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| ninetyfivevette | How can I keep the tires planted in the corners? | ||
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Guru Newb
 
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What would it take to keep the tires planted to the pavement on uneven surfaces? The front-end skipping all over the place is very unnerving and in some cases has been dangerous. My shocks (QA1), wheel bearings, bushings and other suspension components all seem fine.
What seems to happen is the front-end gets upset, gets light and then the rear end likes to follow. In this case I was aggressively accelerating on to the highway, went over a transition strip that occurs on a banked slight curve, which caused momentary steering loss, followed immediately by the rear kicking out to the right. I've got a few issues going on here, I realize, but this was not an aggressive bump by any stretch. I've had minor cracks in pavement cause this in similar situations, but don't affect other vehicles to anywhere near the same degree. Where can I start? |
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Posted on: 2008/6/4 21:40
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| patgizz | Re: How can I keep the tires planted in the corners? | ||
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Senior Guru
 
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drive slower in curves with bumps in them?
i have to do that on the curve right out in front of my house. if i'm going over 45 it'll toss the rear end of the vette or my truck straight sideways. |
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Posted on: 2008/6/4 22:24
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| Travis93 | Re: How can I keep the tires planted in the corners? | ||
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Bad shocks could cause this, it is there job to smooth out the bumps. I know on other sports cars I have had bad shocks showed themselves by making the suspension feel harder not softer like the heavy boats of the 60s and 70s. Anyone know how to check the shocks on the Vette, The push down on the fender test does not seem to work.
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Posted on: 2008/6/4 23:00
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| CentralCoaster | Re: How can I keep the tires planted in the corners? | ||
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Senior Guru
 
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I tested my new Z51 Bilsteins against the originals from 1985, the new ones reextended twice as fast and were much harder to push down.
I guess this extra gas pressure gives them better high speed damping, which should help keep it planted. I need to take the car on some rougher roads to get a feel for the new ones. My next step is to free up the rear suspension with some spherical rod-ends in place of the bushings. The ride is so harsh and skips easily if there's any bumps in the track. |
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Posted on: 2008/6/4 23:07
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1985 Z51, ZF6 |
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| NC Kid | Re: How can I keep the tires planted in the corners? | ||
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Elite Guru
 
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A camber brace would tighten up the front end. No personal experience with it, just read about it on the other forum though.
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Posted on: 2008/6/5 0:06
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| CentralCoaster | Re: How can I keep the tires planted in the corners? | ||
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Most of the people praising that thing have never been on the track.
I sold mine. |
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Posted on: 2008/6/5 5:45
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1985 Z51, ZF6 |
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| 1Fast04Vert | Re: How can I keep the tires planted in the corners? | ||
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Elite Guru
 
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Quote:
And also thinking about selling mine. As far as I am concerned shocks (or lack thereof) are why you are not staying 'planted'. I had Monroe's on for awhile and had the same issues. I went back to Bilstein standards and what a difference, no more problems. Now I have a set of Bilstein Sports coming in and have to decide which set to keep and which set to sell. I hate decisions, decisions, decisions. |
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Posted on: 2008/6/5 13:47
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2004 Vert. 475hp. Built by Vengeance Racing |
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| bogus | Re: How can I keep the tires planted in the corners? | ||
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Grand Imperial Pooh-Bah
 
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Don't go too firm with the C4 suspension.
I am convinced that a majority of the problem is the transverse leaf sprint (TLS) design. On glass smooth (re: Race tracks) surfaces, it's great, add bumps to the equation and it gets all skitterish. TLS just does not do a great job of absorbing bumps and maintaining bump control. I am a firm beleiver in a softer spring and a good shock. I have the Koni Yellows, and even they are a bit on the firm side, but seem to do a great job keeping the suspension planted. My next suspension upgrade will be coil overs. I am convinced they will fix the major problems. It's just not a cheap fix. |
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Posted on: 2008/6/5 14:16
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The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me |
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| BillH | Re: How can I keep the tires planted in the corners? | ||
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The Stig Moderator
 
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There have been posts on other forums about C4's doing this. My 92 will do it on a decent sized bump, in a curve on an interstate. That's with the "revalved shocks" from Corvette Centeral that came with the car. First, tire pressure. I've had this happen on more than one C4. The ones I remember were running Goodyears, at 32psi every little crack in the road would pull at the steering wheel and the wandered on the road quite a bit. At 35psi all this went away. With QA1's the front shocks could have too much bump dialed in. Too much bump will definately cause skating, the tire is not staying in contact with the road as much, there's less weight on that corner when this happens and that's where the loss of steering can happen. The rear coming out could be due to steering corrections or not enough rebound dialed in. Additionally, this could be an alignment problem. Too little toe in on the front can easily cause this. Same at the rear. |
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Posted on: 2008/6/5 14:42
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Every man dies but not every man lives. |
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| BillH | Re: How can I keep the tires planted in the corners? | ||
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The Stig Moderator
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The gas pressure does help on the high speed damping. The main reason for the gas is to help prevent bubbling in the oil which has an effect like when you have a bubble in your brake line. |
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Posted on: 2008/6/5 14:48
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Every man dies but not every man lives. |
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| jhammons01 | Re: How can I keep the tires planted in the corners? | ||
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Senior Guru
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My loose rear end has been diagnosed as the bushings on the rear trailing arms (Dogbones) are gone. Allowing the critical rear wheel to become misaligned when you need it most.
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Posted on: 2008/6/5 14:49
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| 1Fast04Vert | Re: How can I keep the tires planted in the corners? | ||
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Elite Guru
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If you need them I have a complete set with the energy flex bushings already installed. Send me a PM if you are interested. |
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Posted on: 2008/6/5 15:20
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2004 Vert. 475hp. Built by Vengeance Racing |
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| jhammons01 | Re: How can I keep the tires planted in the corners? | ||
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pm sent as the Dogbones are on by wish/todo list.
Not sure if a set from a 95 will fit an 84.... |
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Posted on: 2008/6/5 15:32
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| BrianCunningham | Re: How can I keep the tires planted in the corners? | ||
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I've got QA1's on the car now.
What settings are you on? Singles or doubles? When the last time you had your wheels/tires balanced? What's your alignment? |
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Posted on: 2008/6/5 16:08
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Polo Green 95 LT1 6-spd http://mysite.verizon.net/vzevcp74/ 383 LT1/Vortech Supercharger/AFR heads/Rod end suspension/Penske-Hardbar dual rate coilovers/Wilwood 6pot brakes NCCC Governor: http://BayStateCorvetteClub.com |
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| ninetyfivevette | Re: How can I keep the tires planted in the corners? | ||
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My QA1 are only singly adjustable, I believe- I'd have to dig through my receipts to verify. They were not terribly expensive, so that's a good guess.
Wheels and tires were balanced maybe 2K miles ago- but that was at least 3 years now. Alignment was set for "aggressive street" which I grabbed from CF about 3-4 years ago (maybe 5K miles ago). As I write this, it feels more and more like I have a few things to do! Most of which are cheap or free, which is a good place to start. |
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Posted on: 2008/6/5 20:16
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| CentralCoaster | Re: How can I keep the tires planted in the corners? | ||
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Senior Guru
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I'm curious how a coilover only C4 would compare to a leaf-spring C4 with heim-joint suspension.
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Posted on: 2008/6/5 23:49
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1985 Z51, ZF6 |
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| ninetyfivevette | Re: How can I keep the tires planted in the corners? | ||
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Me too- if it was as simple as buying stuff and bolting it up, I'd be down. I've read a couple accounts of people installing coil-overs and the word "transformed" always seems to come up. I like the Hardbar setups, especially their 2.25" dual rate progressive springs. |
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Posted on: 2008/6/6 0:59
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| BrianCunningham | Re: How can I keep the tires planted in the corners? | ||
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If you have a single knob, they're singles, which is what I have. Unfortunately when you adjust rebound compression, you also adjust compression. The early QA1's are a simple dashpot. Ease of adjustment is their main selling point.
Since they're easy to adjust, try a different setting, and drive over those same bumps. I'll be switching over to coilovers and rodends. I'll really looking forward to seeing the results. |
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Posted on: 2008/6/6 16:08
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Polo Green 95 LT1 6-spd http://mysite.verizon.net/vzevcp74/ 383 LT1/Vortech Supercharger/AFR heads/Rod end suspension/Penske-Hardbar dual rate coilovers/Wilwood 6pot brakes NCCC Governor: http://BayStateCorvetteClub.com |
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| Strick | Re: How can I keep the tires planted in the corners? | ||
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Guru
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I'm one of the guys that installed the camber brace and cross bar in my 92 vert. I also boxed the X-frame. This took the "wooble" out of my vert when bumps were encountered. With this set up, in the auto cross, my front tires seem to hold better in hard turns and the corners, or out side edge, of the tires don't wear as much. Replacing my rear wheel bearings (with tappered bearings) took some of the vibration out of my acceleration out of a turn. Maybe my driving skills got better.
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Posted on: 2008/6/6 20:35
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92 LT1, 6 speed, 3.54 rear, headers, B&B catback, Hurst shifter, polished ZR1 5 spoke wheels, Meziere electric water pump, other mods. |
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| BillH | Re: How can I keep the tires planted in the corners? | ||
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The Stig Moderator
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I'd like to get in a C4 with coils too. In the last month, I've been a HPDE instructor in a stock C5 Z06, a stock C6 with the Z51 and a C5 Z06 with the coilover package. The coilover car just outpreformed both the others. The car felt more predictable on the track, more forgiving. The driver got into some push and some oversteer situations in the same corners that the C6 did and the car was easily corrected and able to get the hammer back down faster than the stock C6. The C6 driver had to saw on the wheel more to correct and stayed off the gas longer to get the chassis to settle down. |
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Posted on: 2008/6/7 15:02
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Every man dies but not every man lives. |
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