Last time out with our car we mainly made some damage. The car pulled the left front wheel up and in the next run the car pulled right hard making it undriveable. I has been pulling right for a while even in a good run, four link rear with 1/3 run preload on the right upper bar. The car also twists pretty bad mainly raising the left front. Last night we measured the body, it seems straight. The wheelbase was slightly off 0.15", but we fixed that and now the axle is straight in the car. Front end alignment was off a bit, very different from one side to another, we didn't get it very good but at least it's "symmetric" now. Is there any hints, shock adjustments, prelaod/torsion bar adjustment things that would help us? Here is a video of the wheelie launch: http://www.youtube.com/watch?v=rBZjrkUn6jE
And here of the last qualification run where it went right hard when the throttle was pressed: http://www.youtube.com/watch?v=aEHELDeG6Lc
Could it at least partly have been just a driving error? Sorry about the quality of the videos.

Before the race I tried to compensate wheel weights a little with a tighter right reas spring, 125 lbs on the left, 150 lbs on the right, is that a mistake? We also had a 40 lbs ballast in the very right rear corner, effect of that?

In this good quality video from 5:00 you can see the last qualification launch from both front and rear, the not so pretty elimnator trial can be seen at 8:34: http://www.youtube.com/watch?v=SpG_-sDJ6Eg

We have our national finals a week from now, and any help would be appreciated to get it sorted out.

have you removed the differential from the suspension & checked all the welds? the ones where the tubes go into the housing & the ones where the spring perches are. i was doing similar but not as exagerated wheelstands last season. my problem was the tube on one side was going out of round making my ladder bar mounts become misalined. i even had a mother of a strongback brace & it still distorted. i'd be removing the rear end for an up close & personal inspection if i was you. before your next outting, that looks dangerous.

No we haven't, but the four corner laser measurements last night didn't reveal anything wrong at least when standing still. The rear axle is a Strange Dana 60 and the IC point is currently about 5.5" high and 44" long We tried longer but it didn't seem to work as well. With this set up (except the unpaired rear springs and the ballast in the right rear) the car has run succesfully. It has always pulled slightly right when I have driven it, and also always raised the left front corner more. I believe we have never run on a such good track before though.

do you have a strongback on your rear end housing? if things are moving you could very well still have all the measurements right but you said in post 1 you've noted some variations on your previous settings. this could be due to twisting of your tubes.

It's a Dana with an LPW cast cover, can't really brace a Dana. We had never before checked the chassis with "pro equipment", but all the dimensions and angles were pretty close and now should be up to par. Rear shock broke? Or settings completely wrong? There is about 1/2" travel inwards and 4.5" our when standing still. The rear coiovers are Strange double adjustables and front suspension is rebuilt stock with Konis and hte travel limited to about 2".

looks like you need an anti- roll system in that thing. what kind of shocks?

Strange double adjustables in the rear, Koni "stock" in front. An anti roll bar would propably help the symptoms and we'll install one during hte winter, but does it cure the problem? Rear locator is a wishbone, all the rear suspension parts are from quartermax.

i just had that same problem amonth ago. my duster went from picking the front end up even to justthe left front and a lot of body rol to the right. i checked all the suspension and thing was ok. then i pulled the coilovers in the rear off and found that the right ones shaft was bent. they were koni. i replaced both with a set strange double adj. iam hopefully going to nyirp sat. for tnt i hope the change fixes my problem. btw your car is awsome.

What was the scale weights ?

First put a anti roll bar on it... that will change
everything.... then your going to start all over
EDIT
check all the welds like others have said but put
the anti roll on it

Has something changed or is this a new deal that you are just sorting out? Something is very wrong IMO but it's real hard to diagnose from looking at videos. It looks to me like your RR tire is lifting which could well indicate a shock problem on that corner. The anti-roll bar everyone is talking about is a good idea.

Dana's will break the tube loose on the passengers side.

You can see it if sometimes you look closely at the plug welds. Alot of times the very center will be busted out of them.

The car I have now had a axle tube broke loose and it had alot of other welds cracked from the continuous flexing.

As others mentioned, I'd be looking at the coilovers. Check the coils closely for breaks. We had a coil break, but you could hardly tell visually that it was broke as the two pieces stayed close together at rest. And another vote for the anti-roll, no chassis car should be without one.

very interesting mine went from wheelsup straight to doing the same thing.

the shock settings have been 4 and 7, but I just can't remeber my logic now which one is which. We had the coilovers out during the laser measurements, replaced by solid bars, and the springs were ok. Didn't pull them apart though and check how they feel. Anyway, we currently have about 1.5" compression and perhaps 1/4" preload. I could add about an inch or so relatively easy, but that also changes the link settings, so perhaps I should alter them too? Or is it too many changes at once? As you can see, we are fairly virgin with the four links; I did put some preload in there, but was it in to right direction? Can't check it anymore because correcting the rear axle/wheelbase alignment we shortened the right lower bar without touching the upper. Now the upper bar is "free", so it seems there is no preload.

Does that rear have a spool or sure-grip?
Check both axles.

Usually you will find something binding,bending,flexing or broken.Find the problem before adding or changing anything. Start at the front of the car and work back,don't overlook anything, mounts,alignment,suspension bolts....everything.

Yes, it has spool Haven't checked the axles yet, they are 40 spline solids. We had three chassis professionals with us yesterday, and they checked about everythin possible and also drew a map of hte chassis to later check dimesions easier.

If you look at the last video at 5:00-5:10 the car loads the right rear a lot. You are asking a lot from the shocks with that car. I would take the shocks apart and check them?

Can you get a video of the passenger side rear tire to see if the rear end is moving around?