Alignment wizzards, PLEASE HELP! Scared to go full throttle over 60MPH....

[-FROG-]

Posted this on both viper boards because I am in need of answers for my own safety.

I NEED HELP FROM YOU TECHNICAL VIPER SUSPENSION PROS!

I have been comfortable with my car up to the 130's but now, I am scared for my life at 60 when on the throttle... SERIOUSELY!

I just had my alignment done at a local speed shop that deals with road race and race suspension cars. I Had on BRAND NEW rear tires and the fronts are in GREAT, like new shape. The reason I got it aligned was NOT because of toe or caster, but because of my camber... from lowering it with Eibach springs and spring caps. My rear tires were being destroyed from the camber off so I had to get the camber taken care of.

I'm not putting down the shop or anything like that. I just need to find out whan needs to be corrected so I don't kill myself. So basically the steering is VERY VERY tight for normal driving. ANY little twitch in the steering wheel will cause the car to turn left or right making it feel real squirley at highway speeds and a little on normal roads. When on FULL THROTTLE, the car gets super squirley up in 3rd gear when I start increasing to about 70+MPH. I had to pull over today as I was test driving it because it pulled so hard to the left and got into a weird groove that I couldn't pull out of, so I eased it over slowly to a safe speed. No cars around so it was all good.

I called the shop and they told me that they may have set up the alignment to take care of the camber and lessen wear on the tires and it's possible they did not go by Viper specs, but just speced it out a little as to my request. They are a race shop, so I assumed they would have done it right to begin with and know how to properly align a car for street / drag strip, but the guy is supposed to get back with me and let me know if they went by Viper specs or just pulled a little camber.

I'm attaching a pucture of the spec sheet they gave me to show the before and after. What do you think? Does it look good or is it wrong?

*Edit* the shop contacted me and said they did set the car up to factory stock settings. I have no idea of knowing but I'm sure they are honest with their work.

You must be registered for see images

 

[kcobean]

Watching this thread with some interest, as I'm getting ready to lower my ACR and will need to re-align.

 

[Tom Sessions]

Looking at the spec the front looks ok. Rear has way to much toe in.They have it set at 0.41 total. I would go for .05 per side or 0.10 total toe in. I would also want to see the adjustment cams on the rear control arms. Is the rear caster off? Rear caster is measured with the DRB 3 and inclinometer that hooks up to the rear knuckles.If thats not available then As a rule of thumb the cams should be positioned the same front and rear on each arm. If you have one cam at 3 oclock and one at 9 oclock to get the right camber reading your caster is going to be way out. Just my 0.02

Every car I have lowered drives so much better when done correctly

 

[TexasPettey]

Those specs don't look like they should cause a problem. Severe TOE out would cause a twitchy feeling in the steering. Perhaps they forgot to tighten up after they got the alignment set. That might cause it to slide around.

 

[Greg Good Cylinder Heads]

+1.

What TexasPettey said.

 

[01sapphirebob]

Tom did the alignment on my '01 ACR. I would trust what he says.

 

[Tom Sessions]

Is that the one I did at the tech session last year at Fredericks dodge?

 

[-FROG-]

Good information guys, thanks.

Those specs don't look like they should cause a problem. Severe TOE out would cause a twitchy feeling in the steering. Perhaps they forgot to tighten up after they got the alignment set. That might cause it to slide around.

Texas Petty, That's one way to explain the steering in my car. REALLY TWITCHY! And under accelleration, it can get into a "groove", slightly to the left or the right, depending on where the steering wheel is slightly pointed and whe you steer out of the groove, it almost twitches over to the other side UNsafely like it's getting ready to spin out.... like MASSIVE OVERSTEER. It's almost like the rear tries to wrap around to the front, unfortunately, NOT from horsepower, but from steering.

You guys are mentioning TOE on the rear... I wonder what the best setting would be? I'm going to try and gather the best information on the boards to present to the alignment shop to get me set up right.

 

[Tom Sessions]

Rear toe in 0.05 per side total toe 0.10
And look at the Cams for correct position

 

[kcobean]

Tom, since Wilmington is a bit far for me , can you recommend camber/toe settings for a lowered car (and caster if you think it needs to change from factory)? I need to provide these to Ferrari.

 

[2000_Black_RT10]

There's some factory alignment info in this doc.. setting up ballast weight, camber, etc.. around page numbers 55 to 69..

http://www.wincom.net/mnllehti/998_999_Recalls.pdf

 

[01sapphirebob]

That would be the one

Is that the one I did at the tech session last year at Fredericks dodge?

 

[bluesrt]

1 would put the alighnment at more negative camber and caster and see what you get. i think it needs more in my opinion

 

[mjorgensen Woodhouse]

Other things to consider than the great info above is that the "flatter" the tire is to the road (less camber) the more the car will twitch and follow the crown or ruts in the road. The camber in the rear at -.90 and as Tom suggested .10 total toe in will make it track better AND reduce the inside wear. The wear was no doubt caused by the excessive toe in not the camber. Rules apply to the front also. camber at -1.2 and toe at 0 or maybe .07 total toe "in" will help the stability and get you away from the twitchy feel.

Just another thought, if you are hitting the bump stops under acceleration in the rear this rapid spike then the rebound from it could cause instability. Driving on the bump stops is never a good thing and the combination of springs AND caps can get you there.

Good luck!

 

[Catwood]

Did you check corner weights? I once set that wrong and the car lost 10 seconds a lap on a gen 2 because the rear wouldn't stay behind the car.

If you just lowered it perhaps it is causing some of the issue.

 

[kcobean]

Did you check corner weights? I once set that wrong and the car lost 10 seconds a lap on a gen 2 because the rear wouldn't stay behind the car.

If you just lowered it perhaps it is causing some of the issue.

For those of us who are track idiots, is there any info or a guide on how to corner weight/balance a car?

 

[Catwood]

you will need scales and the abilty to adjust ride height.

Usually the scales will tell you what to do in terms of adjustment

or you can use this

Corner Balance Calculator

increasing ride height on one corner raises the weight on that corner, lowering does the opposite.

I did it with me in the car and a full tank of gas Others opinion will vary.

 

[-FROG-]

PROBLEM SOLVED!!!!!!

Thank you all for taking the time to respond to my delima. I sincerely appreciate it VCA!

I figured out what the problem was and I think it was a combination of things. Part of it is from my own stupidity... I'll share some details about my thoughts for those that may be interested and may run into similar problems in the future. I may not use the "proper" technical terms related to alignments, but I think you will get the idea. Also, forgive me for writing another "book" like I usually do when I get on my own personal technical car topics, I just like to be a clear as possible for anyone else in the same boat down the road.

Anyhoo, I took the car out for another test drive today and noticed it was tracking a little better going down the road. Not so "twitchy" like it was a few days ago. I was doing some thinking while driving and remembered from a few years ago, I had a drag mustang I built a few years back and the front tires were toed in CRAZY, like turned 30 degrees in, on each front wheel. These front tires were pretty skinny, like about a 195/40/15. It looked ridiculous with the bad Toe, but I built the car from the ground up and of course there were a few adjustments I had to make because I swapped the front end off another car. The front tires were destroyed on that mustang literally in 1 week after cruising through the neighborhood making a few little test drives for about 2 miles total. My uncle aligned it for me, because he did alignments and the front tires sat perfectly straight when he was done! However, the steering still felt weird. I can't recall if it was "twitchy" like the Viper was but I do recall it was not perfectly normal, right after the alignment was done. After putting a few miles on the Mustang, I noticed the steering felt better and seemed to be gradually getting back to normal. Obviously, this was because of the MASSIVE coning and wear on the front tires, was starting to create a new tread pattern, more adjusted to the new alignment. So, this was an extremely dramatic case of what was partially the case with my current Viper alignment.

I now have 100 miles on the Viper from driving it over the last 3 days since the alignment and I noticed it seemed to be tracking a little better at higher speeds. I slowly hit 80 a few times earlier today and I didn't notice the "pulling" to the left or right as much anymore at the slightest turn of the steering wheel like it has been doing. This is what made me recall my Mustang adventure from a few years back because it took a little while for the new alignment, to create a new tread pattern on the front tires. also over the last few days, I have been aggressively turning the steering a hard left and right at slow speeds, to see if the front tires would dig in a little better, in a way, kinda "scrubbing" them a bit like NASCAR drivers do, to help them adjust to the new alignment tread pattern. Since my front tires are 275, and NOT a 195, like on the Mustang, it took a few more miles for the front tires on the Viper to create a new tread pattern / groove.

Today I decided to go ahead and check the air pressure in the tires as well because I noticed a new tread wear line around the diameter of the front tires. I figured it was from me doing my NASCAR like "scrubbing" of the front tires throughout my drives. The front tires checked out ok at about 34psi. Then I went ahead and checked the rear tires that are brand spanking new 345/30/18 BFG G-Force Drag Radials. I had these tires put on about a week ago and put them on my car without driving it, except for taking it up to the north part of town for the alignment. checking the rear tires I saw they had 44psi in each one. Well heck... there is the other half of my problem with steering on full throttle. Typically the guys that do my tires put the normal 32psi n my tires but I guess some new guy decided to put MAX psi in them. SO, I didn't think it was my Horsepower messing with my steering while the car was at full throttle, but it was the horsepower/torque forcing my rear end around to the front of the car at higher speeds. Especially since the G-Force tires are a solid SLICK in the center area where the tires were "ballooning" out from the high 44psi. I let out some air, to about 32psi and took the car out for another test drive. IT FEELS GREAT! I made a few passes up to about 120 and the car felt totally controllable and I felt more safe and "In Control" of the vehicle.

So lessons learned here are....
1. First check tire pressure
2. After an alignment on older tires, it may take a few miles for the tires to adjust to the new alignment.

Soulspeed is the shop that took care of my alignment for any of you Austin guys that may be interested. The Dodge dealership was charging me $450 to do it and said it was a 5 hour job for their so called "Viper Techs" MINIMAL! Soulspeed charged me $129.00 and had the car done in 1 hour. They did a good job and I was happy with their service. Though some folks may question or have a few disagreements about the alignment result pictures I posted, I know they are all in good faith but the soulspeed specs feel good. Thanks again for all of your help and insight.
Paul Daniels -FROG-

 

[pteam]

When I bought my current viper it darted from side to side, it turned out that the dealer who put new tires on didnt have the rims and tires balance properly and it made it really bad. I got an alignment and it only helped a little. It wasnt until I had the tires and rims balanced with new weights on the rims was when it got 95% better.