Top Speed Preparation Questions
Thread Starter
Racer
Joined: Jan 2006
Posts: 256
Likes: 0
From: San Diego/Eastlake Ca
Top Speed Preparation Questions
Okay, maybe not quite top speed, but I will be going to a event, on a closed course, where I will be maxing out my 5th gear on 27.5" Mickey Thompson ET Streets (345/35/18).
This is straight line only and I want to make sure that I have certain things covered.
I have a C5 ZO6 TT making approx. 700 rwhp. A mph Calculator shows that with tires these tall, I should be close to 185 in 5th gear.
Is there anything that I need to be aware of? I intend to check fluids and get an allignment right before the event. Aside from that, are their any other safety concerns that I should address?
I've also heard of aerodynamic issues with the FRC body style. Since I don't have any intention of going past 190, am I alright?
Any advice will be greatly appreciated.
This is straight line only and I want to make sure that I have certain things covered.
I have a C5 ZO6 TT making approx. 700 rwhp. A mph Calculator shows that with tires these tall, I should be close to 185 in 5th gear.
Is there anything that I need to be aware of? I intend to check fluids and get an allignment right before the event. Aside from that, are their any other safety concerns that I should address?
I've also heard of aerodynamic issues with the FRC body style. Since I don't have any intention of going past 190, am I alright?
Any advice will be greatly appreciated.
Team Owner
Joined: May 2005
Posts: 23,682
Likes: 9
From: Flagstaff Az.
I would change the brake fluid if it has been in for a year, change the diff and tranny fluids if they have 50,000 or so on them, have access to an air pump for the tires, give the shock mounts and half shafts a visual. A high speed run generates a lot of diff and tranny heat, so the lube should be freah.
Hope you get the speeds you are looking for.
Hope you get the speeds you are looking for.
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
I have not participated in this type of event. If I were I'd add the extra qt of oil to the engine. Also, I would question the design max speed of the Mickey Thompson ET Streets tires. Personally I would want something different for a speed run versus a time run on a drag strip. What safety gear will you have?
Hope it all goes well for you!
Hope it all goes well for you!
Thread Starter
Racer
Joined: Jan 2006
Posts: 256
Likes: 0
From: San Diego/Eastlake Ca
Thanks for the info. I am questioning the tires myself too. I want to have something sticky but that kind of speed does build up a lot of heat.
I am checking the fluilds and the shocks look good. I'll definately look into adding a little extra oil as well. The half shafts are new too.
If I were to get different tires, what would you guys recommend? I need something that'll hold the power so I'm guessing I'm limited to road race tires or maybe the drag radials.
I have a fireproof jacket but the car doesn't have any additional safety equipment (like a cage or fire supression system). Is this necessary since I don't intend to go top speed, just a little faster than a stock C5 ZO6 would maxed out.
I am checking the fluilds and the shocks look good. I'll definately look into adding a little extra oil as well. The half shafts are new too.
If I were to get different tires, what would you guys recommend? I need something that'll hold the power so I'm guessing I'm limited to road race tires or maybe the drag radials.
I have a fireproof jacket but the car doesn't have any additional safety equipment (like a cage or fire supression system). Is this necessary since I don't intend to go top speed, just a little faster than a stock C5 ZO6 would maxed out.
Instructor
Joined: May 2005
Posts: 197
Likes: 0
From: Evans CO
I would double check your wheel/tire balance and your alignment as well. Also, I would research on what mile drag people are using for tires. There are people going over 200mph so that would be a great resource.
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
Are these OEM or aftermarket? All shafts are not built the same. Some of the aftermarket units have CV joint boots that are softer than the stock boots. This can be an issue at high speed. The softer boots can balloon to the point they make contact with things they should not causing them to fail. If you have the aftermarket I would suggest comparing the boot stiffness to OEM. If they are soft get something else before your run. 
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Thread Starter
Racer
Joined: Jan 2006
Posts: 256
Likes: 0
From: San Diego/Eastlake Ca
They're aftermarket half shafts since I will be making some occasional trips to the drag strip.
Figure this is for several runs from 40 mph to about 185 mph. The car will cool down a little between runs. I was thinking about getting some R888 or something along that line if I don't use the Mickey Thompsons. I know there are guys using the ET Streets and going really fast on them, but since I'll be in full throttle for near 3/4 of a mile, that builds a lot more heat as well.
Figure this is for several runs from 40 mph to about 185 mph. The car will cool down a little between runs. I was thinking about getting some R888 or something along that line if I don't use the Mickey Thompsons. I know there are guys using the ET Streets and going really fast on them, but since I'll be in full throttle for near 3/4 of a mile, that builds a lot more heat as well.
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
On the 1/2 shafts you might want to read here.
http://forums.corvetteforum.com/c5-t...ned-to-do.html
Peter
http://forums.corvetteforum.com/c5-t...ned-to-do.html
Peter
Burning Brakes
Joined: Feb 2006
Posts: 1,085
Likes: 3
From: Ottawa Ontario, Canada
IMO that's a MINIMUM with ET Streets... I don't think I'd want to be going that fast with a tire that has no sidewall stiffness to it. I don't buy into the "bias ply at both ends or else..." old wives tale, but it does point out how soft the sidewalls of real slicks are.
What gears are you running? What RPM does your engine start making boost? How hard do you need to "launch" from a 40mph roll - ***** out? If you could start in a taller gear like third you may be able to put down everything you've got with a Nitto RII, a Toyo R888, or some flavor of drag radial (depending on the surface). you may want to try a few different combos ahead of time if possible (i.e. go to the track and see first hand what it's like). With 700rwhp you'll need every advantage you can get!
As far as overheating the tires goes, unless you are maintaining a high speed for long periods I wouldn't worry TOO much since it takes a while for heat buildup and tire failure to occur... but you didn't hear it from me!
EDIT: Lingenfelter did a PILE of top speed runs in C5s (220+mph if I remember right), check into his mods for aero etc.
What gears are you running? What RPM does your engine start making boost? How hard do you need to "launch" from a 40mph roll - ***** out? If you could start in a taller gear like third you may be able to put down everything you've got with a Nitto RII, a Toyo R888, or some flavor of drag radial (depending on the surface). you may want to try a few different combos ahead of time if possible (i.e. go to the track and see first hand what it's like). With 700rwhp you'll need every advantage you can get!
As far as overheating the tires goes, unless you are maintaining a high speed for long periods I wouldn't worry TOO much since it takes a while for heat buildup and tire failure to occur... but you didn't hear it from me!
EDIT: Lingenfelter did a PILE of top speed runs in C5s (220+mph if I remember right), check into his mods for aero etc.
Last edited by Blue Angel; May 12, 2010 at 09:20 PM.
Team Owner
Joined: Jul 1999
Posts: 50,808
Likes: 10
From: Buy USA products! Check the label! Employ Americans
Short high straight line speed does not add heat like running a road course. No clue on Mickey tires Are they rated?. Make sure you have proper rake in the car and everything is tight on the suspension.
Last edited by John Shiels; May 12, 2010 at 09:22 PM.
Thread Starter
Racer
Joined: Jan 2006
Posts: 256
Likes: 0
From: San Diego/Eastlake Ca
Thanks for all the info. I'm probably going to buy a pair of R888's for the rear and then check pressure, fluids, etc. I don't have time/money to do ground effects but this isn't something I'll be doing often. I'll search the racing section to and maybe post there as well. Thanks again!
Drifting
Joined: Mar 2002
Posts: 1,298
Likes: 12
From: Salt Lake City UT
Air pressure is critical. Especially in these type of events.
888's like a lot more pressure than Hoosiers. 36 to 38 cold in this type of event.
A good resource is Jim or Chris at Carroll Shelby Enterprises
(602) 437-4977
888's like a lot more pressure than Hoosiers. 36 to 38 cold in this type of event.
A good resource is Jim or Chris at Carroll Shelby Enterprises
(602) 437-4977
Tech Contributor
Joined: Oct 1999
Posts: 41,058
Likes: 9,820
From: Charlotte, NC (formerly Endicott, NY)
I would want the same type of tire front and rear. R888's are fine. I wouldn't do this with any type of drag tire. They are built to solve a different problem.
Bill
Bill
Le Mans Master
Joined: Aug 2000
Posts: 6,273
Likes: 14
From: Austin TX
A few years back a fellow named Ken Baker almost killed himself and destroyed his C4 by running the Big Bend Open Road Race unlimited class on non Z rated tires.
One of his tires exploded at about 175.
One of his tires exploded at about 175.
