Suspension and brake questions

[Pjackb]

I’m buying a 1970 3 speed auto in decent condition,

To bring it to be my dream 510 I’ve planned amongst other things an extensive overhaul of the car including manual swap, L20B Stroker, brake and suspension upgrades. The car is a twin for the Red Baron build thread and I’m going on a similar journey The Red Baron https://the510realm.com/viewtopic.php?f ... =red+baron

For the engine I located and purchased a L/Z hybrid engine with manual transmission (Z22 block, U67 head, Cam, Sus, ZX 5spd), so for the go I’m good.

I plan to use the car exclusively for the street and not looking at doing anything crazy, I want better brakes than stock and would like to lower the car around 1.5-2” in the front and maybe 1” in the rear (TBC). For wheels and tires I looked at what I have in my stockpile, and I will be running a slightly taller than stock 195/55/15 tire on either a 15x6.5 ET22 or 15x7 ET18 wheel.

Regarding suspension and brakes I’ve taken the time to read countless of build threads, asked questions on forums and on FB and I’ve pretty much nailed down my suspension and brake upgrades but still have a few unanswered questions.

I’ve elected to go with the Silvermine Coilover kit at all for corners , for brakes I’m keeping drums in the back but still on the fence between the 10" front kits from Silvermine , DP Racing, Specialty Engineering ( Which all look the same to me ), any recommendations ?

Biggest question I have however is regarding adjustable LCA and tension control rods, I don’t feel I need them for what I intend to do with the car but not sure 100% and would like to hear opinions

Thanks
Jack

[cartel]

I wouldnt use Silvermine.

if your shortening the housings yourself buy parts from DP.. not df.. same for brakes

every car i own has coilovers in it...
but if you're only looking to go slightly lower than stock I don't see the point.. put in a set of Springs ..a sway bar .. plus also all depends on what struts you want to run what spring rates if you're not doing anything special for tires then I don't see the reason to put coilovers in the car if the rest isn't suited to match.

If you want more Caster than stock..you need adj TC rods ...if you're looking to get the strut housing shortened I can do that at work.
and u need camber plates.

one of my cars had BC racing coilovers in it when I bought it that might be all you need to me they weren't nice enough and not stiff enough . but they come with bolt in camber plates

[Pjackb]

Thanks for the response

I wouldnt use Silvermine.

Why ? they seemed to get good reviews across the board

but if you're only looking to go slightly lower than stock I don't see the point.. put in a set of Springs ..a sway bar .. plus also all depends on what struts you want to run what spring rates if you're not doing anything special for tires then I don't see the reason to put coilovers in the car if the rest isn't suited to match.

It's been my experience that springs only to lower the car tend to be either bouncy or too harsh unless you're lucky and have a good match of struts and springs. a good street coilover set will be well matched spring and shock and will offer good ride while improving handling which is all I'm looking for. I also like the flexibility of adjusting the damping (have you seen the roads in QC?) and ride height

[cartel]

the strut insert has to match the spring Rate.

there are plenty of threads here on spring rate and Insert selection. I wont rehash that.
as far as adjustable most strut inserts don't adjust virtually at all the only one that truly does is the koni race which I'm guessing is well outside the realm of what you're looking to accomplish. and others that do are triple that expense ..jrz. etc.
Tokiko is nla..kyb doesn't adjust.
the best rear coilover for the money is the camaro qa1..
the BC setup is soft and that might work well for you.

[datzenmike]

You don't need adjustable coil overs because you will never adjust them once your height is set where you like. You can tweak the stock coil and dampers to get 2" of drop and a firmer ride in conjunction with 280zx struts for the larger caliper and vented rotor. Rear spring the same with a really good shock absorber. If you don't work on your car yourself then just buy what ever sounds good.

Adjustable tension rods (increased castor) are more for high speed racing straight line stability. Increases steering effort around town. Not needed at all

[bertvorgon]

Mike is more or less right when he says you really don't need more than factory castor, for the setup you are imagining. Also for what you are envisioning, adjustability is a waste of money, drop the car to your ride height and call it dialed.

Not only does castor give high speed stability, but, increased castor upon turning INDUCES more negative camber, which at the front of the car helps with front end bite from the tires upon hard cornering. For those driving their cars hard on serious canyon carving (or racing in any form) increased castor is a requirement for that front end "bite".

[Pjackb]

Thanks guys
First I did read a LOT of the suspension discussions and recommendations on this site an elsewhere, I’ve evaluated pros and cons of the majority of options and came to the conclusion that based on my personal expectations, preference for new parts and mechanical skill level a coil over kit is the simplest route to get to the quality of components I want without having to worry about matching spring rates , suspension travel etc.
The ZX option is certainly attractive but when I start looking at the cost of finding and buying ZX struts and refurbishing them, getting Inserts , springs etc. it add ups quickly , I do know I get the brakes but I won’t put junkyard brakes on my car so I’d need to get new rotors and rebuild calipers anyway (still cheaper I know )

So while I do respect your opinion and expertise and recommendations the way I see it is that I’ll probably spend slightly more on a coil over kit I know but I can I can easily install them by myself in a few hours get the look/stance while keeping suspension travel and ride comfort and to me that’s worth the spend . And having had coils on many many cars I like the adjustability even though I tend to play with them a few time to get the height and ride I want dialed in and then get it aligned and mostly never touch again.

Not only does castor give high speed stability, but, increased castor upon turning INDUCES more negative camber, which at the front of the car helps with front end bite from the tires upon hard cornering.

Adjustable tension rods (increased castor) are more for high speed racing straight line stability. Increases steering effort around town. Not needed at all

I was more or less concerned that if I lowered 1.5-2" it started affecting suspension geometry that why I was asking if adjustable TC and LCA were required

[Pjackb]

the BC setup is soft and that might work well for you.

I have many friends running BC Racing on their Z and they're quite happy , But I couldn't find anything for 510s on their website
Could it have been a ZX coils retrofitted to the 510?

[datzenmike]

I was more or less concerned that if I lowered 1.5-2" it started affecting suspension geometry that why I was asking if adjustable TC and LCA were required

You may be thinking of bump steer. That IS affected when lowering below stock height. Easily corrected with bump steer spacers. I made my own out of 1/4" aluminum. Two of them and longer bolts set the lower control arm back to level. Corrects the induced toe in as well.

[bertvorgon]

I think to answer your question fundamentally, if you JUST cut a spring ( front) and lower the car that way, what you get is a bit more NEGATIVE camber...that is good. Castor will not change nor required. Toe will change but that needs to be checked anyhow after any mods.

What would be required is that after doing that, like any suspension modification, is you will need a regular alignment to set toe.

I will throw this in too. If just want to lower the car and not mess with anything else, it is possible to pop the top off the factory shock ( strut), drain and flush the fish oil out, and then put in some Motorcycle fork oil, Like Belray, etc, with maybe a 5 to 10 weight oil. I ran 20W for my early race years and it actually worked not badly, considering that maintained the bump/rebound characteristic of the factory shock, but, slows things down to control the slightly stiffer cut spring.

The rear is a given, you will get a bit more camber and any toe change is out of your hands in the rear...it is what it is. Only thing in the rear is over TIME, you might see a bit more tire wear. Nothing major.

As Mike said, correcting the bump steer is good, as that really does effect how the car might feel on a bumpy corner. "twitchy" is the word that comes to mind. Some people might not even notice it, depends on how sensitive a driver you are and the feed back through your seat of the pants and the steering wheel.

Speaking of the steering wheel...your steering box. All the wonderful suspension in the world is not worth the powder to blow it to hell if the box has a ton of slop.

Here is my post on how to check that, get it as close as you can, again, they suffered lack of proper adjustment over the years and had way too light of an oil in there.

viewtopic.php?f=1&t=20127&p=179694&hili ... nt#p179694

Hope that helps some.

keith

[datzenmike]

Generally steering boxes use the same as transmissions GL-4 90 (ish) weight

[Pjackb]

Hope that helps some.

keith

Helps a ton thanks really appreciated

Speaking of the steering wheel...your steering box. All the wonderful suspension in the world is not worth the powder to blow it to hell if the box has a ton of slop.

Here is my post on how to check that, get it as close as you can, again, they suffered lack of proper adjustment over the years and had way too light of an oil in there.

viewtopic.php?f=1&t=20127&p=179694&hili ... nt#p179694

keith

Thanks for the heads up on the box

Generally steering boxes use the same as transmissions GL-4 90 (ish) weight

I use straight 150W gear oil in my roadsters steering boxes makes them tight and smooth , would that be too heavy for the 510 box ?

[datzenmike]

I guess you don't drive in the snow...

[Pjackb]

I guess you don't drive in the snow...

haha
I have other cars for that

[bertvorgon]

I put heavy gear oil in mine...do not drive in winter and like to think that bought me some more years of service.

My 510 box died back in the 80's, as did the other Specialty cars, so we put in HL510 boxes in the 4 cars. At the time, we bought brand new worm and sector gears too, so that really tuned things up.

There is no doubt mine is a bit worn now, but after almost 40 years of racing on slicks and other high load tires, it is hanging in there.