mecheng10

Like the title says, at what point does the stock suspension become a bottleneck?
I am not talking about for stance or for cornering ability,
I am talking about in a straight line drag racing/roll racing
I know that the stock supra suspension is good for about 9s and 1.3 60' times
What about the stock sc300 suspension?

mecheng10

suspension gurus any insight?

INTIMAZY

iTrader: (5)

About the same. It's a very similar design with minor tweaks in geometry depending on what you're trying to do. The SC will squat more than the Supra but the limiting factor is really the camber change as the wheel moves up. Weight transfer vs camber at full load. Solid axle is just better for that.

That being said, a little positive camber and the Supras have been known to lay down 1.2 60-foots and pull into the mid 8's on not much more than just drag coilovers. I don't think SC's would be worse off.

mecheng10

That was what I was thinking.
I am kinda weary of using straight drag suspension setup. its not safe for the street where I live. this winter has caused tons of potholes and the streets are rough and a drag suspension would make that god awful and dangerous.

im know people have tried it with their na-t, but I cant find anything about them anywhere.

INTIMAZY

iTrader: (5)

It's less the suspension as it is the alignment IMO. Driving with positive camber on a typical crowned road with grooves worn in from traffic can be 'exciting.'

Even my roadcourse toy gets a bit hairy at highway speeds with 1/8" of toe out up front combined with -3 degrees of camber all around. Whether its on street tires or slicks.

mecheng10

thanks for the insight.
im just going to do it and see what happens. give people some insight on it possibly. and why lose the lexus comfort if you don't have too!
that is if the snow finally stops...

Candela

iTrader: (1)

Wouldn't hurt to upgrade the stabilizer bars to make it a bit more nimble for off the dragstrip, that'd be akin to the suspension setups of most new luxury cars today - soft springs + hard bar = comfort & decent cornering ability, even in stock trim though toyota/lexus put out these cars with fairly large stabilizers. And yeah Intimazy is right it's more so alignment, wouldn't have to have your entire alignment changed all the time either, just the camber and how it effects the toe in the rear.

mecheng10

I do have supra sway bars. just waiting to get mounted

at what point does chamber become to excessive that you experience instability?

INTIMAZY

iTrader: (5)

Hard to say. Toe excess makes a car much more unruly on the roadway than camber does. Camber is bad in rain or low traction straight-line performance. There are 'slammed hella flush' SC's and Civics with terrible camber but they still are generally pretty drivable at highway speeds. Put 1/4" of toe-in or out on either corner of the car and that suddenly becomes scary at 65mph. 1/8" of toe-in or out can again be excessive depending on tires and whether it's front or rear. Up to 1/8" should generally be fine on our RWD long wheelbase chassis although an eighth-out on the rear wheels would probably make it wander a bit.

Toe is complicated. Toe-in of the rear wheels actually improves stability depending on the situation. It's very dependent on what tire you run, how much camber gain accompanies toe, and road surface irregularity and crowning, and whether you're talking straight line or a corner. The concept is different for front wheels as toe-out generally improves turn in response.

As a general sweeping statement, you want your tires straight up and down, pointed perfectly straight for the purposes of drag racing. However, suspensions are dynamic systems and the camber gain and toe changes that occur during squat need to be accounted for at static ride height pre-squat. Gaining traction for a 60-foot will usually take precedent over stability when crossing the 1/4 mark. Most are ok with a car getting a bit more squirrely further down the 1/4.


None of this even touches front suspension geometry and the holy grail of caster.