Best mod for stability at high speed?
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
Originally Posted by craigo
Try lowering your front end a little also if you haven't already.... it's easy. But I'm a BIg believer in balanced and aligned tires.... that's the place to start.
balance, alignment, and the proper rake, IMHO is the most important. Rear jacking puck points need to be 4-5 mm higher then the front jacking puck points.
I drive 140-150 routenly over the backstraight at VIR. If the rake is off just abit the car feels unstable. If the car is lowereed more then an inch with no rake you will have a come to Jeuses meeting real fast.
Dont lower the car more then an 1" in front and then the proper rake. Next is the alignement, corner balancing and tires.
Thread Starter
Burning Brakes
Joined: Aug 2005
Posts: 796
Likes: 0
From: Crapachusetts MA
Car is stock, has 58k on it. I am going to get an alignment done, and check up on the tie rods, etc, but once you mention this most shops say you "need" to have it done anyhow, sigh.
I have a feeling most shops will not know what rake means, or how to fix it. The Goodyears do feel a bit all over the place at high speeds, although at low speeds they tram much less than my old michellins.
I have a feeling most shops will not know what rake means, or how to fix it. The Goodyears do feel a bit all over the place at high speeds, although at low speeds they tram much less than my old michellins.
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
ride height is measured just behind the jacking puck holes on the frame. Left to right should be equal, not within specs. SPecs can be 1/2" differnce. SO the left front should be equal to the right front. THEN the measuered the rear.
The rear is also measured just behind the jacking puck holes. The rear should be 4-5 mm higher then the front.
Actully ride height can be meausered in several places but this winds up being a uniform place for ppl to measure.
The Good year tires. How old are they?? Not How much tread do they have, but the physical age??
Tires that are more then two years old loose much of the rubbers grip ability and become hard, even with full tread. Tread is more for water to be moved out of the way.
Next is what air pressure are you running?? Most of the time you want to start at 30 psi cold for the fronts
If you do a lot of high speed driving on the track use newer tires for better rubber compounds and grip.
Good Luck
The rear is also measured just behind the jacking puck holes. The rear should be 4-5 mm higher then the front.
Actully ride height can be meausered in several places but this winds up being a uniform place for ppl to measure.
The Good year tires. How old are they?? Not How much tread do they have, but the physical age??
Tires that are more then two years old loose much of the rubbers grip ability and become hard, even with full tread. Tread is more for water to be moved out of the way.
Next is what air pressure are you running?? Most of the time you want to start at 30 psi cold for the fronts
If you do a lot of high speed driving on the track use newer tires for better rubber compounds and grip.
Good Luck
Instructor
Joined: Jun 2005
Posts: 155
Likes: 0
From: Brooklyn Park MN
Originally Posted by ScottP1985
Somethings up. Mine's stable all the way up to 170. Seems to get tighter all the way up! (On a closed course)
I have been perfectly stable at 171 mph (Don’t ask how I know). However I am slammed with CoilOvers.
Le Mans Master
Joined: Jun 2004
Posts: 6,654
Likes: 5
From: Silver Spring MD
Originally Posted by ivandrea
Before I got the MCM hood I couldn't get over 150 with out the car getting squirrly. Felt like alot of front end lift. 2 weeks ago I had it at 160 and it was very responsive. Not much road left to push it any higher. With the A4 and 3.42 rear I think 170 is acheivable espescially with the hood on now.
Burning Brakes
Joined: Feb 2004
Posts: 831
Likes: 0
From: Poland oh
Originally Posted by CUlookin
It's not your hood that stabilized the car but your gill spears...
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Melting Slicks
Joined: Dec 2004
Posts: 3,049
Likes: 0
From: The second childhood is the best one of all.
Originally Posted by spinedoc77
Seems like anything over 100 and my vette gets a bit unstable, kind of feels like the front tires are coming up off the ground, if that makes sense. I have brand new tires, Goodyear F1's, although they are the stock 17 in front and 18 in rear, and I do miss having 18's all around like my old car. Is it an issue of the wheel size, or is there any other mod for high speed stability?
Thread Starter
Burning Brakes
Joined: Aug 2005
Posts: 796
Likes: 0
From: Crapachusetts MA
The tires are brand new, less than a week old. I am not sure if I have BSM's or not, are they those "spears" everyone keeps talking about? lol. Would it make a difference if I was feeling unstable with the top down?
Safety Car
Joined: Jan 2005
Posts: 3,675
Likes: 58
From: Hayward (Bay Area) CA
You all are talking about speeds that I would like to achieve, but have not yet driven. As one person here mentioned that if the car is all stock and in good condition, it should do 171 mph, without a problem. My car is all stock. Its a 99 coupe, A4, 2.73 gears. What is the best speed I can achieve? I haven't lowered the car, or done any mods. Just a Blackwing. So, if I want to go 150 - 160+, what would I need to do to feel that stability ??? 
Thanks in advance for your feedback and answers...
Thanks in advance for your feedback and answers...
Burning Brakes
Joined: Aug 2003
Posts: 1,164
Likes: 1
Originally Posted by Vette_Fan
You all are talking about speeds that I would like to achieve, but have not yet driven. As one person here mentioned that if the car is all stock and in good condition, it should do 171 mph, without a problem. My car is all stock. Its a 99 coupe, A4, 2.73 gears. What is the best speed I can achieve? I haven't lowered the car, or done any mods. Just a Blackwing. So, if I want to go 150 - 160+, what would I need to do to feel that stability ???
Thanks in advance for your feedback and answers...
Thanks in advance for your feedback and answers...
Drifting
Joined: Oct 2003
Posts: 1,884
Likes: 2
From: Walnut CA
Originally Posted by mark b
Dont listen to most of these guys....Get adjustable shocks and set them firm. This will cause the car to remain planted, and tighten up the dampness so you remain on the ground and stable to top speed...tires effect it too, but not as much... Isee 150, 160+ and the car is stable. but the road has ALOT to do with it. most roads are not designed for those speeds...you have to experiment and find where the really smooth roads are.. Or go to a fast track, with long straights. And i have r/flts and the car is still stable...before I put the Hals in the rear, my car floated at 120+ too...you do have to sacrifice alittle comfort though....
Safety Car
Joined: Jan 2005
Posts: 3,675
Likes: 58
From: Hayward (Bay Area) CA
Originally Posted by Paras
I would agree with the shock comment but I would also say that rake is important. I've felt HUGE differences in a car with different shock valving...
Your feedback and comments are very important. Plz keep em coming. Thanks..
Team Owner
Joined: May 2001
Posts: 36,836
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Originally Posted by spinedoc77
would aftermarket or z06 sway bars help?