60ft questions

[lazaris]

So when the transbrake is released and the rear suspension is shocked, there will be no rear end separation with that much static anti-squat?

Oh it will separate alright. Very violently at that. However at that point the angle change doest nothing because the hit has already happened.

 

[oldtimer]

George,

You will not get rear end rise when using the Brake. Thats why I asked. If you are foot braking the car you will, as it loads the rear suspension.

Laz,

If I raised the rear of my car up 1" with a spring replacement, that should move the both upper and lower front CA mounting points up and therefore my IC should move forward, shouldn't it. If so, with your sim, could you tell me where it would be now approx. It should be better at least. yes/no ?

George

 

[lazaris]

George,

generally rasing the rear ride height will move the IC higher up which actually increases the hit on the tire. You would have to measure your upper and lower control arm points again after a ride height change. Just because you raise or lower the ride height 1" does not mean their IC points would equally move 1". This is because the upper and lower are unequal lengths.

 

[oldtimer]

"Quote"

If you'd like, post the numbers you get and I'll run them through the sim and get the results back to you.

Don,


Here are my numbers;

RLCA rear point = 9 1/8" off ground
RLCA front point = 11" off ground
RLCA length 18 3/4" bolt to bolt

RUCA rear point = 21" off ground
RUCA front point = 19" off ground
RUCA lenghth = 7 1/2" bolt to bolt

rear weight = 1536 lbs. or 43%

Thanks, I haven't been able to weigh it with the back end up "yet"

George

With those numbers and an assumed 23" GC, your IC height is 12.36" IC length is 32.39" and as I suspected a 179% anti squat.
__________________


Laz,

With my numbers above, how much would I need to lower my RUCA's rear mounting point to give me 125% anti squat ?

George

 

[lazaris]

You need to lower it to 19.70" 19.75" would equal almost 128%.
Are you going to be using the brake?

 

[oldtimer]

You need to lower it to 19.70" 19.75" would equal almost 128%.
Are you going to be using the brake?

Are you going to be using the brake?

Yes !

George
__________________

 

[lazaris]

I would be looking for less anti squat then.

 

[Alky V6]

I would be looking for less anti squat then.

I agree.

 

[oldtimer]

Don And Laz,

What A/S would each of you feel that I should be aiming for. ?

What would be the "ideal anti squat" knowing what you two know about our Buicks and our power levels ? Laz, from your signature, it would appear that we may be close as far as power levels.

George

 

[Alky V6]

I would start at 100% A/S. This will transfer the most energy to forward movement. If the tires slip too much at the initial shock of the launch, then increase A/S.

 

[lazaris]

Your going to find with low 9 high 8 sec power leaving off the brake the less AS you need. Most likely less than 100%. But again it depends on a lot of other things as mentioned prior. If you can get a video or 2 of the launch off the brake I can better tell you what it needs.

 

[oldtimer]

Don/Laz

You both have been a great help. I've learned a lot and my suspension understanding has been much improved.

Thanks again, I'll keep you both posted and I'll try to get some videos.

Also, I've ordered Dave Morgan's Doorslammers book.

George