA safety video:

https://www.youtube.com/watch?v=pNZ4siYGkag

j-c-c
Guru
Guru
Posts: 1698
Joined: Sat Sep 03, 2016 9:03 pm

Re: Nascar question

Post by j-c-c » Mon Jan 15, 2018 1:24 am

Would a shock filled with nitrogen have that much force/volume? Do they use steel or alum shocks? A gas steel shock could have over pressurized from heat, alum would fail before that much pressure from a rotor fire heat issue, I would think. There was little fire I saw from the actual blast. The fire on track until stopped, did have enough time to heat up a lot of surrounding items in that area, I would have guessed a RR tire blow out on first glance..
Last edited by j-c-c on Mon Jan 15, 2018 1:31 am, edited 2 times in total.

j-c-c
Guru
Guru
Posts: 1698
Joined: Sat Sep 03, 2016 9:03 pm

Re: Nascar question

Post by j-c-c » Mon Jan 15, 2018 1:25 am

:D

Post Reply