Setup for top speed run?

Well, I have completed three road course track days. The SLC is amazing. Passing brand new corvettes and Porsches is pretty awesome. Now, I want to try a high speed run. There is an event coming up called "No Fly Zone Arizona" on December 12. It is a 1/2 mile run at an airfield in Gila Bend, AZ. I know I won't reach top speed in the SLC in just a 1/2 mile but I thought it would be a good trial run. I did a google search for alignment setups for top speed run and got nowhere so I was hoping to get some help here. What toe-in should I run for front and rear? What about camber front and rear. Should I run street tires or run the Hoosier R7 slicks that I use for the road course? I plan on removing the rear race wing and the front canard winglets. Any other suggestions? SLC WHP East
 

Neil

Supporter
I'd run camber at about -1 degree F & R and toe-in as close to 0 as you can get. Don't remove front canards- keeping the nose down at high speed is critical. Are you planning to attend?
 
Isn’t there some type of speed run in Nebraska once a year for several miles. I seem to recall different classes etc. Nebraska May no be right, but I seem to remember reading about this recurring event.
 

Randy V

Staff member
Admin
Lifetime Supporter
There's also the Texas Mile - unless that's been cancelled....
I agree that you need front downforce. Tires should be something that are rated for the speeds you expect to be running.
Buy the best helmet you can and have it prepped for the HANS Device, a Nomex fire suit, Belaclava, Gloves and boots... It only seems like it is expensive overkill until you need it...
 

Doug Dyar

Supporter
Isn’t there some type of speed run in Nebraska once a year for several miles. I seem to recall different classes etc. Nebraska May no be right, but I seem to remember reading about this recurring event.
Yes there is. Yep. Nebraska.

.
 

HCF - John

Gearbox / Brake Systems
GT40s Sponsor
Michael,
What sort of gearing do have in the transaxle?
Best,
John

Well, I have completed three road course track days. The SLC is amazing. Passing brand new corvettes and Porsches is pretty awesome. Now, I want to try a high speed run. There is an event coming up called "No Fly Zone Arizona" on December 12. It is a 1/2 mile run at an airfield in Gila Bend, AZ. I know I won't reach top speed in the SLC in just a 1/2 mile but I thought it would be a good trial run. I did a google search for alignment setups for top speed run and got nowhere so I was hoping to get some help here. What toe-in should I run for front and rear? What about camber front and rear. Should I run street tires or run the Hoosier R7 slicks that I use for the road course? I plan on removing the rear race wing and the front canard winglets. Any other suggestions? SLC WHP East
 
Hi John, I have the Ford Ricardo transaxle so the final drive ratio is 3.36. 1st = 2.6, 2nd = 1.7, 3rd = 1.2, 4th = .9, 5th = .7, 6th = .6. No traction control or ABS. The rear track tires are 345 Hoosier R7 slicks. The fronts are 285. Engine is around 600HP.
 

Howard Jones

Supporter
Michael:
1. What has your top speed be up to date on the road course you have run?
2. What are the suspension setup setting as is. Ride height, toe f&r, camber, caster, spring rates F&R. Tire treasures? rear wing type and AOA settings.
post pictures of front canards.
3. what speed do you expect to run at max for event and time at speed. example: 125mph for 5 seconds.

My advice is to be as conservative as possible and still make the vent useful. Be aware that these cars are extremely sensitive to aero tuning beginning at about 135MPH begin to overcome mechanical grip set up at about 140 and you are all in aero at 150. Beyond 150 would be avoided until the car feels rock solid at 140.

I run my car a COTA and have seen 150+ on most laps in anger. Only recently have I found what I believe is a good spring rate setup. F800 R900. I am running the OEM RCR rear wing with 1/2 gurney @ 6 degrees AOA and big ass canards on the front. The splitter is fully filled in with foam and has two aero correct tunnels incorporated into it.

The car will make enough front downforce in this configuration that it is undriveable at high speed ( +130) with the rear wing off the car.

My advice (free) is run the car you know (everything like the last time you went to the track) and work up to speed with test plan and stick to it. something like this:

1st pass: easy launch 1,2,3,4 hold to 5000 revs per shift max and 100 mph top speed. Easy breaking
2nd pass: do 1st pass again. you should be going for an exact repeat of 1st pass in the feel of the car in your hands. A feeling of complete control is what you are going for. nice easy shifts and no loss of grip at any time.
3rd pass: all good so far? I would add 25 mph. nice and easy 1,2,3,4 and then just add a bit more power to indicate 125. remember added speed and length of run to breaking evolution.
4th: do 3nd run again exactly; You will really feel it this time and should be completely comfortable at 125mph. It should not take a lot of power or drama to get there, Just a nice smooth application of power and nice easy shifts, modest breaking.
5th: do everything the same again but add speed to 140. You may want to use 5th just to keep things nice and smooth. Things are now starting to get real. Especially rear wing downloading. If you are feeling compression in the rear suspension then you are at the limit with that amount of downforce. Be very careful of the transition from 140 down to 125. Lift power smoothly and allow to settle before adding brakes. Do not downshift for braking at any time during the day. Get it under 125 before you ask for any hard brake effort. You know what it feels like at 125, wait for it.......wait for what you know.
6th run: Duplicate 5th run again to gain muscle memory and your ability to visually predict the mental image of the run beforehand. This is called Pre-event visualization, That what pro racers are doing in the cockpit before a start. Have you ever seen a pro ski racer going over the course in his mind with his hands at the start gate, That's what you are going for.

This can be a very productive day and a lot of fun if you treat it as a first outing and a learning test session. BUT, pulling off all the downforce, trimming it out, and going for it above 140mph ............................you'll shoot your eye out kid.

Check tire pressures every run all day!!!!
 
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Hi Howard. The East track at Wild Horse Pass is small. Max speed is 120MPH and just for a second before hard braking.
Ride Ht.: Front is 89mm. Rear is 115mm
Stock Caster setting, which I think is 4.5
Camber: Front = 1.7 Rear = 1.1
Toe in: Front and rear is just below 1mm
Springs: Rear = 8" and 850 lbs. Front = 4" and 700 lbs.
QA1 shocks: Front compression and rebound is 9 clicks. Rear compression and rebound is 7 clicks
Cold tire pres. = is 26. Hot has never exceeded 35 psi.
Tires: Hoosier R7 slicks: Rear 345 and Front 285
Front canards and rear race wing is set at 2.5 degrees.

The car handles better than my driving skills and has never made me feel uncomfortable.
My goal is to run at a one mile speed run, like "The Texas Mile". At 600 HP and a Ricardo transaxle, I believe the car should reach 200 MPH.
There is a Ford GT40 on you tube at The Texas Mile that broke 300 MPH with no front canards and no rear wing.
Thank you for your advice. It seems like this is a subject that people don't want to talk about.
 

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Howard Jones

Supporter
That's a pretty good road race setup. Not really much different than mine. In the future, you might think about adding 100-150 lbs springs on each end if you intend to add more downforce. I am running my wing @ 6 degrees AOA but its the RCR OEM fiberglass one. It does make significant levels of downforce, however.

Ride height. I run right at 4.5 inches at the rear and just under 4 inches at the front. Call that 3.75. I measure at the chassis in line with the center of the tire under the car. I think this is critical to get good front grip. If I run my car nose up at all it gains a lot of understeer, especially at < 70mph off power center corner. I think you are good on RH as long as you can prevent rear compression at high speed. This was evident on my car at about 150 and I needed to add spring to help correct it. I have NO idea what will happen above 160, but it will get worse. Really watch out for that!

How about putting some tie wraps on the shock rods to indicate shock compression and see what is going on. Really be careful with this. A nose-up condition will get harry very quickly. That's all I got on this high-speed stuff. Maybe talk to others who are more experienced with mile stuff. Good luck
 

Neil

Supporter
Beware generating any yaw angle; the downforce disappears rapidly and you can go airborne. I've had 3 friends crash at 200+, one at 432 mph, by getting slightly out of shape at high speed. All went airborne and although the crashes were horrendous, the drivers survived but were injured by the tremendous G forces. Their sturdy roll cage structures withstood the impacts but the G forces on the driver are can be fatal by themselves. A standard GTC roll cage is not enough protection at 200 mph.
 

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Hi Howard. The East track at Wild Horse Pass is small. Max speed is 120MPH and just for a second before hard braking.
Ride Ht.: Front is 89mm. Rear is 115mm
Stock Caster setting, which I think is 4.5
Camber: Front = 1.7 Rear = 1.1
Toe in: Front and rear is just below 1mm
Springs: Rear = 8" and 850 lbs. Front = 4" and 700 lbs.
QA1 shocks: Front compression and rebound is 9 clicks. Rear compression and rebound is 7 clicks
Cold tire pres. = is 26. Hot has never exceeded 35 psi.
Tires: Hoosier R7 slicks: Rear 345 and Front 285
Front canards and rear race wing is set at 2.5 degrees.

The car handles better than my driving skills and has never made me feel uncomfortable.
My goal is to run at a one mile speed run, like "The Texas Mile". At 600 HP and a Ricardo transaxle, I believe the car should reach 200 MPH.
There is a Ford GT40 on you tube at The Texas Mile that broke 300 MPH with no front canards and no rear wing.
Thank you for your advice. It seems like this is a subject that people don't want to talk about.
That is not a Ford GT40 - it's a Ford GT. Not trying to be pedantic, I'm saying it because the GT, while looking retro, is in fact a modern car with full manufacturer backed aero development. An accurate repro Ford GT40 is an ancient car by aero standards. There's lots of development that has been done since then, but it's "preparer" critical ie not everyone has the same basis of understanding.
I think most people are reluctant to weigh in on set-up for top speed runs because they haven't done it themselves, and don't want to give you bad advice. Watching the Mercedes GTR flips at LeMans should give you a proper sense of the stakes.
 
Thanks Howard. I'll post more info. when I get it. I measure ride ht. in the same places just in metric. Neil, that is my biggest concern and is why I am seeking information. Tom, sorry for the misinformation, some days I spell my name wrong. I am a big fan of the Ford GT. I have seen a few You Tube videos of flips and that is terrifying and expensive. I don't want to be that guy. I just want to say that any advise would be helpful and if I end up crashing that would be my fault and not because of info I got here or anywhere else for that matter. I have searched other forums for top speed info. and silence is all I get. Does anyone know of a book out there that would be helpful?
 
^ you might look at the Carroll Smith books - Prepare to Win, Tune to Win. Haven't read them myself, but I think they are considered good resources for race prep. Top speed prep might be different, though I don't know why - a safe race car will likely make a safe straight liner, provided you dial out the toe out at front, Maybe at the expense of some top speed, which isn't really important if you aren't chasing records.
 

Neil

Supporter
It may help you understand high speed setup by learning what is required to run at Bonneville. They have been running top speed events there for 60 years and the SCTA (Southern California Timing Association) rule book has evolved over the years from their experience with high speed accidents. I'd suggest you buy the latest rule book and check out their requirements for a car similar to yours. Pay particular attention to the chassis & safety equipment section.

 

Howard Jones

Supporter
The place to start would be to choose an event. Then read their rules as to top speed safety equipment requirement. Then pick a speed that suits their requirement and matches your car construction as far as safety equipment is concerned. Note: if they do not require full-on racecar cages and crash prep such as fuel cells at speeds above 150MPH then I would find another venue. It just blows my mind to see some guy running his street Lambo at 175 mph. There is absolutely no way to survive a rollover or worse in a streetcar at anything like those speeds.

I think I have to add this. I would not expect to survive a flip in my car at +190mph that landed upside down..................and then proceeded to reduce itself to a pile of parts spread out for several hundred yards..........................

Please be careful my friend.
 
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