Handling issues at high speed
03-02-10, 07:36 AM
#1
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Handling issues at high speed
My car is getting light in the front end and the steering wheel is also not loading up at top end, about 100mph and up.
Running 18" with standard suspension and carbon back wing.
My friend says he thinks it's the back wing but I am not that sure. The wing is 1 of the smaller ones out there.
Please help.
Running 18" with standard suspension and carbon back wing.
My friend says he thinks it's the back wing but I am not that sure. The wing is 1 of the smaller ones out there.
Please help.
03-02-10, 07:44 AM
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03-02-10, 09:22 AM
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if your wheels and tires are a bit "taller" than standard 16" + 225/50/16 .. your car might have additional ground clearance causing .. a lot of air to rush under the car ...
and if you have bigger back wing it can cause to compress the rear suspension in relation to the front which might explain the light steering feel
start by determining if your suspension is in good shape ..
and if you have bigger back wing it can cause to compress the rear suspension in relation to the front which might explain the light steering feel
start by determining if your suspension is in good shape ..
03-02-10, 10:42 AM
#6
Racecar - Formula 2000
To add to what was said above, the down-force from the rear wing may be causing the car to have "positive rake," i.e., the front of the car higher than the rear, at speed. This would cause air to pack up under the car and would cause your symptoms.
Can you get someone to observe/photograph your car from the side at speed to confirm?
If this is the (only significant) problem, lowering the front should cure it.
Can you get someone to observe/photograph your car from the side at speed to confirm?
If this is the (only significant) problem, lowering the front should cure it.
03-02-10, 03:59 PM
#7
I know some rear wings are also adjustable. If yours is adjustable you may try decreasing the amount of angle in it to decrease the amount of down force it is placing on the rear of the car. If I am incorrect in this please someone correct me. I do not have an extensive knowledge of wings.
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03-02-10, 04:13 PM
#8
The average "carbon back wing" is larger than US stock rear wings.
I'm with the other guys - make an adjustment to rake, rear wing angle, or just dismount the rear wing for a trial - and see if that solves your problems.
Of course it's also wise to make sure that all components in your suspension, steering, and wheel bearings are in good tight shape. At high speed, small amounts of play in any of these components will become a dangerous handful.
I'm with the other guys - make an adjustment to rake, rear wing angle, or just dismount the rear wing for a trial - and see if that solves your problems.
Of course it's also wise to make sure that all components in your suspension, steering, and wheel bearings are in good tight shape. At high speed, small amounts of play in any of these components will become a dangerous handful.
03-02-10, 04:17 PM
#9
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You could look into a front undertray (helps reduce front lift) and front lip, though FD's usually have something there stock. Maybe a set of front canards? Though I don't really see those as necessary unless you have an all out time attack car. Most likely it's a suspension thing. Also, I always felt the power-steering gets a little light on all FD's at high speed.
03-02-10, 04:31 PM
#11
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When I first did these runs in the late 90's, I had a Ferrari 512TR as well and drove it past 175 or so around the same time as the FD. The Ferrari was much less comfortable feeling at that speed than the FD. The FD is a really stable car at high speeds and there shouldn't be and noticeable lift in the front nor undo downforce on the rear.
Gordon
Gordon
Btw, no issues for me at 140+ (and no wing of any kind, you don't need it....or a front lip for that matter)
03-02-10, 08:13 PM
#13
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Someone may have mentioned it but 100 mph is practically cruising speed for one of these cars so this is likely an alignment problem..... Just check the basics 1st.
03-02-10, 08:30 PM
#14
Where does this bolt go?
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I have a R1 with 18's. The car is very stable over 100. The car does sit higher with the 18's but I enjoy the same stability with the stock rims. This is probably an alignment problem or extremely worn suspension parts.
03-02-10, 11:40 PM
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Here is some picturs of the car.
I am running 245/40/18 at the rear and 225/40/18 in front.
The wing is fixed.
Think I will try removing the back wing and have a run and check.
Going to up grade the suspension soon aswell to something fully adjustable so will do the lowering aswell to check.
Mainly doing highway running.
Also putting down big power at the moment with big single turbo conversion.
I am running 245/40/18 at the rear and 225/40/18 in front.
The wing is fixed.
Think I will try removing the back wing and have a run and check.
Going to up grade the suspension soon aswell to something fully adjustable so will do the lowering aswell to check.
Mainly doing highway running.
Also putting down big power at the moment with big single turbo conversion.
03-03-10, 07:45 AM
#17
Yup, easiest thing is to remove the wing and run back to back tests. If that's inconclusive, start looking at the fundamentals like suspension components.
FWIW, I've pulled a little trailerette with my car, and/or loaded up the back with track equipment many times, and the car does handle a little funny at highway speed. Rake and rear weight (real or artificial) are big contributors.
FWIW, I've pulled a little trailerette with my car, and/or loaded up the back with track equipment many times, and the car does handle a little funny at highway speed. Rake and rear weight (real or artificial) are big contributors.
03-03-10, 08:21 AM
#18
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it is the wing. if a wing loads the rear it raises the front. once air gets under the front you can eventually fly. the more speed the more weight shifts rear and you end up wandering w the front w a light steering effort. in addition as the front raises the camber changes to more positive which further decreases your front tire contact patch.
the FD is a dream to drive at 165... you can read a newspaper and steer w your knees
adjust/lose/replace the wing.
BTW, toe should be just less than 1/8th inch fr and zero rear. tire pressure 30 fr 27 rear set cold. camber 1.2 neg fr and r
good luck,
howard
the FD is a dream to drive at 165... you can read a newspaper and steer w your knees
adjust/lose/replace the wing.
BTW, toe should be just less than 1/8th inch fr and zero rear. tire pressure 30 fr 27 rear set cold. camber 1.2 neg fr and r
good luck,
howard
03-03-10, 08:57 AM
#20
Maybe. When you start adding aero to the car, your suspension needs to be able to handle it. i.e. if you begin to generate more downforce in the rear, it will compress your rear suspension more. If your suspension isn't designed for the additional downforce, you end causing more harm than good with the handling of the car. If you ever look at the stats for the most of the Japanese circuit/touge cars, they will have very high spring rates in the rear with their large GT wings.
03-03-10, 09:18 AM
#21
it is the wing. if a wing loads the rear it raises the front. once air gets under the front you can eventually fly. the more speed the more weight shifts rear and you end up wandering w the front w a light steering effort. in addition as the front raises the camber changes to more positive which further decreases your front tire contact patch.
the FD is a dream to drive at 165... you can read a newspaper and steer w your knees
adjust/lose/replace the wing.
BTW, toe should be just less than 1/8th inch fr and zero rear. tire pressure 30 fr 27 rear set cold. camber 1.2 neg fr and r
good luck,
howard
the FD is a dream to drive at 165... you can read a newspaper and steer w your knees
adjust/lose/replace the wing.
BTW, toe should be just less than 1/8th inch fr and zero rear. tire pressure 30 fr 27 rear set cold. camber 1.2 neg fr and r
good luck,
howard
. I agree with you, that GT wing is creating too much rear downforce for a stock suspension and all other aero stock.thewird
03-03-10, 12:27 PM
#24
Nice car!
R1 lip like you have was used to lower the front coefficient of lift to get it closer to the rear lift at the expense of aerodynamic drag.
With the addition of your aftermarket rear wing you have shifted the balance to of lift to the front again.
In addition to the needing to equalize the coefficeints of lift front and rear (or get from stock lift to equal downforce)- I found suspension damping plays a huge roll in high speed stability.
When I was tuning my FC for the last race with new suspension I had to keep increasing the front damping untill the floaty high speed feeling went away and it was back to rock solid as usual.
In addition I have found my heavier wheel and tire combinations require more damping to keep the tire's contact patch on the ground- I see you have heavier wheels as well.
Good luck!
R1 lip like you have was used to lower the front coefficient of lift to get it closer to the rear lift at the expense of aerodynamic drag.
With the addition of your aftermarket rear wing you have shifted the balance to of lift to the front again.
In addition to the needing to equalize the coefficeints of lift front and rear (or get from stock lift to equal downforce)- I found suspension damping plays a huge roll in high speed stability.
When I was tuning my FC for the last race with new suspension I had to keep increasing the front damping untill the floaty high speed feeling went away and it was back to rock solid as usual.
In addition I have found my heavier wheel and tire combinations require more damping to keep the tire's contact patch on the ground- I see you have heavier wheels as well.
Good luck!