510 scrub radius and wheel fitment calc

[Boy Blunder]

The biggest thing on my 510 was getting rid of the rear positive toe change, THAT just transformed the car back in the early 80's and has now benefited most on this site, to keep the rear inline with an imperfect independent suspension.

These two books were my bibles for a lot of years, long before the Internet came along.

Thanks for chiming in again.

If I may kick this horse again.. Remind me. What did you do back then to get rid of the rear positive toe change? I have discussed this inherent issue often with the previous owner/builder of my car. My 510 is " dampened stiff as hell" with not-kidding-you Koni 30 series circle track spec shocks. The shocks are monsters.. yet running a 250lb AFCO spring. Im fairly convinced on my setup that the shock is doing more work than the spring. I know I'm not getting mathematical here, but I can tell you the solution on my cars build is to limit the travel of the rear suspension by the force of the dampening itself.

[bertvorgon]

Let me re-phrase that...I have made sure the rear does NOT toe out.
We fixed that back in the 80's by making the rear camber/toe brackets ( which Byron now sells ), so that we can run static toe in, and enough that as the suspension goes through it's travel, it does not ever go to toe out. That I/we run quite stiff springs also helps with the AMOUNT of suspension travel. As you say, we all try to eliminate the large travel, but, at the same time, we do need some travel to be compliant with bumps. The balance becomes running enough rear toe-in, that in the largest real world bump in a corner, you do not toe-out.
The shock issue is just that...an issue. re-read the suspension thread where I talk about the need for proper valving to compliment the spring. I never liked the Koni shocks, just found the bump/rebound was way too stiff, so that I got "jacking" in lineal slaloms, etc.
Yes, by making the shock/travel as minimum as possible will work of course, the ability to have some compliance and feed back as to what the rear is doing is important. I slalomed for a ton of years, so I did not care about the large rear toe in I run, as tire wear was not an issue. The ability to not have the rear steer the car was the all important criteria. Even today, where all my driving is on the street, on our high speed drives, I still run the same rear toe-in. I want nothing to do with high speed oversteer, for all the reasons.

[SteveEdmonton]

I have done some reading on the bluebirds list and it seems like the 280zx strut spindle angle is slightly disputed...
http://www.datsun510.com/bbmail/2006-2/5878.html

This image from datsun510.com also supports your findings....


I have 2 sets of zx struts. 1 set with 510 perches that I ran on the car before with the 14" early 200sx rims and the set I'm am running now that are done up with coilovers and zxT snowflakes.

The first setup with the 200sx rims and 510 perches/random springs suffered visible from positive camber issues (no camber plates first year).

After doing up the coilovers on my other set of zx struts and installing them with camber plates and everything this year, I am maxing out my camber plates (positive) to give me front camber of between 0* and -0.5*.....

I am thinking that I may be a victim of crazy angle zx struts.
When I get home I will most definitely take them all apart to compare and try to get to the bottom of this

Jordan, did you ever get to the bottom of this "positive camber with 280ZX struts" issue? Anecdotally, I thought I observed the same thing when I installed the same setup you're talking about, a month ago. 280ZX struts, 510 perches & springs. It looked like I had positive camber. So I pulled that setup, popped in my old 510 struts, and ordered a set of coilovers to deal with the problem.

However, when I mentioned this in another thread a few days ago, members of the brain trust assured me that all 280ZX struts have 10 degrees of spindle angle, just like the 510 struts. So I finally did what I should have done a month ago: I pulled apart both my 280ZX struts and the stocker 510s, to compare angles. And sure enough, they're both 10 degrees.

That leaves me puzzled, though, about why I thought I saw positive camber with the Frankenstrut combination (ZX struts, 510 perches & springs). What was up with that? Something installed wrong? Optical illusion? Plain old mistaken-ness?

This isn't just an historical question either. I haven't actually installed my coilovers yet, and so going back to the 510 perches & springs remains a live option. No caster / camber adjustability of course (my camber plates are the ones from DP racing that have some built-in caster), and if I run with the stock 510 springs I'd obviously not be upgrading in the handling department the way I would be with the 300 lb coilovers. If I cut them by a coil, I'd be getting a bit of an improvement, but clearly not the same as with the new springs.

So anyway: Did you ever account for the positive-camber issue you encountered with 280ZX struts and 510 perches / springs (your setup #1)?

[Byron510]

Just for reference, I put a lot of effort into this spreadsheet years ago, it's a good time to post it again.

The illusive 12 degree strut has never to my knowledge been recorded, only reported many years ago but someone and it somehow became gospel. If it exists, that it need to be documented. But I have measured over a dozen ZX struts, turbo, NA and through the whole 4 year production run.

Byron

[SteveEdmonton]

Thanks Byron. I guess it wasn't clear, but my goal was not to perpetuate that myth of 12 degree struts, which I think contributed to my own "perceived issue." My actual measurements, when I finally did them, confirmed what you have documented much more fully.

Rather, I'm curious why both Jordan and I seem to have had unexpected camber with this particular combination of parts: 280ZX struts with 510 perches springs. Simple coincidence? In particular, if he learned something as a result of his experience, I'd be glad to know what it was, to help me in my present situation.

Maybe the combination of your data-table and Jordan's and my experience can help others avoid this problem in the future.

[Byron510]

Hi Steve,
Understood. The chart was posted more for general interest as the original post from somewhere before 2006 seems to be non-exist anymore on the site.
You didn't by chance change the steering arms as well to the 280zx did you?
I didn't see it mentioned, but I thought I'd ask.

Byron

[icehouse]

The 300z struts have the same strut angel as well. I just checked a set I had laying around the other day.

Steve adding caster with your camber plates will add some bump steer to your setup. Just to let you know.

[duke]

Another thought on scrub radius. I recently swapped over to 280zx steering arms (for a faster steering ratio). Because of the location of the ball joint hole in the arms (further outboard than the 510 arms), wouldn't this reduce scrub radius? I know that I had to lengthen my LCA's 1/2" to keep the same front track. In doing this swap it does feel like I lost a little bit of feeling from the steering. I'm wondering if this is because of the loss of scrub.

[broke]

Hello, I'm here to claim my prize for finding the ZX struts with the different angle to a 510.

The more I google my C32 strut conundrum (see my other post in suspension) the more I see folks claiming these don't exist. Yet I also see people saying their camber is f@&ed after fitting ZX struts. So here's my proof that there is a difference. Had to drag these inside and use some leftover wallpaper behind them because the lighting's so terrible in here.

F1CEB061-35F0-4778-93CD-C775DD8BD9B4.jpeg (221.61 KiB) Viewed 1416 times

As you can see, the 510 strut tube (the rusty one) is at a very different angle to the ZX one.

Part # to prove it's a ZX strut:

EF9A8692-1071-4773-BB1E-50A5CBB0D1AE.jpeg (185.21 KiB) Viewed 1416 times

Now when I first looked at these in my other thread here, I thought the 510 spindle was at a different angle than the ZX one relative to the base where the ball joint attaches. However, I didn't notice the small unmachined area shown - as it turns out, the spindle angles may actually be the same relative to the balljoint mounting area - they may not be also, I don't have anything to accurately measure it and the phone doesn't like focusing on the shiny areas.

D9B1EDA8-3965-411B-8701-59CB45F2CED2.jpeg (339.33 KiB) Viewed 1416 times

HOWEVER I also noticed that Byron and others have been measuring the angle of the strut tube relative to the flat area on the bottom of the strut, assuming that the ball joint mounting flat will always be perpendicular to the strut tube, when in fact it definitely isn't on some of them.

Therefore it's the angle of the spindle relative to the strut tube that should be measured. This, I think, is where people get the idea that the difference in angles is a myth.

660BFD66-E69B-4832-BF6D-085D09199ACE.jpeg (250.91 KiB) Viewed 1416 times

It makes sense when you think about it - If Nissan were going to change the tube angle, then logically the base would have to be machined at an angle to correct the ball joint angle to keep it in the same spot, otherwise it might be possible to over-articulate it.

This also makes me wonder if it's not the ZX struts that have differences, but the 510 ones. I'm aware there is an early and late 510 strut, same with the ball joints and steering arms. Unfortunately I don't know what year the the 510 strut I have here is, and there are no numbers I can see stamped into it either.

I talked to a mate here who lives and breathes S130s and he doesn't think there are any variations. Perhaps some re measuring of people's strut stashes is in order.

[Byron510]

Good day, Broke,
Way to wake up an ancient thread, my friend!

Ok, method…
Every single Datsun strut I measured in my spreadsheet, including the Z31 set I last added (thanks to Jeff donating a set to the cause) - every single one of them has a base (where your steering arm bolts to the bottom of the strut) that is absolutely perpendicular to the strut tube. There are no exceptions that I have ever seen. And I have seen and machined more than my share - especially 510 and 280ZX, S12 and 300ZX. Having a strut in a lathe will tell all.

The reason for the bottom of the strut being perpendicular to the strut tube? It’s the easiest way to manufacture them, Hands down. Why add another operation. Now what does change between all of these cars is the angle of the ball join stud compared to the Center line of the strut tube, which totally affects the static camber of any set up. Mix and match wrong, and it’s a huge difference - but that’s another story- we are talking only struts here…

The other constant is that the backing plate area behind the the spindle will always be perpendicular to the spindle axis - because it’s all machined in the same operation.

So a measurement between the two (spindle forging base and the back of the spindle face) will net you the spindle axis variation from horizontal.

Your arc in the photo above will show 100 degrees.

So, I have to clarify because I wan to learn about what you claim to have;

- a strut tube bore in the spindle casting that IS NOT perpendicular to the base and also not 100 degrees from the spindle axis?

- a strut tube bore in the spindle casting that IS perpendicular to the base but not 100 degrees from the spindle axis?

Let’s see a measurent, and a method and tooling used to which your measurement was taken. Obviously an accurate measurement can’t be taken off a heavily corroded and or dirty surface - were talking 2 degrees here which is easy to foul up.

As a machinist, I’m used to dealing with accurate tooling. And I can attest that the accuracy of what has been measured is correct.

Also, remind me again - the C30 is the same platform (chassis) as what we got in North America as the Maxima - correct?

Love to hear from you, and let’s see if you ah e truly found this mythical 12 degree strut.

I am damn near positive however, that no Datsun in my list above ever came to North America with a 12 degree spindle angle on any strut - and here in North America is where the myth began!

Byron

[broke]

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