C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

Tons of understeer

Thread Tools
 
Search this Thread
 
Old 02-25-2002, 10:45 AM
  #1  
BeaterShark
Drifting
Thread Starter
 
BeaterShark's Avatar
 
Member Since: Sep 1999
Location: Wylie TX
Posts: 1,411
Likes: 0
Received 0 Likes on 0 Posts

Default Tons of understeer

I took my car to a local Khana race (low speed autocross). I was amazed at how much understeer my car has. At speed, it would just keep going straight even though the wheel was turned. The parking lot used had quite a bit of gravel, but it looked like the other cars did have the problem near as bad as I did.

I believe that this would be due to bad weight transfer, so I started thinking about how I deviated from stock. I have Al heads, intake and radiator, VB 460 lb/in front springs, a Lakewood bellhousing, 17" Wheel Vintiques with 255/50 back and 245/45 front and a VB fiberglass spring in back.

I would think that the bellhousing pretty much offsets the Al stuff on the engine. In the turns, the car is pretty much staying flat even though I have the stock front sway bar and none on the rear.

The car was aligned within factory specs less than 3000 miles ago. I don't think this is an alignment problem, but I'm open to any theories.
Old 02-25-2002, 12:16 PM
  #2  
Marks69BB
Melting Slicks
 
Marks69BB's Avatar
 
Member Since: Jun 2001
Location: NC USA
Posts: 3,281
Likes: 0
Received 3 Likes on 3 Posts

Default Re: Tons of understeer (Chris A)

Are you running a front anti-sway bar?
Old 02-25-2002, 12:24 PM
  #3  
ylose
Melting Slicks
Support Corvetteforum!
 
ylose's Avatar
 
Member Since: Aug 2001
Location: Elkhorn WI
Posts: 2,043
Likes: 0
Received 0 Likes on 0 Posts

Default Re: Tons of understeer (Marks69BB)

yes he does have it
the car is pretty much staying flat even though I have the stock front sway bar and none on the rear



[Modified by ylose, 10:24 AM 2/25/2002]
Old 02-25-2002, 12:28 PM
  #4  
Marks69BB
Melting Slicks
 
Marks69BB's Avatar
 
Member Since: Jun 2001
Location: NC USA
Posts: 3,281
Likes: 0
Received 3 Likes on 3 Posts

Default Re: Tons of understeer (ylose)

:jester :conehead
Old 02-25-2002, 12:38 PM
  #5  
77inprogress
Advanced
 
77inprogress's Avatar
 
Member Since: Jan 2001
Location: hemet CA
Posts: 59
Likes: 0
Received 0 Likes on 0 Posts

Default Re: Tons of understeer (Chris A)

You may be able to avoid some of this by changing your technique. For example just before entering a turn, a quick jab at the break will transfer weight up front and squash the front tires giving you more traction up front via increased weight and a larger footprint. Easing on the gas in the turn may induce a push but jumping on it willl surely set you loose. There is a balance here and time will help you figure you car out. BTW vettes were designed as pushers (understeer) from the factory and setting the alignment to factory specs will only reinforce this. This was done as a pusher is far safer for the average Joe (no offense to all the Joe's out there) than a loose car is, however loose cars are generally quicker. Play with the caster a little bit and you may be surprised. Have fun trying to get her figure out!


[Modified by 77inprogress, 10:40 AM 2/25/2002]


[Modified by 77inprogress, 4:25 PM 2/27/2002]
Old 02-25-2002, 01:59 PM
  #6  
stngry63
Racer
 
stngry63's Avatar
 
Member Since: Sep 2001
Location: Nashville TN
Posts: 367
Received 0 Likes on 0 Posts

Default Re: Tons of understeer (77inprogress)

Even thought the C2/C3 cars can be made to corner flat, the front can still show a big camber change. The low profile tires may be loosing traction because of this. There are a few things to try though; tire pressure, run zero to positive camber on the rear, negative camber with zero toe-in on the front. You'll just have to tinker.
Old 02-25-2002, 02:02 PM
  #7  
ddecart
Team Owner
 
ddecart's Avatar
 
Member Since: Aug 1999
Posts: 42,480
Received 15 Likes on 9 Posts
SPARTAN
CI 3-4-5-6-8-9-10 Vet
CI-9 AutoX Winner
CI-3 Go Kart Champ
St. Jude '03-'04-'05-'06-'07-'08-'09-'10-'11

Default Re: Tons of understeer (Chris A)

You've stiffened the front suspension with the 460lb springs. What have you done to the rear?
Old 02-25-2002, 03:38 PM
  #8  
Lt1er
Drifting
 
Lt1er's Avatar
 
Member Since: Dec 1999
Location: Reno nevada
Posts: 1,462
Likes: 0
Received 0 Likes on 0 Posts

Default Re: Tons of understeer (stngry63)

I auto-X and your never going to do wel with anything near stock alignment settings. VB&P has the base settings. To set your tire pressures right you need a tire temp guage.

Without correct settings and good tires no amount of suspension mods will make it go faster
Old 02-25-2002, 05:16 PM
  #9  
flynhi
Le Mans Master
 
flynhi's Avatar
 
Member Since: Aug 2000
Location: Austin TX
Posts: 6,254
Likes: 0
Received 10 Likes on 9 Posts

Default Re: Tons of understeer (Chris A)

Introduce a bit of oversteer with a rear stabar. Start with 1/2".
Brake earlier and use throttle (throttle induced oversteer) to power around corners.
Old 02-25-2002, 08:43 PM
  #10  
Frank75
Burning Brakes
 
Frank75's Avatar
 
Member Since: Sep 2000
Location: Maine
Posts: 922
Likes: 0
Received 0 Likes on 0 Posts

Default Re: Tons of understeer (flynhi)

Kind of radical, but what happens if you remove your front sway bar? Might roll more but be more balanced. I agree with others that best solution would probably be to stiffen up the rear. You need a skid pad (don't we all - LOL)!
Old 02-26-2002, 12:01 PM
  #11  
BeaterShark
Drifting
Thread Starter
 
BeaterShark's Avatar
 
Member Since: Sep 1999
Location: Wylie TX
Posts: 1,411
Likes: 0
Received 0 Likes on 0 Posts

Default Re: Tons of understeer (Frank75)

77inprogress - I tried changing my technique, but it didn't help much. Also, you stat that when the car "pushes", it's oversteer. Is this correct? I've read that if the front end pushes, it's understeer and if the rear slides it's oversteer.

stngry63 - I do have a lifetime alignment from Firestone, but I'm sure they will not let me use it to "tweak" my settings. Is there any way (ie instructions) that I can make changes myself?

ddecart - I have a VB dual mount rear spring set at the second to stiffest position.

flynhi - I will probably get a rear stabar. I would have already, but the car does not roll at all now.

I believe the biggest problem was the amount of gravel in the parking lot. It may have just made my understeer that much worse. I tried to brake early and use the throttle for some oversteer, but the throttle would at first just push the car more and by the time I got the rear end to swing around, I was way outside the turn. I did run this car once about 1 1/2 years ago and I was "hanging" with the C4s and C5s pretty well and was having fun. I do remember some understeer, but not nearly as much as I noticed this last time. It was just plain not fun driving it. I did still manage to beat the 3 late model Mustangs that were there.

Old 02-26-2002, 12:31 PM
  #12  
Noel Carboni
Pro
 
Noel Carboni's Avatar
 
Member Since: Jan 2002
Location: FL
Posts: 534
Likes: 0
Received 0 Likes on 0 Posts
Default Re: Tons of understeer (Chris A)

if the front end pushes, it's understeer and if the rear slides it's oversteer.
Yes, that is correct. It's easy to get the terms backwards.

I will probably get a rear stabar. I would have already, but the car does not roll at all now.
Actually, before buying much more I'd try moving that rear spring setup to the stiffest position.

Since it sounds as though you like your car stiff, I recommend a VB&P rear sway bar and their adjustable end links with very hard bushings and poly pivots (I have a 3/4" bar, though I only have a single mount 400 lb VB&P rear spring from days of yore). You can use the adjustable end links to fine tune your balance, even at the track, by tightening/loosening the link nuts.

-Noel
Old 02-26-2002, 12:35 PM
  #13  
JohnS_77
Melting Slicks
 
JohnS_77's Avatar
 
Member Since: Dec 2000
Location: Lexington, North Carolina
Posts: 3,242
Likes: 0
Received 0 Likes on 0 Posts

Default Re: Tons of understeer (Chris A)

The parking lot used had quite a bit of gravel
I remember sweeping the parking lot at course set up, the night before some of our events here. I'm suprised they let you run on it.
Old 02-26-2002, 07:08 PM
  #14  
77inprogress
Advanced
 
77inprogress's Avatar
 
Member Since: Jan 2001
Location: hemet CA
Posts: 59
Likes: 0
Received 0 Likes on 0 Posts

Default Re: Tons of understeer (Chris A)

Chris sorry about that! Post has been corrected. Sometimes when I post from work I type before I think! My bad! You are correct.

Get notified of new replies

To Tons of understeer




Quick Reply: Tons of understeer



All times are GMT -4. The time now is 07:37 AM.