suspension handling and junk

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suspension handling and junk

Postby Adoom » Sun Sep 29, 2013 5:48 pm

Went to Manfield in THE STARVIA yesterday. It was WET. REALLY WET!

Even with my semi slicks I was breaking traction in 3rd and 4th on the straights :lol: GOOD FUN!

I was understeering on the corners(no brakes).
Dad was following me and said that he could see daylight under my inside front wheel.
To me, this explains the lack of grip at the front causing the understeer.

On the runs after this, I could tell when that inside wheel went back onto the track because it suddenly wanted to oversteer due to too much lock.

Any suggestions on how to keep both front tyres on the track?

Front springs are 250lb, rear are 200lb.
2.9deg negative camber on the front.
I have a standard KP60 front anti-rollbar. There are no aftermarket options available for the front, the only practical option I can think of is to clamp two together.
There is a rear anti-rollbar it is the same as an AE86, whiteline have an adjustable option($$$).
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Postby strx7 » Sun Sep 29, 2013 6:30 pm

front wheels coming off the ground is caused by too much body roll in the rear, generally a trait seen in a rwd gravel rally car when put onto a circuit and either a very small or no rear swaybar, reminds me of the days of the old baypark track watching escorts, rx3's & rx7s coming around champion onto the front straight.
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Re: suspension handling and junk

Postby wde_bdy » Sun Sep 29, 2013 8:14 pm

Adoom wrote:I have a standard KP60 front anti-rollbar. There are no aftermarket options available for the front, the only practical option I can think of is to clamp two together.


Custom isn't that hard to get, can also get extra castor at the same time. Q from Club K had his one made for his car from Chamberlains in Christchurch I think.
http://homepages.ihug.co.nz/~quibel/Project2b.htm
Not sure what his spring rates where.

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Postby 85AW20v » Sun Sep 29, 2013 9:59 pm

For my AW when getting the suspension sorted out the guy told me when it's wet disconnect the swaybars front and back to soften everything up as much as possible. I've never tried it as I can't be bothered mucking around under the car at the track on a wet day.
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Postby GDII » Sun Sep 29, 2013 10:05 pm

I'm pretty sure you can't disconnect the front swaybar in a standard KP as its doubles as the castor arms.
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Postby Adoom » Sun Sep 29, 2013 10:07 pm

GDII wrote:I'm pretty sure you can't disconnect the front swaybar in a standard KP as its doubles as the castor arms.

This.
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Postby Mr Revhead » Sun Sep 29, 2013 11:12 pm

Lifting front means too soft in the rear. Or too hard on roll in the front.
Lifts the inside front due to squatting in the rear and rolling.
Trick is to harden it a little, or prevent rear roll with out making it too hard and turning it into sideways.

Or maybe you need to alter your wet lines?

Or, if you have lowered and shortened shocks etc, do you still have enough droop in the front?


Any yeah, the old RWD rally cars were very entertaining on the track! :lol:
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Postby Adoom » Mon Sep 30, 2013 1:21 pm

Mr Revhead wrote:Lifting front means too soft in the rear. Or too hard on roll in the front.
Lifts the inside front due to squatting in the rear and rolling.
Trick is to harden it a little, or prevent rear roll with out making it too hard and turning it into sideways.

Or maybe you need to alter your wet lines?

Or, if you have lowered and shortened shocks etc, do you still have enough droop in the front?


Easier to make the rear stiffer than make the front softer.

Wet lines... It does it in the dry too, just not as badly because there is enough grip from that one tyre to stop it understeering too badly. So I probably should make some changes to the handling anyway.

I have shortened Konis with ~60mm coils on adjustable lower spring seats. The springs are only slightly compressed at full droop. Not sure how I could increase the droop without a lot of redesign.
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Postby Mr Revhead » Mon Sep 30, 2013 1:46 pm

I was just running through everything I could think of. Not all will be applicable to your car. You need to work out which one is the problem :P

I'd doubt very much its too soft in the front.
Droop depends home much its rolling.
Its all relevant and a combination of things. Not just one thing
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Postby strx7 » Mon Sep 30, 2013 2:26 pm

You may be able to make the rear sway bar from a 130surf fit your car without too much issue as they run along the diff housing then come fowards (just thinking easy to make work and readily available)
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Postby QikStarlie » Mon Sep 30, 2013 8:37 pm

i'd try harder springs in the rear before you touch the swaybar /add rear bar. i've had good results retaining the stock bar setup

i run, 275lb front 250lb rear. coil overs all round. so effective rate on rear, will be a little higher than if you are still using the stock spring position.

stock swaybar. with modified mounting points at the front for more caster - 4-5degrees

1-2deg camber. front and rear. (diff case mod)

also found increasing front track as much as possible gave a lot more grip up front.

was having a play with another kp at puke a few months back. it was doing similar to what you explain. unsure what suspension setup it was running. but was able to out handle it with the above setup, on street tyres. they were on semi's
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Postby touge_ae101 » Tue Oct 01, 2013 10:23 pm

Its all a trade off. going stiffer in the rear may sacrifice grip. if you look at a lot of oldschool rwd cars they lift in inside front and it isn't necessarily a bad thing!

if you really want to get it sorted go see nick at mag and turbo palmy. he has set up the hayabusa starlet front end for years and knows exactly how to make a oldschool rwd car work perfectly. I know there are a lot of internet theories etc out there but very few actually work. you'll find the people who have the knowledge and experience won't be.posting it on the internet for free.. I've come to the conclusion your better to pay the right people to do the job so you'll be happy with the results. you may even be surprised at how cheap it is to do really.

^^ comment above refers to everyone except kpr/qikstarlie.. he is the $&#$% mang!
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Postby Adoom » Wed Oct 02, 2013 9:12 am

QikStarlie wrote:stock swaybar. with modified mounting points at the front for more caster - 4-5degrees


I'll trust this guy to know what he is talking about since he races a Starlet.

Positive caster right? So you moved the swaybar forwards? Aren't there spacers at the wheel end? Removing those should give slightly more positive caster. Did you work out how many mm forward per degree of caster? I could work it our myself, but I am currently driving a keyboard and the car is at home.
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Postby QikStarlie » Wed Oct 02, 2013 11:36 pm

yeh, positive. probably easiest if i post the sheet. this is untouched, just got mate to chuck it on the machine for a check. Obviously it needs to be evened up. but gives you an idea what has been altered from stock.


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To get the extra caster. i made up some 10mm steel plates that bolt to the stock sway bar mounting points. with some new threaded holes further forward. from memory i used ep82 lower arm brackets with a custom urethane bush to stop some deflection (i cant remember the reason for not using the stock brackets. im sure you can make something work!)

i also removed those spacers off end of the sway bar. doing that alone wont gain you that much though. It got to the point i'd dialed so much more into it, it was starting to give the control arm bushes a hard time. along with a few other reasons, i ended up moving the steering rack and control arm points forward to correct the angles. my build thread over on oldschool should cover it from here on. save writing a novel here.

this should link you to the steering/suspension stuff!

http://oldschool.co.nz/2011/forum/index ... ntry895112

^ some of it may seem like ive set it up for drifting, but have more so for cornering. just happens to work well for both
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Postby Adoom » Thu Oct 03, 2013 9:25 am

Cheers, I'll have to find my wheel alignment sheet.
QikStarlie wrote:
^ some of it may seem like ive set it up for drifting, but have more so for cornering. just happens to work well for both

I assumed it was too short to 'drift' successfully, because once I have enough oversteer going on, I can't recover and end up in the gravel or paddock. But you don't seem to have that problem...
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Postby QikStarlie » Thu Oct 03, 2013 5:14 pm

caster helps alot with that. wheel will return to center faster. if you watch the last vid i posted, you'll see i pretty much dont turn the wheel at all. plus i run a quick rack and more steering lock. even if you want nothing to do with drifting. its good to have. might be the difference between ending up in that paddock or not!
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Postby Adoom » Thu Oct 03, 2013 11:30 pm

Here is the fast run. It's not very fast until it stops raining at about 9:00
http://www.youtube.com/watch?v=iOQT5HI25TM&feature=youtu.be
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Postby ~SlideWays~ » Fri Oct 04, 2013 8:31 pm

Adoom wrote:Here is the fast run. It's not very fast until it stops raining at about 9:00
http://www.youtube.com/watch?v=iOQT5HI25TM&feature=youtu.be


Man that rattle is annoying!

I recorded the same run with my set up of 'phone wedged under headrest' looks super slow from that angle.

EDIT: uploading it now.
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Postby Adoom » Fri Oct 04, 2013 10:34 pm

~SlideWays~ wrote:
Adoom wrote:Here is the fast run. It's not very fast until it stops raining at about 9:00
http://www.youtube.com/watch?v=iOQT5HI25TM&feature=youtu.be


Man that rattle is annoying!


I know right. But I heard the EXACT same noise on a GT40 in car track footage so I googled it and apparently it's the clip on the bracket. You can get a special rubber bung that pushes into the clip that should stop it. I'm just going to try blutac...
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