Cant Hook

[TurboTerry87gn]

Tuning relults

Well I finally got to the track to do some suspension tuning. Here are the rusults.

Rear tire pressure was set to 12.5 psi and checked before each run. I tried my best to lauch at 15 psi each time... All shock setting are clock wise clicks from zero.

these are the setting left to right respectily:
driver side air bag, passenger side air bag, Driver side QA1 shock setting, passenger side shock setting, 60 foot time.

1: 11psi, 19psi, 5 clicks, 6 clicks. 1.734 60'
2: 11psi, 19psi, 0 clicks, 0 clicks. 1.729 60'
3: 10psi, 15psi, 0 clicks, 0 clicks. 1.723 60'
4: 20psi, 20psi, 9 clicks, 9 clicks. 1.701 60' very stiff
5: 00psi, 00psi, 3 clicks, 4 clicks. 1.655 60' best 60'
6: 00psi, 00psi, 0 clicks, 0 clicks. 1.688 60' very soft
7: 00psi, 00psi, 4 clicks, 5 clicks. 1.690 60'
8: 00psi, 00psi, 2 clicks, 3 clicks. 1.744 60'

I tried to do the same burnout each time.

I'm going to put the original rear springs back in and go back tomarrow.

 

[Luke]

Nice...

Well I finally got to the track to do some suspension tuning. Here are the rusults.

Rear tire pressure was set to 12.5 psi and checked before each run. I tried my best to lauch at 15 psi each time... All shock setting are clock wise clicks from zero.

these are the setting left to right respectily:
driver side air bag, passenger side air bag, Driver side QA1 shock setting, passenger side shock setting, 60 foot time.

1: 11psi, 19psi, 5 clicks, 6 clicks. 1.734 60'
2: 11psi, 19psi, 0 clicks, 0 clicks. 1.729 60'
3: 10psi, 15psi, 0 clicks, 0 clicks. 1.723 60'
4: 20psi, 20psi, 9 clicks, 9 clicks. 1.701 60' very stiff
5: 00psi, 00psi, 3 clicks, 4 clicks. 1.655 60' best 60'
6: 00psi, 00psi, 0 clicks, 0 clicks. 1.688 60' very soft
7: 00psi, 00psi, 4 clicks, 5 clicks. 1.690 60'
8: 00psi, 00psi, 2 clicks, 3 clicks. 1.744 60'

I tried to do the same burnout each time.

I'm going to put the original rear springs back in and go back tomarrow.

Keep recording your suspension setup and changes before each run and you'll get you're car dialed in faster. Are you using a 2-step? What RPM do you leave at to leave on 15psi?

I had a 1.65 60' launching at 8psi at 3600 RPM on the 2-step (engine seems to bog past 3700). Setup TH400/Brake, TE-60 (28 PSI), Alcohol injection, other bolt ons, stock internals, MT ET Streets 275/60R15 @ 15psi. Are you still getting wheel spin? You must be! You are leaving at twice the boost as I am.

 

[Boost231]

wow something is going on for sure. im doing 1.68 60's on 100% stock suspension and its a low 12 sec car.

 

[Chuck Leeper]

What's the video showing?

 

[TurboTerry87gn]

Put my stock springs back test this friday

I put my stock springs back in and if it dosent rain friday I will do more testing and post my results. I can't get any one to come out to the track with me to video, so the best i can do is record the data.

Now I'm running stock springs, metco lca with ic bracket, adj uca's, air bags, Qa1 12 way rear shocks, stock front springs, comp engineering front shocks set at 70/30 if I remember correctly.

What air bag pressure do most people run here, with stock springs?
I'm going to start at my best 60' shock setting with zero psi.

The car sits higher and level now. the "trick" springs made the car high on the passenger side like it had an air bag in it aired up, I didn't realize how much diffrent they were from the stock springs.

 

[Luke]

Air bags

I put my stock springs back in and if it dosent rain friday I will do more testing and post my results. I can't get any one to come out to the track with me to video, so the best i can do is record the data.

Now I'm running stock springs, metco lca with ic bracket, adj uca's, air bags, Qa1 12 way rear shocks, stock front springs, comp engineering front shocks set at 70/30 if I remember correctly.

What air bag pressure do most people run here, with stock springs?
I'm going to start at my best 60' shock setting with zero psi.

The car sits higher and level now. the "trick" springs made the car high on the passenger side like it had an air bag in it aired up, I didn't realize how much diffrent they were from the stock springs.

Wow. I'm really suprised you put the airbags back in? You're 60' seemed to show that 0psi in both was the best way to go. You gotta make changes to your suspension slowly so you can see your progression. Also keep in mind that the best shock setting for your QA1s will probably be different now that you're using different springs.

I'd only adjust the passenger side airbag first start at 0 and work your way up in 2psi increments (1psi increments if you can get to the track early enough to squeeze in a lot of runs). Once you determine your best 60' with the passenger side bag, you can start adjusting the drivers side in the same way. Stop adding psi when your 60' stops improving. I've seen that most people use 12 - 18 psi in the passenger side. In my situation every time I'd add psi in the bags my 60' would get worse. If that happens to you pull out the bags and see what you get.

Questions:
What's your converter stall speed?
Are you using a 2-step?
What RPM are you at when you leave at 15psi?
Most importantly: Did you get wheelspin on your 1.655 60' run?

 

[Nick Micale]

I know lots of good info has been posted in this thread, but I will just give you my results of dealing with 60's and good reaction launches.:smile:

I have the "usual" suspension with low cost arms, KYB used shocks and the all-important HR bar. My car would easily do 1.60's and 1.50's and ocassional 1.40'.

When I changed my converter, which was a 9" that I thought was fine, with a 15 psi launch and a decent track, I can get 1.35's! [Does NOT now launch like the pic below!]

Set at 8-10 psi on the 2-step, consistant 1.42's are normal on a decent pad.

Just passing on what I did to make mine work after a year of frustration.:biggrin:

 

[Scott Atk]

My experience:
You already said that you were running Moroso springs which have a stiffer passenger side. You shouldn't need bags with those springs. I suspect that's why your best 60 was with 0 psi. Now if you switch back to stockers that's a different story. You also said it now sits higher. That's bad. If your car is squatting it will be worse the higher the car sits. The lower the car sits with the stock geometry the better the anti-squat is.
Chavo's explanation was pretty good. Only thing I disagree with is if you see squat make the shock's stiffer. I battled this for years when running "load handler" springs in the rear. Stiffening the rear shocks is a bandaid for squat. Get the geometry set so you have zero squat or an inch or two rise.
good luck, Scott

 

[GARY HARVEY]

Scales Anyone (don't be scared of your car... be safe) !!!

Balance... It's the starting point. if the steering wheel needs input on launch, you have a problem.
If the bite is too heavy and you plant the slicks too hard it will slow the car.
A little heavy doesn't hurt (for) when track conditions go away and they usally do.
NO input to the steering wheel is the ticket.
PLEASE... Find and work with one pro (and don't jump around).
Bite the bullet and find someone setting up the cars that are at the front of your division in points.
Weigh yourself and have a bag full of whatever ready unless you mind sitting in the car (hot here in Houston).
LLoyd Swint and John Harrison are the ONLY suspension pro's in the entire East Texas Division that do this for a living and are very good @ their skill.
Any time you make modification to your car geometry changing stuff, a return trip needs to be on your short list to get things going straight again.
In the long run you will be much happier with your car and a great deal of money will be saved paying attention to a Suspension Pro. :biggrin:

 

[TurboTerry87gn]

Track results 8-31-07

Here are the results.

Tire pressure, d/s bag, p/s bag, d/s shock, p/s shock, 60' time.

1: 12.5 psi, 0 psi, 0 psi, 3 clicks, 4 clicks, 1.693 sec.
2: 12.5 psi, 0 psi, 5 psi, 3 clicks, 4 clicks, 1.686 sec.
3: 12.5 psi, 0 psi, 10 psi, 3 clicks, 4 clicks, 1.729 sec.
4: 12.0 psi, 0 psi, 7psi, 3 clicks, 4 clicks, 1.727 sec.

I was going to go up 2 psi at a time on the d/s bag but the track was packed. here are the vidoes.

These are the last two passes:

YouTube - Bad 60 foot

YouTube - bad 60 foot 2

 

[Chuck Leeper]

Just my..

$.02..
1. Not much pitch rotation for a trans braked launch. Looks like the initial hit pulls the ft a slight bit, then it almost immediately falls back... Tires breaking loose? Can't tell from the vid. Try the vid from directly at the side of the car, next time. A stripe on the sidewall helps to see spin.

2. Engine tune affecting the tq curve, so that the loss is allowing the ft end to drop? What do data logs show on the engine at/near launch?
Here's what it "looks like when it's right". Compiled from 1000's of runs at NHRA events..
This is for a 1/4 mi run, with 1/8th Et close to yours:
1.46 60', 4.36 330', 6.81 660', 10.75 1320,@ 123.5mph.

This may/may not help, as I'm not one of the gooruu's from east TX.

 

[TurboTerry87gn]

Power

Mabe I'm not eaving with enough power or mabe it's the converter. I was running straight pump gas last night so I did't wan't to hurt the motor. 15psi launch.

I will put some shoe polish on the tires and try it again. If I have to I will put in race gas and leave with more power.

Check back Wednesday for more videos.

 

[Luke]

Wow, Those videos were a much better angle than the first one. Now you can really see how much body roll you have at launch. Still can't tell just where it's starting to spin, Maybe it is time for an anti-roll bar? I think You mentioned you're using ET Streets or BFGs? If so, you're seriously overdue for a set of true slicks... Maybe you can squeeze more out of it with what you have but you're well over my power range so I can't help as much as these other guys. Good luck!

 

[TurboTerry87gn]

Things I'm going to try

After reading numeruos articals about shocks, instant center, center of gravity, these are my thoughts.

My car initally hooks too well. Looking at the video in slow motion, the front rises as the rear squats just a little, then the rim pushed down with so much force it crushes down on the tire and seperates the body from the axle, the front end reches full extension at about 2 feet out and fall right back down.

1: remove LCA relocation bracket, to reduce the antisquat as it hooks too hard initally.

2: Install Racesuspensions.com sway bar and remove air bags.

3: Install "anti hop" brackets to move the IC back to keep the front from lifting so easily.

4: Install new front shocks to control front end rise.

5: Notch frame and install 10 wheels and diffrent tires.

I'm going to do these in this order and one at a time to see the results. I will post my results.

 

[11secondgs]

dude your hooking and once your pinion shifts upward, you lose traction.

Go get a set of ssm lift bars, with weld in brackets, adjustable uppers and get that pinion at -4* on level ground, and buy a new pair of mickey thompson slicks. If you can't find lift bars for the lowers, get the metco's with the relocation bracket which is the same thing.

Get the 255/50/15's as they hook better becuase there is more pressure on the ground per inch of contact.

That will fix all your problems. Also, tune your car to hook on the slippery streets. If you can hook there, you will hook 2 x's better at the track.

 

[Luke]

After reading numeruos articals about shocks, instant center, center of gravity, these are my thoughts.

My car initally hooks too well. Looking at the video in slow motion, the front rises as the rear squats just a little, then the rim pushed down with so much force it crushes down on the tire and seperates the body from the axle, the front end reches full extension at about 2 feet out and fall right back down.

1: remove LCA relocation bracket, to reduce the antisquat as it hooks too hard initally.

2: Install Racesuspensions.com sway bar and remove air bags.

3: Install "anti hop" brackets to move the IC back to keep the front from lifting so easily.

4: Install new front shocks to control front end rise.

5: Notch frame and install 10 wheels and diffrent tires.

I'm going to do these in this order and one at a time to see the results. I will post my results.

Just brainstorming with you... when you talk about separating the body from the axle, are you talking about the drivers side? I think I see what you're talking about. It's obvious that it's forcing the passenger side tire down. As the rolling motion of the car pushes the passenger side down it, pulls the body upward on the drivers side. It lifts the axle pulling your drivers side tire upward enough so that it can spin freely. Once one wheel spins, the other wheel is going to spin with it. Now I see that the Anti-roll bar (and slicks) are probably your best bet for solving your traction issues. This will also make your car feel like you never removed the front sway bar and get rid of your air bag headache.

As for those "anti-hop" brackets, it looks to me like you already have them installed on your Metcos. Correct me if I'm wrong, but aren't instant center brackets, LCA relocation brackets, and antihop brackets all the same thing?

 

[johnplogii]

The anti-hop brackets go on the upper arms at the rear end housing.

 

[TurboTerry87gn]

Results 08-05-07

these are the setting left to right respectily:
driver side air bag, passenger side air bag, Driver side QA1 shock setting, passenger side shock setting,launch boost psi, 60 foot time.

The tire pressure was set at 12.5 psi.

0, 5, 3, 4, 15psi, 1.664
2, 7, 3, 4, 15psi, 1.680
0, 5, 4, 5, 17psi, 1.728
0, 5, 2, 3, 15psi, 1.702

I removed the Metco LCA IC bracket's to move the IC down so the tires don't hit so hard.

I had to quit early because my seat broke where the front bolt bolts the bracket to the floor.

I was in a hurry today so I forgot to put shoe polish on the tires and I left my USB to serial adaptor at home so I couldn't data log.:redface:

These videos are in order as above:
YouTube - Launch 08-05-07_01
YouTube - Launch 08-05-07_02
YouTube - Launch 08-05-07_03
YouTube - Launch 08-05-07_04

 

[TurboTerry87gn]

Changes

I ordered my sway bar so it will be in soon but in the mean time I'm going to put the trick springs back in and change the setting on the front shock from 70/30 to 60/40.

I want to control the front end rise so the cars starts moving forward before the front end hit it's full up limit.

By removing the LCA IC brackets it has moved my IC forward so the front end is rising, this is why I'm going to adjust the front shocks.

The rear end goes down as the weight transfers and it seems to bounce back up from the bags unloading the tires. I tried tightening the shocks but the 60' went up. This is why I'm going to try the trick springs again with NO bags this time.

I took some measurements and plotted the IC of the brackets on autocad.
With the LCA IC brackets installed the IC is way above the neutral line and forward of the CG.

By removing them the IC is lower so the Antisquat dosen't hit the tires so hard, but now the IC is too far forward so the front end lifts eaisly. From my measurements it looks like the UCA needs to be raised 1.5 inches with the LCA in the stock location. This would put the antisquat at 100% and just behind the CG. I don't know how muck the "antihop bars" raise the UCA but I want to try 1.5" up.

The only assumption I made was with the CG location. I took this info from a stock car i found on the internet. 23.5 inches from the ground and 61.5 inches forward of the rear axle center line.

I also found a program at:
4 (four) Link Software Program for Drag Racing Suspension
after doing my autocad lay out. I found a way to crack the software sort of.
You are only allowed to use the Camaro file, but if you rename the buick gn file to Camaro, and camaro to what ever it will open the BuickGn file as it "thinks its opening the camaro file" enjoy!

 

[johnplogii]

Two things I see here.

1. I just looked up your tire on jegs. It measures 27.6" tall and only 8.6" wide. Like I said before I could never get an ET street bias ply to work for my car, and mine are 10" wide. I think an 8 1/2" tire on a car with that much power is not going to work well. It may if it were an actual slick & your suspension was set up absolutely perfect, but neither is the case.

2. I still have traction problems myself and have recently figured out that if I launch the car at 15psi I 60ft 1.58-1.60. If I launch at 10psi it goes 1.50-1.53. Just make sure it will spool fast launching at low boost. I tried this before & it didn't help but I had an exhaust leak I only recently fixed.

So I say try launching it softer until you get some good 28 x 10.5 x 15 M/T ET drag slicks on a 10" wide rim. Do you know anyone you could borrow some from?