Lowering in dubai

Wheels, tires, suspensions, brakes etc.

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kingkenny
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Post by kingkenny » 13 Jan 2008, 10:22 pm

can't find anything explain how alightment relate to the handing , but i can try to make a list to explain .

front toe in increase : reduce oversteer turn in / increase understeer turn in

front toe out increase : increase oversteer turn in / reduce understeer turn in

rear toe in increase : reduce oversteer turn out / increase understeer turn out

rear toe out increase : increase oversteer turn out/reduceundersteer turn out

front negative camber increase : reduce understeer /increase oversteer

rear negative camber increase : increase understeer /reduce oversteer
Last edited by kingkenny on 13 Jan 2008, 10:36 pm, edited 1 time in total.

kingkenny
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Post by kingkenny » 13 Jan 2008, 10:33 pm

caster is something relate to the steering feel , more toward to the back the steering feel lighter and also tend to turn , also give you more negative camber while cornering(better traction on the front) , usually better cornering but also feel a bit less connection with the front tires , too much caster also cost you diffcult to control .

in the other hand , caster more toward to the front , will give you more steering feel , heavier steering , easier to feel the front tire , most drag car like to have their caster toward to front .

not finish yet , will come back for more real sample and detial !!
Last edited by kingkenny on 14 Jan 2008, 1:20 am, edited 1 time in total.

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Post by kingkenny » 14 Jan 2008, 1:14 am

now let me share some of my experience when i set up my custom alightment .

first of all , to do this change and fine tune your suspension doesn't gain you a sec lap time directy , but sometime the right setting match the right driver will gain you more than a sec per lap . there isn't any 100% correct set up , it's depend on the driver , also depend on the course , like for stragiht line drag race , high speed circuit race or like me target on the low speed autoX , both setup can be pretty different. before you do it to your car , i have to tell you aggressive camber and toe setting will cost you more tire wear , so if your budget is low and daily drive over 100km , than you better think twice before you did this to your car .

to do these adjustment , i heard this could be DIY , but i don't know how .or just like me , go to wheel shop which can do four wheel alightment(laser scan, cost around 200dhs each time) .most the time , we can't expect setup it once for all(if there is a suggest number somewhere , better start from there) , cause it is hard to find the compromise between straight line , high speed and low speed corner also braking ability(samlp : some serious toe out or negative camber , will side affect braking straight line ability) .

continue.....

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Post by kingkenny » 15 Jan 2008, 1:26 am

sorry dude , i was try to type some sample what i did to my car !! but the internet is slow and break down everytime , and i loss my long post twice !!
:evil:

if anyone have more question about this , may be we can talk when we meet , i try my best to help !!

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prossett
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Post by prossett » 15 Jan 2008, 7:54 am

I hate it when that happens!!! :evil:

Very informative, kingkenny - don't stop now! I'm definitely DIY so how does that work, you know, without the 200 each time. I think it'll be good to do the pro alignment once, to get a starting point after changing suspension from stock, but then minor 'tests' I want to be able to do myself...

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Post by stone-head » 15 Jan 2008, 8:52 am

very informative kenny (Y) (Y) , thanks
I did my home work too & found these couple pics , they say it all
Image
Image
manually aligning wheels can be done using -old fashion - strings & pendulum or this SARD product
https://www.rhdjapan.com/jdm/SARD-Laser ... auge-25286
mostly toe in & out depends on suspension arms & bushings , if bushings are soft then during
hard drive , cornering & braking will change their geometry , but u can adjust their geometry only
while car is stand-still , so take it a couple of laps & see if it needs toe in or out & so forth .
thanks kenny I really didn't know these info .

ohh one more thing it even depends if steering rods are connected in front of the wheel hub or
back of wheel hub , so it's all about trial & error & driver feel

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prossett
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Post by prossett » 15 Jan 2008, 12:04 pm

OK, here's my understanding so far... and in expressing it maybe it will help others and also maybe you guys can point out misunderstandings.

Jazz has a MacPherson Strut front suspension, which is basically a bottom wishbone with the shock/spring attaching to the top of the uni-body chassis.

Looks like this:

Image
Source: http://www.autozine.org/technical_school/

So, if I lower my darling Jazz, with a new coilover or just shortened springs, this is what would happen:

The shock/spring gets shorter, and the bottom wishbone angle goes up. So the wheel camber is now negative (with the bottom part of the wheel sticking out) - like this:

Image
Source: http://www.wikipedia.org

So, to tune the suspension back to stock handling, I would need to move the wishbone in towards the chassis.

Image
Source: http://www.autozine.org/technical_school/

I suppose there are bolts that you loosen where the wishbone attaches to the chassis, and probably also some room to slide that puppy in a few mm.

Now, the rear.

Jazz has a torsion-beam rear suspension, which is a weird one for me - never seen it before. Apparently, there's a metal bar which connects the two wheels and which flexes up and down. It's like a long wishbone joined to the bottom parts of both wheels. Then the shock/spring combo attaches at the top to the uni-body chassis.

Something like this:

Image
Source: http://www.autozine.org/technical_school/

So, that seems to be really good news for lowering, because the bottom part of the torsion-beam suspension runs along the chassis, not towards the centre of the car, and so camber should remain exactly the same when lowered.

As the spring/shock gets shorter, the entire arm moves up, getting tighter (more torque) so I suppose I could loosen where the torsion bar connects to the chassis to return to stock balance - see pic, the arrow points to where the bolt would be.

Image
Source: http://www.autozine.org/technical_school/

Sounds about right to you guys?

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Post by kingkenny » 15 Jan 2008, 2:27 pm

i don't know much about DIY , but i watched how the pro-track racer set up their car on the track after every lap , i like to learn it too . :)

nice find ! let me contiune my resach , and see if i could find something !!

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prossett
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Post by prossett » 15 Jan 2008, 4:25 pm

And time for me to put theory into practice and go have a good look under my Jazz... I'll take some pics and try label them.

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Neo
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Post by Neo » 04 Jun 2008, 11:12 pm

Good info...
I think Prossett could continue posting his study and I am making this a sticky for others to learn...

Honestly I aint an expert in this section either....

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grayfox666
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Post by grayfox666 » 18 Oct 2009, 1:10 pm

Does anyone know who is the distributor for KW Coilovers in UAE?

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dj drift
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Post by dj drift » 18 Oct 2009, 2:55 pm

no...google it :D

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grayfox666
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Post by grayfox666 » 18 Oct 2009, 5:43 pm

I did man. If you can find me KW V3 Race Spec Coilovers online for 6N2 that ship intnl, ill buy you a beer :) . I thought not to have headache and see if they have it locally.

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TNT
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Post by TNT » 18 Oct 2009, 5:56 pm

Erm, use Shop & Ship?

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grayfox666
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Post by grayfox666 » 18 Oct 2009, 6:31 pm

Tnx guys. but i need help with finding it locally. :)



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