Getting the itch again!! Top speed events..

foofinator · Oct 17, 2012

I have been cruising around looking at all the top speed events around now. I've run the Texas Mile twice in my 2004 Cobra. Both times blew a motor. 120 top speed the first time, 173 the second time. I had an in-trunk intercooler tank, 6 pt cage, and 3.08 rear gears installed for this stuff.

I hit ~190 on the datalog both times before the engine let go, the 173 run I just tried to stay in it LOL. Lost some valves and shit on that one.

I know very few (maybe 1 or 2) 03/04 Cobra's have accomplished this goal. I really wanted to hit 200 MPH. Now I'm looking, and they have 1/2 mile events... hmmmmmmmm

ttocs · Oct 17, 2012

always thought the silver state challenge looked like fun.

OnyxCobra · Oct 18, 2012

why are you blowing motors?

the.greg · Oct 18, 2012

I think the number one killer of termis is high speed runs. I've read several reasons, one being the high heat sustained during high speed runs can cause the pistons to expand and contact the cylinder walls(I've read stock piston/cylinder clearance is as little as .001 clearance compared that to aftermarket ones that are between .0020-.0030.) another being that many cobras had uneven head cooling issues. Both issues can be significantly reduces/mitigated by the evenflow head cooling mod and better heat exchanger/radiator and try to allow plenty of cool down time between runs. Also a little richer tune wouldn't be a bad idea for this.

foofinator · Oct 18, 2012

No idea why I was popping motors. Most seem to think the load in 5th gear was just too much. 4th takes me to 180 or so, this went fine. Shifting to 5th... didn't last but mere seconds! I considered dropping to a 2.73 rear end ratio to avoid overdrive all together.

I have a spare-tire intercooler tank, big ass HE (which works against the system with all the ice I use on these runs), LFP radiator, head cooling mod.. etc. etc.

the.greg · Oct 18, 2012

foofinator said:
No idea why I was popping motors. Most seem to think the load in 5th gear was just too much. 4th takes me to 180 or so, this went fine. Shifting to 5th... didn't last but mere seconds! I considered dropping to a 2.73 rear end ratio to avoid overdrive all together.

I have a spare-tire intercooler tank, big ass HE (which works against the system with all the ice I use on these runs), LFP radiator, head cooling mod.. etc. etc.

Sounds like youve done all the cooling mods you can. Must just be the extra load that 5th and 6th add. Is it a option to get a specific high-speed tune thats on the rich side? I found this link that addreses this issue, section 3.6.2. Were you able to determine why you blew the engine?
http://stangshiftergaskets.com/2003_2004faqs.htm#_Toc35092307