More front end grip

[Gayo]

Funnily enough this is the exact opposite of Toadeh thread , anyways:

Yesterday, I had my first race with the CR2. It was a non-permanent track on a sports hall, with most of the turns on the very slippery floor, the others being on carpet.

Well, I had the hardest time trying to make the car steer on the slippery stuff. On entry, with steering at full lock, the car had to be almost stopped before rotating slowly to the exit. A shame as the CR2 was brilliant everywhere else, powering down nicely even on the dreaded slippery floor.

My car was setup exactly as per the base setup (Oswestry) that can be found here:
http://atomic-carbon.gforceimages.ne...2_Oz_May09.jpg
I am running the idler mod, standard slipper, Orion 7.5 and IP 4200 35C saddles. I also use a pinion diff; it was rather free with 1000 cps.

I tried all kinds of tyres: Minispikes, Minipins worn or not on the rear, Staggered, Minispikes and Minipins on the front. I ended with almost new Minipins front and rear.
I went to the 30WT-green springs combo on front, I even fitted silvers, but it didn't made much difference. I tried the inner shock hole on rear bones to make the rear softer and have more droop, but the car felt less sure-footed with no steering gains, so I went back to the medium hole.

Weight-wise, I followed the 65-35 rule by using no weight on front, 30g near the motor. I also tried 70g under the cells but it didn't felt any different. As you would guess, I quickly added lead on front by stuffing 10g behind the bumper and 35g under the servo. Again, it felt no different, dead slow on slippery corners.

What I didn't try is:
- use less rear wing/a front wing
- add way more weight on front, like using a brass bulkhead
- soften dampening (it feels rather stiff like this)
- mess with links, roll points, antisquat, etc
- take out the idler mod

In fact, the CR2 felt a lot like my old X-6. there were lots of mid 2WDs on the track, but rear-motor cars seemed slightly faster on that day. So is this mid-motor related? Or do you have to use the brakes mid-corner?

Sorry for this long reading but I had to explain everything. Any help welcome!

My car that day:



Cheers,
Raphaël

[V-Rossi]

- 2° of anti-squat
- Make the front camber links longer or the rear ones shorter.
- Experiment with wheelbase
- Front inner shock position on wishbone

These are the things I would try.

[Northy]

Are you using a geared diff? If you hold the spur and spin one wheel as hard as you can how long does it spin for?

G

[discostu]

front tyres

[Legacy555]

25 degree castor blocks are worth trying

[Gayo]

Thanks for your answers

Originally Posted by V-Rossi

- 2° of anti-squat

Car is already like this.

Originally Posted by V-Rossi

- Make the front camber links longer or the rear ones shorter.

Yes, in stock form, rear links are really long, almost twice as long as those from an X-6 with hangers.

Originally Posted by Northy

Are you using a geared diff? If you hold the spur and spin one wheel as hard as you can how long does it spin for?

G

Yes, geared diff. Maybe 0.5s ? It stops rather quickly, but not instantly. Do you think that the thick diff action prevents the car's rotation?

Originally Posted by discostu

front tyres

What do you mean? Do you like my tyres or do you suggest me to try other ones? I think I tried everything.

Originally Posted by Legacy555

25 degree castor blocks are worth trying

Do you have a part #?

Thanks! Keep them coming!

[GRIFF55]

I'd go longest on the front links and get yourself a front wing on there!!
http://www.m-k-racing.com/product_in...d=7481&<osCsid>

[Ferret]

Originally Posted by Gayo

Yes, geared diff. Maybe 0.5s ? It stops rather quickly, but not instantly. Do you think that the thick diff action prevents the car's rotation?

What gear diff is it? The one from the DT? Don't you have a problem with the dogbone length in relation to the outdrives?

[Legacy555]

Originally Posted by Gayo

Do you have a part #?

Thanks! Keep them coming!

LOSA1123 Fr 25 Deg Spindless & Carriers VLA XXXCR

[Gayo]

Originally Posted by Legacy555

LOSA1123 Fr 25 Deg Spindless & Carriers VLA XXXCR

Thanks!

Originally Posted by Ferret

What gear diff is it? The one from the DT? Don't you have a problem with the dogbone length in relation to the outdrives?

Yes, from the DT. Well, the dogbone is a little on the short side, but still enough to run full droop on the shocks.

I have two CR newbie questions :

- Do you ever play with VLA? What is it supposed to do? Less roll? Faster reaction, RC10 tub-style?

- It seems to me that the steering miss some ackerman. What happens when you add washers under the stud on the steering rack : less or more ackerman?

[Gayo]

Originally Posted by Gayo

- Do you ever play with VLA? What is it supposed to do?

- It seems to me that the steering miss some ackerman. What happens when you add washers under the stud on the steering rack : less or more ackerman?

Anyone

[Arn0]

Originally Posted by Gayo

- It seems to me that the steering miss some ackerman. What happens when you add washers under the stud on the steering rack : less or more ackerman?

Adding shims on the rack will give you more Ackermann effect.

I read stuff for the VLA once but can remind it.

HTH

BTW, nice car (Clicky)

[V-Rossi]

Thanks to mr. Doughty:

short front VLA
- sharper initial turn-in
- less on power steering (slightly)

long front VLA
- car seems to have more bodyroll into corners
- seems to have more on power steering (slightly)
- front VLA does not seem to affect bump handling that much

rear short VLA
- generally less rear end grip
- car feels sharper changing direction
- not as good over the bumps

rear long VLA
- more bodyroll in the corners
- general feeling of more rear end grip
- better on bumps

[Gayo]

Thanks guys. Hopefully weather gets better so I can try all that stuff

[sparrow.2]

Chocolate is better over bumps but vanilla gives better initial steering

[flipside]

Note that changing VLA changes your suspension feel completely. So just changing VLA without adjusting springs, oil and prob pistons will not let you test the VLA itsself!

So in fact it is very hard to really test this.

From my days of running the normal CR, I remember that I used to run long VLA front and rear on high grip, and short VLA front and rear on low grip (dirt). The short VLA made the car feel as if it were on rails, I liked that a lot more on dirt!

In the end I also ran short VLA rear on astro or carpet, to get more rotation in the car. With the mid motor now, maybe this will not be needed anymore.

Gonna try the short VLA on a dirt track one time, and if it's not drastically better, and the long VLA also feels ok, I will simply stick to long VLA always, as you can go crazy over these kind of setup options :-) For me it would be better if losi would have never came up with something like this :-D

And indeed, time for some better weather so we can start scraping that shiny CF chassis on outdoor tracks!!!

[Gayo]

Flipside : Yes, I am aware of that. Changing VLA changes a lot the wheel rate. You have to go to a softer spring with a shorter arm. To be fair, I'd guess that you also have to change piston and turnbuckle position... What a mess


Sparrow.2 :