60ft questions

"Quote"

I currently have a kit to correct the geometry when a 12-bolt is installed and I have a few other kits in the works too.


Kevin, do you have a kit available for a Ford 9" in a '87 Regal ?

George

I will have a kit that should bolt in but as you see from your car the 9" rears already have the upper mounting ears raised up which moves the IC in front of the rear axle so I think you'll be fine. The only thing that you may have to worry about is the height of the upper mounting hole from the axle centerline. This extra height adds more leverage and maybe too much leverage to pull on the chassis. The more powerful the car is the closer you will want the mounting point to the axle tube but again this is all worth testing on your end and I woulnd't worry about it until you try it.

KS

George,

If you have 8 sec potential your going to have move the mounting location. The Moser rear puts it 2" higher than the stock location. IC will be just in front of the rear. This is going to crush the tire on a tranbrake launch, so much so that it will distort the contact patch. Amongst other issues... Ask me how I know. You dont need that much hit from the suspension with 8 sec power. Also with the IC in that position its going to cause car to bunny hop on the leave. I just had new brackets made on mine to adjust the uppers where I want. It gives me 4 holes to adjust. The highest being still 1" lower than it was before with stock Moser mounting location. If you need any help tuning it just let me know.

Thanks Laz,

I appreciate your offer. Let me do my measurements to see just where everything is and I'll report back.

Are you running a AMS1000 Boost Controller ?? I was hoping that I could tune my launch with controlled boost, but I haven't had it to the track since I've made a few changes.

I have test launched the car in my paved driveway ( 300 ft ) @10 lbs. and it launched fine with the exception of veering to the right slightly. I'm sure that it will react differently on a fully prepped track though.

George

No I'm not. Good luck.

"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

George, I left my laptop at work. The sim is on it. I'll take the numbers to work tomorrow and get back to you with the result.
The control arm lengths are actually measured perpendicular to the rear axle centerline vertical plane. Not from bolt to bolt. That's OK though. If the mounting points are stock, I'll just use what I have on file. The important numbers are the others you provided.

Don,

The measurements for the length of the control arms I did with a plumb bob. I marked the floor where the bob pointed and measured the distance between the marks, squared to the framerail, not on the angle that they sit.
I just used the centre of the mounting bolts as a reference for the string on the plumb line. Does this make a difference ?

George

That sounds good George. I'll use your numbers.

Don,

If it's not too much trouble, do both sets of numbers. I'd be interested in seeing the difference

Thanks again

George

Will do.

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.

George. A few questions:
What's the diameters of your tires?
What is your ET goal?
What is the weight of the car?

Tires = 28 / 10.5 x 15

et goals high 8's for now

car weight with me in in it ( race ready ) 3564 lbs - 2028 front/ 1536 rear

George

I got the same numbers as lasaris. Looks like it should hit the tires pretty hard. Maybe too hard.

As the car launches and the rear rises, or separates, the I/C will move forward and upward. A 1.3" separation in the rear at launch will move the IC and A/S to:
Length 47"
Height 16.8"
A/S 163.4%
This will be right in Dave Morgan's box.

I like it. Give it a try and let us know how it works.

Don and Laz,

Thanks so much for taking the time to help. I'll give it a try and see what happens. If required I'll drop the upper arms down on the diff.

What software are you both using? I need to get a program like this.

George

Are you planing to leave on the foot brake or trans brake?

Good question Laz. I've just did some modifications on my brakes in order to allow me to build boost on the footbrake. I've changed the pedal ratio, installed a smaller bore master cyl. and removed the combination valve to give me full pressure to the rear.

The idea was to get up on boost in the pre-stage lite and bump to stage. Then to transbrake.

I'm thinking that if I can control boost with my AMS1000 controller, I should be able to launch reasonably by timing when the full boost comes on; approx. 1.2 or 1.3 seconds, ramped ( I could be flawed in my thinking though)

Again, your opinions and experienceare valued.

As Don pointed out, with rear end rise, the dynamic IC should be much more favourable than the static #'s. What do you think ? I haven't launched the car with more than 10 lbs boost yet. Car seems to plant tires OK at that level of boost.

George

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.

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?