As you can imagine there is not allot of information regarding autocross alignment specifications for a Lexus, especially the luxo barge variety.
What is the hive's opinion as a starting point? The car in question is a 1999 GS400 lowered 2 inches. I am sure the same alignment would work for willrunifchased's LS400 as well.
At best it's a guess. If you are driving in I would leave a generic 0" toe and add another degree of negative camber to the factory spec so you aren't scrubbing off tires on the trip. Yes it could be more but I'm guessing that neither Lex Toys are running for FTD
Go -2 or so on camber. camber doesnt "scrub" tires, toe does.
I plan to get FTD for the Aristocrat class.
I am thinking max caster, -1 to -2 degrees of camber if I can get it. The toe front and rear is what I am trying to figure out.
As stated 0 is the best all around choice
Front and rear.
A little out on the rear will help turn in but not good on the road and wears the tires.
Zero front and a little toe IN in the rear should give you reasonable tire wear and act predictably. The reason being that luxo barges have rubber bushings and under hard braking, accel or corner loads they will move. The zero in front will toe out a little braking into a corner and give you good crisp turn in. The little bit IN at the back will (ideally) go to zero under full accel and brake and slide predictably.
Toe out in the rear of a RWD car is typically a no no unless you have very fast hands. On a FWD that won't turn, maybe.
Quasi Mofo wrote: I'm guessing that neither Lex Toys are running for FTD
This year, the big race is in the middle of the fleet!
0 toe all around as much front camber as you can get, -0.5 rear.
Max caster, at least 2 degrees camber,, zero toe in front, slight in at the back. As stated above, you can run a LOT of camber and not have wear issues, way over 2 degrees.
mazdeuce wrote: Max caster, at least 2 degrees camber,, zero toe in front, slight in at the back. As stated above, you can run a LOT of camber and not have wear issues, way over 2 degrees.
I don't think it is adjustable with my current setup, I will get as much as possible that is even side to side.
pimpm3 wrote: I plan to get FTD for the Aristocrat class. I am thinking max caster, -1 to -2 degrees of camber if I can get it. The toe front and rear is what I am trying to figure out.
Someone certainly will! Let's hope it's you... For now... Muahahahhhha
Hey, no modification rules, so nothings stopping you from hogging out the bolt holes on the shock towers to get more camber.
After tires, I would think your biggest handling improvement would be in spring rate.
They were designed for a soft ride, and then are throwing lots of weight into the corners.
If you can decrease body roll, you will gain a lot.
You've probably got about a 300# spring on a 3800# car. For reference, we are riding an 800# front spring on an 1800# car.
SVreX wrote: After tires, I would think your biggest handling improvement would be in spring rate. They were designed for a soft ride, and then are throwing lots of weight into the corners. If you can decrease body roll, you will gain a lot. You've probably got about a 300# spring on a 3800# car. For reference, we are riding an 800# front spring on an 1800# car.
Not sure of stock rate but your guess of 300 lbs is probably spot on. The springs I bought for the car are 500 lb in front and 615 lb rear. I also upgraded the front Sway bar from 28mm to 30mm and the rear bar from 14mm to 20mm.
According to Car and Driver a stock GS400 weighs 3650 lbs. I am hoping to take 150lbs out of it for the autocross / drag race between the heavy seats, spare, rear exhaust etc...
Should be able to get a lot of negative camber fairly easily. I know I can on the ls400. Probably want to shoot for -3 up front and as little as possible in the rear.
Weight reduction will be our largest advantage. My front seats are probably 75 lbs each.
I may swap out for the stiffest optional springs on my coilovers.
All the camber front. All the camber -0.5-1 degree rear. Zero toe F 1/8 toe in rear. Whatever caster you can get after camber, even L/R.
pimpm3 wrote: According to Car and Driver a stock GS400 weighs 3650 lbs.
Wow, svelte at only 3650.
According to C&D, the '90 Infiniti Q45 weighs in at 4020.
pimpm3 wrote:SVreX wrote: After tires, I would think your biggest handling improvement would be in spring rate. They were designed for a soft ride, and then are throwing lots of weight into the corners. If you can decrease body roll, you will gain a lot. You've probably got about a 300# spring on a 3800# car. For reference, we are riding an 800# front spring on an 1800# car.Not sure of stock rate but your guess of 300 lbs is probably spot on. The springs I bought for the car are 500 lb in front and 615 lb rear. I also upgraded the front Sway bar from 28mm to 30mm and the rear bar from 14mm to 20mm. According to Car and Driver a stock GS400 weighs 3650 lbs. I am hoping to take 150lbs out of it for the autocross / drag race between the heavy seats, spare, rear exhaust etc...
Teach me something about those spring rates. They seem backwards. Wouldn't you want the heavier springs in the front?
Your 150 lb diet should be easy. Probably has that much in the glovebox. 
In reply to SVreX:
The spring rates do seem odd since the same brand coilovers are stiffer in the front.
Just did a quick perusal of internet pics to understand what kind of suspensions the Lexi's are running. You both have multi-link setups front and rear which, like the Miatas double A-arm, require lots of spring rate. Id put as much spring as you can find with a bit more in the front than rear. Im talking north of 800lbs per inch up front. Maybe 1000? 
Waay back in the day there was someone making poly bushings for the entire suspension for a really good price. I'd pick some up if you can swing the time and budget. Yours both are probably toast and are going to make the alignment a moving target. The bushings are a bit amusing to install-lots of fire required. They were fine on my dd SC400, still comfy.
It seems like heavier springs in the rear would just increase the car's natural tendency to dive when cornering.
I know my ls400 has been super easy to work on the suspension. Usually it takes me an hour and a half to install coilovers on a Miata. It took me less time installing the suspension on the Lexus the first time.
Will probably run 1000/800 setup in the ls400. I may even have time to test it out.
General rule: Under steer-- stiffer rear than the front Over steer-- stiff front softer rear.
I am going to be running stock alignment mostly because of the 3000 miles of driving to and from there.
iceracer wrote: General rule: Under steer-- stiffer rear than the front Over steer-- stiff front softer rear.
Isn't that backwards at least with my track car, I have heavier rear springs to make it turn in better. It is FWD though...
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