On the 'mildly' Cheap SS Monte Carlo chasing a 9.0___

[64nailhead]

Way to go 81Cutlass - Trick Chassis is the only place I could find that has any. Everyone is 4-6 weeks out on shocks. Should have them this week. The guy at Trick said they have a boat load of the stock to 2" drop ride height double adjust rears - NO ONE else does.

Build all the boost and ramp timing to suit conditions. Won't blow flames if you don't do it that way. Lol

I'd have a peek at that tune and log if your not grudge racing. Sounds like a ripper.

I'll send them over tonight. There is some interesting stuff occurring in them. I'm yet to see the exact cause of some of it.

 

[motorheadmike]

Not to tell you how to suck eggs... but... tire type will dictate suspension set up. What tires are you running and how is your suspension set up? Absolutely good shocks matter. Take some time and deliberately verify what it is your car is set at - change it if needed.

 

[64nailhead]

Not to tell you how to suck eggs... but... tire type will dictate suspension set up. What tires are you running and how is your suspension set up? Absolutely good shocks matter. Take some time and deliberately verify what it is your car is set at - change it if needed.

I have been told the same. Drag radial. I'm sticking with Mickey Thompson ET Street S/S.

I'm aware that a bias ply requires a different setup and doesn't mind some wheel spin, unlike radials.

 

[motorheadmike]

I have been told the same. Drag radial. I'm sticking with Mickey Thompson ET Street S/S.

I'm aware that a bias ply requires a different setup and doesn't mind some wheel spin, unlike radials.

So then all you need to do is verify that you have some anti-squat dialed in. Upper arms parallel to the ground, lowers angled upward to the front. Fine tune from there with more or less anti-squat.

 

[64nailhead]

Upper arms parallel to the ground,

One of our forum sponsors would dispute that. Front needs to be lower according to Mac.

My uppers are lower in the front and the lower bars are parallel to the ground, or within a degree or two.

 

[81cutlass]

I'm interested to see where you end up with on the instant center.

I know when I built my 8.5 I was very careful to stick the suspension pickup points in the stock locations assuming coke head GM engineers in the 70's knew more than I do.

After dialing in my car this spring I am glad I stuck my upper control arm pickup points on the rear side as low as I can. It's really tough to get the instant center above the center of gravity line (antisquat) if you put the rear end pickup points high on the rear end unless you move the frame side UCA's pickup point higher.

EDIT

From my studies, and my understanding, it doesn't matter if the top bars are up, down, or level, what does matter is that the instant center (functional center of rotation of the 4 link at the instantaneous position at ride height) sits above the line drawn from the contact patch of the tire to the center of mass of the car so mechanical advantage makes the tire plant harder.

If you do that by putting the rear end side top mount high and can resolve that by moving the rear end side lower down sufficiently, that's acceptable.

The detitanation matters but now necessarily how you get there. I think everyone just chooses to put the upper arms level because it makes the setup easier on the lower arm.

 

[motorheadmike]

I'm interested to see where you end up with on the instant center.

I know when I built my 8.5 I was very careful to stick the suspension pickup points in the stock locations assuming coke head GM engineers in the 70's knew more than I do.

After dialing in my car this spring I am glad I stuck my upper control arm pickup points on the rear side as low as I can. It's really tough to get the instant center above the center of gravity line (antisquat) if you put the rear end pickup points high on the rear end unless you move the frame side UCA's pickup point higher.

EDIT

From my studies, and my understanding, it doesn't matter if the top bars are up, down, or level, what does matter is that the instant center (functional center of rotation of the 4 link at the instantaneous position at ride height) sits above the line drawn from the contact patch of the tire to the center of mass of the car so mechanical advantage makes the tire plant harder.

If you do that by putting the rear end side top mount high and can resolve that by moving the rear end side lower down sufficiently, that's acceptable.

The detitanation matters but now necessarily how you get there. I think everyone just chooses to put the upper arms level because it makes the setup easier on the lower arm.

Agreed, many ways to skin a cat. However, you just have to choose a method and stick with it. My wagon and Monte are drastically different in how they are set up (because of the ride height) - but both have some anti-squat dialed in because they are on radials.

I would also suggest that the M/T S/S may be the wrong tire to turn mid-9s on and exacerbating the conditions seen.

 

[GroceryGetter83]

I would also suggest that the M/T S/S may be the wrong tire to turn mid-9s on and exacerbating the conditions seen.

These are the tires I have on my Cutlass as well; I can't say that I am all that happy with them. Street or strip, I spin a LOT with them.

I am going to try these next time I think (edit: 275/50R15 size however):

 

[gbodygarage]

Im new to the whole drag racing thing, been circle track my whole life. But i love this car.

 

[64nailhead]

Interesting you turned wheel hop into spin with lower pressure. I was told up and down by the local guy that runs drag week in the mid/high 9 second NA red Chevy 2 that you start high on pressure and work down until you stop spinning. Once you start chattering you went too much. He just placed 2nd on the summit drag week last week with like a 9.73 average so I trust him on that.

I wonder if the wheel hop is not tire pressure and something else related.

Regarding tire pressure :

ET Street R (Bias), ET Street R, ET Street S/S, Pro Drag Radial, Pro Bracket Radial and ET Drag Air Pressure Guidelines

ET Street R (Bias), ET Street R, ET Street S/S, Pro Drag Radial, Pro Bracket Radial and ET Drag Air Pressure Guidelines

www.mickeythompsontires.com

Is 20 psi too much? According to the people that make the tires yes. According to my testing, yes 20 psi is too much.

Try it at 17-18psi and see what happens. What's the worst that can happen, you'll spin and waste a run?

I'm not saying your acquaintance is wrong, but ever car, every setup, every track, etc, etc, is different. The same goes with the instant center rules. Your setup will define what you need.

I'm no expert and I'm living and learning. But one thing for sure, I'm not going to be scared to try something different. For example, I was told that I need to add timing to build boost, but the world's worst hot side doesn't like additional timing - it builds power and boost simultaneously and the sloppy transbrake can't hold it. But if I cut timing once on the chip, then I can hold the car easily at 12psi and 3500rpm's because it's making about 80hp lol (until I let go of the button.)

I really hope to see you get ti the track and make your car work!! 🙂