Alignment question, pulls left - Page 2

ckelly · 05-10-2003, 07:48 PM

Took the car to DE today, obviously still pulls left, instructor commented on it as well. Also noticed the car would turn a lot better to the right than the left, I drove it and agreed, feels really weird turning left, like it wants to dive in at first, but then understeers, kinda strange and unstable feeling. Turning right is really good, maybe a little oversteer at speed, but maybe normal.
Braking doesn't have any more effect on the pulling left syndrome, does it all the time. If it was a corner balance, and if i balanced the car with ballast for me in it (230), then the instructer (125?) drove it with me in pass side, wouldn't that change things? Does the EXACT same thing.

I'm completely confused on this, I've got an appt (after much arguement) at the alignment shop to have it checked again on weds, I guess we'll see what that brings.

Is there some way I can check it too, or does it really need to be on the rack?

Other than that DE was great, cold miserable misty rain all afternoon, so got some good slipping and sliding in, kinda spooky

Tyson Schmidt · 05-10-2003, 07:58 PM

Clay, you just described a textbook case of corner imbalance. I suspect you'll need to raise the LF and RR to load these corners more. Or drop the RF and LR to achive the same.

Good luck!

ckelly · 05-10-2003, 08:15 PM

Even though moving weight (drivers) around the car doesn't have any effect? and just going straight, no brakes?

ckelly · 05-10-2003, 08:17 PM

Raise as in ride height, or raise the wheel into the wheelwell (lower ride height)?

Tyson Schmidt · 05-10-2003, 08:58 PM

Raise as in trying to raise that corner of the car.

It doesn't matter what you load into the car. It's like a bar stool that has one leg that's too short. Doesn't matter where you sit on it, the leg is still too short. Same goes for corner balancing.

dean · 05-11-2003, 02:35 AM

Listen to Tyson. He is correct, an other alignment without a cornerbalance first will do nothing except lighten your wallet

ruf-porsche · ruf-porsche's Garage

What do you mean by pull left? Does it pull left while its under braking, or does it pull (drift) to the left when it in a straight line and you remove your hands from the steering wheel? If it pull left under braking it probably the brake, if it drift while it's in a staright line it's probably an alignment. I see that the caster on the left and right are not the same. Caster is critical for a car to track in a stright motion.

Think of a shopping cart with with the front caster for wheels. How many time have you gotten a shopping cart that doesn't go straight? Most of the time one of the wheel isn't any good, or the cart been bang up so much that one of the wheel is out of alignment.

Wil Ferch · 11:49 AM

I'd sharpen the focus strongly on two things..
- verify CB is correct , as you suspect.
- verify that caster is indeed the same for both sides...more important than getting it maxed out.

Wil Ferch

ckelly · 05-12-2003, 11:19 AM

Given the caster specs that I listed, is the difference enough to cause the problem?? Assuming CB is correct or within a reasonable amount.

Wil Ferch · 05-12-2003, 11:52 AM

I guess I'm saying double-check the caster and CB that was listed to you earlier. May be cheap insurance to go to another ( or same) alignment shop just to verify the results handed to you earlier, by going on the rack again. This sort of thing happened to me before and drove me nuts until I double-checked at a different alignment shop. Result? The readings *were* different and all of a sudden...explainable as to what was wrong.
--Wil Ferch

Steven Alarcon · 12:19 PM

The Factory Tollerance is 20 lb. difference from side to side
without drivers weight. Since the car did not pull prior to you
doing the work, I would guess it is the Corner Balance. If you
also replaced tires at the same time the work was done you
could have a radial tire pull. This can be checked by rotating the
tires side to side, on just the front tires. The car sould pull the
other direction or even track straight. Are the tires directional?
Try this anyway to prove it is the Corner Balance. No Alignment
on the planet can correct a bad corner balance.
I don't think I would mess with the ride height adjusment
yourself, any change in ride height will effect the toe adjustment
which will cause rapid tire wear. Check the tires first and if it isn't
a radial tire pull, take it back to your tech and have him recheck
the Corner Balance.
Hope this Helps,
Steve Alarcon

Wil Ferch · 05-12-2003, 12:28 PM

Ahhhh. ..the famous Steve Alarcan....Todd Serota's favorite alignment guy ( Todd..of TrackQuest school..DE... fame..on Rennlist).

I'd listen to Steve....

--Wil Ferch

hobieboy · 05-12-2003, 01:08 PM

well - I'm having my CB checked this weekend... Hpefully that would get rid of my right drift problem.

A question for the experts - if I am doing CB myself, I need to get my alignment re-done/checked at the end. Is that correct?

thanks...

ckelly · 05-12-2003, 01:19 PM

Well, as stated before, I replaced the torsion bars, did the corner balance myself, with drivers weight, got within 4 lbs according to my Ruggles scales (accuracy?) and then had it aligned (with drivers weight). Now I've got the pull and strange handling, not just on braking, all the time. It did not pull before the torsion bar change, or alignment even. No new tires, and they are directional. I'll put it on the scales again to double check, I'm still planning on getting it on the rack again, just to make sure.... Should I insist that the camber numbers are exact?? How much is too much off?

Anyone know of a good alignement/corner balance shop in the Lincoln/Omaha area????

Steven Alarcon · 05-12-2003, 02:38 PM

When the Corner Balance is done with the drivers weight in the
car the weight will not be within the factory tolarance of 20 lb.
The corner balance should be done on a ratio of the weight.
A good book on this is HOW TO MAKE YOUR CAR HANDLE by
Fred Phun. This book will explain what is commonly done by
the computer on digial corner balance scales. You need to find
someone in your area to put your car on this type of scales. They
will push the cross-weight button and the number you want to
see is 50% with the drivers weight and the car perfectly level.

Good luck!
Steve Alarcon

stlrj · 07:19 PM

Did anyone happen to notice how far out of spec his alignment numbers were or are they totally meaningless? According to my spec book, an 80 SC is normally set at +0.5* camber in front and 0.0* camber rear.

If I took my car in to have aligned, I would insist on having it done as close to factory spec as possible or else accept whatever dubious handling that may result.

Why not have it aligned all over again and this time have it done by the book?

Joe

ckelly · 05-12-2003, 07:45 PM

I asked for some common street track alignment specs here. The majority of the responses I got was -1.0 front and -1.5 rear, max but equal caster.

I used the corner balance calculator here http://vintagebus.com/cgi-bin/balance.cgi to figure my corner balances. However, when playing with my older Ruggles scales tonight, I noticed a fairly serious discrepancy in the accuracy. If I would stand on one scale, it would read 240, then to another 218, then another 223, and another at 238. Hmmmm, using 4x multiplier for the rear....makes accuracy out the window. Anyone ever tried using different scales other than the Ruggles ones? Looks like an ordinary bathroom scale to me.

Even so, I still have a really hard time believing the corner balance is causing all of my problems....the car was lowered by the PO, when I spoke to him about it, he said he just crawled under the car and adjusted the fronts down, and lowered the rear spring plates as low as they'd go, didn't balance the car at all, only had a basic alignment done, cost him 50 bucks. Car drove perfectly straight. Even when I got done with the torsion bars and test drove it un-aligned, unbalanced, it drove straight, didn't pull. Only thing I did was take it to the alignment shop and now it pulls.......????

Once again, how important is that caster number, how close is close enough?

Tyson Schmidt · 05-12-2003, 08:08 PM

It takes a large difference in caster to cause a pull. When aligning a car, we were taught in Tech school to build in a slight pull to the left to compensate for road crown. You'd make the left camber .2 degrees more positive than the right, or, the left caste .4 degrees less positive than the right to achive the road crown compensation.

It takes about .5 to 1.0 degrees caster difference left to right to cause a noticeable pull, but depends greatly on car, tires and other variables.

911pcars · 05-12-2003, 09:34 PM

Clay,
You or the shop should have road tested it before giving them the thumbs up. It's probably been too long since you had it done to go back and say do it again (gratis). I'd suggest talking to them and see what they can do for you. If they're reputable, they should work with you on this.

However, if your corner balance equipment is off, this could explain the car's abnormal handling symptoms.

Sherwood Lee
http://members.rennlist.org/911pcars

ckelly · 05-13-2003, 03:48 AM

Yeah, I called them the same day I had it aligned, I noticed it on the way home. They road tested it, but just around the block, in traffic?!?! I called them immediately and that's when they argued with me that it wasn't the alignment, maybe it's not, but after another call I finally convinced them to at least put it on the rack again and double check it. Got to have it there by 8am tomorrow, we'll see what that turns up, if anything. I'd at least like to know for sure, I know I'll have to have it redone if my CB is off too. Oh well.