Front shock positions and general front end on FS

[RogerM]

All, I've been working hard over the past few weeks on set-ups for the FS after running largely the same car all summer.

One thing I have done which has really helped the car is move to the outer hole on the front wishbone, readjusting shock length to maintain the same droop.

The main reason for going for this change is wanting to achieve the relationship between wheel bump speed and damper piston velocity you get from a more inclinded shock.
I tried the inner hole on the tower but found that it was limiting me to using just the stiffest spring (#75 lime green) on the front to give me the smooth steering response I was after, we all know how much front end the FS can generate!
By moving to the outer front wishbone hole and sticking with the middle hole on the tower I achieved what I wanted and put myself back into the middle of the spring range as moving a hole on the wishbones is approximately 2 spring grades.
This meant that I was now using a #65 yellow instead of a #75 lime green (and #60 dark yellow where I would have run a #70 silver previously).

This option is particularly useful on really high grip surfaces (like Silverstone was for the F3s) and fresh carpet.


I've also been trying to run the front axle height low (spacer in low position under castor block) with the droop also adjusted back to normal. This is to effectively lower the front roll centre for a given ride height which smooths the car out again.

Finally is reduced ackerman (removing all spacers between ball stud and rack), again with the aim of making the car smoother.

The last two have been as a direct result of conversations with Nick Caro who has spent a lot of the summer improving his FS base setup, with some really good results along the way. Nick is really flying with this car now


Now people who don't know the FS might think that its an oversteering monster to require such taming but as we know this isn't the case at all, but neither does it lack steering.
What I have tried to do is produce a car with the same ultimate amount of front end bite late in the corner but one which does it in the smoothest and most progressive way possible.
I now have the car to the point I no longer feel the need to run a front one-way, amazing when you consider that all my 4wd cars since the mid 80s have had one-ways in, but still maintains all the late corner steering I had running one! Taking me a little getting used to but when you string it all together it makes the car much quicker around a lap and easie rto be consistent with.


The FS just gets better and better with every turn of the wrench.


The last thing I have been playing with is changing the up/down travel balance.
By using the longer shock eyelets from the RB5-SP2 on all 4 shocks and modifying the towers so that maximum up-travel is achieved just a fraction before the driveshafts contact the outdrive edges I feel the car is a little more forgiving to "iffy" landings from big jumps, especially those where there is a corner right at the landing point.
Obviously as with all the other changes mentioned here I have reset the droop levels to the same as kit, front slightly less than rear too.

I feel this will be an advantage now we are heading indoors to the tight tracks for the winter and has given no noticable negatives under normal conditions.

Hopefully towers will be available to accomodate this in the next few weeks, they should also correct the arc made as you adjust the shock inclination so that at a 'typical' ride height there is no change in droop across the range of inclinations.



Also for those of you that haven't tried the slipper "pinned" with matching (we favour white) pads in then go and try it. Again it makes the car feel a little more consistent and easier to push with. I was a little concerned that it might lock the rear end of the car in a little too much, previously I'd only pinned the slipper in very slippery conditions. This has proven not to be the car, the front is still nice and agressive but now you can get on the throttle earlier mid corner = faster lap times.

I wish I had afforded myself the oppertunity to play with these sort of things over the summer ... might have finished a bit higher up the tables.

[carlin]

Ahh Roger your sharing our speed secrets thats not good lol

Fantastic read & i hope people do try the above things as Roger has done because i found this very useful. I will be trying them out again this weekend at Broxtowe if time is not ahead of me

[Gayo]

Wow, thanks Roger! Will try ASAP!

Would you have a setup sheet to share?

[RogerM]

I struggle with doing the setup sheets as I have no PDF writer at work and no net access at home!! If I was more organised I'd still them on a datastick and take them to work ... need a netbook like Nicks I think!

[Fabs]

Been running longer shock shafts and outer front hole since petit last year Rog'! Best of that is you know it as you seen me drill my cartridges, I used your drill bits !

Been running effectively -1 ackermann since EIR...

[Gayo]

Fabs : yeah Philippe shown me your shocks with Losi shafts (I think), his car was awesome. So you have to drill the cartridge? Do you also use AE-style o-rings?

Roger : did you change something piston-wise when moving to the outer hole or is it still 3-b? And what oil?

Thanks

[Fabs]

Originally Posted by Gayo

Fabs : yeah Philippe shown me your shocks with Losi shafts (I think), his car was awesome. So you have to drill the cartridge? Do you also use AE-style o-rings?

Roger : did you change something piston-wise when moving to the outer hole or is it still 3-b? And what oil?

Thanks

Losi shafts require de-drilling of the cartridge, of the teflon inserts in the cartridge and losi o-rings...

There seem to be longer shock shafts from Kyosho but I haven't tried them yet !

[RogerM]

I am NOT using longer shock shafts.

I have the 46mm Kyosho shafts in the box but they are too long and the piston hits the shock top cap before the spring platform bottoms out.

There is plenty of adjustment on the stock shock eyelets to get the droop balance you need with the kit 42mm shafts. I check the drop by using a ride height gauge to pick up the car until it just lifts off = actual droop measurement.

The other way of cause is to place the chassis on top of something to raise it off a flat surface (2 brand new wheels have always work ok for me) then measure the height from the surface to the axle centre.

The FS (and RB5 for that matter) are really hard to judge droop by eye due to the shape of the chassis edges ... even worse if trying to do it with the body shell on!

I am running 3B with 40wt AE oil as the basic set up, drop to 35wt AE oil when temperatures / track conditions dictate but it's 40wt 95% of the time.

2C pistons in the front can make the car feel a little calmer but make it less able to deal with the subtle bumps ... useful for smoother tracks with big jumps and / or high speed direction changes though.

Fab' ... that reminds me, you owe me some shock parts buddy
When you say -1 ackerman I take it you mean you are using the low height ball studs there?

[Fabs]

I don't have issues with the pistons hitting the cap??? And the losi shafts are longer than K ones.

You are though doing the same thing, lengthening the shock assembly, but what I've done is keep the fully compressed shock the same length...

-1mm is with tamiya hard ball studs which are the same as the kyosho short one on the steering knuckles of the FS, but with longer thread and hex print.

[RogerM]

Fully compressed shock hasn't changed in my case either .. I'm using kit shafts, eyelets ect. All that has really been done is change the inclination and thus the relative velocities of wheel and psiton.

Thanks for the ball stud info Fabs ... do they fit in the Kyosho rod ends though? If so happy days.

[njc11]

Fabs... you changed to the other blue corner...

What right do you have posting on here now!

lol!

Ive yet to try the combo both you and Rog are using... but ive tried middle middle and more recently inner and middle and love the feel of the car.. But intend trying what you two run..

Running inner tower and middle wishbone i have to actually wind the kit ball end in by 1mm... So from the bottom of the cartridge to the top of the ball end is 19mm.. on middle middle its 20mm..

Rog can you measure this distance for me with what your running so i know! 97038 is the longer ball end part number, this comes with the RB5SP2 kit.

Ta!

[Fabs]

Rog, you said you were using the SP2 eyelets all round...

Also you wanna try the GHEA pistons, I put them on at the euros and they were awesome.

Nick I don't know what you're talking about...

[carlin]

Originally Posted by Fabs

Rog, you said you were using the SP2 eyelets all round...

Also you wanna try the GHEA pistons, I put them on at the euros and they were awesome.

Nick I don't know what you're talking about...

Fabs,

What size Ghea pistons was you running as i have been thinking of trying these out. But i didnt know of anyone else who used these so just wondered what to try out.
I'm going to be running indoors anyways not a outdoor person lol

Roger,

You know running the SP2 eyelet,am i correct in saying that you still run the shocks the same length as per kit?
Also i was thinking of trying the diff length shock caps as this will lengthen the shocks themself wouldnt it?

[njc11]

Rob,

They are the tamiya Ghea pistons he uses... they go in ok and may need a shim to stop any movement up and down.. i guess they must be a little thinner..

[carlin]

Originally Posted by njc11

Rob,

They are the tamiya Ghea pistons he uses... they go in ok and may need a shim to stop any movement up and down.. i guess they must be a little thinner..

Cheers Nick, think i order some give it go! 2 x 1.3 should be good starting point?
But time ticking away for them new Big Bores on order too

[Fabs]

At the euros, as the track was getting rutted in 4WD, I went from normal pistons to GHEA 1.2 with 350 front, 300 rear and the car was awesome, it was great on the rutted section, and it was landing the big jump without ever bouncing. It was a huge improvement !

[carlin]

Originally Posted by Fabs

At the euros, as the track was getting rutted in 4WD, I went from normal pistons to GHEA 1.2 with 350 front, 300 rear and the car was awesome, it was great on the rutted section, and it was landing the big jump without ever bouncing. It was a huge improvement !

Fabs was these the Tamiya or which brand you was running?

As i've ordered the Tamiya 2x1.3 Tamiya pistons

[RogerM]

Sorry guys I wasn't clear enough.

As far as the basic set-up is concerned it is ALL KIT PARTS!!!

The reference to the longer eyelets was to go with the revised towers I have designed. The reasoning is to give maximum uptravel without loosing any droop capability. When I was going to PDA a lot the one place I couldn't push as hard as the B44s for example was on the landings that led straight into a corner ... the new towers and longer eyelets sort that out a treat!!

I know only a very few tracks need that but it's always good to have it in hand and doesn't hurt the car the rest of the time anyway ... and you can always use external limiters if you want to reduce uptravel.

[Fabs]

Doesn't make sense to me roger.

If you're not changing the droop, and not having a longer stroke, then you've not changed the uptravel on the car at all...

[RogerM]

The stroke is increased as after raising the whole shock, with the new towers, which also correct the arc the shock swings through as you change inclination, you then reset the droop by adjusting the shock length by unscrewing the eyelets a little.
The longer eyelets are needed or else you run out of thread engaugement and risk a failure.

With the standard kit towers there is still some possible uptravel clearance between driveshaft bone and outdrive which can not be used as you have fully compressed the shock.
My modified tower design gives scope for using this uptravel but requires the change in shock length to accomodate it without loosing droop.


There are 2 different things discussed in my first post;

1) what I have been doing with the standard kit components (outside hole on wishbone)
2) what revised componenets I have been working on to improve the car (new towers) in a specific area

Hope that makes more sense now ...