Traction issues

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hkeller said:
I will try the caltracs first and then some new sticker shoes.. Can i even get a 17 inch drag radial...or do i need to order some new wheels too...
HKeller
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Try bfg's...The radial T/A KDW series with the leaf pattern is a good street tire.
 
Traction is gained by weight transfer, the back need to drop and front need to come up.

The Caltrac Bar moves the "Instant Center' forward wich is the fulcrum or lift point of the chassis. Buy moving this forward it makes it easier for the engine to lift the front end up and as we all know from our 1st physics lesson in grade school for every action there is an equal and oposite re-action. Front wieght is lifted-Rear wieght is applied.

So with this theroy in mind, how do we get max weight transfer to the rear?

#1 A soft enough spring rate to allow the back end to drop (Calvert's mono-leaf springs)
#2 Move the instant center forward (Caltrac bars)
#3 Contol the speed of the rear spring compression (Calvert's 9 way adjustabe Rear Shocks)
#4 Get the front end up as quick as possible and hold it up (Calvert's TRUE 90/10 Front Shocks)
 
I'm sure you can get drag radials in 17" wheel size because a lot of newer muscle cars with the big wheels get converted to drag cars too. They will have to have a thicker sidewall though in order to spread properly like another poster mentioned. If you do want it to be capable on the street and road course though I'd go with suspension mods first because drag tires aren't meant to corner worth a damn. OR get an extra pair of wheels and mount drag tires on them so you can switch them out when you're having a bad day and want to have some fun. Yet another option would be to get some good sticky high-performance street tires with a slightly bigger sidewall in the back instead of your current tires.
 
The cheap way out. Put some tires on it. Use slant six T bars. The question was ask, is it a sure grip. I assume it is. Does it have frame connectors. How tall are your tires?
Small Block
 
Before you spend big bucks, look at your rer gears. What are you running? A 408 stroker will give you massive torque beginning at around 1500 RPM. If you are geared to low you are going to spin. I found that 3:23s or 3:56 (I think) are better plus a taller tire.
 
S6 t bars will suck on the street. You need to decide how it is going to be driven as to what suspension setup you want. Caltracs and monoleafs with drag radials will be great on the track. Multi leafs are better for a street driven car.
 
cuda66273 said:
Traction is gained by weight transfer, the back need to drop and front need to come up.
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The back definitely should not drop. Weight transfer--yes. Front lift--yes. If the back drops, it's because the differential is lifting, thus lifting the tires off the ground. That's the last thing you want for traction. Look closely at real race cars with stock type rear suspensions. The rear of the car lifts too. SS springs of the correct weight for your car and a properly adjusted pinion snubber are the easy way to do it. Cal-tracs are another way to prevent the front from wrapping up and the right from lifting.

As for BFGs. I can't figure out why my '64 273 GT Dart spins the tires so easily, along with my '69 273 Swinger with 3.23 Sure-Grip. They are both slow, but spin the 215/60-14 tires easily. My '69 Charger R/T with 235/70-14 BFGs on a 3.23 peg leg gets great traction. It's easy to get a quick launch without going up in smoke.
 
Chargers heavier where it counts and the sidewall may help too. BFGs are not known for great traction. Never have been. I always liked GT Qualifiers back in the days before Hoosier and M&H...lol.
 
I just fitted a set of calverts on my 68 cuda (minus the rear shocks - using edelbrock IAS). My rear springs were junk and I needed new ones anyway so went with the split-mono leaf. I putted around with it a few days and I liked the on-street feel. It was a bit more harsh, esp over bumps but it also has a solid front bushing so I was prepared for some street feel transfer. It was certainly not overwhelmingly hard or anything, just firmed up enough to feel it. I have a built 360 in mine but not a stroker.

Unfortunatley I spun an axle on my first hard pull with them so not much experience in whether they hooked or not yet. The car was spinning a bit when it broke but the axles were too short for the carrier so its not like I was making gobs of power or anything. :-D I too am running BFG 16" street tires for the look but I hope I can get some hook also. If not I'll procure a 15" or 17" rim and run et streets to the track.
 
Were you in first gear when the rear broke? It's important to try to remember...

Also, you may find changing to a urethane front eye bushing is less clunky, with very little performance difference from aluminum. I've replaced the aluminums and it made all the difference in a few cars. Not sure how a mono-leaf will react to it, but I'd suspect similar to std leaves...
 
moper said:
Were you in first gear when the rear broke? It's important to try to remember...

Also, you may find changing to a urethane front eye bushing is less clunky, with very little performance difference from aluminum. I've replaced the aluminums and it made all the difference in a few cars. Not sure how a mono-leaf will react to it, but I'd suspect similar to std leaves...
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Yes I was in first... and yes I have the trans apart with $1000+ in parts coming from John at CRT (including super-sprag). Turns out I didn't hurt the sprag but since it is open anyway I am going deep into it with billet drum, etc... If you had something else in mind than by all mean reply or PM me :D

I will consider the bushing if I find it too harsh.
 
I had the wheel spin issue with my duster. I like more of a "G" machine so while messing around one day I "rebuilt" my rear springs from 2 sets of old used ones. I have 6 leafs per side with a "extra" front segment. In the front I have the .89" bars and a 1 1/8" sway bar and also have a 3/4" bar in the rear. kyb shocks all around and rubber in all the bushings but the strut rods and sway bars. With a 300hp 360 and 4sp and 3.91 I had to try and spin the tires. and Thats with 255-60-15 Cooper Cobras not the "stickyest" tire out there. I think the stiff front segment of the leaf springs was the key to traction. Now if you go to the drag strip u need drag tires as the dissimular compounds do not like to stick and you will spin for ever. LOL
 
More weight over the rear wheels will fix it , try this :)

traction Daytona.jpg
 
Just wondering.. Your really doesn't look like a drag car. Are you just worried about straight line traction? Because Clatracs Affect some aspects of cornering. I don't remember what right now but I'm pretty sure it has to do with roll centers and weight transfer. I'll look it up and get back to you.
 
375inStroke said:
The back definitely should not drop. Weight transfer--yes. Front lift--yes. If the back drops, it's because the differential is lifting, thus lifting the tires off the ground. That's the last thing you want for traction. Look closely at real race cars with stock type rear suspensions. The rear of the car lifts too. SS springs of the correct weight for your car and a properly adjusted pinion snubber are the easy way to do it. Cal-tracs are another way to prevent the front from wrapping up and the right from lifting.
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375inStroke is right. The quality is defined "Anti-squat" or "rise" depending on who you ask. I prefer "Anti-squat" because its easier to understand what its doing. The axle torque is converted to lever force that pushes the rear end into the ground, artificially loading the rear tires(making them think they have more weight on them and therefor creating more traction) and at the same time "lifting" the rear of the car. This is what the caltracs do, and why they help traction. SS springs also are designed to produce "Anti-squat". Mopar suggests 2-3" of "rise" for a street/strip drag car, meaning at launch the rear should raise 2-3" from static height. The only problem with high "Anti-squat" values is that its almost impossible to get roll-understeer, so it can feel like the rear is "sliding" out from under you during hard cornering. Hence the reason I asked what you were wanting to do with your car.

If anyone doesn't understand this I'd be glad to try to explain it in more detail.

Hope this helps,

Benjamin Kadron
 
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