Time to hit the Track.

[malex]

Okay, Low gear set and Hoosiers... are the tires Radials or Bias Ply?

Reason I'm asking is the Radials are fast as Sh@# …. I mean easily a 1-2 tenths. BUT they are real touchy on marginal tracks, and they are good for about 30 passes and the side walls will be out of them.

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They're Bias slicks. I actually spoke with Hoosier today and they suggested that it sounds like I'm running too much air. That could be, I was under the impression that the stiff sidewall liked more air. I was at 16 lbs when I broke. What are others running their stiff sidewall Hoosiers at?
On a good note, the transmission was just fine inside so that's good!

 

[Mike Gaines]

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They're Bias slicks. I actually spoke with Hoosier today and they suggested that it sounds like I'm running too much air. That could be, I was under the impression that the stiff sidewall liked more air. I was at 16 lbs when I broke. What are others running their stiff sidewall Hoosiers at?
On a good note, the transmission was just fine inside so that's good!

Mike....
My best tire pressure ( by lots of trial runs) is 17bs. Less, or more, air didn't help. The tires "wrap" but not severely. No enuf to have them cup up in the middle.
I leave at 3600 rpm off my trans brake. Ultimate 5000 flash 9"
I have exactly the same tire as yours, but i run tubes to make them even stiffer.
My car weighs about 3800lbs with me and 5 gal gas.
Cal trac 9 way shocks are on setting number 1.
I have 5 1/2 inches of free travel on my front end
The bars have 2 flats of preload on the passenger side and zero preload on drivers side (with me in the car and 5 gal gas, ready to go)
Car pulls the front wheels about 12-18" off the ground for about 18 to 20 feet out. It hooks !!!!
1.40-1.42 typical 60'
10.15 to 10.17 @ 131+ mph.
There is now no more that I can do for better performance EXCEPT to lose weight, which is my next major project. I think I can get about 150 more pounds out, which should put it at 10.00.
I have now wrung every bit of ET out of the poor girl and she will not give me any less et's. without losing weight

 

[Endangered Species]

Yha, that's what I'm thinking. I watched your video and it looks like the car is trying to plant the tires but it can't over come the tires before they lose traction.

We run Phoenix tires and at most we can get away with 14lbs.. on a good track. We were usually between 12.5 and 14 lbs.

Remember also, you have a low gear set, you are hitting the tires a lot harder than you were before, that's another reason you may want to leave at a lot lower RPM.

 

[malex]

Mike....
My best tire pressure ( by lots of trial runs) is 17bs. Less, or more, air didn't help. The tires "wrap" but not severely. No enuf to have them cup up in the middle.
I leave at 3600 rpm off my trans brake. Ultimate 5000 flash 9"
I have exactly the same tire as yours, but i run tubes to make them even stiffer.
My car weighs about 3800lbs with me and 5 gal gas.
Cal trac 9 way shocks are on setting number 1.
I have 5 1/2 inches of free travel on my front end
The bars have 2 flats of preload on the passenger side and zero preload on drivers side (with me in the car and 5 gal gas, ready to go)
Car pulls the front wheels about 12-18" off the ground for about 18 to 20 feet out. It hooks !!!!
1.40-1.42 typical 60'
10.15 to 10.17 @ 131+ mph.
There is now no more that I can do for better performance EXCEPT to lose weight, which is my next major project. I think I can get about 150 more pounds out, which should put it at 10.00.
I have now wrung every bit of ET out of the poor girl and she will not give me any less et's. without losing weight

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Mike, so #1 setting means that your rear shock rebound is at the lightest setting? If so, do you not have a lot of rear separation (car rising away from the tires).

 

[malex]

Yha, that's what I'm thinking. I watched your video and it looks like the car is trying to plant the tires but it can't over come the tires before they lose traction.

We run Phoenix tires and at most we can get away with 14lbs.. on a good track. We were usually between 12.5 and 14 lbs.

Remember also, you have a low gear set, you are hitting the tires a lot harder than you were before, that's another reason you may want to leave at a lot lower RPM.

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Thanks for the help and I will try a lower RPM setting. That's sure taking quite a run at the converter.
With my car, when the rear shocks are set soft it's going upwards to max travel and then unloading the tires. Bounce and spin.

 

[Endangered Species]

That's what it looks like.
Have you been able to tighten up the rebound a bit to keep it from over extending... then tighten up the compression?

 

[malex]

That's what it looks like.
Have you been able to tighten up the rebound a bit to keep it from over extending... then tighten up the compression?

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That is what Wooks and I did going into the pass when I broke. But yes, we increased rebound from 17 to 18 and compression from 10 to 12. We also snugged up the cal tracs a little as well.
The previous round Wooks was parked behind me in the staging lanes and he said that my car separated badly, spin and bounce.
I think we were likely on the right track, just never got to find out.

 

[dvw]

I think the failure was u joint/fastener related pure and simple. I also believe in the u bolt style retention for the joint. Do not over tighten the u bolt/or retaining straps. Definately use a Spicer joint with no grease fitting. If it hooks at high air pressure, do it. When you start making power the need for the suspensions role in assisting hook is lessened. That's why the shocks need to get tighter. You may run out of adjustment and need them to be valved even tighter yet. Time will tell. I've chased this stuff hundreds of passes. Once you get it right you'll be amazed. No such thing as "hooks to hard". We dead hook the kids 3750 lb car on M/T Pro bracket radials @ 4200/14 lbs of boost. It's found the weak link in the drive train a few times. But has never hurt the junkyard Dana w/junkyard gears still in it.
Doug

 

[malex]

I think the failure was u joint/fastener related pure and simple. I also believe in the u bolt style retention for the joint. Do not over tighten the u bolt/or retaining straps. Definately use a Spicer joint with no grease fitting. If it hooks at high air pressure, do it. When you start making power the need for the suspensions role in assisting hook is lessened. That's why the shocks need to get tighter. You may run out of adjustment and need them to be valved even tighter yet. Time will tell. I've chased this stuff hundreds of passes. Once you get it right you'll be amazed. No such thing as "hooks to hard". We dead hook the kids 3750 lb car on M/T Pro bracket radials @ 4200/14 lbs of boost. It's found the weak link in the drive train a few times. But has never hurt the junkyard Dana w/junkyard gears still in it.
Doug

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Thanks!
This makes complete logical sense pure and simple. Greatly appreciate your input, it's a clear picture now. I've researched years old postings on suspension and paid close attention to yours. From a few years back to seeing your car launch now, you've definitely found it. I'm excited to get back in the ring!
With my recent breakage, I'm actually embarrassed to say that what my car was running were stock yokes, front and rear, and combination u-joints to step up to the 3.5" aluminum driveshaft. Once I did the measurements on the broken yoke and front u-joint I was shocked... Who the F would install a nice shaft and use inferior yokes and u-joints. I had noticed the grease nipples on them and wondered if those 1350 u-joints are good enough, then thought, they must be, being on a nice shaft like that. My fault though, I assumed that what I was told and sold was legit 1350 u-joints and I didn't actually measure. The dana, spool and moser axles are legit at least, that I know. I'm surprized those pieces stayed together as long as they did.

 

[Mike Gaines]

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Mike, so #1 setting means that your rear shock rebound is at the lightest setting? If so, do you not have a lot of rear separation (car rising away from the tires).

I am running the Cal Trac Shocks that are 9 way adjustable.
They are to be set on "1" with a transbrake and "9" when using a footbrake.
I do not know what the shock actually does when it is set on "1". (or 9") You might call Cal Trac and see what they say.
I do know that the rear of the car lifts about 2.5 inches when it launches and Cal Trac tech guy says that is ok.
I know nothing about shocks that are double adjustable like yours.
Like i said, i just use the 9 way adj Cal Trac Rear Shocks.

 

[Cranky]

It's usually an indication that the rear end is being planted if the body is rising in the rear....but if the body rises too fast, it can unload the rear tires. Need to see a vid of what the car is doing as it's launching. I had trouble with a car that was rising too fast in the front and pulling the front tires up a good foot or so. That's usually a good sign if the car keeps the front end up but to fast rising on mine meant it landed too quickly and too hard which unloaded the rears. Slower acting shocks fixed it...

 

[dvw]

They are to be set on "1" with a transbrake and "9" when using a footbrake.
I do not know what the shock actually does when it is set on "1". (or 9")

I know what Calvert suggests. His shocks adjust mainly rebound (extension). #1 being loose to #9 being full tight. However it makes no sense that a trans brake launch wants to hit the tire harder using a loose rebound setting. My bet is that it'll go quicker with a tighter rebound setting. I have yet to see a car when it wasn't spinning go slower when tightened up.
You'll never know until you try it. Otherwise there is no sense buying something that can be adjusted.
Doug[/QUOTE]

 

[malex]

It's usually an indication that the rear end is being planted if the body is rising in the rear....but if the body rises too fast, it can unload the rear tires. Need to see a vid of what the car is doing as it's launching. I had trouble with a car that was rising too fast in the front and pulling the front tires up a good foot or so. That's usually a good sign if the car keeps the front end up but to fast rising on mine meant it landed too quickly and too hard which unloaded the rears. Slower acting shocks fixed it...

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Yes Cranky, I posted a video on page 12. Check it out, sounds like what you described.

 

[Cranky]

If you've mentioned this before, I missed it but what is the front to back weight bias? If it's nose heavy, getting the suspension to act right will be a bit harder. Are you still running rear spring hangers instead of sliders with the CT's. If so, that would be my first thing to change. Also, what's the rear spring rate? Too many go over board with too high spring rate thinking it's better. Imo, it's easier to make a car work with a spring rate that's on the light side than one that's on the high side.....and the vid makes me think that maybe you are over sprung....?

 

[malex]

If you've mentioned this before, I missed it but what is the front to back weight bias? If it's nose heavy, getting the suspension to act right will be a bit harder. Are you still running rear spring hangers instead of sliders with the CT's. If so, that would be my first thing to change. Also, what's the rear spring rate? Too many go over board with too high spring rate thinking it's better. Imo, it's easier to make a car work with a spring rate that's on the light side than one that's on the high side.....and the vid makes me think that maybe you are over sprung....?

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I haven't done a front to rear weight ratio but the front is about as light as it can get without going to glass fenders. Still running shackles on the rear but they swing freely. Split mono-leafs are for a 3400 lbs car, which is what I'm at with driver. Sliders are something to look into.
One thing is for sure though, the car is too busy jumping instead of slinging forward. My shock rebound is going to get cranked on, on both ends. Shock compression is something I havent paid much attention to but it must also play a role in stiffening up the rear.

 

[Mike Gaines]

My settings (as described above) work for my car.
Like you can see in my signature below, the car runs 10.15 to 10.17 and the car weights almost 3800lbs.
Like I said, Cal Trac Tech tells me to set the shocks on #1 with a transbrake and that is what I do.
The car launches with virtually NO wheel spin and cut consistent 1.40 60' times.

 

[malex]

My settings (as described above) work for my car.
Like you can see in my signature below, the car runs 10.15 to 10.17 and the car weights almost 3800lbs.
Like I said, Cal Trac Tech tells me to set the shocks on #1 with a transbrake and that is what I do.
The car launches with virtually NO wheel spin and cut consistent 1.40 60' times.

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Your car is working well with your combo Mike. I hope to find what mine likes soon.

 

[malex]

Transmission is A-ok, bolted back in and just waiting on my new Strange driveshaft and billet yoke for the Dana.

Dble acting shock question: Tighening the rebound on the shock helps to keep the car from separating from the diff. Will increasing the compression on the shock also help the rebound eliminate separation?

All back together, waiting for my new driveshaft to ship.

 

[Tex013]

Transmission is A-ok, bolted back in and just waiting on my new Strange driveshaft and billet yoke for the Dana.

Dble acting shock question: Tighening the rebound on the shock helps to keep the car from separating from the diff. Will increasing the compression on the shock also help the rebound eliminate separation?

All back together, waiting for my new driveshaft to ship.
View attachment 616492

Compression holds tyre to track , rebound is extension/separation
Compression will not alter separation
I run #10 of 19 comp and #5 of 19 ext , this is radial tyre . I am going to try tighter ext next track day .
Radial setup is often reverse to crossply .
As to Mike's setup , that is what Viking advised me but after mucking about this year I am not sure it is best for me


Tex

 

[dvw]

Shocks do not eliminate suspension movement. They control its speed. Tighter slows the movement. Separation is a function of instant center location. A Cal Track equipped car will always separate. This is due to a relatively short and high instant center location. Try tightening rebound first to slow the separation. If it's still an issue you may have to lower the front spring eye location. Watch here when my son worked on a buddys car. Granted not a cal track car. but you'll get an idea of what happens when you tighten it up. This shows you how valuable cell phone video is. Who here saw anything until it was shown in slow motion?
Doug