Dragaholic

iTrader: (180)

What's the most accurate way to do this? From the center of the wheel to the fender, top of the tire to the fender, ground to the fender, etc.? Also, what's the best ratio for drag racing? Level, higher in the front, lower in the front, etc.?

In my opinion, I would say from the center of the wheel to the fender because if you do it from the top of the tire and you have 2 different size tires from front to back, well then...

Or is the fender not what you want to go off of? Anyhow, I plan to make some adjustments when I get home from work today to get the car ready for Friday.

Oh also...what's a range of travel the front suspension should have? I was thinking 2 inches. Thanks in advance.

Out1aw

iTrader: (1)

Honestly, no one setup is going to work for every car. Best way to figure it out is take it to a test & tune, make some passes, and adjust it to where you think the suspension is working the best. It all is based on how your car specifically transfers its weight and hooks.

Dragaholic

iTrader: (180)

Well it's transfering too much weight because I can't keep the front end down. This was with the old setup with a lot less power, so I know that I need to make adjustments prior to even going. I almost put it on the rear bump on one of the passes and I don't want that.

Steve Burger

iTrader: (33)

What shocks are you using?

Dragaholic

iTrader: (180)

QA1 R series fronts and Strange double adjustable rears.

FASTFATBOY

iTrader: (23)

Stiffen the fronts up and air the rear tires up and kinda work backwards every pass, I would put limiters on the front if you are real worried.

David

Steve Burger

iTrader: (33)

That's where I was headed. Start with all of the shocks stiff and about 20lbs of air. Also set the anti roll bar neutral and know where your pinion angle and LCAs are set. Have someone watch the launch and adjust from there. Make only ONE adjustment at a time so you can see the true effect of the change.

It's a pain in the *** but will be worth it in the end.

Pro Stock John

iTrader: (34)

If you don't have travel limiters you should get some. My turbo Formy has gone 1.35 on DR's with the front tires only coming up like 4-6 inches off the ground. We have many examples from 6-8 years ago of folks standing their cars on the bumper from leaving with too much power.

Another thing I remember was a chassis expert tell me to lower the 4x4 look I had in the rear.

Bitemark46

Try and stiffen up the front struts or put in some travel limiters (i.e. chains). Also you could try and soften the rear to get it to squat a little. -Mark

EDIT: haha. I left my post open and took 20 mins to finally submit it. So what I said was already mentioned.

Dragaholic

iTrader: (180)

FASTFATBOY, what does more air pressure do?

Steve Burger, stiffen the front and the rear? The car leaves straight, so I would think there's no need to mess with the anti-roll bar. Right or wrong?

What's a good rule of thumb for drag racing on these settings:

Pinion angle
Front end travel
Shock settings
Tire pressure

My car 60 ft. in the mid to upper 1.30s with the old setup, I'm looking for 1.20s.

C'mon guys, you should know I already have travel limiters. That's why I was asking how much travel the front end should have.

FASTFATBOY

iTrader: (23)

All cars are different in the way they apply power to the ground. Starting with high air pressure and stiff shocks will decrease the possibility of a wheelstand and tearing up the car. It will spin the tires instead of wheelstand.

I am by far am no expert at this and cant get my car to hook for **** on the street, but I am still learning it. As you will have to do with yours...go buy a notebook and use it as a log book, write all the details on each pass down.


David

RAGENZ28

iTrader: (5)

I agree and disagree with some things in the previous posts.

Shock settings vary for each car, some cars will leave harder with stiffer rear shocks.

Some cars will also leave harder with more air pressure in the tires.

As far as tuning tire pressure I have always tried to run the psi that gives me the fastest 60 ft without losing mph or being unstable on the top end.

Travel for front ends usually 4-5" on cars that don't wheel stand and 2-4 on cars that tend to wheel stand.

Pinion angle I think -2 is a good starting point.

On anti roll bar adjustment I setup the right side so it has no play but isn't tight going on.

RAGENZ28

iTrader: (5)

To start I would leave everything alone and limit the front end to 3" travel and start with that. If it still is lifting too much then try stiffening the front shock 2 clicks, then a click at a time after that.

RAGENZ28

iTrader: (5)

My old car rear shock #4, 1/4 turn anti roll bar preload, front shock 80/20, front end travel 3", -1.5 pinion angle, 250 shot off the transbrake, 6 psi tire pressure, Intersection at 59 1/4" 4.75" off the ground. 114.5 wheel base. 33x16.5 4.86 gear th400 4500 stall.

Pic of 1.30 60ft

Bitemark46

The thing you need to remember is that when you change something do it one at a time. Changing all those variables you listed is like opening a can of worms. You wouldn't know what worked or what didn't. Make a pass or two while working on one thing. If it works great, leave it. If it doesn't, change it back to the original setting then go to the next variable. -Mark

Pro Stock John

iTrader: (34)

I'd start conservative if you are running a lot of converter. If you run a 2step I'd max it at 4500, have the front shocks at 2 soft and the rears at 8. I'd work from there. Pinion angle is something that most of us don't know how to adjust. From what I've gleaned over the years if the car does not work, mess with the pinion angle. Madman is the expert on that stuff, so if you get along with him ask him or pay for his time.

RAGENZ28

iTrader: (5)

Pinion angle will effect the efficiency of the power transmitted from the drive shaft to the rear end.

Basically the straighter the angle between the drive shaft and rear end the more power is transmitted.

So adding more pinion angle will tend to "hit" the tire softer vs. less pinion angle which will hit the tire harder.

Solid mounted control arms will run less pinion angle than poly bushing control arms do to the pinion rotating "up" more.

In theory assuming that traction isn't a problem the car would run fastest when under full power the drive shaft and pinion have a 0 degree angle between each other.

Dragaholic

iTrader: (180)

The setup has changed dramatically, power wise. Everything else remained the same. I was going low 10s on a cam only motor, trapping 128 mph, cutting mid to 1.30s in the 60 ft. I figured I had the suspension setup pretty well. I didn't want to change anything because it was doing so well with such little power. However, since my car liked to pick up the wheels so much, I only wanted to change the transfer and I figured the best way to do that would be to limit the travel. I don't remember how much travel it has in it now, but I will verify when I get home. I wanted to reduce it to 2", but we'll see where it's at now. I also wanted to lower it because it's kinda high in the front.

I was mainly concerned on how much travel the front has and how to setup the height. Do you want it lower, higher, or level in the front compared to the back? Then at what points to I get these measurements from?

The converter flashed to around 5700 rpms on the dyno, so I figured around 5800-5900 at the track. I have a Lingenfelter 2 step, which I plan to start out at 4000 rpm.

Bitemark46

I believe lowering the front will give the struts more travel during weight transfer so will give it a "running start" effect. So you'll have more momentum when the strut reaches max travel. If you raise the front ride height you're reducing the amount of travel so the momentum would be less thus it "shouldn't" carry the fronts as high.

-Mark

EDIT: if you notice in my sig pic my front ride height is higher cause when the nose was lower it would lift too quickly then fall on its face causing the hook and spin result. Since I raised it the nose doesn't lift as much and gives an consistant amount of load xfer to the rear.

Nimitz87

iTrader: (17)

subscribing...

Chad