IC and gearing

whatbumper wrote:What are the actual lengths of the arms measured squarely in the car?

I was getting 7.5-ish" upper and 18" lower.

Lower arm is angled slightly up towards the front of the car.  Upper arm does the same.

Not my pic, but this is what the upper mounts look like.


As is:
http://www.baselinesuspensions.com/graph-stock.php?ucal=7.5&rup=17.125&fup=17.625&lcal=18&rlp=10.125&flp=11.25&wtdist=66.37&cght=18&wb=101&Tire=28&scalefactor=5&Xint=-1,680.00&Yint=-94.88

UCA in lower front hole:
http://www.baselinesuspensions.com/graph-stock.php?ucal=7.5&rup=17.125&fup=16.625&lcal=18&rlp=10.125&flp=11.25&wtdist=66.37&cght=18&wb=101&Tire=28&scalefactor=5&Xint=54.19&Yint=13.51

BigBlockRanger wrote:

whatbumper wrote:What are the actual lengths of the arms measured squarely in the car?

I was getting 7.5-ish" upper and 18" lower.

Lower arm is angled slightly up towards the front of the car.  Upper arm does the same.

Not my pic, but this is what the upper mounts look like.


As is:
http://www.baselinesuspensions.com/graph-stock.php?ucal=7.5&rup=17.125&fup=17.625&lcal=18&rlp=10.125&flp=11.25&wtdist=66.37&cght=18&wb=101&Tire=28&scalefactor=5&Xint=-1,680.00&Yint=-94.88

UCA in lower front hole:
http://www.baselinesuspensions.com/graph-stock.php?ucal=7.5&rup=17.125&fup=16.625&lcal=18&rlp=10.125&flp=11.25&wtdist=66.37&cght=18&wb=101&Tire=28&scalefactor=5&Xint=54.19&Yint=13.51

if BOTH arms arms are angled upwards, the IC will be long, and the imaginary point of intersect will be beyond the car's center of gravity.

In my experience it is best to measure the arms from bolt hole center to bolt hole center using a plumb bob. I do this at race weight, plotting the "point" on the floor and measure from plot to plot.

bigblockfox468 wrote:
If you can snap a picture of this s box your talking about and the holes for moving the front UCA is throwing me a curve...I don't have anything like that

You don't need it...

I'm gonna make this as simple as possible.....there has to be a starting point and below is how to get there. Make sure the ARB has zero preload to start. that can be addressed later


1. GET THE CAR AT RACE WEIGHT. THIS MEANS RACE WEIGHT, CORRECT TIRE PSI, FUEL, HELMET, GLOVES, ETC.

2. THE LOWER CONTROL ARMS (LCA) SHOULD BE AS CLOSE TO LEVEL AS POSSIBLE, IF NOT POINTING UPHILL TOWARDS THE FRONT OF THE CAR EVER SO SLIGHTLY.

3. THE UPPER CONTROL ARMS (UPA) SHOULD BE HIGHER ON THE HOUSING THAN THEY ARE ON THE TORQUE BOX AREA. I SAY AREA BECAUSE SOME HAVE STOCKS MOUNTING POINTS, SOME HAVE S BOXES, SOME HAVE A HODGE PODGE OF SOME HOME MADE HORSESHIT! THE IC LENGTH IS DETERMINED BY WHERE THESE TWO POINTS WOULD INTERSECT SHOULD THERE BE AN IMAGINARY LINE. START WITH THAT LINE INTERSECTING AS CLOSE TO THE CENTER OF GRAVITY AS POSSIBLE, WHICH IS TYPICALLY RIGHT BEHIND THE DRIVER'S SEAT IN A FOXBODY CAR. THIS IS A STARTING POINT.

4. THE TUNING PART CAN NOW TAKE PLACE. RAISING AND LOWERING THE CAR WILL CHANGE IC LENGTH AND HEIGHT, AS WELL AS THE A.S. VALUE OF THE CAR. SHOCK ADJUSTMENT NOW STARTS TO KNOCK ON THE DOOR. SPRING CHOICE, FRONT RIDE HEIGHT, CONVERTOR CHOICE, ETC ALL PLAYS A HUGE PART.

But the above info should get these things down the track. People want a magic number for their cars and they don't exist! My IC is different than Mike's, than Eric's, etc. Test test test......


That'll be $300 dollars please

I am gonna copy and paste this into my thread as well Tony.

yellowhorse7 wrote:

bigblockfox468 wrote:
If you can snap a picture of this s box your talking about and the holes for moving the front UCA is throwing me a curve...I don't have anything like that

You don't need it...

Yeah, once I seen what it was I kinda thought my relocation UCA kit does away with that deal   

yellowhorse7 wrote:


That'll be $300 dollars please

Damn...I can only imagine what my bill is   
Only trying understand.....what's next boss, waiting for further instuctions  

Didn't mean to hijack this on you BB Ranger... back to business now. What did you use for the center of gravity/camshaft height measurement and I still don't understand what dictates which side you use for the numbers you have to put in that calculator  ......YES I'm polish

how high is the rear of the car if both the lowers and uppers point up?

Side view.  Rear fender lips are at 29", fronts are 26.75"



I'm not looking for every last .01 second out of this thing, but would like to get it at least inside the ballpark.  The track is closed until March, so it will be a while before I can do any testing.  I will see how it works first just with the addition of the arb, but I would like to have a plan of what moves to make if it does not improve quite to my satisfaction.  And it would be nice to run the radials instead of the slicks.  The radials typically would hook on a good track, then spin.  My avatar pic is on the radials just before the car spun and headed towards the wall.

Just updating this a little.

Went to the track on Saturday. Had to run on the MT ET Street radials (275's) for the event I was participating in (no slicks) and the car would just spin like it was sitting in water at the hit.  Spin, pedal it, hook, haul ass.   60's were dismal 1.8's.  Tire pressure changes, shocks, nothing helped.  Track wasn't optimum as this was the first weekend of the season, but friends were 60'ing about what they normally do, both with radials and bias tires.

At first I though it was hitting the tires too hard. But thinking about it more, it wasn't even trying to hook or lift the nose at the hit. That makes me think the IC is so far out there that it just spins. This jives with the measurements I took right after the sbox install.  If I drop the front of the upper bar 1 hole, that would bring the IC back in to 54" out and 13.5" high, which sounds workable to me.  Thoughts?

You can see in this pic that it has black tracked about 5 feet out and the nose never even tried to come up.... looks a little rich too, but that may be because I was pedaling the crap out of it to get it to hook.  haha.

Measure the mounting points front the floor again. Do you know corner weights?

Ha corner weights....

RR - heavy
LR - heavier
RF - stupid heavy
LF - are you joking? heavy

That's about as good as it gets.

I'll try to remeasure those tonight or tomorrow at lunch.

I should know better than to measure it all before it has had a chance to settle in good.

I remeasured yesterday taking great care to get all the correct numbers.

As it sits now, the IC is 126" out and 17" high. Yowza. Anti-squat is 57% which explains why this thing, even with air in the left airbag to counter the body twist (prior to the ARB), used to cram the body down on the rear tires.

By dropping to the other hole it gets better, but not perfect. IC is 37.06" out and 12.06" up. Anti-squat is pretty high at 136%, but I'm not as concerned about that as I am pulling the IC back to a more reasonable location.

Go ahead and drop a hole.

BigBlockRanger wrote:By dropping to the other hole it gets better, but not perfect.

No such thing. They are just numbers

Earlier in this thread Tony posted a starting point of behind the front seat for IC length. For BBR's situation going from bias ply slicks to Drag Radials is there a general rule of thumb for IC and % anti-squat when comparing what works best for a bias ply slick vs. a Drag Radial of the same diameter? I understand that every car is different but I suspect there is commonality when moving from one type of tire to the other.

His IC was somewhere East of the front license plate on an East bound track and yet it hooked well on the slick. Not so much on the DR. There is a bit of self interest in this question as I am atempting to build my own version of BBR's car.

I really think the slicks were a crutch for a poor chassis setup in my case. Anxious to make a pass on radials and then on slicks after I do some control arm adjusting.

you have been getting a lot of good information. what follows is what I discovered made my fox hook.

4. THE TUNING PART CAN NOW TAKE PLACE. RAISING AND LOWERING THE CAR WILL CHANGE IC LENGTH AND HEIGHT, AS WELL AS THE A.S. VALUE OF THE CAR. SHOCK ADJUSTMENT NOW STARTS TO KNOCK ON THE DOOR. SPRING CHOICE, FRONT RIDE HEIGHT, CONVERTOR CHOICE, ETC ALL PLAYS A HUGE PART.


I am surprised no one has mentioned adjustable uppers. I saw none in the pictures. My fox will now 60 ft in the 1.20's with the small block. When my car skated around off the starting line I found the lower pointing up not level. I changed that and with adjusting the front ride height and the pinion angle the car now hooks great. wheels up a foot and gone'

Wish I knew how to post a picture on here to show you the launch.

CDMBill wrote:Earlier in this thread Tony posted a starting point of behind the front seat for IC length. For BBR's situation going from bias ply slicks to Drag Radials is there a general rule of thumb for IC and % anti-squat when comparing what works best for a bias ply slick vs. a Drag Radial of the same diameter? I understand that every car is different but I suspect there is commonality when moving from one type of tire to the other.

His IC was somewhere East of the front license plate on an East bound track and yet it hooked well on the slick. Not so much on the DR. There is a bit of self interest in this question as I am atempting to build my own version of BBR's car.

1. Yes, in higher power applications it makes a bigger difference. There are some guys who will tell you that they don't change a thing when switching tires except for a shock setting but IMO they are leaving 60/330 on the table and honestly, aren't being honest lol. Typically a radial car will want a shorter IC and a higher AS. You'd be surprised at how much AS some of the FAST radial tire guys have. Look back on some of Dave's, Bumper's and my posts and you will see why. You'll have to dig and put 2+2 but the info is there. On a personal level I've decided to stop being a forthcoming on what I tell people as it has bitten me already. Rich was right....

2. With an super long IC, one that is in FRONT of not only the COG but the car itself, it will be near impossible to hook anything but a slick. And even then 60/330 is being left on the table. When I was learning Dave @ TEAM Z explained it to me like this: try lifting an 8ft 2x4 from the very end. Then cut the board to 3ft and try lifting from the same place. Which one is harder? So now you have impossible weight transfer AND the body trying to separate from the rear end. I'd bet that the track was decent when it worked on the slick. I'd also bet that he had the front end super loose.

Plain and simple guys have to stop getting so caught up in these numbers! Follow the guidelines that I explained before and TEST! A radial tire will work and in most cases out-perform a slick (opening a can here lol).

Larry Williams wrote:

4. THE TUNING PART CAN NOW TAKE PLACE. RAISING AND LOWERING THE CAR WILL CHANGE IC LENGTH AND HEIGHT, AS WELL AS THE A.S. VALUE OF THE CAR. SHOCK ADJUSTMENT NOW STARTS TO KNOCK ON THE DOOR. SPRING CHOICE, FRONT RIDE HEIGHT, CONVERTOR CHOICE, ETC ALL PLAYS A HUGE PART.
.

hey, that's good advice!.


Adjustable uppers (more specifically RELOCATED) really excel in stock spring/shock location.

Your info. is safe with me because I don't understand most of it.   

every camp has their own way but I wouldn't use relocated uppers. Dbl adjustable uppers and the rest of what you have will get you where you need to be until you hit the shock limit.

The problem is that most of us that set up cars for a living have too much time and money invested and thousands of passes to get their data so we all don't like to give out all of the answers at any given time. If it's so easy then everyone could go out and 60' in the 1.0's to 1.teens like we have a lot of cars in on drag radials. including cars going teens with sub 1000 hp combos on stock suspensions.

whatbumper wrote:The problem is that most of us that set up cars for a living have too much time and money invested and thousands of passes to get their data so we all don't like to give out all of the answers at any given time.  If it's so easy then everyone could go out and 60' in the 1.0's to 1.teens like we have a lot of cars in on drag radials.  including cars going teens with sub 1000 hp combos on stock suspensions.

x2. Also, when you give people advice based solely on conversation with having NOT seen the car and it doesn't work, then we are the bad guys.

Understood...

yellowhorse7 wrote:

whatbumper wrote:The problem is that most of us that set up cars for a living have too much time and money invested and thousands of passes to get their data so we all don't like to give out all of the answers at any given time.  If it's so easy then everyone could go out and 60' in the 1.0's to 1.teens like we have a lot of cars in on drag radials.  including cars going teens with sub 1000 hp combos on stock suspensions.

x2. Also, when you give people advice based solely on conversation with having NOT seen the car and it doesn't work, then we are the bad guys.

Yep.

We have a former customer that went 1.18-1.19 like clockwork but changed the ride height of the car for "looks" and it doesn't work now, goes 1.28-1.30's now, but doesn't want to get it fixed... That's why I called him a former customer.  Lol

Put some SSM lift bars on it..... I went a 5.80 on some 235 street radials earlier, then the next pass tried to scrape the bumper cover off again.......