60ft questions

[Super6]

pinion angle

Get some light weight wheels 15''x8''w/ 4''bs 28.5''x10''s slicks and leave at 15psi. Try a set of Phoenix slicks you will love them.

my wife will not let me change the rims i bought some trak stars one time and she was mad for two weeks...i finally sold them. i have some widen stock gn wheels 8" though that i will be using.

it's just a six...i know they are a least 4 years old ....gives me a good reason to spend more money

Highpsi87..pinion angle 4 degrees up on the rearend
2 degrees up on the driveshaft
are you suppose to subtract the two? thanks Bob

 

[johnplogii]

Sounds like you have 2 degrees positive pinion angle. You want negative, how much depends on the bushings or joints you run. 4 year old 28 x 9's on a 7" rim just are not going to cut it at that power level. I fought 60fts for almost 2 years in my car & most of it was tire/wheel combo.

At a similar power level I got these results

16 x 8 gta wheel with 28 x 10 x 16 hoosier slicks-mid to low 1.50's with a handfull of 1.48-1.49's. I bought 3 new pairs of these in 2 years.

Switched to 28 x 10.50 x 15 M/T slicks on a 15 x 8 rim-High 1.40's to low 1.50's with a best of 1.45.

I put those same tires on 15 x 10 rims & it really came around. 1.40's all day with a best of 1.42 & a busted ring & pinion

This year I have fitted the car with 325/50/15 M/T radials on the 10 inch rims & really hope to get them to work well.

John

 

[highpsi87]

Reset the UCAs to achieve 4* negative (down). Try it, and if it isn't corrected try another 2*. I wouldn't go more than that though. It should make a noticable improvement. Lighter 8" wheels would be a step in the right direction as well as 90/10s as posted by Underboost and bison. A 9" slick is too wide for a factory wheel, and the wheels are HEAVY. Post up your results!

This link may help with the pinion angle!


BaselineSuspensions.com.........Setting Pinion Angle

 

[Alky V6]

Get a new set of simple off the shelf 50/50s for the rear, if they're old. A loose old set of shocks for the front, or better, 90/10s.

I'm not seeing much rise going on in the rear. The tire is not being planted. Are you using stock control arm mounting locations? Stock attachment points will give you body squat. That is the opposite of what you need to plant the tire.

 

[Super6]

thanks guys

DonWG,i am using stock mounting points for the control arms...what do i need to do different there?...the metco's came with a relocation for the lower bars is that what i need to use? i don't have time to do anything to the car before this weekend so i will try and get all this done before Bowling Green, shocks, slicks, and wheels...might get threw out for the wheels...anyone got an extra room and a big garage?:smile:

highpsi87...thanks for the link...i will get to work on this stuff and hope to see some of you in Bowling Green and post results after i get them done....i appeciate all the help you guys have given me........Bob

 

[Super6]

Sounds like you have 2 degrees positive pinion angle. You want negative, how much depends on the bushings or joints you run. 4 year old 28 x 9's on a 7" rim just are not going to cut it at that power level. I fought 60fts for almost 2 years in my car & most of it was tire/wheel combo.

At a similar power level I got these results

16 x 8 gta wheel with 28 x 10 x 16 hoosier slicks-mid to low 1.50's with a handfull of 1.48-1.49's. I bought 3 new pairs of these in 2 years.

Switched to 28 x 10.50 x 15 M/T slicks on a 15 x 8 rim-High 1.40's to low 1.50's with a best of 1.45.

I put those same tires on 15 x 10 rims & it really came around. 1.40's all day with a best of 1.42 & a busted ring & pinion

This year I have fitted the car with 325/50/15 M/T radials on the 10 inch rims & really hope to get them to work well.

John

John, do you have a frame notch? i really don't want to notch my frame. thanks for the info too..........................Bob

 

[Alky V6]

DonWG,i am using stock mounting points for the control arms...what do i need to do different there?...the metco's came with a relocation for the lower bars is that what i need to use? i don't have time to do anything to the car before this weekend so i will try and get all this done before Bowling Green, shocks, slicks, and wheels...might get threw out for the wheels...anyone got an extra room and a big garage?:smile:

highpsi87...thanks for the link...i will get to work on this stuff and hope to see some of you in Bowling Green and post results after i get them done....i appeciate all the help you guys have given me........Bob

Lowering the LCA rear mounting point would bring the instant center in front of the rear axle. That would help.

 

[johnplogii]

Bob, I do have my frame notched. I have a friend who does not & fit 28 x 10.50 x 15's on 15 x 10's with 4.5 bs with only rolled lips it's real tight & will work on some cars & not on others. Sometimes the rearends are off center(which you can fix with adjustable uppers) and sometimes the body is not centered on the frame(my car is like this)

John

 

[lazaris]

I would not mess the control mounting location. The car is not pitch rotating enough. You need to work on the front end. If you look at the video closely you'll see as soon as the front end tops out it starts to spin the tire and not at the hit. Moving the uppers higher to change the IC will only make it harder to for the car to pitch rotate and hit the tire harder which is not needed here. You also need to put in a good rear shock to keep the rear planted once it pitch rotates.

 

[bison]

Shocks, weight removal from the front, and a harder launch will change things a lot. The back of the car looked ok. Not squatting too much. As Lazaris stated changing the IC will limit rotation and weight transfer to a degree and make the problem worse even though by a mechanical standpoint its more efficient. Id suggest the tall 9" Phoenix slicks also. I think the sidewall was 28.5x9. I used them with a lot of success even when they still had the Firestone name on them. If your wife didnt buy the car and doesnt drive the car then she shouldnt have much say in what rims you run.

 

[Alky V6]

So when do you guys think it is the right time to tune the instant center?
It would seem to me that the instant center should be the first item on the list when tuning the suspension. The stock control arm layout is setup for a lot of squat. The more load on the rear suspension, the more squat. Hence, when the car reaches a certain attitude it unloads the tires. How is that helping in this situation? Are you trying to make the squat work for the launch? Just trying to learn something.

I just studied the video again. This is what I'm seeing. Correct me if I'm wrong. On the initial hit, the car squats a small amount, the cars weight coming down on the rear springs loads the springs to allow a good bite. Then the spring rebounds, and at the top of rebound, since the suspension is not doing it's job to keep the tires planted (too much squat) the tires unload. Simply, the car bounces off the tires. Shocks with a stiffer rebould would help, but why not setup the IC to help keep the tires planted? Why put it all on the springs and shocks? I had the impression that the IC adjustment was a very major setting.

 

[Slow91z]

I've seen too many cars hook with the stock mounting locations to make me think that moving them is manditory.

I personally went 1.47 with stock mounting locations, Metco lower bars, stock upper bars with good bushings, ATR rear sway bar, junk shocks all the way around, and stock springs.

This was off the foot brake also.

Now when a car is lowered I think moving the lower mounting point is manditory.

 

[Alky V6]

I've seen too many cars hook with the stock mounting locations to make me think that moving them is manditory.

I personally went 1.47 with stock mounting locations, Metco lower bars, stock upper bars with good bushings, ATR rear sway bar, junk shocks all the way around, and stock springs.

This was off the foot brake also.

Now when a car is lowered I think moving the lower mounting point is manditory.

So you don't know if it might have helped to move the IC?

I always assumed that the lower powered situations would benefit more from increased anti-squat. Have I been reading it wrong?

How do you guys know the IC is OK if you haven't tried moving it around? This fella wants to improve his 60ft. That means experimenting a little. No one's interested in seeing how more anti-squat might help?

 

[Slow91z]

So you don't know if it might have helped to move the IC?

If I could have launched it hard enough to make it spin I would agree, but it took all I could throw at it.

I forgot to mention that was 28/10.5 Stiff Sidewall ET Drags on 8" Pro Stars.

 

[Alky V6]

I just think it would be interesting to see how a more appropriate IC would work with his present setup. Heck, a pair of traction bars have to be a lot cheaper than a new set of wheels and slicks.

 

[Slow91z]

Agreed.

But I think he needs to try screws and launching it harder before anything else.

I don't know if I would screw GN wheels, I'd probably get different wheels 1st but that's up to the individual.

 

[lazaris]

"Correct me if I'm wrong. On the initial hit, the car squats a small amount, the cars weight coming down on the rear springs loads the springs to allow a good bite. Then the spring rebounds, and at the top of rebound, since the suspension is not doing it's job to keep the tires planted (too much squat) the tires unload. Simply, the car bounces off the tires. Shocks with a stiffer rebould would help, but why not setup the IC to help keep the tires planted? Why put it all on the springs and shocks? I had the impression that the IC adjustment was a very major setting."

The car unloads on the rear because the front end travel ends first and too soon. Not because the rear unloads the tire first. Once this travel ends weight transfer has stopped and the rear has no where else to go but back up. This is where the rear shock setting comes into play to assist . Changing the IC like your suggesting does not "keep" the tire planted. It will actually make the rear tire unload faster in his situation. It will however amongst other things hit the tire harder as I've said which is not needed here. The instant center is a major change but in this case not the right choice for his current configuration.

 

[karst#9]

Slicks are too old. IMO

x 2. 4 year old slicks are the problem. I'm suprised it's 60 footen that good with those

 

[Super6]

i got my screws put in my old slicks. i am going to try more boost on my launches and see what happens..........thanks Bob

 

[it's just a six]

I will guess & say it will spin the tires more next time you run it.