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EFI/N2O JUNKIE
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If you were to leave higher than 3000 would it still stick? Maybe I'm asking too much of my car trying to leave at 3800...
I have left at 5500 off the trans brake. I have been using a Hoosier 29.5x10.5 bias ply slick.

This past weekend I ran 28x10's, but left at 2500/2800 Deep to hit a Pro 500 Tree for 10.00 racing.
 

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Discussion Starter #23
Ok thanks guys. Next week I'll get more video and see what I can make happen. I need to leave harder than I am and it's hard for me to believe a 10 second pass needs to manage power on launch. Should be able to take more
 

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hello do you happen to have any pictures of the rear suspension front ladder bar cross member area and ladders also how is this all tide into the chassis of the car
 

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Discussion Starter #27
hello do you happen to have any pictures of the rear suspension front ladder bar cross member area and ladders also how is this all tide into the chassis of the car[/QUOTe

Otherwise PM me your number and I'll text u pics I have of the build
 

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Discussion Starter #29
Just got back from more testing. Little looser all around with shocks and putting launch rev limit at 3k instead of 3800 and car left good on motor with a 1.44 60'. Bottle on with a kinda aggressive progressive curve (but at the time didnt think it was too bad) completely overpowered the tires. So couple questions. Has anyone had any good success with m/t 325 50r15 et street r's? Or should I be looking into a PBR or a more professional radial. Second should I really have to take a lot of power out of it to get it to hook? Car has been 1.30 before on a fluke that I cant duplicate. I know theres power there to go deep in the 1.20s but i cant seem to figure out the chassis-tire side of things. Anybody out there on a ladder bar and radials going fast?? Any brainstorming would be appreciated, nobody around here seems to have an idea of where to go from here!
 

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Just got back from more testing. Little looser all around with shocks and putting launch rev limit at 3k instead of 3800 and car left good on motor with a 1.44 60'. Bottle on with a kinda aggressive progressive curve (but at the time didnt think it was too bad) completely overpowered the tires. So couple questions. Has anyone had any good success with m/t 325 50r15 et street r's? Or should I be looking into a PBR or a more professional radial. Second should I really have to take a lot of power out of it to get it to hook? Car has been 1.30 before on a fluke that I cant duplicate. I know theres power there to go deep in the 1.20s but i cant seem to figure out the chassis-tire side of things. Anybody out there on a ladder bar and radials going fast?? Any brainstorming would be appreciated, nobody around here seems to have an idea of where to go from here!

Just my opinion but if you're trying to get a radial to work with a ladder bar, the ladder bar should be going uphill to improve antisquatt. Use extension valving to control how hard it applies the tire, but you need to be very stiff on compression.

Also unless that 325 is on a 12" wide wheel, you're not doing yourself any favors, go to a 28x10.5 radial or a 275/60 radial if you have a 10" wide wheel. If that 325 is on a 12"wheel, then it's not the tires fault in my opinion.

Get someone to take good video of the car from like 5-10 feet away and down low so you can see what happens. If the car is making it out a few feet and blowing the tire off then the timing of the front end rise needs to be adjusted. Either top it out sooner, or slow it way down with shock valving.


Also, you may need to manage power with a launch timing curve,especially on a marginal track. Try dumping 6-8 degrees for the first 1.0-1.2 sec..


In my opinion, guys telling you to have the ladder bar level or down hill are setting it up like a slick car and it's not going to apply the radial like it should. You need/want separation not squat.
 

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Just my opinion but if you're trying to get a radial to work with a ladder bar, the ladder bar should be going uphill to improve antisquatt. Use extension valving to control how hard it applies the tire, but you need to be very stiff on compression.

Also unless that 325 is on a 12" wide wheel, you're not doing yourself any favors, go to a 28x10.5 radial or a 275/60 radial if you have a 10" wide wheel. If that 325 is on a 12"wheel, then it's not the tires fault in my opinion.

Get someone to take good video of the car from like 5-10 feet away and down low so you can see what happens. If the car is making it out a few feet and blowing the tire off then the timing of the front end rise needs to be adjusted. Either top it out sooner, or slow it way down with shock valving.


Also, you may need to manage power with a launch timing curve,especially on a marginal track. Try dumping 6-8 degrees for the first 1.0-1.2 sec..

In my opinion, guys telling you to have the ladder bar level or down hill are setting it up like a slick car and it's not going to apply the radial like it should. You need/want separation not squat.
I can tell you with authority that you definitely do not want the ladder bar running uphill. I have been racing a ladder bar car for over 40 yeas and the optimum on my car and I run radials is 2 degree down angle on the bar. You might get away with zero but never uphill.
 

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Discussion Starter #33
Thanks for the feedback guys, my bars are running 3-4 degrees down hill to front and I get some seperation, not sure if I need more, next hole up would put me at zero to ground. Front joint is 6 up and 37 in front of axle centerline. Next hole would put me at 7.5 up. Compression is at full tight rear always cause that's when I have the best luck. Rear springs are 130 and I've been contemplating going to 110

This may be a useless video cause I have slicks on for 1 pass just to see but maybe any of you guys can see what the suspensions doing. I really think something with geometry is severely off on this car and I just cant figure it out. By the way in this vid left on 30% and progressed all in in 1.0 second. 250 hp. I know way too hot, but was hoping for a miracle last run of the season!
 

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I can tell you with authority that you definitely do not want the ladder bar running uphill. I have been racing a ladder bar car for over 40 yeas and the optimum on my car and I run radials is 2 degree down angle on the bar. You might get away with zero but never uphill.
100 percent agree.

I had a pickup truck years ago that had the ladder bar mounts too high in the chassis. Made the bars run level to uphill and nothing would make it work. Cut the mounts, lowered them so the bars ran downhill and it fixed it.
 

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I have never run a ladder bar, but I would plot out the available holes to see what the actual antisquat is, every car is different and it seems like without plotting things out to see where the instant center is in relation to the neutral line, you're just guessing, even minor rear ride height adjustments can make a huge difference in the way the car works.
 

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Thanks for the feedback guys, my bars are running 3-4 degrees down hill to front and I get some seperation, not sure if I need more, next hole up would put me at zero to ground. Front joint is 6 up and 37 in front of axle centerline. Next hole would put me at 7.5 up. Compression is at full tight rear always cause that's when I have the best luck. Rear springs are 130 and I've been contemplating going to 110

This may be a useless video cause I have slicks on for 1 pass just to see but maybe any of you guys can see what the suspensions doing. I really think something with geometry is severely off on this car and I just cant figure it out. By the way in this vid left on 30% and progressed all in in 1.0 second. 250 hp. I know way too hot, but was hoping for a miracle last run of the season!
Check the angle in comparison to the bottom edge of the frame or rocker panel. The bar should be down angle to the rocker panel. Don't worry about the relationship to the ground. Just step back about 10 feet and sight in the bottom of the bar in comparison to the rocker panel. It should have a down angle in the front of the bar when comparing it to the rocker panel or bottom edge of the frame
 

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Discussion Starter #38
I have never run a ladder bar, but I would plot out the available holes to see what the actual antisquat is, every car is different and it seems like without plotting things out to see where the instant center is in relation to the neutral line, you're just guessing, even minor rear ride height adjustments can make a huge difference in the way the car works.
Good idea. I found billy shope's website and a ladder bar antisquat calculator. According to the calculations with a 108 wheelbase, 16" center of gravity height and 36.5 instant center I'm at 111% antisquat currently with front of bar 6" from ground. I can go to 7.5" gives me 139% and another hole up 9" goes to 166%. But that 9" is definately pointing the bar uphill. Should I go to 7.5 and start all over with trying shock adjustments? What's a good antisquat number?
 

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EFI/N2O JUNKIE
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Check the angle in comparison to the bottom edge of the frame or rocker panel. The bar should be down angle to the rocker panel. Don't worry about the relationship to the ground. Just step back about 10 feet and sight in the bottom of the bar in comparison to the rocker panel. It should have a down angle in the front of the bar when comparing it to the rocker panel or bottom edge of the frame
This is all I ever did with mine, and it works perfect.
 

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Good idea. I found billy shope's website and a ladder bar antisquat calculator. According to the calculations with a 108 wheelbase, 16" center of gravity height and 36.5 instant center I'm at 111% antisquat currently with front of bar 6" from ground. I can go to 7.5" gives me 139% and another hole up 9" goes to 166%. But that 9" is definately pointing the bar uphill. Should I go to 7.5 and start all over with trying shock adjustments? What's a good antisquat number?
Anti squat is what creates separation. I run 169% anti squat in my Chevy II. Its a 4 link car, but anti squat is anti squat. The car doesn't care
what "lever" you use to create it. Math doesn't lie. I don't see the car separating without out moving the bar up. Your own calculations seem to support that. Controlling the front end travel will play a large part in this equation as well, imo. Loose extension and very tight compression in the rear shocks is what works for me.

My car at rest



My car 100' out

 
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