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Author Topic:   Leaf springs
Speedway65
Member
posted October 06, 2003 01:05 PM
New to leaf springs.What is the benefit to toeing the front of the leafs in versus the rear.And if its that much better how much?

3100 nova 4/10 high banked clay

c21
Member
posted October 06, 2003 01:24 PM
I meant the front!Just worded it wrong


c21
Member
posted October 06, 2003 03:23 PM
I know it says 1 to 3 inches difference.Is that overall or per side?


c21
Member
posted October 06, 2003 04:48 PM
only on mono leafs. its not recommended for multi leafs.

monos in mods with coil eliminators to be specific.

c21
Member
posted October 07, 2003 09:54 AM
Nova's are also wider at the back, I believe.


66jj
Member
posted October 07, 2003 02:20 PM
no novas and chrysler oem cars are mounted parallel.

c21 have you found a usefull landrum tech, I bought parabolics in 99, and tried them, the same rates as my landrum multis and they bent as soon as I hit the gas. junk. I called landrum and they claimed they must have been bad, and wanted to send me another set the exact same, I made them send me stiffer ones and finally tried them in 01, and they were way way softer than my multis though they didnt bend, I finally made them work but I had to add leafs to both, thus defeating the purpose of using them, lw.

I tried talking to them about the parabolics again the last couple weeks to find out how they are constructed, etc and see if they might not fade like the multis supposedly do on dirt, and never could get to someone who had a clue how they are made, or if they are going to work out or not?? In my opinion they didnt work for me on pavement thats for sure, the 225 were even too light.



istock59
Member
posted October 07, 2003 02:40 PM
I think you better'd go lay under your Nova with a tape measure 66jj, because I'm 95% sure the 75-79 variety of Nova isn't parallel mounted. Way back when we built a 75 Nova (granted that was 10 years ago), I recall debating the fact that the front mounts were narrower than the back. We considered moving them to make the leafs parallel, but in the end, we ended up leaving it just as the factory built it. Worked fine that way too.


c21
Member
posted October 07, 2003 03:41 PM
when you say you added a leaf to the back of the 200, thats going to increase its rate to what a 225??

and the one added to the front is only going to effect axle wrap etc.

I was going to run both 225 parabolics to start, i will be running 3150 total wt and as little rear as possible.

Are your leafs bowing the wrong way on your car with all that rear wt??

in 02 I had a 3300 lb car at 47percent rear with 200-225 parabolics and had to add one whole leaf to both I think. I had to add the leafs basically to stiffen them, they were so soft even after putting the 225 on the rr my car would push when on the gas. way too much rear squat for pavement, I was getting 4 plus inches at first.

This is why I was thinking I could use them in a IMCA stock car at 3150 with less rear wt then most people seem to run?

when I had multis on the same car I ran 200-175 with no problems whatsoever. landrum dinglings sold me 150-175 at first in parabolics to try, I honestly hit the gas pulling out of the pits and the fronts both bent in a reverse V and my cell bar was on the ground..

66jj
Member
posted October 07, 2003 07:15 PM
whats IIRC


c21
Member
posted October 08, 2003 12:04 PM
Istock 59 Ok I measured a nova 75-79 your right!!!! the springs are 3.75 closer in the front total. I learned something.

I have raced camaros for the last 10 years on pavement.

yes that was hooked in the pits but a 10 inch slick on pavement, will do that easy..

maybe a something you dont know but, the rear of a leaf is the rated part. the front is the trailing arm basically. increasing the rate will only happen in the rear.

thanks for sharing your info, dirt is new to me. we have some simular ideas for sure. I have never owned a spring over 850, so im going to start there. I dont really understand why these guys are running so stiff maybe its monkey see monkey do??

later jeff

66jj
Member
posted October 08, 2003 06:45 PM
Istock 59 Ok I measured a nova 75-79 your right!!!! the springs are 3.75 closer in the front total. I learned something.

I have raced camaros for the last 10 years on pavement.

yes that was hooked in the pits but a 10 inch slick on pavement, will do that easy..

maybe a something you dont know but, the rear of a leaf is the rated part. the front is the trailing arm basically. increasing the rate will only happen in the rear.

thanks for sharing your info, dirt is new to me. we have some simular ideas for sure. I have never owned a spring over 850, so im going to start there. I dont really understand why these guys are running so stiff maybe its monkey see monkey do??

later jeff

istock59
Member
posted October 08, 2003 10:18 PM
Cool 66j, thanks for confirming it. I was afraid the alzheimers was kicking in!! LOL

I run a 1200 and an 1100 in my Terminator. Any less than that and the lower a-arm will bottom on the frame. And we all now how well a car handles when the front suspension goes solid... Perhaps the Nova/Camaro has more travel, so you can get away with lighter springs. Or maybe the distance from the spring to the pivot (bolt) is longer. Dunno. But I know I couldn't run a 850 on the RF...

66jj
Member
posted October 09, 2003 10:07 AM
Are your shocks pointing to the front like I have seen on other terminators??

If so that part of your problem, they have no control. when you hit a bump your a arm moves say 2 inches, your shock half to quarter that because its at such a severe angle forward, and so far from the tire.

shocks should be following the plane of the lower a arm, terminators are going against it.

shocks on a gm car should be 15 degrees in towards the centerline of the car and about 7-10 leaning back. they will fit behind the a arm at proper angles, (but will get ruined if wredked) or on top of the upper, like larson does, thats a nice job.

c21
Member
posted October 09, 2003 10:28 AM
A good thread going here guys!

66jj: Shock angle doesn't have that much to do with spring rate for the metrics. My former car, a SCS chassis, had it's shocks on the backside, just as you described and required virtually the same spring rates to keep the lower a's off the frame. Plus mounted on the backside the mount is further from the lower balljoint than on the front side, so even tho the angle is better, I doubt it's control is better. And on the backside the shock is much more likely to get ruined with a bent upper.

I'm not a fan of the upper mounted shocks. To me it looks like they have to be laid over too far to be effective. Now if IMCA lets us have tubular uppers (which is the rumor), then maybe they can be stood up a little more, then I might be convinced...


c21: Terminators are built on the small metric frame. Not sure what you mean by the motion ratio. Also, IMCA rules won't let us chop up the frame as you describe...


c21
Member
posted October 09, 2003 12:29 PM
istock59,

I will quote steve smiths book

"Mounting angle effects motion. usually more angle will lower the motion of the shock. this doesnt change the dampening force, but it slows the momentum ratio down. therefore the shock piston doesnt provide as much control. you want as much control as possible."

control is what keeps your tires on the ground, not bouncing around.

If you mount them on the top a arm they can be at the perfect angles. the tops are just under the hood, you must have seen a bad job of it.

the way yours are mounted the a arm is going back when it moves, the shock is not on the same plane it is going forward, somewhere in the travel theres a completely dead spot, or bind.

your right,

shocks wont keep your car from bottoming out. more ride height will. what is your frame to the top of your lower a arm clearance?

66jj
Member
posted October 09, 2003 12:59 PM
C21,

I pasted this on spring mounting from afco.

Mounting the leafs so that the front eyes are slightly inboard of the rear eyes will cause the leafs to have more lateral stiffness. This can make the chassis feel tighter and may help prevent the rear suspension from binding due to excessive lateral deflection of the leaf. However, if the leafs are offset too much, the suspension becomes too stiff laterally and rear side bite is lost.

Whenever the body slidesę over the rear end during cornering, the splayed leafs can cause rear steer that will help the car to turn.

Also, if the right front spring eye is mounted more inboard than the left eye (measured from the corresponding tires), the right rear tire will tend to be loaded less than the left rear tire during acceleration. As a result, the chassis will tend to be tighter off the corner. Corner exit handling tends to be loose under opposite conditions Generally, moving the front spring eye 1 1/2" laterally will produce a noticeable effect to corner exit handling.

Its my understanding you want side bite in a dirt car thats why you would want your leafs straight. I assume chevy splayed novas because they are top heavy, and narrower than a camaro.

This right here at the end is saying non straight rs leaf will not have as much bite on that corner. Its the same as a 3 link system if the links are straight your pushing the car equally on both sides, if you angle one a little that one pushes the car less on acceleration.

The front of leafs are very stiff, for braking and axle dampening during acceleration, when you compress them look at the back all the spring effect is in the rear, thats why its longer, and usually thinner.

I ASSUME YOU CANT RUN THE FIBERGLASS LEAFS??

I CANT OR I WOULD IN A HEART BEAT


c21
Member
posted October 09, 2003 01:36 PM
66jj, I've got the same book. But you also have to consider the distance from the lower mount to the BJ.

Take a look at the jpg uploaded with this post. It's a picture of my old SCS car. Shock angles are about as perfect as you can get on a metric, but look at the distance from the BJ. A good 6". And it can't be any closer and still have clearance for the caliper to turn past. Even where it's mounted was very close to the tire and upper a-arm. So when/if the upper a-arm bent, bam, the shock is toast!

I don't have a pic of the shock on my Terminator, but it's lower mount is probably 2" from the BJ. And there's no issue with the brake caliper. And the upper a-arm bends away from it when it's bent. Less than ideal angle? Sure. But when it's 4" closer to the balljoint, it probably controls BETTER. And when you factor in the damage potential, IMO it's a no-brainer. I'll keep mine mounted in front...

As far as bind, no. I cycled the suspension without a spring in it, and located the lower mount accordingly.

Not sure on frame to A distance. I'll try and measure tonight. Haven't done much in the garage since we ran at Knoxville a couple weekends ago.


istock59
Member
posted October 09, 2003 02:41 PM
I take that back. Here's a pic (sorta) of the RF shock on my Terminator.



66jj
Member
posted October 09, 2003 05:54 PM
yours on your terminator look like they are way closer to the upper a arm than the terminator I have looked at repeatedly, Andersons, his lay way way out to the front..

jeff

makaveli
Member
posted October 10, 2003 11:19 PM
quote:
Originally posted by 66jj:
yours on your terminator look like they are way closer to the upper a arm than the terminator I have looked at repeatedly, Andersons, his lay way way out to the front..

jeff



woopes


makaveli
Member
posted October 10, 2003 11:21 PM
well 66 i think theres alot of monkey see monkey do on metrics all i know we have 1000 in the lf and 900 in the rf thinking about going lower


Elmo
Member
posted October 16, 2003 10:59 PM
You guy's have to remember that Metrics and Ca-Nova's are two completely seperate animals. Anything that works on one will most definetly not work on the other, let alone a different driver. I've seen metrics with 1400RF. Take into account the smaller front end and it's ludicrous. Also take into account the different anti-dive built into these two chassis by GM. The discussion on Multi-Leaf rears is great, keep it up.


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