Wheel Alignment Perfect; car still does not go straight

[JBT]

Turn in is just right for me and effortless IMHO. Stuff all understeer. Goes around corners like it's on rails - better than my koni/king NA ever did. Yes, the car has stock suspension but it's nowhere near factory settings, which were positive front camber and 6 mm toe in, all of which were changed within 24 hours of ownership. I have trouble getting the back out too - damn DSC/TC always seems to fix that if I get too ham fisted.

It'll be out on a track day on Thursday and should run just as well as the previous NC did with those settings........and the DSC/TC will be off.

I'm glad to see that you've gone from having an alignment problem to having no problem now.

[JBT]

Why would it go toe out when you're moving?

Forces. Ask an alignment specialist or do a Google search. Here's one.

[eastla]

I'm glad to see that you've gone from having an alignment problem to having no problem now.

LOL!

It is one of those problems that may be in my head?
As far as VDC/TC; mine is always fully switched off so all of the comments I made are based on that.

Can you get the back out with your VDC/TC switched off?

I have a mate with a stock NC who seems to be able to now that his tires are a little worn in.

Seems like the characteristics change significantly with tire wear.

Have you ever tried a more agressive alignment?
I wonder if you would think its better or worse?

[JBT]

Can you get the back out with your VDC/TC switched off?

Of course, if I'm ham fisted/footed enough, but I never drive around with it off unless I'm on a track. Why would I turn off a primary safety feature?

Actually, now that the tyres have 6,500km on them, they're very grippy indeed - most impressed with these Potenzas.

Have you ever tried a more agressive alignment?

Nah, the car spends most of it's time in non-track driving and there is little point in causing all the extra tyre wear associated with more camber.

[eastla]

Can you get the back out with your VDC/TC switched off?

Of course, if I'm ham fisted/footed enough, but I never drive around with it off unless I'm on a track. Why would I turn off a primary safety feature?

Actually, now that the tyres have 6,500km on them, they're very grippy indeed - most impressed with these Potenzas.

Have you ever tried a more agressive alignment?

Nah, the car spends most of it's time in non-track driving and there is little point in causing all the extra tyre wear associated with more camber.

My VDC/TC cuts in WAY too early which in the end made me decide to have it off.
I have a feeling my mods have made the VDC/TC come in even earlier than stock

I cant even accelerate hard out of a side street with out all my power being reduced with the TC.

I have to agree about the Potenzas; they seem to be a very good tire.
At first they were very noisy (screeching) but now they have quietened down and seem to stick beautifully.
I think that this has helped me get the over steer; due to more front end grip.

[eastla]

Why would it go toe out when you're moving?

Forces. Ask an alignment specialist or do a Google search. Here's one.

Oh well, as long as eastla is happy having changed nothing. I'd still be checking the dampers and sway bars.

I am happy with the handling; always have been.
But still will be getting my wheel alignment looked at; also will check the suspension out once I get a friend to help me; rather not pull my boot trim apart on my own.

Will probably do these things after the track though.

[JBT]

Ok, but whats wrong with a bit of toe out? It shouldn't be making the car wander differently on or off power, just make the car darty on bumps in extreme cases.

If you like darty, that's fine. What about weight transfer during power on/off? Surely that would load/unload the front suspension and cause some changes - not necessarily desirable with static zero toe or toe out.

That link was just one of dozens available - they all say much the same thing.....facts about alignment terms and settings.

An MX-5 is a sports car.....and a road car. You can also use it, like any car, as a race car. You may want an alignment for track use, others may not. Neither is wrong but they are all compromises.

[eastla]

Ok, but whats wrong with a bit of toe out? It shouldn't be making the car wander differently on or off power, just make the car darty on bumps in extreme cases.

If you like darty, that's fine. What about weight transfer during power on/off? Surely that would load/unload the front suspension and cause some changes - not necessarily desirable with static zero toe or toe out.
.

That makes sense to me; probably some of my problem.
But considering I like the rest of the handling and feel it is probably worth the slight inconvenience to me.

[eastla]

Either way it shouldn't affect the car, not what he is describing anyway.

Could you please clarify what you mean?

[eastla]

Either way it shouldn't affect the car, not what he is describing anyway.

Could you please clarify what you mean?

I mean, the fact that you have an agressive alignment doesn't mean you should be getting a car that tracks differently on to off power, as you described in your first post, so that changing the setup to a more street friendly setting shouldn't be what you have to do to get rid of it. Something is set wrong.

Oh, thanks for the clarification

[eastla]

Update:

I decided to get a wheel alignment again today.

There were a few issues with the before alignment.
Mainly the camber at front was not 100 percent equal.
Also, there was quite a bit more caster on right than left.

Now after the alignment.
I have more caster to the left than right.
Also have 2mm toe in at the front.
Back is around 2mm toe in
Camber front is approx 2.3 and back approx 2.

Well it seems to be going straighter now; have not tested it fully but it is definately improved.
Steering feels better too.
Better centre feel and at speed feels more direct.
Not sure how it will perform with hard cornering yet.

[JBT]

That looks a bit more \"street friendly\".....hopefully you'll like it. I'm thinking about getting a bit more negative camber on the front of mine.

[eastla]

That looks a bit more "street friendly".....hopefully you'll like it. I'm thinking about getting a bit more negative camber on the front of mine.

Yeah it is a bit more street friendly while still being aggressive enough for my track days.
After some more driving I have to say the whole car seems to handle better.

The front end seems to have more grip and also gives me more information through the wheel.
If anything I can get the back out a little easier than before too.
My steering wheel centres itself better and seems to give a more direct feel .
So far there seem to be no disadvantages and only positives.
Also, now my car goes pretty damn straight!

As far as your alignment goes.
I think you may be surprised at the improvement you get with more camber.
If you go to neg 1 on the front that is still fairly conservative too.
You wont have any real problems with tire wear, especially if you drive enthusiastically fairly regularly.

But if you want something a little more aggressive but not as agressive as mine.
Go something like
Front -1.5 and back -1 camber
Keep 2mm total toe in on the front and back
Max out the caster, but stagger it with more to the left than right.

If you are after a very safe car that will understeer push when you over cook it reverse the camber above.
A lot of this has to do with particular driving style too; also the condition of your tires.

But I know that with my driving style and tire condition I would have way too much understeer for my liking with more camber on the back then the front.

[eastla]

Glad we could be of service

I had a good feeling that the alignment was the main cause. I've seen it too many times. I mean, i don't work at JAX and do dozens of alignments a day, but i see enough alignment specs to tell me what is wrong with an alignment just by a few numbers and a complaint.

Good to hear it's improved

Thanks again,
It is a big improvement and does go very straight now.

[Charlie Brown]

Good to hear that it’s all working well now eastla.
I agree with your alignment comments to JBT however I’m not sure if he would be able to get -1.5 camber up front with standard springs. Some owners can only get -1 while others -1.6. Just the luck of the draw I guess.

JBT, I’d max out the negative camber on the fronts and then set the rears 0.3 less.
Wear won’t be a problem. I’ve been running -2 to -2.3 for the last 25K on this set of tyres and the insides only show about 1mm more in tread wear and I’d still have another 15 - 20K left in them.