After completing 4 open road races this year I thought I would share a few of my lessons (learned the hard way).

These events are actually high speed rallies. (Silver State, Gold Rush and Bonneville 100) This year I drove 340 miles at an average speed of 145 mph.

Here are a few of the things I discovered:

Oil Coolers

At the Silver State in May oil temps were as high as 280. Installation of an oil cooler kept the oil temp under 240 for the next three events.

Tire Balance

Your tires can feel fine at highway speed and not be balanced.
I replaced both rear tires because of a nail in my driveway. During the drive to Nevada the tires felt fine at 70-80 mph. I did a little testing on the way, discovered a vibration at 100+ and found the one of the new tires was 1.25 oz. out of balance.

Cruise Control

I found that the cruise control works over 140. Some C5 owners say they have used it at 160.

Active Handling

Its possible to set off the Active Handling while driving over a bump and going straight. The system must go on when the tires are unweighted.

Also, when the active handling system goes on the cruise control goes off. This is obvious now but at 140 my first thought was engine problem.

Aerodynamics

The car feels fine at 165. But, after watching the in car video it looks like the front end is getting light at this speed. Note for next year...look for some small (inexpensive) changes to the front air dam.

At these speeds the amount of air under the hood causes the hood to bulge about a 1/2 inch (visible at the seem above each front tire. (see note for next year above)

Tire Monitoring System

Its possible to knock the tire pressure monitor off line on rough road.
But, 2 minutes after hitting a bump the XXX on the display was replaced by the actual tire pressure



These events are a lot of fun. Most are held in Nevada. There is one in Nebraska and one in Texas. Where else could you drive this fast for 90 miles and not worry about a ticket? (OK maybe in Germany)

Hope to see some of you at these events next year. :cheers:

Anyone have any suggestions on my aerodynamic problems?


[Modified by Road_runner, 9:25 AM 11/2/2002]

 

Sounds like you had a blast, you could try lowering the front of the car is you havent already, or you could add the caravaggio canards on the front, not sure if they work for that maybe someone else knows. :cheers:


[Modified by rrobert22, 1:38 PM 11/2/2002]

 

:cool: Can you post the videos? I would like to see them :yesnod:

 

What oil cooler did you go with?

 

Sweet!! :cheers:

I'd like to know what oil cooler you went with also, as I've seen 280 oil temps roadracing here in Texas and Oklahoma? :cheers: :cheers: I'd love to do an open road race event. Of course, I make due with what traffic will allow me around town in the meantime. :D

 

:cheers: I've actually met C5 owners that never had their cars over 85 MPH. Sounds like you are enjoying yours! :D

 

QUOTE] :cool: Can you post the videos? I would like to see them :yesnod: [/QUOTE]

Videos are 36 minutes +
I've never tried to post a clip but I'll give it a shot Sunday :cheers:

 

DRM radiator/oil cooler....
I did one day at the track in September and the oil did get to 245 that day.

The Texas road race is in Fort Stockton. Check this link for more info.


http://www.bborr.com :D

 

So which class did you enter under, what upgrades other than the oil cooler (fuel cell, full fire extinguisher system, cage etc), and what did it cost?

 

I guess I could have read your sig. :D Ah, the Big Bend Open Road Race. I actually almost went to 'watch' that this past year, but I ended up not making it. I never seriously considered entering, but I wanted to go watch. Maybe I'll enter or atleast watch next year. I need to get all the coolers if I'm going to run it hardcore at that high of speed. However, I do wonder if it's necessarily 'harder' on the car than roadracing it on a track slowing to as low as 30mph and as high as 120-140mph, slowing down and speeding up, slowing and speeding. At the very lease, I'm sure a differential and tranny cooler would be good to have.

Thanks for the info!! :cheers:

 

Road_runner:

To help with the aerodynamics, make sure your small side air dams or the center spring loaded air dam isn't folding under at the high speeds. The side ones could be strengthened with some alunimum pieces.

Also you could remove the rubber sealing strip at the back of the hood (at the base of the windshield). This should allow the air under the hood to escape and also help to keep the front end better planted. I hope these suggestions are useful to you. :cool:

 

very interesting :yesnod:

 

A BIG 2 :cool: for you. Great tips. I had my 97 coupe on 1 road course this year, Willow Springs. I found it would leave the ground over turn 6. At this point the road is going from a slight up hill to level. :eek: Pretty scary at ~80 - 90. The same day I rode as a passenger in a Viper. He could hit 6, probably faster and the car stayed down on the road, using about the same line.

I've had 165 indicated "elsewhere" and the car did start to feel light, IMO.

From these 2 experiences I decided to 1. go with new shocks, Blisten Sport and probably Z06 sway bars front and rear. 2. try the cnards up front and, I'm looking for a rear spoiler. Something small and molded in on the rear. I don't think you need much if your experience is similar to mine. I'm thinking about 100 pounds front and rear down at ~125 - 150MPH. That would increase with speed but, shouldn't cause a lot of extra at highway speeds.

The air dam suggestion someone posted about stiffning up the corners sounds reasonable. Probably a fairly inexpensive mod that can't hurt on the track. It may present problems over curbs and such on the street but, that's better then lift off at 170 . :eek: :eek: :eek:

I didn't notice the hood bulge, pulling the rear seal my be the trick. I think I would add the front seal first.

Good luck, post what you learn from any mods, I'll do the same. :cheers:



[Modified by scool93535, 9:49 PM 11/2/2002]

 

I am thinking here that the lift on the hood is not air forced from under the hood rather lift from air going over the hood pulling it up. If you had a DRM Hood that would not happen.

Heat Exchanger type Oil coolers work much better than the unit that you currently have.

If you are going to be in Events going that fast. I would look into installing a front spoiler as well as a rear wing. :eek:

Have a fun and safe time at those Events. :)

vetterdstr :cheers:

 

Great information and thanks for sharing...

Nick

 

Thanks ... always wondered what would happen if I took out the weather strip

:cheers:


[Modified by Road_runner, 4:00 PM 11/3/2002]

 

There's a race in Nebraska too. Because of the surface and size of the road, the highest speed allowed is 140 but it is a very challenging event. This year they also added a one mile "shoot out". We were able to go as fast as we could from a standing start in a measured mile. Take a look at the results. You will have to cross reference the road race results to the shoot out to see what the cars were, but there are a few surprises. – C.
http://www.sorcrace.com/


[Modified by Mr. C's 5, 8:17 AM 11/4/2002]

 

Most of the upgrades are listed in my sig.

The fire extinguisher is Halon. $140

The Belts and Harness bar cost about $700

The cooling system was expensive. Over $5000 for the replacement radiator, small radiators for the trans & diff. electric pumps that circulate the fluid and installation. I can't defend the cost except to say that $5000 for somthing that works is a better deal than $3000 for a system that doesn't.

I entered all of the events in the Grand Sport class at the following target speeds.

Nevada Open Road Challenge 145
Bonneville 100 135
Gold Rush 140
Silver State Classic 150

:cheers:


[Modified by Road_runner, 1:36 PM 11/4/2002]

 

Those NV races are wonderful grass roots events. On some of the roads coming home to AZ I went 156mph. My A4 shifts into high gear at 142mph. Try the following links for coolers. They're trick! http://www.fluidine.com http://www.bakerprecision.com http://www.batinc.net/main.htm

 

Here are a few short clips from the 2000 Pony Express.
Check out the Doria Corvette if you can. :cheers:

http://www.racehome.com/picpexp00vid2.htm