1320Chicken

iTrader: (4)

I'm just looking for a starting point. The more I've read the more it seems that my suspension has been out of whack for years. I made a couple changes today so I need to go back over everything and tweak it at the track. Here's the setup

Ride height 27 front 29" rear
26" tire up front 28" in the rear
Strange single adjustable front and rear
300lb springs in front BMR 1.25" drop in the rear
UMI tunnel mount TQ arm
Adjustable LCAs with rod end
Relo brackets
Tube K and A arms
3300lb race weight

My main problem is the car bobs going down the track. Not noticeable inside but if you watch the roofline on video it's obvious.


Right now the LCAs are in the middle hole and TQ arm is in the bottom hole. I'm having a tough time actually visualizing instant center on the car. Since I put the lowering springs on I know all the rear angles have changed but didn't get a chance to measure them today. All of the suspension is a combination of polly and rod end of that makes a difference. Any input is appreciated as id rather have a decent starting point than blindly making adjustments.

phoenix rises

iTrader: (3)

im curious as well

ss4chad

iTrader: (26)

Everything under my car is adjustable so I had a shop in Texas do a suspension tune on my '02.

Chad

JD_AMG

What do you mean by "bobs" down the track? Like bounces, but you can't feel it? Do you have a video?
Is this causing any real issues?

Carl at CRP

iTrader: (9)

Have You compared the video of Your car to a friends car making certain its not the track?

Carl

IDriveChevy

iTrader: (5)

Is the car on slicks? Sometimes a car on slicks will tend to dance or bob down the track. What are your 60' looking like? That will give you a good idea of how well the suspension configuration is working for you.

01ssreda4

iTrader: (96)

Dont know what bobs mean.

1320Chicken

iTrader: (4)

Last time I was at the track a buddy was a couple cars back in the lanes. All he could see was the roofline of the car at the starting line. He described it as the car looked like a boat going down the track kind of bouncing up and down. He took a video and tried to send it to me but the quality went to ****. On his phone I could see what he was talking about. We came up with the suspension loading and unloading. I have no idea if we are right or not because I feel nothing inside the car.

As far as it causing any real issues, I doubt it. Every now and then it won't sixty as well though. Just randomly one pass the sixty will be off .05 or so. When it does that it doesn't feel like it spins. I don't know how to describe it but it feels like the sidewall wrinkles up and unloads all at once. Maybe the rim spinning inside the tire? It's strange but feels like something loads then suddenly unloads.

I'm running the new ET street S/S at 18lbs and the sixty foot averages a 1.51. Maybe what I'm feeling is all in the springs, maybe the settings are too loose to control them?

This is all me and a buddy talking but neither of us have had a car pull these sixty foot times before. We were both usually 1.65 and up. Being this is new to me I just want to find a good starting point so I can mess with it and see what gets the best and most consistent results.

Important to point out is that this was happening with old comp 3 way rear shocks and V6 rear springs. I just put the strange shocks and BMR springs on last week and haven't ran it since. I'm figuring that lowering the car has messed with the angles of the TQ arm and control arms.

IDriveChevy

iTrader: (5)

If you were getting a 1.5 that is pretty good, I wouldn't worry if you didn't feel it. It could be the old junky shocks and springs. See if it's any better with the new setup. If you lowered your car just make sure your LCAs are at the proper angle and your pinion angle is correct.

1320Chicken

iTrader: (4)

Do you have any suggestions on the control arm angle? I'd imagine 2* of pinion angle is still the standard, correct?

01ssreda4

iTrader: (96)

Yes that should be fine.

IDriveChevy

iTrader: (5)

You'll have to look at your car and just make sure they are lower than the front control arm mounting points. I think you mean -2* (aka the torque arm is down towards the ground at a 2* angle)

1320Chicken

iTrader: (4)

Ok thanks. Yeah you caught me on the technicality. I meant -2* lol