MR2 struts all around

[Xylemer]

I am in the process of building coil overs for my 73. I plan on having the car very low. I have purchased a set of Tokico HP 240z Fronts and MR2 rears and I am thinking the 1.5" section I will be removing is not gonna get me as low as I wanna be.

 

Has any one tried using MR2 inserts all around. I have ordered a front insert for testing purposes, but I wanted to know if anyone else had any experience with using smaller front and rear inserts.

 

Any help will be greatly appreciated.

 

Thanks,

 

Andy

[mklotz70]

I only chime in because I've been adding info to a strut mod thread I started on Ratsun awhile back. http://forum.ratsun.net/showthread.php?t=6895

 

The tokico's were out of my price range and I had no need/desire for the adjustability. I found that 300zx front struts are the same length and travel as the MR2 rears that all the 510 guys use up front. The hole in the mount will have to be opened up a bit since the shaft on these inserts is bigger. I've been really pleased with the ride so far, although I haven't driven on them much. The 300 inserts are 3/4" shorter than the 280zx. There's a button on the bottom of the insert, I've been tempted to remove it, but I'm not sure why it's there. That would gain another 1/4". I'd feel better about taking it off is someone could tell me why it's there.

 

For really short....there's a vw insert out there that is even shorter. You're probably after inserts that are tuneable, so this info may not do you any good.

[Xylemer]

Thank you for your help. I have read through your thread 10 times. There is great information there and part of the reason why I asked this question.

 

I have a found a lot of info on the Napa website about strut dimensions. Which brings me to my next question.

 

Why do people not use the SW20 89-98 MR2 inserts?

 

Here are some specs:

 

240z Front

Contents : 15.125"

Strut Body Length : 15.125"

Strut Compressed Length : 15.625"

Strut Extended Length : 21.125"

Strut Parts Pack # : P804

Strut Travel Length : 5.5"

 

 

240z Rear

Strut Body Length : 16.875"

Strut Compressed Length : 17.375"

Strut Extended Length : 23"

Strut Parts Pack # : P804

Strut Travel Length : 5.625"

 

92 MR2 Front

Contents : 13.125"

Strut Body Length : 13.125"

Strut Compressed Length : 13.625"

Strut Extended Length : 20.125"

Strut Parts Pack # : P822

Strut Travel Length : 6.5"

 

 

92 MR2 Rear

Strut Body Length : 14"

Strut Compressed Length : 14.5"

Strut Extended Length : 21.5"

Strut Parts Pack # : P822

Strut Travel Length : 7"

 

79 VW Scirocco

Contents : 12.5"

Strut Body Length : 12.5"

Strut Compressed Length : 13.875"

Strut Extended Length : 20.125"

Strut Parts Pack # : 17090011

Strut Travel Length : 6.25"

 

I am thinking about using SW20 MR2 Rear inserts for the rear and VW Scirocco fronts for the fronts.

 

This will make it 2.875 less in the rear and 2.625 in the front. Plus the this combination will have more travel if I am reading the dimensions correctly.

[mklotz70]

First reason that came to mind is this...... somebody, somewhere posted the year/make/model of the MR2 strut option. Everyone pretty much follows suit. Not many will take the time to dig through tons of other y/m/m's to find a different/better option.

 

Second reason.....the MR2 is a rear engine car, so I'm guessing the rear strut inserts would be valved more closely to what you'd want on the front of a Z/510. The option you found has a good length, but maybe it's too soft? I really don't know, that's just my guess for a possible reason why it's been ignored.

 

 

I came up with the Colt option while digging through an ACDelco strut catalog I found here....

http://www.acdelco.com.au/PDFs/Catalogue_ACDelco_Shocks.pdf

 

I went to the section with the sizes, found the shortest bodies, then tracked those down using the search feature, to find they're application. Since it's an Australian catalog, not all of the applications are going to cross to the US. Might be a good resource for guys trying to find shocks too. All the numbers I was crossing were GC (gas cartridge) #'s and shocks would be GS (gas shock).

 

Glad you like that thread. Thanks! On top of all the time spent digging up the info for myself and doing the mods....it takes a good deal of time posting it all. Nice to hear the info is being used. Helps to make it feel like it's worth it

[johnc]

the MR2 is a rear engine car, so I'm guessing the rear strut inserts would be valved more closely to what you'd want on the front of a Z/510.

 

Exactly. The other option is a Rabbit shocks (these things are SHOCKS not struts or strut inserts).

[JMortensen]

Plus the this combination will have more travel if I am reading the dimensions correctly.

If your plan is to get the car really low you really don't want more travel. More down travel means that you could potentially hit the chassis on the ground before the suspension bottoms. So to prevent that you'd have to run bigger bumpstops, which would mean you would be reducing travel with the bumpstop, so why bother with the extra travel in the first place.

 

If you're going to lower a car you should increase the spring rate (a lot) to keep it off of the bumpstops and try to have enough travel so that you can drive without constantly having to worry about bumps in the road, etc. If the weight of the car is the same and the spring rate goes up, it stands to reason that the car would use less actual motion on the strut. For example if you have 500 lbs per corner and a 100 lb spring on there, the car will sag 5 inches. If you put 500 lb springs on, it will sag 1". Likewise, it will move less when hitting bumps with the heavier springs. IMO, rebound travel should be roughly the same as the compression travel, but having a LOT more rebound than compression doesn't make a whole lot of sense.

 

If you have 6 inches of travel but your car is running 4" of sag, then what you really have is 2 inches of compression travel and 4" of droop on the strut. You don't need a huge amount of droop travel on a Z (again, especially one running stiff springs), and in fact it might be worse to have it then to not have it from a handling perspective. Search "droop limiter" and you'll see some other interesting conversations on this subject.

 

When you get a Z really low you start screwing with all of the geometry, roll centers go underground, bumpsteer get's really extreme, you will have pro-dive in the front, etc. You might take a look at all of those factors too before you get too excited about getting it as low as possible.

[Xylemer]

Jon, thanks for your input and advice. That really helps.

 

My plan is not to put the car on the ground. I just want my Z a little lower than most Zs I see on the forum.

 

I have not owned a Z with coil overs, so I just assume that the Zs I see here, are either set-up for correct geometry or if they go lower, the car will be on the bump stops.

 

I want to go with shorter inserts so I can have low and still have compression. I know there is a fine line between this and scraping frame.

 

I am thinking about going with the 300zx front inserts for the rear and the VW for the front.

 

Jon, you also mentioned stiffer springs. I was considering 225 or 250 lbs springs. I do not wanna go much higher, since it is not suggested to go higher, with those struts.

 

What would you suggest?

 

I do not plan to tack this car, but I also want it to be safe. It is not my daily driver either.

 

An input will be greatly appreciated.

 

Thanks in advanced.

 

-Andy