Still having stability issues

Chuck33079

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.

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shadow85

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.

shadow85

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.

Chuck33079

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.

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shadow85

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

SouthArk370Z

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

Kudos to Chuck33079 for his excellent advice.

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shadow85

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?

Rusty

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

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OptionZero

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

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shadow85

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.

OptionZero

This is why you need to learn about various alignment settings yourself, like chuck says. You can speak intelligently about your car's setup with this shop

YOU'RE the one driving it an experiencing the stability issues

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shadow85

Yes I did read that unequal caster can make the car pull towards the side with less positive (more negative) caster.

So I guess I am going to have to go and argue with the technician on Monday that I don't care what he said about the road crown on our roads and that the caster difference is normal for alot of cars here, that I want them to be as close to equal as they can? And if he says no then I'll goto another shop?

cv129

No. You just have to tell them the alignment numbers you want.

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Spooler

Don't set the toe in the back to zero. You need some toe in for stability. That's what you have been complaining about isn't it.

AlWakRa

This is what I do all the time, and always with oem spec for rear toe, which is a slight toe in.

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