Toyspeed.org.nz Message Board

by **matt dunn** » Tue Jul 17, 2012 12:54 am

Also zero toe front and rear seems wierd to me too..

Need some toe in or out.

by **atmosports** » Tue Jul 17, 2012 8:09 am

I've generally only run zero toe in one make series when we've tried to reduce any tyre scrub/drag mainly on the straights. Only other time I've taken rear toe off was at teretonga on a day with a massive crosswind across the front straight, seemed to help stop the car from wondering(Driver's comment not mine).

All in all though, I've generally left to in/out as driver preference as some like it either way. Last FWD car I ran we run about 2-3mm of toe out on the front as under acceleration it ended up toeing straight & generally run about 3mm of toe in on the rear, that total toe i.e 1.5mm each side, can't remember what it was in degrees if you work that way. Easiest way is to make some way of checking it qucikly/accurately at the track & then go & run a few laps then adjust one way & see what difference it makes,then try the other way & see what works better.

by **fxgt race** » Tue Jul 17, 2012 9:26 am

Evo 4wd in the charade, I take it you are using evo hubs, is it all custom rose jointed or running of charade front arms , nice to see a picture of suspension pick up points and how its done.

by **TWSTD** » Tue Jul 17, 2012 9:41 am

I will have to double check the rear toe settings - i cant recall if they are actually 0 or not.

The car is using a CM5A GSR front end. Subframe, hubs, axles, the lot. The rear is using the factory 4wd charade subframe with mitsi diff in it. All rear arms and hubs are daihatsu still with machined axles to take mitsi diff on one end and daihatsu hub on the other. There are some pics up in the build thread on my facebook page. I will post some in this thread soon.

by **TTEETT** » Tue Jul 17, 2012 10:03 am

I ran them once and loved them.

We ran them (235/40/18) at mid 30's cold.

Mine lasted 5 days of competitive driving.

by **TWSTD** » Tue Jul 17, 2012 10:45 am

This is the only image i have at present sorry. Not that useful:

by **saft** » Tue Jul 17, 2012 11:49 am

have you done any calculations/models of what your suspension is doing under load?

by **TWSTD** » Tue Jul 17, 2012 12:12 pm

No, but as we are using a complete GSR front end it will be doing whatever a CM5A is doing. Mitsi has already done that research...

by **KinLoud** » Tue Jul 17, 2012 4:04 pm

Hi
Question.... Wondering if you have an Ackerman steering problem?
MixIng non factory hubs with factory bits could be creating the problem
What's the current effective steering arm length compared with factory?

by **TWSTD** » Tue Jul 17, 2012 4:23 pm

The complete front setup IS A STOCK LANCER SETUP. Subframe, arms, hubs, struts,steering rack / arms etc etc all stock mitsi.

by **wde_bdy** » Tue Jul 17, 2012 4:36 pm

Change is wheelbase affects your ackerman too so Kinlouds question is valid, running KE70 front suspension in a KP for example causes ackerman issues. Guessing your car is fair bit shorter than an Evo.

Callum

by **TWSTD** » Tue Jul 17, 2012 4:40 pm

We actually only shortened the overall wheelbase by a small amount. Couple inches at most.

by **Bazda** » Tue Jul 17, 2012 5:56 pm

The rim size isnt an issue. I run 225/45s on my 16x7 rims and have done so for a while. My tyres never looked like that.

My tyre pressures would increase alot more than everyone has stated on here. For me around 10psi max! So I would start around 23-25psi cold and come in near 35psi at times on a hot day.

Being a shorter wheel base and using the same suspension setup as stock off the lancer I would have thought the car would be more responsive in the steering.

From looking at your in car vids the car suffers really bad understeer. Small changes arent going to make a big difference, it needs a big change and then see what direction it takes you.

ie: Totally different shock/spring rates (not sure if you have any shock dynos to see what rate they have been valved?), more caster on the front, look into Roll center adjustment. Move the ackerman back to how it should be for your wheel base.

by **TWSTD** » Tue Jul 17, 2012 7:51 pm

Bazda wrote:From looking at your in car vids the car suffers really bad understeer.

You can say that again! Although the more recent vids show less understeer (and from the drivers seat there was less too):

http://www.youtube.com/watch?v=fBejK_zU ... re=g-all-u

http://www.youtube.com/watch?v=XQu1zyESAjc&feature=plcp

We have experimented with various spring rates. At present we have 10KG all round. We started with 8/6 and the car was very unstable with the softer springs and very easy to unsettle mid corner. Ie changing gear mid corner was a risky activity LOL. Then we upped to 10/8 and then again the rears up to 10kg. Each step make improvements and saw drops in lap times around HD (where all testing has been done to date). Camber adjustments also improved the understeer as previouslly noted.

We have had the shocks dyno'd and confirmed valving is appropriate. We are out of caster adjustment so its currently at its max (in fact we had to run the camber tops at 45 degress to get any caster at all).

Also note we have no front sway bar. I have been thinking we should get a custom swa bar made and that would perhaps allow a softer front spring to make it more compliant without the instability and roll you get from a soft spring with no sway bar.

I am open to suggestions on ackerman setup and roll centre adjustment. Whats involved here?

by **strx7** » Tue Jul 17, 2012 8:18 pm

TWSTD wrote:The complete front setup IS A STOCK LANCER SETUP. Subframe, arms, hubs, struts,steering rack / arms etc etc all stock mitsi.

so all the measurements ie: how far back the rack sits is identical? where the bottom arm pivot points are in relation to the roll centres etc.

just because all the bolt in bits are the same, the whole overall geometry cold be no where near it.

by **DVSMOTORSPORT** » Tue Jul 17, 2012 8:42 pm

So youv gone 8kg front 6kg back, then 10kg front 8kg back, then 10 front 10 back if I read correctly. What about going stiffer in the rear than the front to try for some oversteer????

by **TWSTD** » Tue Jul 17, 2012 8:50 pm

Correct. I have not tried stiffer than 10kg in the rear as its already pretty stiff and im going for traction, not loss of traction (at either end!). I hope that with a sway bar we could take the front down a notch though.

by **mjrstar** » Tue Jul 17, 2012 9:02 pm

Factory evo / GSR will understeer pretty badly at the track..

What diffs / swaybars do you have?

by **TWSTD** » Tue Jul 17, 2012 9:10 pm

No front sway bar (see previos comments), open front and centre diffs.

Factory 1.3L charade rear sway bar, just fitted carbonetic rear LSD (which helped a bit as evident in the videos)

by **wordnz** » Tue Jul 17, 2012 11:51 pm

+1 for rims being too narrow.

The narrow rims will be pulling the sidewalls in, and the center of the tyre will be ballooning out.

May not be visible, but during hard cornering the tyre flexes a lot, and if its not sitting as flat on the rim as possible, you will run into issues.

Look at how much a tyre flexes during cornering: http://www.youtube.com/watch?v=v-DMkO3g2SI

Now imagine your rim being too narrow, it isn't going to support the edge of the tyre of optimum grip.

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