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  #1  
Old 08-05-2002, 03:17 AM
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cageman cageman is offline
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Default What to do, MY CAR PUSHES BAD ON DRYSLICK

I have Afco 31 XHD rear leafs, they are 195 # springs, Should I go to a softer spring for dryslick, Im afraid on a tacky track the softer springs will twist out of my car, the next softer is a 165 and a 155 pounder, the car lights up the tires with hardly any throttle and Is a cement truck through the corner, I have 51 % rear and the cross I cant quite remember off hand, I am running 75 pounds of left rear bite and on a tacky track it is fast but tonite it sucked so bad, I didnt see the track going that dry and I missed the setup boat completely. My car is 3650 with me in it. I have a little redeaming to do to claim a win this friday but all my Mod racing buddies say that I will just have to go lighter and replace them every 5 to 6 races. My springs look good now but Im afraid that there is a few more dry tacks yet this year. If it works on dry It should still work good on tacky too right?
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  #2  
Old 08-05-2002, 10:34 AM
AVENGER29 AVENGER29 is offline
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Wet tacky tracks are easy, dry slick, powdering tracks are hell!!!
Wish i knew what a tacky track was, at 102 degrees today, we almost always race on severe dry slick tracks.
First, you need to adjust your drivin style, dry slick is very much like asphalt, dont try throwing the cars into the turns, ease in and out, very smooth, keep the ass end under you. Reduce to a softer spring, we run 175 and 150 landrum springs, our cross is between 52.5 to 53.5%, rear at 54.5%, left at 54%. We are a little liter at 3200 lbs, dont know what you are allowed and not...
We can run racing shocks, Pro shocks, lf 75, rf 763, lr 95, rr 94. We have to run spec tires, but are allowed a large right front, we run 16 psi right front, 14/15 right rear, 12psi both right side, no bead locks, but when mounting the tires we always paint the inside edge of the bead, let it get tacky, then finish mounting the tire.
Our brake bias is set neutral, and I"ll adjust thru the race, as condition requires it. Rule of thumb, loose less rear brakes, tight more rear brakes, we also run our front bias neutral on dry slick and right front reduce dramatically for wet/tacky.

avenger
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  #3  
Old 08-05-2002, 10:43 AM
Racedude_5 Racedude_5 is offline
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Landrum makes springs in other rates and for some reason I like the feel of their springs a lot better than Afco, I run a 25lb stiffer spring on the left rear and it really helps that loose feel right in the midddle of the turn. And if you can keep the car from getting loose in the middle it makes you smile a lot more comming off the corner. I dont have to change springs for tacky track or dry, the same seem to work either way and that is the beauty of leafs you get them right and they are pretty much dead on anywhere. I run a little lighter car (3300) and I have a 150# on the right and a 175# on the left about 3" of stagger on te rear with about 2" of wedge. I dont have a set of scales to tell you what percentages that is. hope this helps
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Old 08-05-2002, 12:50 PM
Rich33 Rich33 is offline
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I've ran both AFCO and Landrum spring in my street stocker. I've ran the 155 lb AFCOs on my car (3200 lbs) and they were TOO SOFT. Watch out...you'll be dragging your bumper off the corners if you try those.

I've got 200 lb Landrums in it on both sides now and the car is good, but my rear percentage is higher than yours. If you think softer springs are the way to go, I'd consider the 175 lb Landrums, but there's no way I'd go softer than that.

Some other things to consider to hook up on dry slick: More rear weight percentage (I know you're pretty heavy now, though), a split valve shock in the LR, and your right foot!
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  #5  
Old 08-05-2002, 02:22 PM
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cageman cageman is offline
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My car gets real loose when I get lots of mud under the 1/4 panels and it drives good with no mud, but on a dry slick how would I cure that in corner entry, Im a little worried that it will be too loose in the entry if I put any more rear in it. I tried getting Landrum springs this spring and they were unable to get me a set after waiting a month and a half, Thats why I went Afco, I got them in a day, so I was kind of burnt from Landrum after that, they just kept giving me the runaround about why they dont have the springs

So should I get a 175 for the right rear and put that in, or should I put two 175's in.
I race this friday and Sat is a big race that Im thinking will be dry and I have to run American racers for that race.
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  #6  
Old 08-05-2002, 08:23 PM
340king 340king is offline
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Exclamation Roll Stiffness and Balance

Pushing or understeer can be a combination of things, but here are some things to consider.

First, you might have a roll stiffness imbalance. The front of the car may be too stiff for the dry slick track. I don't remember what you were using for front springs and shocks. Softening the rear may make this worse rather than better if I am right. Are you using a sway bar? If so loosen it before a dry slick feature to see if it helps. I used a 1/2" threaded rod with lug nuts for stops on it on my B body. This allowed adjusting the preload or gap in the linkage. I would loosen up the bar to a gap of about 1/2". This allowed me to roll into the corner without the aid of the bar and then come onto the bar in the middle of the corner. This loosened the car on entry and limited (body) roll in the center of the corner.

Another area that can cause problems is roll center to center of gravity height distance. Too low of a COG can cause the front end to wash up the track. It didn't appear from your photos that your car was that low.

Are you running any front stagger? This can help by creating a harder braking force on the inside front tire. The smaller diameter means that the tire exerts a slightly higher force to the ground with the same amount of brake pedal application. This can help corner entry, especially on dry slick since you use the (front) brakes so much more there. Are you using a variable bias adjuster?

Shocks can make a big difference on entry and some on exit. Driving style can influence how effective shocks are in tuning. Smooth drivers can use shock package changes with good effect.
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  #7  
Old 08-05-2002, 11:45 PM
I8URACING I8URACING is offline
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Question stagger

I think you will have a hard time getting much for stagger out of the mod tires. Since the problem is mostly with corner entry, I would think that the front end is where you should concentrate. I was also thinking that lighter springs (smaller torsion bars) might be the answer.

Good luck up in Minot.
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  #8  
Old 08-06-2002, 04:31 AM
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I am going with a 166 pound r rear spring, I dont have brake bias and I cant have it, I also have to run a stock shock, they dont know that I have afco springs in it either, the two other dodges were having the same problem as me, but they have fury's and have junkyard springs and cross t bars. I have .996 tbars in my car with NO swaybar at all, I think the rear is not rolling over at all and I need a softer spring on that side, I have the same springs on both sides, after watching the tape of my race I can see that the car is not rolling over at all on corner entry like it was the day before, and the pass side spring is starting to bend by the front hole so I think she's on her way out allready (Gee after only 22 races)
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  #9  
Old 08-06-2002, 04:47 AM
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Wht can I do to make my brakes adj without The techs seeing it, I mean like real obvious. I have the alum master cyl and no power brakes. Would a r front shut off help, Im new to this concept so give me some Ideas.
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  #10  
Old 08-06-2002, 02:48 PM
Rich33 Rich33 is offline
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This topics seems to have diverged from the title (pushing on dry-slick), to your question about rear springs (softer to hook up better off the corner, right?), to brake bias.

First, about brakes. A lot of guys I know hid their brake bias adjusters under their seat. Tech didn't look for it there and they could still adjust it while racing. I think that you've got to get the spring/shock/crossweight issues solved first before worrying about this.

If you're worried about performance on dry-slick, don't shut off your right front brake. You do a lot of straight line braking before the corner on dry-slick, therefore shutting the RF off will hurt more than help. That's helpful on a wet track, but even then it can hurt you if you have to brake to avoid a wreck or heavy traffic.

Stock shocks? An AFCO street stock shock is a stock replacement. If you have to, paint it all black and tech wont be able to tell the difference. The SS shocks for Chevies will work if you cut off the wrong ends and carefully weld on the right ones back on.

If you'r pushing on dry-slick, ensure that your front suspension isn't bottoming. put a zip-tie around the the shock shafts and check their travel. I've had a push on dryslick that was caused by the RF suspension bottoming. Raising up the torsion bar a turn-and-a-half fixed it. this was on a car lighter than yours with 1.04 bars in it.

I'm not sure those lighter leafs are gonna help much. I still think even a 166 is too light for the weight of your car. Consider adding rear weight (or even better lightening the front) and then adjusting the cross as required if the car loosens or tightens on entry as a result.
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  #11  
Old 08-06-2002, 03:15 PM
340duster1 340duster1 is offline
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I am going to assume the problem is push on turn entry or in the middle of the corner. I would look at the front suspension first as this is doing most of the work on turn entry.

The pushing usually indicates the rf is too stiff for some reason. First, I would check for RF suspension binding if it is binding during travel it can act like a very stiff spring. Next I would try less wedge %.

I had the same problem with my duster, First it was a wedge problem 54% cross(now it is 49%) then I still had a slight push in the middle of the turn on dry slick and it was a binding problem (actually bottoming out), so I raised the front ride height an inch or so and now it corners well.

The dodge front suspension has alot of antidive built in which creates a built in push problem on turn entry, so you must compenstate with wedge etc.

Everyone may not agree but, the way I look at things is your right front gets you in the corner and your right rear gets you out(rear stagger is very important for exit), these are the primary places to work on. Adjustments to the left side are tweaks to work with once you are fine tuning. Stiffening up the rf (with shocks, springs, more tire pressure, or wedge%) makes you push and stiffening up the RR (shocks, springs, more tire pressure, reduced wedge) makes you loose.

As for your right front brake you could try a proportioning valve to your rf to reduce pressure and/or cut trim the center out of the right front pads, they will wear quicker but you will reduce the braking area on that side. I tried these with some success, but they were only bandaids for other problems. Now I don't need them.

I hope this will give you some ideas, incidently I run 1.040 t-bars with the mopar perf dirt rear leaf springs #14 and #15 (125lbs)and am having good success.
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  #12  
Old 08-06-2002, 04:02 PM
Rich33 Rich33 is offline
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I'm in general agreemet with everything 340Duster1 said, but I do want to add a couple of things.

1) If you're not pushing until you're on dry-slick and you're running .993 bars I'm leaning toward bottoming the suspension rather than being too stiff. Check your travels!

2) Rear spring rates for leafs are measured differently by different manufacturers. Be careful. Landrum and AFCO rates numbers seem to be close to the same. The MP are comparable to higher rated AFCOs and Landrums, even though their number (125) is really low. Watch out for the Speedway house brand leafs. They're a lot stiffer than the same number in Landrum. Generally I like running the Landrums or the AFCOs because they give you different rates to play with. JMHO
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  #13  
Old 08-06-2002, 04:28 PM
340duster1 340duster1 is offline
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Default Rear Spring Rates

Rich, Any idea on how the different manufacturer's rate them, this has alway had me curious. Since leaf springs are variable rates do some measure first inch of travel? or some the average of the first few inches? any ideas. I would like to know because next time I purchase springs I may try afcos or landrums but have no way of knowing what compares to the chrysler springs.

Another note for the corner entry push, I also tried stiffening up my rear leaf springs (added a short leaf) to help reduce the entry push, (again working on the wrong end of the car........I should know better) and all it did was loosen up the corner exit.
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  #14  
Old 08-06-2002, 05:46 PM
Rich33 Rich33 is offline
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I dunno. But, it seems like the MP 125 springs compare real favorably to the Landrum 175's. I bought a set of those Speedway Motors house brand springs rated at 200 lbs for the wife's Camaro street stock and - geez - the car was stiffer than heck in the rear. I ended up taking a leaf out of both sides.
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  #15  
Old 08-06-2002, 10:22 PM
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cageman cageman is offline
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The brake question was just that.
The way I went was with a 180 # Howe leaf, I went 200 miles to get it today, Im putting it in tonight and I am scaling the car tommorrow night, I have a 1/2 inch diff in front to rear height, thats what I was told to do, as for bottoming out Im close but only on a rough track, not smooth, I have stock shocks that have that damn sleeve over them, so I will cut those off too so I can see what travel i have, our rules say that afco bilstein etc is not a stock shock, It is frustrating cause shocks can help this problem too but I cant, and I have won the past 6 out of ten so they are watching me, I have quick release pins on my shocks cause I pull them every night.
I needed a softer r rear spring anyway and that spring was kind of bending a little anyways, they do have 22 nights on them.
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  #16  
Old 08-07-2002, 08:38 AM
Rich33 Rich33 is offline
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Good luck, Cageman. Go whip up some more on those guys and let us know how the changes worked for you.
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  #17  
Old 08-07-2002, 10:16 AM
340duster1 340duster1 is offline
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Good luck from canada as well, whip some of the chevy boys. I'm racing too this weekend so hopefully I can pull off a few wins....and whip some shevys.
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