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Old 12-17-2013, 11:53 PM   #6151
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IMO running 2 cars in the same class is counter productive and you lose focus when tuning set up. 0.2 is starting to split hairs and could be many places in the car. My first query is are both your motors equal? Ie I have 3x d3.5's and 1 is definitely quicker than the other 2 at the same timing mark on the can. Are the tyres the same age and wear? How worn in is your diff? Cleaned and lubed bearings? (Kit bearings are full of crap grease) Are both cars tweak free and sway bars set the same? There is potentially 0.4 there!

For starters I'd put the electrics from the fast car in the slower car and repeat to make sure that's not the difference.
I agree running two cars is probably not optimal. I though get a lot of pratice :-)

0.2 ads up, running 32-33 laps indoor it will make a difference. On the outdoor track where the lap times are over 20 seconds the difference would be less and also the motor would count more. I am running TP4.5 and HW 3.0 with 10-15 boost and Turbo. I could not say that I am lacking power. I have tried to make it as "labratory" as possible, using the same set of tire, body and swithing back and forth.

I have not focused on the swaybars, they are more or less only set to the recomended height and that it is moving freely and symetric measureing with droop blocks. I will look into that.

Both cars is not total tweekfree i need to adjust some on the springs to get the hudy wheels to lift equal so you are right there is room for difference here. I will look into that more.

I do brakeclean the beerings and oil them. I am running cheep aftermarket bearings in the oldcar that are not rubberseald. I did not think of that would have impact. But you are right, my cheep aftermarket bearings runns lighter.
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Old 12-18-2013, 12:01 AM   #6152
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Shock build and condition of orings/bladders could make a difference, too.

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Old 12-18-2013, 10:26 AM   #6153
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Hi Bjorne,

I would check a couple things......first take the pinion off the car and just give the front wheels a spin to see if you have some kind of drag issue in the drive train.......remember we had some steering hubs that seated the bearing in a little deep and would cause the hex to drag on the hub.

Also check the DCJ spinning the back tires and turning the car left to right, just to make sure you don't have a DCJ touching one of the C-hubs, again making sure there is clearance.

Lastly, depending on how narrow your running the car, take the shocks off and on a car stand slowly rotate one of the wheels while moving the arm of the car up and down to make sure you don't have bind with the axle in the plunge........you will be able to feel it tighten up as the arm goes up and down. This is either too narrow with the suspension blocks or a slight trim on the pin cushion can sometimes fix this. Also if your running shrink wrap on the front spool, if too tight, it can snag the cross pin and cause drag problems as well.

Just some food for thought..........
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Old 12-18-2013, 11:49 AM   #6154
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Tomorrow next testday with Marc

Have build a car now with higher rollcenter, hpi springs again instead of yokomo springs, putty diff in front, longer wheelbase and so on. Wanna get some more impressions about the car and what it does because i have sometimes the feeling that the 0.5mm rc have to much chassis roll, maybe especially for stock classes?

Gary, maybe you've tested with the rc a lot around, too? :P
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Old 12-18-2013, 12:19 PM   #6155
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Tomorrow next testday with Marc

Have build a car now with higher rollcenter, hpi springs again instead of yokomo springs, putty diff in front, longer wheelbase and so on. Wanna get some more impressions about the car and what it does because i have sometimes the feeling that the 0.5mm rc have to much chassis roll, maybe especially for stock classes?

Gary, maybe you've tested with the rc a lot around, too? :P

This sounds great, keep us posted on what you find.

RC, yes lots of testing, but I think there are a couple things that make it a little difficult for us to really compare notes.....that is, from what I've seen you guys run on larger tracks than we usually see here, and more competitors so your traction level is probably higher as well. From that I would venture to guess we try to get a little more roll to get more traction as well as our terminal speed isn't as high, so we don't see the roll as much as you probably do. In theory it shoulc all work the same, but theory isn't driving the car, so sometimes adjustments are made to make the car "feel" better to the driver, but in theory it shouldn't work.

I do think that there is something going on with the lower RC of the car and thats why its difficult to get a good feel difference between the 2.00mm chassis and the 2.25mm chassis, this is where it would be interesting to have something like a 0.3mm shim, and also have some shaved lower suspension blocks with possibly 0.2mm off of them, OR a 2.20mm chassis but of the stiffer weave. Either way, I have to agree with you that I think there is something there that needs further testing.

Uppers are whole other story, but in short, I think the rear is just about perfect but the front, inners could be raised a bit, just to eliminate all the spacers we tend to run. Of course these are more for the fine tuning, where the lowers really produce the big changes.
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Old 12-18-2013, 12:54 PM   #6156
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Shorter links will give a higher RC, that combined with maybe a bit softer dampening will perhaps provide a different feel.

I have always felt that the car is a bit tail happy but since changing the rear wheelbase to 4 mm in front of rear arms I have a much more settled rear end. Now I can run 0.5-3.0 blocks (2.5 toe in) which gives me more steering.
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Old 12-18-2013, 01:51 PM   #6157
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So you guys all talked about hard plastics nowdays. From what I understand, they will make the car stiffer so it will be better on high traction track to prevent too much roll. A lot of you seem to have changed all the plastics to the hard plastics. Do you also use those in lower traction tracks? and do you see any obvious difference in high traction track between stock plastics and hard ones? How do you justify the cumbersome work to change those back to medium plastics when you take your car to not-too-high traction track? Would you not change the plastics to hard if you go to low to medium track often?

And 2mm hard chassis that came in market lately, is that any good in low to mid traction tracks? I've already thought Eryx works much better in high traction track relatively speaking and I was thinking of getting thinner chassis, not the hard 2mm one. What are your thoughts? And again, do you see improvement with that hard 2mm chassis on high traction track compared with stock chassis?

You guys seem to understand fully about arm sweep in relation to the suspension brackets. Where did you learn all that? Where do I find in depth info about that? I know Johnny and some others explain fairly thoroughly but finding threads here takes lots of time and it's just not time efficient. So I want a hard copy of that.

Thanks
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Old 12-20-2013, 11:57 AM   #6158
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So you guys all talked about hard plastics nowdays. From what I understand, they will make the car stiffer so it will be better on high traction track to prevent too much roll. A lot of you seem to have changed all the plastics to the hard plastics. Do you also use those in lower traction tracks? and do you see any obvious difference in high traction track between stock plastics and hard ones? How do you justify the cumbersome work to change those back to medium plastics when you take your car to not-too-high traction track? Would you not change the plastics to hard if you go to low to medium track often?

And 2mm hard chassis that came in market lately, is that any good in low to mid traction tracks? I've already thought Eryx works much better in high traction track relatively speaking and I was thinking of getting thinner chassis, not the hard 2mm one. What are your thoughts? And again, do you see improvement with that hard 2mm chassis on high traction track compared with stock chassis?

You guys seem to understand fully about arm sweep in relation to the suspension brackets. Where did you learn all that? Where do I find in depth info about that? I know Johnny and some others explain fairly thoroughly but finding threads here takes lots of time and it's just not time efficient. So I want a hard copy of that.

Thanks
Wow, tough questions. I think I've read this at least a dozen times trying to think of a way to answer, and actually make sense, so here goes.

Plastics. I feel that the difference between the hard and med plastics aren't enough to warrant chasing them. I do find that the hard plastic makes the car feel more direct with input and feed back. I can't remember the last time I ran the medium plastics, and really the only medium plastic part I go back to are the c-hubs, and this is only when running on a track that tends to be hard on parts, specifically the c-hubs. The rest of the parts seem to be able to take a lot of abuse before breaking. I prefer to try and tune around the stiffness of the car then trying to determine the flex and if it flex happens the same everytime. The plastic being too variable opposed to something like a carbon fiber top deck that returns to the same postion over and over.

***Just of note since we are speaking of plastics, if you do happen to run the med or the old soft arms, when your not using the car of a period of time, I would take any load off the arms, like get the car off its wheels and back the shocks off. I only suggest this as I have seen arm start to sag after a long time of load on them.

The 2.00mm chassis. the weave on the chassis is different, even over the old 1.75 and the 2.00mm chassis that came out pre-Eryx, so don't get confused over that. Now the new 2.00mm chassis is definately stiffer than all the previous chassis except for possibly the 2.50mm one, but again that was pre-Eryx. The 2.00mm has been the chassis of choice for the Team since it came out, it doesn't seem to have snap roll issues, but this could also be additional car setup. Truthfully, both the Eryx chassis have performed very well and it would be a toss up on which one to use. There are a few advantages in running the 2.00mm chassis though, but if it dictates on track performance, I'm not sure. Since the chassis is 0.25mm thinner it lowers our cofg that much more, and also enables us to get a different geometry for rc, its just taking advantage of this that determines if it pays off. If you where to calculate it out not based on mass, but just for rough speaking, that turns out to be about .75% lower cofg overall on the car in comparison to the stock 2.25mm chassis.

So in answer to your question, I think the performance gain is more in the suspension geometry change than the chassis stiffness itself. JMO

Arm sweep. Most of what I learned was from asking lots of questions just like you. Also looking at the car and trying to visualize all the things that are being effected when doing a arm sweep change, and it does effect several aspects of the front of the car. But the easiest thing to remember about arm sweep is that if you use it, in the simplest terms it gives the feel of the suspension stiffening which will give you more initial turn in. When you do use it, even just changing the suspension bridges, pretty much all the other front suspension geometry has to be checked as they are all affected in some manner. Now for instance, by going from a zero sweep to lets say a 1mm arm sweep, amoungst everything that changes, one of them is the location of the bottom shock mount. Would the same characteristic of the car be able to be simulated by just changing the upper shock mounting hole? I don't think so and I don't think there is a cross corelation to even come up with a theory that would be a solid rule of thumb. Something like if you where looking for a spring just slightly harder than what you have, running 0 arm sweep, could you get the same thing by going to 1mm of arm sweep? Its sort of the same thing, but then again, not really, as there are so many other things changing too. I would only use arm sweep for getting the intial turn in of the car that I'm looking for, after that its back to tuning each of the other individual items on the car to get the final balance and best drive. Keep in mind that anything over 1mm is probably on the excessive side and if you're there you should look at other aspects of suspension tuning to get your turn in feel, ackerman being a good option.

Hope that answers some of your questions, if not, just ask.
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Old 12-20-2013, 12:43 PM   #6159
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Wow, tough questions. I think I've read this at least a dozen times trying to think of a way to answer, and actually make sense, so here goes.

Thanks always Johnny for your thoughts

Plastics. I feel that the difference between the hard and med plastics aren't enough to warrant chasing them. I do find that the hard plastic makes the car feel more direct with input and feed back. I can't remember the last time I ran the medium plastics, and really the only medium plastic part I go back to are the c-hubs, and this is only when running on a track that tends to be hard on parts, specifically the c-hubs. The rest of the parts seem to be able to take a lot of abuse before breaking. I prefer to try and tune around the stiffness of the car then trying to determine the flex and if it flex happens the same everytime. The plastic being too variable opposed to something like a carbon fiber top deck that returns to the same postion over and over.

So the bottom line. Don't use medium anymore, right? I understand hard ones give more direct feel. Not sure if I'm good enough to feel it but I will try it. Eventually.. Not sure when I'm going to break all the plastics that I already have LOL. I'll just change them all in all. Is current Eryx kit coming with hard plastics then? I got mine in April this year and it came with mediums.

***Just of note since we are speaking of plastics, if you do happen to run the med or the old soft arms, when your not using the car of a period of time, I would take any load off the arms, like get the car off its wheels and back the shocks off. I only suggest this as I have seen arm start to sag after a long time of load on them.

The 2.00mm chassis. the weave on the chassis is different, even over the old 1.75 and the 2.00mm chassis that came out pre-Eryx, so don't get confused over that. Now the new 2.00mm chassis is definately stiffer than all the previous chassis except for possibly the 2.50mm one, but again that was pre-Eryx. The 2.00mm has been the chassis of choice for the Team since it came out, it doesn't seem to have snap roll issues, but this could also be additional car setup. Truthfully, both the Eryx chassis have performed very well and it would be a toss up on which one to use. There are a few advantages in running the 2.00mm chassis though, but if it dictates on track performance, I'm not sure. Since the chassis is 0.25mm thinner it lowers our cofg that much more, and also enables us to get a different geometry for rc, its just taking advantage of this that determines if it pays off. If you where to calculate it out not based on mass, but just for rough speaking, that turns out to be about .75% lower cofg overall on the car in comparison to the stock 2.25mm chassis.

So in answer to your question, I think the performance gain is more in the suspension geometry change than the chassis stiffness itself. JMO

Arm sweep. Most of what I learned was from asking lots of questions just like you. Also looking at the car and trying to visualize all the things that are being effected when doing a arm sweep change, and it does effect several aspects of the front of the car. But the easiest thing to remember about arm sweep is that if you use it, in the simplest terms it gives the feel of the suspension stiffening which will give you more initial turn in. When you do use it, even just changing the suspension bridges, pretty much all the other front suspension geometry has to be checked as they are all affected in some manner. Now for instance, by going from a zero sweep to lets say a 1mm arm sweep, amoungst everything that changes, one of them is the location of the bottom shock mount. Would the same characteristic of the car be able to be simulated by just changing the upper shock mounting hole? I don't think so and I don't think there is a cross corelation to even come up with a theory that would be a solid rule of thumb. Something like if you where looking for a spring just slightly harder than what you have, running 0 arm sweep, could you get the same thing by going to 1mm of arm sweep? Its sort of the same thing, but then again, not really, as there are so many other things changing too. I would only use arm sweep for getting the intial turn in of the car that I'm looking for, after that its back to tuning each of the other individual items on the car to get the final balance and best drive. Keep in mind that anything over 1mm is probably on the excessive side and if you're there you should look at other aspects of suspension tuning to get your turn in feel, ackerman being a good option.

So stock suspension bridges in the front are 2.0/1.0 if I remember correctly(I'm at work). But I also remember when you explained this before, you were using lower numbers than that. Not entirely sure about the numbers in stock but I'm pretty sure you guys are using lower numbers than that. If the difference is just 1 no matter what, then why would you use the lower numbers? Just to shorten the front track width?

Hope that answers some of your questions, if not, just ask.
And I simply can not get rid of torque steer in my car ever since I built it. At that time there was quite bad bindings between the ball links and the pivot balls. The plastics were just way too tight. People advised to file down inner lumen of the plastic ball links but Instead of that, I just filed the pivot balls. All bearings are fine. No binding. Maybe a bit of slack in the suspension holes in the rear arm. I think I filed them a bit too large. I know I was not supposed to but it's just a bit.
When I check the tweak, there's always tweak and I can't seem to get rid of it. I balanced the weight Lt and Rt and still it gives the tweak. It must be the reason of the torque steer. Maybe I should rebuild my car.
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Old 12-20-2013, 12:47 PM   #6160
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You can't fix tweak by adjusting weight balance. Tweak is typically caused by an actual twist in the chassis, or mis-adjusted spring collars or droop screws. Tweak stations seem to have fallen out of fashion, but I still find it to be an indispensable tool.
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Old 12-20-2013, 01:07 PM   #6161
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You can't fix tweak by adjusting weight balance. Tweak is typically caused by an actual twist in the chassis, or mis-adjusted spring collars or droop screws. Tweak stations seem to have fallen out of fashion, but I still find it to be an indispensable tool.
Yeah I agree with you and I have the station. And I have re set the spring collars countless times to get rid of it and have set the downstops multiple times already. So I know those are set properly. When I tried to get rid of the tweak, I had to lower one of the collars extremely lower than the others to remove the tweak. Yeah I think you're right Steve about the chassis itself tweaked. What I don't know is why. Cuz it was a brand new car and it was already tweaked when I freshly built it. And as I mentioned the only reason I could think was the binding in the pivot balls. I figured it could go away as I drove more. But it didn't and I ended up filing down the balls. Maybe the chassis got tweaked between the building and filing of the balls?
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Old 12-20-2013, 01:24 PM   #6162
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Yeah I agree with you and I have the station. And I have re set the spring collars countless times to get rid of it and have set the downstops multiple times already. So I know those are set properly. When I tried to get rid of the tweak, I had to lower one of the collars extremely lower than the others to remove the tweak. Yeah I think you're right Steve about the chassis itself tweaked. What I don't know is why. Cuz it was a brand new car and it was already tweaked when I freshly built it. And as I mentioned the only reason I could think was the binding in the pivot balls. I figured it could go away as I drove more. But it didn't and I ended up filing down the balls. Maybe the chassis got tweaked between the building and filing of the balls?
I have chased the tweek a lot.... I followed the instructions that are described in detail earlier in this tread.

You need to loose all screws, also on the chassie that holds the bulkheads. Just a little and then start to tighten up the screws a little at the time and check the flatnes of the chassie on the blocks many times until it is totally tight.

I have had problem with a Eryx chasie that the holes were not totally aligned. It is a pain in the ass, but if you have another new chassie you can screw them togheter to check the pattern are aligned.
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Old 12-20-2013, 01:30 PM   #6163
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I also use the tweak station to un-tweak the chassis itself. Take the wheels off, clean off any crud on the bottom of the chassis, and put the chassis directly on the station. If you only lightly tighten the top deck screws, you can then straighten the chassis out by twisting it, and then re-tighten the top deck screws.

This is assuming that everything is put together right in the first place and nothing is bent. Fine tuning only.

Also, in order to get an accurate reading on the tweak station, the chassis must first be L/R weight balanced.
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Old 12-20-2013, 02:18 PM   #6164
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The first batch Eryx that came with the kits didn't have any markings, they are suppose to be Medium, but they are definately harder than the first gen medium arms, I'd say they are very close to current hard arms, with the extra webbing they have very little deflection.


Arm sweep or other with lower numbers is used to run a narrower front width, used more for lower traction tracks. Also remember that changing the track width of the car will also change the roll center. If you want a really neutral car 2.0/2.0 is a favorite for a lot of carpet racers.


On your tweak issue, does this show on the tweak bar? I'm not a big tweak bar user myself, I prefer the reactive check method myself, but, if you could remove your wheels and put the car on a set of droop blocks......I usually put the blocks just ahead and behind the inner suspension bridges but off the screws, does the car rock if you lightly push down on the rear shock tower to stabalize it, and the push on one corner of the front shock tower or the other? Just trying to establish if its truley a chassis tweak or a suspension tweak. If the cars flat on the blocks, I'd say its suspension tweak, so disconnect the torsion bars and check the car. It just sounds really strange that you have to preload one corner that much to get flat. Lets start there and if you can do the screw method as Bjorne suggested too, but start with the above first before doing that.

Maybe if you could take some pics of your car that might help too.

Let us know.
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Old 12-20-2013, 02:18 PM   #6165
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ha ha the serpent 411 thread is on it 411 page
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