Weight removal effect on alignment?

[speedblind]

Hey all:

Anybody measured this? I finished the suspension of my car and began gutting it, but there's some more heavy stuff to come out. I have an alignment scheduled for next Thursday, and I'm not 100% sure I can get everything out before then. Left to come out is:
A/C - all of it
Heater/heater core
Sunroof/cartridge
Sound deadening goo on the interior
Strip hood/trunk and replace mechanisms with pins

So...I think I'm looking at close to 150-180 lbs. or so, maybe more. My question is whether or not that 150 lbs. will affect alignment drastically enough to require a re-do later on.

[kendogg]

Well, weight removal is obviously raising the car. When raising the car, camber will go towards positive, both front and rear. Front toe will stay the same, while I believe (somebody please correct me if I'm wrong) with no rear adjustment, rear toe will go out slightly. I can't picture a change in front caster though.



Here's a picture of my subframe sitting on the ground to try and visualize the movements.

[Dominic49]

silly trailing arm reinforments...


and yes toe WILL change with suspension travel...

http://e30m3performance.com/tech_articles/susp-tech/rear_curves/index.htm

read it

[Scott///M]

In short, weight reduction will affect your alignment.

When racers do their alignment they will try to come as close to race weight as possible—right down to driver and fuel.

[kendogg]

silly trailing arm reinforments...


and yes toe WILL change with suspension travel...

http://e30m3performance.com/tech_articles/susp-tech/rear_curves/index.htm

read it

Dom - I already said rear toe will change with suspension travel ;)

And those 'silly' trailing arms reinforcements keep my trailing arms from flexing and walking around all over the place unlike most stock trailing arms ;)

[matt]

You have to remember that the control arm and the tie rod are parallel. There should be no front toe change with ride height change, or not much.

The rear end will toe in or out depending on where on the curve you are.

[kendogg]

You have to remember that the control arm and the tie rod are parallel. There should be no front toe change with ride height change, or not much.

The rear end will toe in or out depending on where on the curve you are.

Ahh, good point. I'll edit my post right now then.

[speedblind]

Well, I figure it will definitely change alignment. A friend of mine has a 67 Chevelle that's fully gutted, and the wheels definitely gain camber to a noticeable degree when the engine's out.

My question was more along the lines of how much I should be worried about the alignment change. I suppose the rear is pretty much as light as it will get - all the trunk stuff, stereo, etc. has been removed, so I'm probably good there. The main stuff that still has to come out is in the front/middle of the car: sunroof and cartridge, A/C system, interior sound deadening tar, windows/motors etc.

I suppose I should just get the car as close as possible and have the thing aligned.

[JRKOUPE]

Well, I figure it will definitely change alignment. A friend of mine has a 67 Chevelle that's fully gutted, and the wheels definitely gain camber to a noticeable degree when the engine's out.

My question was more along the lines of how much I should be worried about the alignment change. I suppose the rear is pretty much as light as it will get - all the trunk stuff, stereo, etc. has been removed, so I'm probably good there. The main stuff that still has to come out is in the front/middle of the car: sunroof and cartridge, A/C system, interior sound deadening tar, windows/motors etc.

I suppose I should just get the car as close as possible and have the thing aligned.

IIRC American cars will get more neg camber as they get lighter.......our cars get more pos camber..........regarding the front. Your last comment seems to make the most sense.....

[joshh]

I'd re-do the alignment afterwards.