Mr2 Rear Struts fit in 280zx front strut casings?

[f1ndM3aTaco]

So I got my hands on a set of 280zx front strut assemblies and got them taken apart and almost ready for the T3 kit I got here looking pretty on the shelf.

 

I went with the DIY kit to save money and am now wondering what struts I can consider ordering for the front. I know many people just go with KYB Excel-G and have no complaints, but I would like the added benefit of adjust-ability. So I started scrolling through the parts catalog of KYB AGX's and came across something that looked similar to the struts that I just took out of these 280zx casings, and also what T3 seems to use on their 510 rear coilover conversions. KYB part number 765016.

 

Turns out it's for the rear suspension of a 90's mr2. Cool

 

Measure the extended length of the strut I have: 22in

 

Extended length of KYB 765016 strut as listed on website: 21-3/4in. Cool.

 

1/4in difference in strut length isn't gonna knock off my rear suspension too much right?

 

Only measurement I can't find online is the strut diameter. So I am where I go when I have questions. Here!

 

Anyone used mr2 struts in a 280zx front strut casing? Anyone used anything else? Tokico's are nowhere to be found and many people didn't even like how the HP Blue's handled apparently and KYB is all that shows up so I'm wondering if there's anything else?

 

Cheers and Thanks!

 

[thisismatt]

Here's what I did.  Shortened S12 200sx struts to fit Tokico BZ3125 SW20 MR2 front struts.  I don't remember the lengths, but supposedly they are:

Body Length    13.063in
Compressed Length    13.813in
Extended Length    20in

 

I've since sold this setup to a fellow ratsun member since I sold the car before I ever got to use them 😞

 

[thisismatt]

Oh, one thing that is an issue is the shaft & nut may not be the correct size for your top hats.  Mine required a machined sleeve to mate correctly.

[f1ndM3aTaco]

58 minutes ago, thisismatt said:

Here's what I did.  Shortened S12 200sx struts to fit Tokico BZ3125 SW20 MR2 front struts.

 

 Nice, so Illumina's. Good choice from what I hear.

 

What's the difference between s12 strut casings and 280zx casings? And you shortened how? Like you cut the strut casing shorter? To make the Illumina's fit? Did you tap new threads in the cut casing?

[f1ndM3aTaco]

1 hour ago, thisismatt said:

Extended Length    20in

 

Does having a shorter length affect ride height?

[f1ndM3aTaco]

1 hour ago, thisismatt said:

Oh, one thing that is an issue is the shaft & nut may not be the correct size for your top hats.  Mine required a machined sleeve to mate correctly.

I was just thinking about this.

 

Might have to send my camber plates and top hats back to t3 if that's the case and I decide going this route. Still want to see if anyone has tried this combination before with their ZX or 510. Looks like someone posted something in classifieds that looks like what I might be trying to make but I am not sure what struts he has in them.

 

 

[thisismatt]

14 minutes ago, f1ndM3aTaco said:

 

 Nice, so Illumina's. Good choice from what I hear.

 

What's the difference between s12 strut casings and 280zx casings? And you shortened how? Like you cut the strut casing shorter? To make the Illumina's fit? Did you tap new threads in the cut casing?

They are very similar.  Probably length, but diameter is the same.  I sent mine off to a machinist (Byron from the510realm) to be cut & re-threaded specifically for this size insert, which was the shortest I could find.  Most people just section and re-weld.

12 minutes ago, f1ndM3aTaco said:

 

Does having a shorter length affect ride height?

That's complicated to answer.  All else being equal, a shorter insert without modifying the strut tube will require you to pack the top and/or bottom to encase the insert so it can't slide.  The idea of the shorter insert is to shorten the tube, so you can go lower and maintain bump travel and keep the insert within its operating range, typically with a stiffer spring than stock.

[f1ndM3aTaco]

1 hour ago, thisismatt said:

The idea of the shorter insert is to shorten the tube, so you can go lower and maintain bump travel and keep the insert within its operating range, typically with a stiffer spring than stock.

 

Makes sense. How much did you have to cut your casings to make the mr2 strut fit?

 

I don't know what the original spring rates off the top of my head are for my 79' 210, but I got 300lbs coilover springs from Hypercoil that came with the t3 kit. I know they're definitely stiffer than stock but I am not sure exactly how much more, I ordered based on the recommendation from the service rep I was dealing with. Stickers on the car say car's "emissions curb weight" is 2,250 pounds or something like that.

 

So if I have stiffer springs how do I know how short a strut I can run? Compare compressed length measurements of struts? I don't want to use anything too short (more than a couple inches) cause I'm not trying to drop the car significantly.

 

Thanks a bunch for the responses by the way.

Edited February 23, 2020 by f1ndM3aTaco
missing words

[thisismatt]

300lbs is pretty stiff from what I've heard.  Never got that far on my 510 unfortunately 😞  I think I chose 250lb springs and I was planning a V6 swap.  I don't remember how much was cut off, but here are a couple pics showing the original and cut w/coilover.  I tried to superimpose one on the other in the 3rd pic...

 

 

 

 

 

Looks like I took about a tube diameter in length off.

Edited February 23, 2020 by thisismatt

[datzenmike]

300's a bit much I think. 510 racers max out at around 300 pounds per inch. I would think you would fall somewhere in the 175 to 250 range. My 710's (which is heavier at 2,750) are 150 lb/in which is 50% more than stock and quite a bit firmer but comfortable on the road on long trips. Not that great on rough roads.

 

I think the question is... how much do I want to lower my ride height. Up to 2 or 2 1/2" you can use your stock struts. There's enough travel to lose this much and still have enough travel to not bottom the strut out if the spring is stiff enough. At 300 lb/in I would guess so.

[f1ndM3aTaco]

Thanks for the responses guys.

 

It looks like I'm going to be sending some goodies back to t3 for the proper parts now lol. They said that "wouldn't be a problem" so we'll see how well they hold up to that. From what you guys have said and looking up some more info I think I'm going to go with 250 or 200lbs. What do you think would be better for a spirited a14? I've decided I'm gonna go EFI so I'm hoping to make something right under 100hps by the time I'm done. So 200lbs?

[datzenmike]

Start low and adjust up if needed. The lower you go the greater risk of bottoming out the body/oil pan/muffler etc. so spring rate should be increased to compensate. At some point the ride comfort is compromised and it's no fun driving. Lighten the spring rate and raise the car slightly to get where you want. Keep in mind that to some extent the shock absorber has an effect on bottoming and the stiffness of the tire make and the amount of air pressure inside it. 

 

A light car will use a lighter spring rate than a heavier car and younger drivers can tolerate a heavier rate spring than older drivers. Like I said I run 150 in my 710 and I can't imagine what a 300 rate in a car that's 500 pounds lighter would be like.