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I am trying to tune the suspension geometry using old string method.

 

I am no expert and had to refresh my knowledge on effect of toe in rwd cars. What I use the car for is mostly street driving with occasional drift and from what I have gathered, I need the following 

It is very important for me to have quick 0 to 60 so need rear end grip but also want it to drift when I want it to .

Please correct me if you thing I am getting this wrong

My plan :

Toe:

Slight Toe out in rear for faster acceleration and also over steer for drifting 

Slight Toe out in Front for again helping with oversteer but worried this makes the car very unstable.

Camber:

Camber isn't adjustable in rear as far as I know unless I replace the lower arm so will leave that for now

On front it isn't adjustable either unless I change the top mount .

Height:

I am running coilover so will have higher height at rear and lower height in front.

 

One thing I don't understand is what is the difference between the hicas eliminator which allows you to adjust to and the rear tension rod which also impacts toe under compression.

 

 

I have bought the rear hicas eliminator and did fit it tonight with lots of swearing to get the bushes out . link below

https://www.driftworks.com/driftworks-rear-traction-arms-with-poly-bushes-for-nissan-skyline-r34-98-02.html

again they do two version one with poly bush and one with rod so not sure which one to buy and what is the impact. 

to me compression means under braking or acceleration so would expect toe to change but how does this differ from normal toe set ?

 

Can someone enlighten me on the difference between 

https://www.driftworks.com/driftworks-total-hicas-eliminator-kit-with-rod-ends-for-nissan-skyline-r34-98-02.html 

and 

https://www.driftworks.com/driftworks-total-hicas-eliminator-kit-with-poly-bushes-for-nissan-skyline-r34-98-02.html

 

second link has poly bosh on where it connects to hub rather than rod . what is the impact / difference ?

 

 

Edited by drifter17a

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27 minutes ago, drifter17a said:

Slight Toe out in rear for faster acceleration and also over steer for drifting

Toe out at the rear might be good for drifting, but it will make it nervous and scary on the street. I have zero toe at the rear of my car right now and I will be going back to 0.5mm toe in next time I align it.

Toe out at the rear does not make the car oversteer biased. It just makes the rear end unstable and ready to change direction at the merest whiff of a steering input or a bump or a camber change or a butterfly farting on the other side of the plant.

28 minutes ago, drifter17a said:

Slight Toe out in Front for again helping with oversteer but worried this makes the car very unstable.

Toe out at the front does nothing to change the steering balance of the car. If it is otherwise understeery then it will remain so regardless of how you set the front toe. Same if it is already oversteery.

I have zero toe set at the front at the moment and I would not be changing it to toe out for a street car for love nor money.

I had toe out on my ALFA 116 many years ago. Completely different car - and it was a good thing. Won't be doing it on a Skyline any time soon.

32 minutes ago, drifter17a said:

Camber isn't adjustable in rear as far as I know unless I replace the lower arm so will leave that for now

Rear camber is slightly adjustable with the stock upper arms. Eccentric bolts.

You can buy lower arms to provide camber adjustment, but I am baffled that you have not sen the myriad of adjustable upper arms for Nissan rear ends. You can't even open an eBay page in a browser without being assaulted by recommendations for all the cheap-arse no-name Chinese ones available.

Anyway, the easiest way to adjust camber at the rear is to buy a good quality upper arm (and the traction arm) from a trusted brand.

39 minutes ago, drifter17a said:

On front it isn't adjustable either unless I change the top mount .

Top wishbone. As above.

39 minutes ago, drifter17a said:

One thing I don't understand is what is the difference between the hicas eliminator which allows you to adjust to and the rear tension rod which also impacts toe under compression.

The toe arm (either the HICAS tie rod or the eliminator kit's toe rod) allow you to set the toe. This is the ONLY arm that allows you to SET the toe.

Changing any other arms length will also CHANGE the toe. You cannot set the toe and then change the camber without going back and fixing the change that that will make to the toe. Trust me.

The traction arm is critically important with respect to to in one major way. It controls the change in toe angle as the suspension moves through the arc of its up-down travel. This is called bump steer. This is why I said above that if you change to an adjustable upper arm to set camber, you also have to change to an adjustable traction rod. If you leave the traction rod at stock length and change the camber arm's length, you will introduce a horrendous amount of bump steer. Bump steer is bad. You can never really have zero bump steer, but the suspension needs to be set up with the MINIMUM amount of bump steer. Here's the best bit. Unless you build your own bump steer measuring device, you can't even see it, let along measure it. I built a bump steer gauge and used it on my car recently, only to find that I already had my traction arms set to a satisfactory length to keep bump steer to a minimum.

45 minutes ago, drifter17a said:

to me compression means under braking or acceleration so would expect toe to change but how does this differ from normal toe set ?

No. Compression means when the wheel moves up into the wheel well for any reason at all. Launch will do it. Bumps will do it. Cornering (body roll) will do it.

46 minutes ago, drifter17a said:

Can someone enlighten me on the difference between 

Rod ends and poly bushes.

Rod ends have no give in them at all. They are the roughest and toughest way to connect suspension pieces together. They offer the firmest and tightest control of location. They are unforgiving. They are noisy. They are not really good for a road car (although I now have a number of them on my car). They wear out. They need to be protected from grit and dirt. They need lubrication and cleaning (despite what the vendors may say). They are for race cars. On the road they increase the amount of maintenance you need to do on the suspension by a factor of about 10.

Poly bushes are soft and flexible compared to rod ends but generally much tighter than the original rubber bushes on most cars. They are a good compromise for a street car. They need proper lubrication and will often need to be re-lubricated at various points through their life, or they will gall up and die.

With many adjustable arms these days it is also possible to get them with tough rubber bushes, which are also a sensible compromise for a street car.

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Much appreciate the detailed response

 

i have rod on front tension arm and cover came off so need to fix it 

can you buy the protective rubber on rod end only, i have same item as below and the eye toe shaped thing rubber has come off

https://www.driftworks.com/driftworks-tension-rods-nissan-skyline-gtr-r32-r33.html?gclid=EAIaIQobChMI5_ypvM256QIVVOvtCh30uQNvEAQYCCABEgKYiPD_BwE

 

i look at number of articles and hence why i thought front toe plays a role in oversteer but based on what you said it doesn’t achieve much?

Edited by drifter17a

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i have attached my wheel alignment specs but as it is for an AWD chassis it is not really a blueprint for you. Possibly relevant for your car :

Rear Toe in o to 1deg

Rear camber - see if there is any adjustment on the eccentrics (they don't move that much anyway)

Front castor - more will give you better straight line stability at high speeds (but you need castor rods)

Camber - 3 deg is good for track - chews out tyres on a street car.

I think my front toe-out is probably related to AWD - don't know what RWD cars use....I guess you can't go wrong with zero.

Wheel alignment specs.xls

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4 hours ago, drifter17a said:

can you buy the protective rubber on rod end only

Yes. I have no idea about your neck of the woods. But here you can get them from GK-Tech, and probably many others. They are fairly common. In my experience, all the readily available boots do most of the job, but only most, not all. They still allow grease to get out and they still allow crap to get in. So they help, but they're not perfect.

I have none on the front of my caster rods and I have made some covers out of 0.8mm thick clear PVC sheet and some velcro tie.

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