Rake and ride height
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From: Encinitas (San Diego), CA
Originally Posted by RACER,Jan 9 2005, 09:52 PM
This is true, but these front and rear corners would be on opposite ends. This would never happen on a race car as you now have a 40 lb table with 40 lbs on one set diagnal corners and 0 lbs on the opposite diagnal corners.
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From: Knoxville, TN
The front right and rear left would be the same. The front left and rear right would also be the same. But if you have a table that is 40lbs, 20 lbs on the front left and 20 lbs on the right rear and 0 lbs on the front right and 0 lbs on the rear left, you would be 100% off in cross corner weights as you would have 40 lbs on one cross corner weight and 0 lbs on the other cross corner.
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From: Encinitas (San Diego), CA
Originally Posted by RACER,Jan 9 2005, 10:07 PM
This is not a good example. The race cars that I worked on were 1,300 lbs, therefore small differences in height would therefore affect weight transfer.
You are right when you say extreme, but were are talking about bathroom scales here. I tried it 12 lbs. I had to go upward nearly 45 degree's before I noticed a change. Keep in mind that when you tilt the object, the overall contact surface area changes. This causes the discrepancys in the scale. If you did this with a 1,300 lb race car, or even a 2,800 lb S2K the readings are going to vary much more substantially
You are right when you say extreme, but were are talking about bathroom scales here. I tried it 12 lbs. I had to go upward nearly 45 degree's before I noticed a change. Keep in mind that when you tilt the object, the overall contact surface area changes. This causes the discrepancys in the scale. If you did this with a 1,300 lb race car, or even a 2,800 lb S2K the readings are going to vary much more substantially
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My car appeared to have noticeable rake after I installed Mugen N0s. West End lowered all corners equally then corner balanced. I took it upon myself to later lower the back to reduce oversteer and the rake looks about level. Iirc, I think I measured it and the car was level. Anyway, I always thought handling was better after I got the back down a bit.
rlaifatt
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From: High Knob Mountain
Originally Posted by Prolene,Jan 10 2005, 01:34 AM
My car appeared to have noticeable rake after I installed Mugen N0s. West End lowered all corners equally then corner balanced. I took it upon myself to later lower the back to reduce oversteer and the rake looks about level. Iirc, I think I measured it and the car was level. Anyway, I always thought handling was better after I got the back down a bit.
The car will be corner weighted this Spring.
Cheers,
George
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From: LA
First off, we all know that the S2K, or any street car for that matter do not utilize ground effects. I believe there is a kit, I think Mugen, I'm not sure, that consists of plates that prevent the air flow from collecting in pockets underneath the car. Combined with a modified front end, (aero dynamically efficient) these plates will absolutely make your car faster in terms of overall top speed. These plates by no means are the same as ground effects as they will provide no down force, they just provide efficiency.
[/QUOTE]Rake does not affect aero, but affects the transfer of weight from opposite ends of the car.
yes it does (among other things) Rake changes the proximity of front/rear clearance to the ground. A car with +rake would create a simple venutri section underneath the car. Wouldn't you think that has any bearing on aero?
I agree but note soley for that purpose.[QUOTE]
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From: Knoxville, TN
Originally Posted by Raymond
Ground effect: the aerodynamic modification of the airflow beneath a vehicle caused by its close proximity to the ground. All cars operate in ground effect, though not all exploit the effect beneficially.
I definitely agree that an adjustment in rake can have some sort of affect of air flow characteristics underneath the car. Keep in mind, the S2K is 5.1" off the ground. There are giant pockets underneath the S2K that collect air and generate drag. The front of this car is also aerodynamically challenged as well. By the time the air flow reaches the rear of the car, it is indeed turbulent. Any amount of rake adjustment is not going to do squat in terms of downforce.
When I worked as a racecar mechanic, we normally kept the ride height the same all the time. The idea was to get the car as low as possible with about 1/2" of rake without the car slapping the ground under heavy braking. We did fool with the rake from time to time. I don't think adjusting the rake on a Formula Mazda would affect it aerodynamically, but then again, I am not an aerodynamics engineer.
The undersides of CART Indy cars have tunnels that generate down force. This is refurred to as "ground effects" These tunnels suck the car down when it is driven at a very high rate of speed. The ride height is typically a pre-determined value and adjustments are very minimal. I would agree that an adjustment in rake would have an affect on aerodynamics. Like I said, ride height adjustments on these cars are very minimal, therefore having very little affect on aero, much less on an S2K.
Originally Posted by Raymond
yes it does (among other things) Rake changes the proximity of front/rear clearance to the ground. A car with +rake would create a simple venutri section underneath the car. Wouldn't you think that has any bearing on aero?
