Tune With Camber Links
#436
This Triumph is going to drive me insane. The springs are tuned. The damping is good, probably not great yet. Still working on that. But the handling is awful. When you get off the gas coming into a turn the car hooks pretty hard to the point where its tough to control. If you get back on the gas AT ALL during the turn, the car pushes like a battle ship. I've tried lowering the rear roll center figuring just getting the push consistent from corner entry to corner exit was a good place to start but I'm not making enough head way. I looked at the rear end of the car and noticed that there was some anti-squat built in to the stock configuration for this car. Looks like quite a bit too. Is it possible that the problems I am having are because there is a ton of anti-squat? If not, how should I proceed?
#437
Its a ball diff. You thinking its a bit too tight? I'll check that out tomorrow. I did just rebuild the diff but it was like this before the rebuild as well.
On the anti-squat front, I chopped up an old fiberglass shock tower to make a shim for the rear arm mounts. Looks like it has about 0 degrees now. That would have made the original kit configuration about a poop-ton of anti-squat. It was too dark to try it out after I was done so we'll have to check that tomorrow too.
On the anti-squat front, I chopped up an old fiberglass shock tower to make a shim for the rear arm mounts. Looks like it has about 0 degrees now. That would have made the original kit configuration about a poop-ton of anti-squat. It was too dark to try it out after I was done so we'll have to check that tomorrow too.
#438
TRIUMPH----- are you running an esc with alot of drag break in it? And are you spring collars equally turned down, both rears should be close and both fronts should be close. I like to use a tweak bar to be sure the car is dispusing the load equally. Does the buggy launch straight and jump flat side to side
#439
Joined: Mar 2011
Posts: 2,766
From: Houston
I was out of town in San Antonio over the weekend so I haven't been around to respond.
In regards to the Triumph, when you say you get off the gas and it hooks really hard, are you referring to the back end wanting to come around?
The on power understeer I get. You need lots more roll stiffness in the rear and/or lots less in the front. Remember a higher roll center is more, a lower roll center is less. A sway bar also adds roll stiffness. What you'll find is that when you get this dialed in well you'll probably have the back end come around hard when on the brakes. Reduce the front end rake. There is too much weight transferring forward. If you can't completely get rid of the effect then you need to dial out some of the brake on the transmitter. If you are only making small adjustments in the camber links, you are only going to get small differences in the handling. Start with the roll center in front about as low as you can get it and run a pretty high roll center in the rear with much shorter camber links. When weight is very unevenly distributed such as a rear motor car, the roll stiffness needed will also seem very uneven. We need far more roll stiffness if there is far more weight. The front is much lighter than the rear so it needs far less roll stiffness.
A diff that is too loose is going to turn into the corner well but then lose it midway through or on the way out. A diff that is too tight will not turn into the corner well but will help you pull through the exit of the corner on power.
A sway bar should not move right to left is possible. It should rotate freely. If there were no links connected to the ends of it, it should fall down in it's own and not bind.
In regards to the Triumph, when you say you get off the gas and it hooks really hard, are you referring to the back end wanting to come around?
The on power understeer I get. You need lots more roll stiffness in the rear and/or lots less in the front. Remember a higher roll center is more, a lower roll center is less. A sway bar also adds roll stiffness. What you'll find is that when you get this dialed in well you'll probably have the back end come around hard when on the brakes. Reduce the front end rake. There is too much weight transferring forward. If you can't completely get rid of the effect then you need to dial out some of the brake on the transmitter. If you are only making small adjustments in the camber links, you are only going to get small differences in the handling. Start with the roll center in front about as low as you can get it and run a pretty high roll center in the rear with much shorter camber links. When weight is very unevenly distributed such as a rear motor car, the roll stiffness needed will also seem very uneven. We need far more roll stiffness if there is far more weight. The front is much lighter than the rear so it needs far less roll stiffness.
A diff that is too loose is going to turn into the corner well but then lose it midway through or on the way out. A diff that is too tight will not turn into the corner well but will help you pull through the exit of the corner on power.
A sway bar should not move right to left is possible. It should rotate freely. If there were no links connected to the ends of it, it should fall down in it's own and not bind.
#440
Next time you come to SA, bring your toy and run with us. We start at 7 on saturdays and are usually done by midnight. It's a great group and 1/8 buggy is on fire with sportsman, expert, and and electric class. We also run SC 2wd and 4wd as well as Truggy. We had 6 heats last weekend.
#442
Its a ball diff. You thinking its a bit too tight? I'll check that out tomorrow. I did just rebuild the diff but it was like this before the rebuild as well.
On the anti-squat front, I chopped up an old fiberglass shock tower to make a shim for the rear arm mounts. Looks like it has about 0 degrees now. That would have made the original kit configuration about a poop-ton of anti-squat. It was too dark to try it out after I was done so we'll have to check that tomorrow too.
On the anti-squat front, I chopped up an old fiberglass shock tower to make a shim for the rear arm mounts. Looks like it has about 0 degrees now. That would have made the original kit configuration about a poop-ton of anti-squat. It was too dark to try it out after I was done so we'll have to check that tomorrow too.
I always adjust caster and anti squat according to how smooth/bumpy the track is. never stray to far from stock set-up tho, as far as caster goes anyway.
#443
Tech Apprentice
Joined: Jun 2011
Posts: 65
From: Des Moines, IA
At the advice of my friend Marcus, I added weight to the car. I bought some digital scales to weigh all 4 corners at once and found the right side of the car to be heavier. It needed a quarter ounce more weight on the left side across from the receiver. I also strategically added weight in other areas as well. Yes the car is heavier than it was. It is also more balanced.
To my brain it seems like he is wrong. I weigh 275lbs whether I'm standing on bricks or on top of two beach balls, right?
So, is he correct? Should we balance the chassis with solid mounts instead of the springs/shocks?
#444
I thought I would pose this to the group. There is another thread here where the person is making a case to replace the shocks with something solid, then using the scales to see if the car is balanced front/back and right/left. The springs on the shocks interfere with accurate weighing on the scales.
To my brain it seems like he is wrong. I weigh 275lbs whether I'm standing on bricks or on top of two beach balls, right?
So, is he correct? Should we balance the chassis with solid mounts instead of the springs/shocks?
To my brain it seems like he is wrong. I weigh 275lbs whether I'm standing on bricks or on top of two beach balls, right?
So, is he correct? Should we balance the chassis with solid mounts instead of the springs/shocks?
#445
Joined: Mar 2011
Posts: 2,766
From: Houston
You know I've never thought about it that way. The shocks themselves do have weight so making a solid link that weighs the same as the shocks and springs but at a length that you intend to set your ride height at should work. This will definitely take the spring variable out of weight balance. Once you get it evened, then you go back and install your shocks. Set your spring rates until both sides agree with your previous balancing. Then you know you've got the springs evenly adjusted.
I personally like the idea.
I personally like the idea.
#446
Tech Apprentice
Joined: Jun 2011
Posts: 65
From: Des Moines, IA
You know I've never thought about it that way. The shocks themselves do have weight so making a solid link that weighs the same as the shocks and springs but at a length that you intend to set your ride height at should work. This will definitely take the spring variable out of weight balance. Once you get it evened, then you go back and install your shocks. Set your spring rates until both sides agree with your previous balancing. Then you know you've got the springs evenly adjusted.
I personally like the idea.
I personally like the idea.
#447
Joined: Mar 2011
Posts: 2,766
From: Houston
Yes you do weight the same but if you are standing on 2 beach balls, do you know for a fact that your weight is evenly distributed between them? If one is inflated slightly more than the other but you don't realize it, are you applying more force to one vs the other affecting your weight distribution?
#448
Tech Apprentice
Joined: Jun 2011
Posts: 65
From: Des Moines, IA
Yes you do weight the same but if you are standing on 2 beach balls, do you know for a fact that your weight is evenly distributed between them? If one is inflated slightly more than the other but you don't realize it, are you applying more force to one vs the other affecting your weight distribution?
After reading that plus your question it started to make sense, so I think I have just changed my opinion on this after applying some brain power. It just might be a good day after all.
#449
Joined: Mar 2011
Posts: 2,766
From: Houston
I see in that thread they are arguing about how real race cars corner weight with the shocks on. Normally I'm all for doing what they do in the real world but having a scale model that we are able to hold in our hands changes the rules a little bit. We can do many things much faster and in a much easier way. This is why we can do the spring rate tests by dropping the car or pushing down on the car while on real cars you can only tell by driving them. Perhaps it just never dawned on them to take their shocks off before corner weighting? It does require more effort though.
#450
Tech Fanatic
iTrader: (22)
Joined: Oct 2003
Posts: 814
From: downunder
You will find the links in place of shocks with springs gives a more acurate view of balance in the car regarding positioning of electronics and weight etc.
If you have shocks with springs and you are not in the centre the readings will change from side to side dependent upon the side you pushed the suspension from. As the springs do not return to the same spot both sides unless there is equal and centred force applied.
Put you car on scales and touch each corner lightly, see how much the weight transfers from one side to another.
If you touch the other side it will go the other way. Now push in the centre and see if you can replicate the weights on the scales.
It will be out somewhat but you may not need to be 100% acurate or will not achive this with shocks and springs attached.
If you have shocks with springs and you are not in the centre the readings will change from side to side dependent upon the side you pushed the suspension from. As the springs do not return to the same spot both sides unless there is equal and centred force applied.
Put you car on scales and touch each corner lightly, see how much the weight transfers from one side to another.
If you touch the other side it will go the other way. Now push in the centre and see if you can replicate the weights on the scales.
It will be out somewhat but you may not need to be 100% acurate or will not achive this with shocks and springs attached.



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