B3422w5
Well-Known Member
Nice job!
Finally reacting to a protree
- Thread starter o1heavy
- Start date
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o1heavy
1974 dart sport
Just wanted to share
with the help of protrans
Along with a ton of work trial and error
And countless passes …
This 904 is doing everything I’ve asked
Reliable,, I let go of the button at 5000rpm
And have had no issues roughly 3000lbs
Reaction time is on point …
.00’s to low .020’s is cake …
Just wanted to share there was a time I was thinking this thing just couldn’t react
with the help of protrans
Along with a ton of work trial and error
And countless passes …
This 904 is doing everything I’ve asked
Reliable,, I let go of the button at 5000rpm
And have had no issues roughly 3000lbs
Reaction time is on point …
.00’s to low .020’s is cake …
Just wanted to share there was a time I was thinking this thing just couldn’t react
o1heavy
1974 dart sport
now if I could only get it to drive the stripe for me . Haha
Duane
Well-Known Member
Ok so I am confused. I thought you attributed your progress to the ladder bar suspension versus the Caltracs.
What changes have come from the trans.
o1heavy
1974 dart sport
Ladder bars where a step in the right direction car got consistent and reliable .
The Caltrac’s where just to hit or miss..
Ladder bars let me focus .. on the rest of the car
Continued to grind on it ,
Reaction time got better
Protrans had some valve body transbrake
Release ideas they did them
Reaction time got better
Seat time
Seat time
Car is better
Work work work
Timeslips have proven
That the progress isn’t just a fluke ..
famous bob
mopar misfit
Jim Hale once told me to ride the brakes if needing to slow down , never let off the qas , this was on a hemi superstock type car with a ratroaster intake on it , that gas would puddle in when lifting , but is good advise on any car--------jmo
famous bob
mopar misfit
My ex partner helped a guy with a 500'' duster , the ladder bar set up had to be calmed down , he would carry the front wheels to the second gear change , the only problem was it was way high in the air . That car split 440 blocks bad, they eventually backed the carb off to 9.60`s to keep it alive.
Duane
Well-Known Member
Hmmm, I wonder if your problem was transbrake release all along,
Calvert has on their website the first car to run 6,s on leaf springs.
6.98 et, so Caltracs can work. But if your transbrake had a problem, no suspension can work properly. What made you contact protrans.
How did you conclude that the brake needed to be looked at?
o1heavy
1974 dart sport
I know people go fast on leaf springs
I hear that statement all the time ..
And they can be made to work. Most of the time those guys race 3/4 times a year
On fly paper prepped track
My car is slow and countless passes a year
Some tracks are awesome and some not so much .
I’m not gonna go into the instant center deal with a mopar leaf spring ..
But it can be made to work , for me “working” wasn’t good enough .
And the ladder bars are miles ahead of a mopar leaf spring deal ..
I do believe with less of a first gear the springs would be better ..(powerglide)
if you decide to go with a leaf spring deal along with a .4ths protree let me know .
Never said I had a problem with the brake
What I’m saying is always Looking to better my program IE reaction time etc….. and protrans found a way to make the release faster ..
Duane
Well-Known Member
I have followed this thread. Just saying that you had implied that your problem was all suspension. Then you mentioned trans brake.
I am just saying if you change too many things, it's difficult to say with certainty what worked and what didn't. The instant centre thing
With the 20 inch mopar spring, I simply do not understand.
As I understand it, the bracket that hangs down on the Caltracs is the new pushing point on the car. It is this vector angle change that shifts the instant center. The 20 inch leaf spring become irrelevant.
I've read calverts patent online, and that is what he claims that justified the patent, the changing of the instant center.
The bars and their angle(vector) affect the instant center, not the leaf spring. They work very much like a 4 link. A very successful racer freind of mine told me it took him a whole year to dial in his 4 link to find the sweet spot. Perhaps the Caltracs are the same.
But I am glad your car is working for you. can you shed some light on the change that Pro trans did to the brake.
Talking with Paul Forte of Turbo action, he says many "slow" cars with 4 links or ladder bars are switching back to leaf springs with Caltracs because traction is the same, but leaf springs have superior high speed stability. Go figure
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o1heavy
1974 dart sport
Ok,
I had to get the car to leave the way I wanted it to , and to do it consistently.
I fought and fought the Caltrac’s but could not get them to do what I wanted ,
Caltrac’s tech support was not much help
Other then suggesting shock adjustment.
I decided to move away from the leaf springs. After exhausting myself with them
And went to ladder bars
Car went to doing exactly what I wanted at the starting line ( snatching the tire out of the beams)..
So my next move was to start working on reaction time and sure enough got it where I
Want/need to be competitive in our local index class ..
I would never switch back unless I was footbraking
Putting on a set of Caltrac’s does not change the instant center ,
The instant center is where the front segment of the leaf spring mounts to the Chassis ,
Which in a mopar is short vs brand x
Which in turn will hit the tire very hard
And will release all pressure very quickly down track ..
I had to get the car to leave the way I wanted it to , and to do it consistently.
I fought and fought the Caltrac’s but could not get them to do what I wanted ,
Caltrac’s tech support was not much help
Other then suggesting shock adjustment.
I decided to move away from the leaf springs. After exhausting myself with them
And went to ladder bars
Car went to doing exactly what I wanted at the starting line ( snatching the tire out of the beams)..
So my next move was to start working on reaction time and sure enough got it where I
Want/need to be competitive in our local index class ..
I would never switch back unless I was footbraking
Putting on a set of Caltrac’s does not change the instant center ,
The instant center is where the front segment of the leaf spring mounts to the Chassis ,
Which in a mopar is short vs brand x
Which in turn will hit the tire very hard
And will release all pressure very quickly down track ..
Duane
Well-Known Member
You need to look at calverts drawings of how the bars work.
Even on a 4 link the instant center is a vector drawn from the angle of the bottom bar. That is why 4 links work as good as ladder bars even though they do not attach to the car as far to the front.
It does not matter because it is the vector or angle that is important, not the attachment point. The bars on the Caltracs are the same way. The angle of the bar determines the instant center, not the attachment point. This is explained very well in the hook and launch book.
The Caltrac bracket that hangs down changes the angle of the vector.
The bars and the bracket (when adjusted correctly) take the driving force instead of the leaf spring. This is also explained very well in Calverts patent. It's easier to see the drawing then to explain it.
o1heavy
1974 dart sport
O ok . So if I lengthened the front spring segment that doesn’t change the instant center ..
Duane
Well-Known Member
You mean moved it forward? If the attachment point is still in the same place then that changes nothing. If you moved the attachment point forward like ladder bars do, then that changes the instant center. A longer leaf spring front segment mounted in the same location would not change instant center very much unless you move the axle back.
o1heavy
1974 dart sport
Ok my friend I get it you are very knowledgeable and are a ton of help on this forum, and I appreciate your “help” and with all do respect I hope you have a some fun racing and turn on some win lights ..
If you where local to me I would love to
Get you in the other lane , and I’m in the Houston Texas area just encase your are
Even would be better if you join the local circuit, would love to see how you would stack up .
I Index race 6.50/7.0 which is no secret
I’m simple sharing my experience with leaf springs , ladder bars , protree racing and the like. Hopefully another enthusiast can use my experience to help them get where they need to be faster ..
Looking back I could have done ghings different but I’m ok with my journey
Been a blast .
Duane
Well-Known Member
As I said in my previous post, the main thing is you got the car to do what you want. Always more than one way to skin a cat as they say, and you are out there having fun and clearly turning on some win lights. You are way ahead of me as my car is not quite ready yet. I was only following your thread because I recently decide to change over to Caltracs, but I did a lot of research before making that decision. You are not the first person who could not get the Caltracs to work. Apparently it is very easy to get lost in the adjustments. I am trying to learn from you as well. Your out there racing, that's why I asked about your trans. I was not trying to pick on you. Sorry if that's how I came across. Good luck to you and beat the chebbies lol.
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