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Old 03-02-2014, 09:10 AM   #31
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U the man Martin. Your work in this hobby of ours is truly appreciated!
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Old 03-02-2014, 09:37 AM   #32
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by the time this thread is a yr old the title should be changed to the rc bible and made a sticky,i for one highly appreciate your time (you must have said to yourself "omg what have i done?",lol)and your knowledge
i find some of the answers are explained better here,the book took me ages to get my head around it,but getting there

so heres my dilema
today,low grip ashphalt,windy,track temp about 4/5c air temp around the same due to the chill,sorex 28jb's (i know there supposed to be for carpet,but they work just as well as the ry)
car was mostly fine just a little loose in the rear off power coming off a banked sweeper into a 180 then it overotates as i get back on the power in the slower turns,works fine though the chicane
heres my set up,this is in 17.5 t blinky on a fast large outdoor track

http://forum.teamxray.com/xform/inde...&setup=t4_2014

heres the track,in the same conditions,started damp and dried

https://www.youtube.com/watch?v=y6UsHroJo9U
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Old 03-02-2014, 11:39 AM   #33
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Originally Posted by Wade.... View Post
U the man Martin. Your work in this hobby of ours is truly appreciated!
Thank you!

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Originally Posted by chasingthepack View Post
by the time this thread is a yr old the title should be changed to the rc bible and made a sticky,i for one highly appreciate your time (you must have said to yourself "omg what have i done?",lol)and your knowledge
i find some of the answers are explained better here,the book took me ages to get my head around it,but getting there
"RC Bible" but easier to find what you need to know at learnsetup.com

"omg what have I done" ....lol

Interesting. Maybe I am getting better through practice at explaining these concepts. Also as my experience and knowledge grows, perhaps the additional clarity in my own mind helps

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so heres my dilema
today,low grip ashphalt,windy,track temp about 4/5c air temp around the same due to the chill,sorex 28jb's (i know there supposed to be for carpet,but they work just as well as the ry)
car was mostly fine just a little loose in the rear off power coming off a banked sweeper into a 180 then it overotates as i get back on the power in the slower turns,works fine though the chicane
heres my set up,this is in 17.5 t blinky on a fast large outdoor track

http://forum.teamxray.com/xform/inde...&setup=t4_2014

heres the track,in the same conditions,started damp and dried

https://www.youtube.com/watch?v=y6UsHroJo9U
Nice track.

Here are some things for you to try the loose off-power and loose on-power issues.

1) go from 1.5 negative camber in the rear to 2.0 negative camber
2) go from 2.5 rear toe in to 3.0 rear toe in
3) go from hole 1 in the inboard front upper link to hole 3 (makes the link longer)
4) go from 2mm shims on the outboard front upper link to 1mm shims
5) go from 1mm shims on the inboard front upper link to 2mm shims

You may find that just (1) and (2) will be enough.
(3)(4) and (5) will make the front roll more taking away some front end grip. Also (3) will reduce the camber gain in the front, further reducing front end grip.

The rear roll center is already fairly high, which is good at increasing rear grip, so this is why I focused on lowering the roll cetner in the front.

Let me know how this works out for you.

Cheers.
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Old 03-02-2014, 11:39 AM   #34
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Default if no sway bars how do you approach setup?

Hey Martin, I have your xxx main setup book and I notice that you do not have a area that covers an approach on setting up without sway bars, how should I approach it until I get some swaybar kits in the mean time.
I have a associated 6.0 which I bought used so it didn't come with sway bars and I know some racers have done setups with older cars that don't have sway bars.
just need a push in the right direction on setup approach, thanks for any help.

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Old 03-02-2014, 01:02 PM   #35
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Does increasing droop from 6 to 5mm front increase traction? Same question for rear going from 5 to 4mm? What about 1mm roll shim under arm mounts. What do those do? Also raising or lowering shock positions; explain your theory please?
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Old 03-02-2014, 04:21 PM   #36
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Let me know how this works out for you.

Cheers.
thanks martin,will do,chances are we will have the same conditions again next week
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Old 03-02-2014, 04:27 PM   #37
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Originally Posted by Ol skool nitro View Post
Hey Martin, I have your xxx main setup book and I notice that you do not have a area that covers an approach on setting up without sway bars, how should I approach it until I get some swaybar kits in the mean time.
I have a associated 6.0 which I bought used so it didn't come with sway bars and I know some racers have done setups with older cars that don't have sway bars.
just need a push in the right direction on setup approach, thanks for any help.

ol skool
Good Question. I would run a slightly higher roll center at both ends. This will help the car be more stable in chicanes.

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Does increasing droop from 6 to 5mm front increase traction? Same question for rear going from 5 to 4mm? What about 1mm roll shim under arm mounts. What do those do? Also raising or lowering shock positions; explain your theory please?
If you increase the front droop this will give you more rear grip as you come off the corner under power, because it will allow more weight transfer to the rear tires. If you increase the rear droop this will give you more off power steering as this allows more weight transfer to the front at corner entry off power.

1mm shims under the arm mounts will raise the roll center giving more lateral grip, but it will also make the transitions less smooth and a little more choppy.

I assume by raising and lowering the shock positions, you mean moving the top of the shock towards the middle of the car (i.e. laying them down). This will make the shock package feel more progressive, meaning that your springs will feel softer at the initial part of the roll and increase their stiffness as your roll deeper. This is similar, but not that same as putting softer springs on the car as the overall spring rate will be softer. It is not the same however because the spring rate increases at a greater rate as the car rolls.

Cheers.
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Old 03-02-2014, 06:38 PM   #38
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Going from 6mm to 5mm droop is increasing right? My question for shock placement was because I was under the impression that laying down a shock would give more grip. But a few weeks ago I was having traction issues at a new track and I was told to stand the shocks up to gain traction. So I was confused. It didn't handle any better either up or down. I was running medium upper links with 4mm shim under front inner arm, 0 shim on outer and 3mm shim inner rear with 2 or 3mm shim on outer. 6mm front droop 5.5 rear with 5mm ride height with the 1mm under arm mounts. 3mm rear toe. Car had no rear traction.
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Old 03-02-2014, 09:06 PM   #39
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Going from 6mm to 5mm droop is increasing right?
yes assuming you are measuring using a droop gauge.

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Originally Posted by Josh-n-ya View Post
My question for shock placement was because I was under the impression that laying down a shock would give more grip. But a few weeks ago I was having traction issues at a new track and I was told to stand the shocks up to gain traction. So I was confused. It didn't handle any better either up or down. I was running medium upper links with 4mm shim under front inner arm, 0 shim on outer and 3mm shim inner rear with 2 or 3mm shim on outer. 6mm front droop 5.5 rear with 5mm ride height with the 1mm under arm mounts. 3mm rear toe. Car had no rear traction.
I will try my best to explain...

Laying down the shocks does not produce more lateral grip. In fact it will reduce lateral grip, because it is allowing the car to roll more. The more the car rolls the greater the difference in lateral load between the inside and outside tires, which translates into less overall lateral grip.

Now having said that laying down the shocks may give the impression of more lateral grip because the car will have more steering during off power turn in and it will push more during on power corner exit. The reason for this is not because it has more lateral grip, but because it allows for more longitudinal weight transfer during the off power and on power.

So during off power corner entry you are able to transfer more weight forward because the layed down shocks effectively makes the front spring rate softer.

Also during on power corner exit you will transfer more weight towards the back of the car, giving the rear more grip relative to the front causing the car to push.

Another way to look at this is that layed down shocks allow you to control the balance (oversteer / understeer) of the car threw throttle control.

I remember being at the worlds TC race in Italy in I believe it was 2006, and saw drivers laying down the rear shocks expecting more rear grip and they were surprised that this actually made the rear grip worse

Also I would reduce the inboard shims you are running on upper links both fron and rear to something like 0mm or 1mm to raise the roll centers at both ends. This will give you more lateral grip.

Here is a paragraph from my LearnSetup.com app that summarizes this in a different way

Quote:
Laying down shocks at one end of the car will transfer more weight to that end of the car giving that end more grip to a point. The reason why you can go too far with this is because you may have that end of the chassis hitting the ground, or you may be increasing the lateral weight transfer too much at that end of the car reducing lateral grip to a point that more than offsets the lateral grip at that end created by transferring weight longitudinally. The weight transfer section explains why more lateral weight transfer decreases lateral grip, but the quick summary is it is due to the tire performance curve.
Cheers.
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Old 03-02-2014, 09:19 PM   #40
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Default Updates to LearnSetup.com today

I mades some updates to the content in the LearnSetup.com app today as described in my blog post.
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Old 03-02-2014, 10:08 PM   #41
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Thank you, that was probably the best explanation I've ever heard.
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Old 03-03-2014, 01:47 AM   #42
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Hi Martin,
Great thread and thanks for your time!
If a car handles well and predictable with no major understeer/oversteer issues, what setup changes will make it quicker around the track?
At a typical club meet, i find that i can dial out the handling issues and make the car easy to drive to suit the conditions that day, but i'm then lost and dont know what to change once the car is behaving to get faster lap times.
What direction should i then start focusing on to achieve this? Stiffening up all round because loose=fast??
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Old 03-03-2014, 04:25 AM   #43
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My question is around droop and following on from the above information.

What would be the difference in handling with a droop droop setting of the front 5.4 Rear 4.6 versus front 5.8 rear 5.0?

I run a bumpy med grip track with a T4 14.

Loving LearnSetup.com.
Cheers
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Old 03-03-2014, 06:09 AM   #44
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Not so much a setup question, but a question about how to use your app more effectively. If I am looking for more rotation at the middle of the corner, I should be looking at push neutral power?
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Old 03-03-2014, 07:03 AM   #45
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Originally Posted by Josh-n-ya View Post
Thank you, that was probably the best explanation I've ever heard.
Awesome !!

Quote:
Originally Posted by poop View Post
Hi Martin,
Great thread and thanks for your time!
If a car handles well and predictable with no major understeer/oversteer issues, what setup changes will make it quicker around the track?
At a typical club meet, i find that i can dial out the handling issues and make the car easy to drive to suit the conditions that day, but i'm then lost and dont know what to change once the car is behaving to get faster lap times.
What direction should i then start focusing on to achieve this? Stiffening up all round because loose=fast??
Interesting question, and perhaps one that I have never been asked before As you can imagine, a fairly difficult question to answer as everyone has a different pov on a good handling car. Here is my shot at trying to answer your question. To get better lap times, most drivers I see will need to be able to add and handle a car that has more steering as is less stable or easy to drive. For example your car may be easy to drive, but perhaps it is too stable in the corners and you are scrubbing too much speed. So freeing up the car is typically a good thing, and that means through the entire corner. often the most important parts of the corner to start to add steering is the middle and exit as this determines your speed down the straight. A good change to increase your steering in the middle and exit is to raise the front roll center slightly, and also reduce the front droop a little bit. This will allow you to get to full throttle sooner through the corner as you enter the straight. You can also go up on the rear diff oil from something like 2k to 3k. This will also free up the car on power.

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Originally Posted by aussierevo View Post
My question is around droop and following on from the above information.

What would be the difference in handling with a droop droop setting of the front 5.4 Rear 4.6 versus front 5.8 rear 5.0?

I run a bumpy med grip track with a T4 14.

Loving LearnSetup.com.
Cheers
Karl
Hey Karl, I will assume you are measuring droop with a droop gage and that going from 5.4 to 5.8 and from 4.6 to 5.0 for example is actually reducing the droop of your car. By reducing droop the car will roll and pitch less. So going into the corner you will transfer less weight forward making the car push more, and existing the corner on power the car will transfer less weight to the rear, causing more oversteer more during on power corner exit. It will also help reduce risk of traction rolling on high grip tracks.

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Not so much a setup question, but a question about how to use your app more effectively. If I am looking for more rotation at the middle of the corner, I should be looking at push neutral power?
yes... you have the right idea. I make the generalization that at mid corner you are neutral throttle and this is the case most of the time, but you may find yourself in an off power situation in a decreasing radius corner or on power situation on an increasing radius corner. If that is the case then you will want to look at the push off power and/or push on power changes as well.

Cheers.
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