Still having stability issues
 

Been having this issue for a long time.
Car will not track straight when I let go of the steering wheel, it feels like it always wants to pull to one side almost immediately, also sometimes more pronounced when I hit the brakes.

Cannot do hard launches because it almost instantly wants to fly into another direction off the line! Even with only a small amount of hard throttle it can feel like it wants to do that.

This problem only seems to happen randomly, some days the car feel like it will travel straight at cruise speeds and launch straight, some days I have no hope at all.

I have had 2 alighnments done from 2 different alignments centre in the past 6 months. The 2nd one they also installed brand new MCA street Ultimate coilover and set the softest setting on the back before they did the alignment. After I picked the car up from them, everything felt perfect and stable, but only for a few hours of driving which after it went back to crap again. They said they will look at the car again next week.

Just trying to get any opinions if anyone knows what the hell is going on before I take the car back to them.

Could it be something to do with any of my parts not functioning well?
I have added these parts all at the same time:
Z1 urethane motor and trans mounts
Whiteline diff bushin kit
Quaife LSD
Z1 Premium SS brake lines
Could it be that a long time ago my aggressive offset Meister S13P wheels on the front 19x9.5 +17 scraped the Akebono calipers for a little while, could that have done some damage to cause my current issue? Brakes pushing the wheel or something?

I have uploaded the latest alignment sheet.

https://i.postimg.cc/N0ppTJNg/New-Do...20-18-41-1.jpg

Just off the bat a caster is over a degree different side to side

I can't remember - did you get the SPL FUCA?

Yes I have SPC front camber kit and eibach rear

Caster and rear tow setting are off.
Car Suspension Tuning Guide| Rapid-Racer.com..

You didn't read what i wrote

S P L F U C A

Your caster settings are clearly off, they shouldn't be over a degree different side to side. I don't know if something is wrong with your components or if your alignment techs are incompetent but you should talk to them about what there is such a delta between left/right front caster

The SPL Fuca (not the dumbass SPC ones) have a MUCH greater adjustment range with much better components. It is unclear if the components are the issue or your alignment shop but AGAIN, you should ask them about this

if your suspension adjustment in front is already maxed out, you're going to need to upgrade

then again, you should upgrade them anyways

Ok sorry just realised they are different things lol. Yes I have only the SPC front camber arms and eibach rear camber/toe kit.

And I will purchase what ever the hell is required to get this damm issue sorted lol

So if it is reccommended to install the SPL FUCA then I will go ahead and purchase that. So looking at my alignment sheet, is that the reason why my car is acting abnormal when trying to go straight?

You have over one degree difference in caster. That will cause a pull. Which way is it pulling?

Yeap, he is toed out in the rear at a -0.1. Have your toe settings set this way. This will cause the car to not track straight when and if you start spinning the rear tires.

Front:
Left: 0.5
Right: 0.5

Rear:
Left: 0.9
Right: 0.9

I missed that. Not good either.

And the tech did not go over the effect of the new alignment with you? The rear toe-out (instead of toe-in) is alarming, that a reasonably knowledgeable technician doesn’t give you any warning at all. Toe-out isn’t for everyone, certainly not the safest thing for a street car.

Shadow, I told you months ago you had an alignment that was AFU.


Sent from my iPhone using Tapatalk

He was definitely told. Had the same problem the last time he posted about his alignment:
Same issue with the castor

SPL catalog + better alignment tech

Are you going to some generic consumer alignment chain or a shop that actually does custom stuff for sports cars?

Call Mark Povey at SA MotorSport Tyres (0409 288 380) and ask him for the name of a race alignment shop.

Please stay away from rear tow out - it creates dynamic instability under power and the car can get away from you real quick.

PM me if you want more personal info.

I'm in Vic but I do know a bunch of motorsport people in Adelaide and can connect you to the skills you need.

Not all heroes wear capes, i think OptionZero and BGTV8 just saved the day :rock:

I was just looking at the alignment sheet on my old car and they had my rear toe at 0.15" and front toe at 0.10".

I think mainly it pulls to the right.

Nope none of the techs did :(
And I told them all my severe problem of not being able to keep straight, especially under load.

Yes I do know this, that is why I have been trying to get help here and seeing other alignment shops to sort me out. I just can't get a break being in Adelaide I have no support! lol


Yeah that is why I have been ringing around other shops to see if I can get better results. And there is no way I have been taking my car to generic service shops, not a chance, I love my car so much I spend top dollar to make sure it goes to the most reputable high performance workshops in Adelaide. Unfortunately it just has not proven to be that successful as you can see.

And do I really need the entire SPL catalog or do I just need the FUCA and a better tech. Isn't the entire SPL catalog going to cost me like $5K?? lol

Thank you BGTV8 I will call Mark ASAP. I really need some better help on this one. You are totally rite, the car very quickly gets away from me under power. I have had so many near misses and one actual curb hit!

at minimum, SPL FUCA
used sets pop up all the time but since you're trying to fix the problem you can just get a new set of those now. SPL FUCA adjusts both camber and caster to a much larger range than the SPC crap

I would directly talk to your last tech to see why he left the caster off

It’s also time to take matters into your own hand a bit, need to educate yourself in what camber, caster, and toe do. Even if you have a miracle mechanic, you still gotta know your stuff, as that’s half the battle.

Ok kool, I will order the SPL FUCA.

Btw, is SPC front camber arm and the SPL FUCA replace the same part on the car?

Goddamm if I knew that I would have gone with SPL version in the first place, I had my SPC ordered from Z1 so I had to pay for international shipping anyway :(

And since it was mentioned my rear toe out needs attention, what part should I be looking at buying to fix that up or should that already be fixed with eibach rear camber/toe kit thats already on the car?

:icon14:

Yes
thats why im telling you to switch

Im pretty sure youve been told to go spl before

I know i say it in every post

lol I did not know this because they are worded differently. SPC words it as front camber arms, and SPL as upper control arm.


Ahh man, I can't recall it but I think I remember choosing SPC because it still seemed to have good reviews by ppl on here.

So I emailed SPL aswell with my alignment report to see what their suggestion also is.

This is what they replied with:

"I would get bumpsteer adjustable front tie rod ends and check the rear bushings for the dartiness. A camber arm would not be a bad idea in the rear to get the camber equal on each side and get rid of the deflection in that bushing. The traction arm might also help if you are lowered to keep the toe from changing in the rear to get the car from moving around on you."

i would PM BGTV8 and get a recommendation for a better alignment shop

Talk to them, make sure they understand the problem and can handle it

Your caster numbers show a right pull. Which ever side is closer to zero. That is the side that it will pull to.

You need the SPL upper arms to adjust for camber and caster. The dartiness is from the rear toe. Once you get the SPL upper arms. Try these align specs.

Front camber -1.7
Caster +6
Toe 1/16" in

Rear camber -1.7
Toe 1/16" in

These are good street specs. If you want more of track spec. You increase camber, and start to get the toe closer to zero. Then the car becomes darty.

Im going to try his contact here at SA motorsport tyres first as he reccomended then I will PM him if needed.


Your absolutely correct. It pulls mostly to the rite and very much more pronounced when trying to launch it. At which point the aggressive TC kicks in cuts throttle.

OK I will note this down and present it to the next alignment centre. Curious about drag racing aswell mostly, would these settings also be good for drag racing or would I need a new alignment altogether for that?

At some point in the future when all my car issues have been sorted I would love to hit the strip. :)

For the strip. The rear camber should be close to zero.

Shadow, please don't take this the wrong way but you really need to educate yourself better. I'm not talking about just asking questions on this forum. Learn what all of the alignment settings are telling you, and why they are causing the unwanted behavior. You've had a hard road on this build. Some of it is that you're in a place without a lot of support for a boosted Z, but a lot of it is that you went into this well short of the knowledge level you need for this project to have a happy ending. You need to bring yourself up to speed. Talk to the local autocross and track guys guys. Go on amazon and buy a bunch of books. I recommended Corky Bell's book on turbos before. There's a lot to read on handling as well. Some of the books are older, but physics is physics. You need to know WHY things are happening, not just what part the internet says you need to buy. Not all problems are solved by blindly buying parts and throwing them at the car.

Honestly, become BGTV8's best friend and sponge all of the knowledge you can off him. You can still salvage this project, but you need to study your *** off. My rough math has you well over $25k in parts in US prices, not to mention the shipping and currency differences. I figure you've spent more on mods now than the car itself. You're invested very heavily so you need to bring yourself up to speed before you end up having wasted a ton of money and time (or before you launch a very powerful car into a tree and end up crippled or dead).

You decided to start this game on hard mode. You're in it too deep to punt now. Get a good alignment from a shop that works on track cars. Read a bunch of books. Go get track time with an instructor riding shotgun with you. Become an expert. Work on the car yourself so you know how things fit together and why they do what they do.

Thanks chuck.

I started learning about the alignment settings today. Yep, getting familiar with camber, caster and toe-in/out effects because 2x motorsport alignment shops failed to educate me on it even though they both were in the $$$ price range of alignment services and were happy to take the money. The only thing they left me with, is come back if you have trouble.

I know I went into this adventure without much knowledge into the Z platform or even cars itself mechanically, I was hoping that if I pay the price I could have the professionals sort me out. Isn't that their job and what they charge so much for down here? I didn't go to any cheap workshops or budget friendly workshops, they were all the most reputable and pricey ones. So I was hoping that my hard earned money would be enough to see me through whilst I slowly learn about each little thing, but apparantly it has still proven to be more difficult than that.

But I did learn a great deal thus far, much of it thanks to you guys.

Oh I did not blindly buy parts and throw them on the car, I researched almost all the parts I bought minus a few such as the SPC upper camber arm. And I gave them to the professionals to throw on, and they all told me that everything I bought was of high quality stuff.

Yes you are rite, I have spent alot on parts and almost as much on labor and more than the car itself. I am nerly at 2011 GTR money down here. If I had of known how hard it would be to build a Z in South Australia before I would have just saved for that GTR lol.

Oh, and whilst the car is having stability issues I won't be turning TC off, so I won't hit a tree lol. I hit a curb one time because I had it off briefly and since then I do not turn TC off anymore, not until I am certain it won't lose control in a straight line.


I honestly thought I have been trying that already ?
Both the alignment shops I went to already, had a repuation for track cars and they both directly told me in FB messenger they do drag setups frequently. I am unsure if I made that clear or not in a previous post, but I feel like I don't have much choice down here now. Anyways, imma get the required SPL parts and retry another alignment from one of BGVT8s reccommended guys.

OK So I understand I need to purchase the SPL FUCA to help with my caster difference since my current SPC set maybe already maxed out (waiting for the alignment centre to get back to me on that)

And I also now understand that the rear toe is out and should be toe-in for better stability and street use, but what I am unclear on, is if adjusting the toe to be in on my current hardware is possible or do I need to upgrade the rear parts aswell to be able to adjust the toe-in on my car.

Still waiting to hear back from the alignment shop why my result had toe-out.

You've been trying, but because you don't know the questions to ask you can't tell if they're full of ****. That's why you need to get yourself to the point where you don't ask for a "good alignment", you ask for X degrees camber, Y degrees toe, etc.

Just because someone has a shop and works on cars for a living does not mean they are good at it. It just means they have a shop and work on cars for a living. It's hard to figure out who's good online since bad reviews always seem to disappear and the good ones stay up.

Ok, I will have more input to the next alignment shop this time lol

It sounds like you are on the right track now, OP - knowledge is power.

Kudos to Chuck33079 for his excellent advice.

UPDATE:

Ok I have finaly spoke to the alignment centre to discuss the results of my report.

1. Caster difference of 1°
They told me that this is the absolute norm for our Adelaide roads. Apparantly it is set this way on all cars because our roads have a slope on the left side of the road because of alot road crown here. They told me that even cars from factory here are released with that sort of caster difference. He said the only time they make caster equal is for track or drag cars, so the difference on my result is normal for street use.

2. Toe-out 0.1
For this matter they told me that for a drag setup they want the car to be as close to 0 toe as possible. And on my result that 0.1 is actually 0.001mm or something like that so there really is no toe-out at all. They rekon if they adjusted in the other direction slightly it may have jumped to 0.5 toe-in so thats why they left it at -0.1.

They said when I bring the car back in they may decrease the difference in caster slightly incase my car is more sensitive to the 1° difference and check the toe bolts have not loosened which caused the alignment to shift. They will compare results from the day the car left to what it is now.
Any thoughts in this?

They are blowing smoke up your azz with a sunshine pump. :shakes head: Our roads here have a crown in them too. And the cars are set close to equal caster.

Do they think you're driving on a fuckin' circle track to and from work?!

Well I don't know what they think. But the shop has a 950whp Nissan S15 that they do alignments on for track use, surely they must be capable of fixing me up? Lol

Anyways, Ill see what happens when they re-adjust next week. Ill try and ask them to get me a more equal caster and toe-in as close to 0 as much as possible.