First French National Win for AC S2

[Junior Z]

Hi,

Alexandre Chahin won The French Cup in Stock Category with his Atomic Carbon S2

Best Race Lap Stock Catégory :thumbsup:
TQ qualification Stock Catégory :thumbsup:
Victory Stock Catégory :thumbsup:
6th Position A final Open Catégory :thumbsup:

The track was very quick and sandy:

http://lmrc.free.fr/pages/coursesencours/101_1917.JPG
http://nsm02.casimages.com/img/2009/08/29//090829015253809024342541.jpg
http://nsm02.casimages.com/img/2009/08/29//090829120427809024342108.jpg
http://nsm02.casimages.com/img/2009/08/29//090829115049809024342048.jpg
http://lmrc.free.fr/photos/2009/cftt/DSC_0302.jpg
http://nsm02.casimages.com/img/2009/08/29//090829020227809024342609.jpg
http://lmrc.free.fr/photos/2009/cftt/DSC_0182.jpg

[LhOrLoGeR]

Thanks Junior Z for this post!!!

An other AC S2 have the 4th position in A final modified category with Julien Parnot :thumbsup:

Two AC S2 are in the french cup top 10 :thumbsup:

http://free0.hiboox.com/images/3609/054bc095bc434346c1b9b22fa286f857.jpg (http://www.hiboox.fr/go/images/auto-moto/img-1075b,e584af368ead412c85ff259476a8bd32.jpg.html)

[c0sie]

Videos :)
http://www.gaz-on.net/4eme-manche-du-Championnat-de,397?decoupe_recherche=s2&artpage=5-6

[LOLO]

good jobs guys:thumbsup:

[DaHomie]

Congratulations guys! Can you share or send me your setups? I am also racing the S2 (SWB version) and I am struggling a bit to find that really great setup on dirt tracks.

Again, great results for the S2!

Best regards,
Roy

[V-Rossi]

Set-up that works really well for our (Belgian/Dutch) dirt/clay tracks:

Front:
Silver spring, 30wt, 0-1mm limiters, red piston
30° caster, -1.5° camber, -0.5° toe-in
Losi 7202R or 7202P for very hard, low grip clay/sand (narrow wheel)
Shock position: 2-O
Link position: 2-B
Arms level, no lead!

Rear:
Pink spring, 30wt, 0mm limiters, red or orange piston
4° toe-in, 0-1° anti-squat, short wheelbase, -1.5° camber
Losi Big Shot Red
Shock position: 2-I
Link position: 2-B
CVD's level, 200gr of lead

Spoiler: high and to the back. I was using the X-6 wing mounts, which give your wing a slightly bigger angle.

Motor/Gearing: 9,5T on 27/78, ESC 1-1-1-0

Car is just awesome with this set-up, extremely easy to drive and fast.

[DaHomie]

A big thanks for that one! Really helpful, I will try this setup this coming Saturday.
To specify my problem at bit more I would say that overall I lack some steering and coming out of turns I lack rear end grip.
I guess you have tested a lot of different tyres up front (I know I have). What would happen using proline M3 ribbed instead, 8175 I think is the article number, the narrower one. A lot less steering than with the Losi 7202R/P?

[V-Rossi]

No, a bit more steering to be precise, the Proline M3 wears a bit more, but has a lot of grip. It is important to buy the slim one though.
Note that these type of tracks change throughout the day, I practically never change my set-up radically during the day, but with this set-up I started with blue springs up front, a few hours later green and drove the finals with the silver spring.
Don't try to use things like 25° caster or lead up front to increase steering on dirt/sand/clay.
One thing to increase steering is braking combined with good throttle control, always best :thumbsup:

You lack rear end grip, is this because you hit the throttle too hard and too soon, or is this compared to other cars? If the track is quite fast, the bigger and higher spoiler will help (in fact I was using the X-6 wing ànd X-6 wing mounts on 1 very low grip track).
Try to smoothen up the power with this:
- Smaller rotor
- ESC settings
- Bigger pinion/smaller spur gear

A part of the rear end grip could be improved by using a yellow spring at the back or using some lead behind the rear shock tower: http://picasaweb.google.be/bnkoffroad/BNK2009Round2KampenhoutMBV#5374026755813847362 , just cut out a small plate of lead going from the rear toe-in brace up to the roll center screws, make some holes in it and attach it to the tower using the small holes just underneath the roll center screws.

[DaHomie]

again very helpful V-rossi. I already run 1 oz (29g) of lead behind the rear tower. I also run the X-6 wing though with a very low cut.
Have not tried the yellow spring though so will keep that in mind.
I do however run a 19g brass front bulkhead (GHEA one, not the heavier Trishbits one).
When you run the 200g lead under the lipos, what lipos do you run (weight) and what is the cars total weight set up like this? Mine comes in at 1650'ish race ready.

When it comes to throttle control and also gearing/rotor/esc I definitely see your point. I do however like to think I have at least an ok throttle finger :) I would say I am not known for being the most aggressive driver out there :)

Regarding the front tires I always have felt like the car understeers quite a lot with the proline's, and so yes I have tried both the 25 and even the 20 degree blocks without really feeling any improvement...

Do you run all the rear toe-in using a 4 degree toe-in brace or do you add the rear toe-in using 1 degree hubs?

Again thanks for your very helpful replies V-Rossi.

[V-Rossi]

No problem :)
Personally I just use the 4° toe-in brace without any special hubs (using the B44 hubs which don't wear out as fast though).

Caster is something weird I think, 30° is so much more easy to drive and gives you a car easier to predict in the corners, especially when traction levels can vary a lot in one corner. I once partially f***ed up a National using 25° and 2,5° toe-in on a high grip track, which makes the car lose its balance entirely. I'm using 30° all the time now, just great for this car.

The Ghea front bulkhead is something I use too, the main reason being the crappy AE quality, STD bulkhead just wear out too fast. The weight this bulkhead adds isn't a problem though, just leave it to that.

The weight of my car is indeed around 1650gr, but varies a lot. I'm using the Vampire 4400mAh packs, which are around 250gr. For very low grip tracks I add 2 plates of 50gr under each Li-Po half, so 200gr total. This makes the car weigh around 25-50gr heavier than a conventional Ni-MH set-up.
Very good advice is to test this on every track you race on. Here we have 2 astroturf tracks: the famous Kampenhout, which is high traction with dust on it in the afternoon, and Arendonk, very high grip. With both being the same surface, you'd think weight set-up would be the same, but it isn't. I'm using 150gr or more of lead in Kampenhout, in Arendonk barely 100. While barely feeling this in other cars, this made an enormous difference for me on the S2. The plates I put under the battery packs are 50gr each, but I made a weight of about 50gr (consists of 2 plates of lead taped together) which fits nicely in between the battery halfs. This way you have the option to run something in between 100-200gr. Just make some weights of 25 and 50gr.

Concerning inserts: if you want a bit more side bit grip, try new Losi inserts which are included in Ifmar Studs, Big Shots etc. For increased forward traction you could use a used Losi insert, which is considerably softer.

Any questions, just ask:)


Btw: I have a planted astroturf set-up for very high grip, any need to post it?
Btw²: big kudos to Elvo!

[DaHomie]

Yes please post the very high grip setup as well, would again be very helpful. I am looking to race the S2 indoor this winter (carpet) also, so a high grip starting point would be very useful.
It looks like the tires we will use indoor will be Schumacher Mini Pin rears, though without the pins since we are gracefully allowed since 2 years back to be part of what was earlier a touring car only cup.

[V-Rossi]

This is the Elvo set-up for the Arendonk track, which is very flat and high grip, but I adapted it to the long wheelbase brace which Elvo wasn't running back then.

Front:
Blue spring, 30wt, 3mm limiters
Shock: 2-O, Camber link: 2-B, 1 washer
Camber: -1.5°, -0.5° toe-in, caster 30°
Schumacher Stagger Rib Yellow
Wing on shock tower
Arms below level

Rear:
Red spring, 27,5wt, red piston, 5mm limiters
Shock: 2-I, Camber link: 2-B (second hole from the bottom on tower)
Camber: -2°, 3° toe-in, 1° anti-squat
Schumacher Mini Pin Yellow, outer row cut off
CVD's below level

Other:
Long wheelbase brace on long wheelbase setting
Rear hubs on medium setting
Wing on low and forward position
30gr near nose
100gr of lead under battery pack

ESC: 1-3-1-1
Motor: CS 7,5T on 24/78

During the day (when traction levels are slightly decreasing), I do the following things:
- Front green spring
- Rear shock position: 1-extra inner hole
- 0° anti-squat

What you could change for racing indoors:
- Anti-roll bar
- 23/81 gearing

Car was amazing, easy TQ and victory on club race.

[DaHomie]

This is good stuff, again very thankful for your assistance.
And now I do understand and as well echo the "kudos to Elvo" ;-)