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Let's play "Guess that weight!"

1K views 19 replies 4 participants last post by  motorhead 
#1 ·
Heya, I must be really bored today, because I decided to write about some weights of various parts of the suspension of my '83 280ZX. I suppose it's not altogether idle, because this stuff plays an important part in determining the unsprung weight of your Z.

Anyways, here it goes:

Rear suspension arm: 29 pounds.
This is for a single suspension arm, together with axle components ( i.e. stub axle, companion flange and bearings, installed. ) along with brake tube and bushings. ( No other brake components, however. ) Gee, I just happened to have one leaning against the wall in my office.

Rear rotor: 8.9 pounds, in new condition.
( I like to keep spares around. )

Rear brake caliper: 6.9 pounds.
This is in new condition, with all hardware and including new pads.

Wheel and tire: I'm too lazy to take it off and measure it right now.

Stock rear spring: 5.8 pounds.
( This is in uncut condition. )

Rear shock absorber: 5.7 pounds.
This is for a Monroe gas shock, with all ancillaries and mounting hardware. ( One of the Monroes I pulled off my rear end earlier this year when I put on the Illuminas. ) Other shocks should be roughly comparable.

Tension rod: 2.5 pounds.
This includes bushings and mounting hardware.

Front strut assembly: 59 pounds.
This is for a complete front strut assembly in average condition: it includes the strut, knuckle, ball joint, transverse link, OEM shock and spring, mounting insulator, hub, caliper, pads and rotor, etc., and all mounting hardware. Basically what you would pull whole off the vehicle if you were to detach the tie rod, brake hose, and top strut mount, then remove the tension rod, and the transverse link from its inner mounting, and just pull the rest of the suspension out. ( Hey, I keep a spare front end around, wanna make somethin' of it? :^) )

So what does YOUR suspension weigh?

Doug Dawson
dawson@physics.utexas.edu
 
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#2 ·
> Heya, I must be really bored today, because
> I decided to write about some weights of
> various parts of the suspension of my '83
> 280ZX. I suppose it's not altogether idle,
> because this stuff plays an important part
> in determining the unsprung weight of your
> Z.

> Anyways, here it goes:

> Rear suspension arm: 29 pounds.
> This is for a single suspension arm,
> together with axle components ( i.e. stub
> axle, companion flange and bearings,
> installed. ) along with brake tube and
> bushings. ( No other brake components,
> however. ) Gee, I just happened to have one
> leaning against the wall in my office.

> Rear rotor: 8.9 pounds, in new condition.
> ( I like to keep spares around. )

> Rear brake caliper: 6.9 pounds.
> This is in new condition, with
> all hardware and including new pads.

> Wheel and tire: I'm too lazy to take it off
> and measure it right now.

> Stock rear spring: 5.8 pounds.
> ( This is in uncut condition. )

> Rear shock absorber: 5.7 pounds.
> This is for a Monroe gas shock, with all
> ancillaries and mounting hardware. ( One of
> the Monroes I pulled off my rear end earlier
> this year when I put on the Illuminas. )
> Other shocks should be roughly comparable.

> Tension rod: 2.5 pounds.
> This includes bushings and mounting
> hardware.

> Front strut assembly: 59 pounds.
> This is for a complete front strut assembly
> in average condition: it
> includes the strut, knuckle, ball joint,
> transverse link, OEM shock and spring,
> mounting insulator, hub, caliper, pads and
> rotor, etc., and all mounting hardware.
> Basically what you would pull whole off the
> vehicle if you were to detach the tie rod,
> brake hose, and top strut mount, then remove
> the tension rod, and the transverse link
> from its inner mounting, and just pull the
> rest of the suspension out. ( Hey, I keep a
> spare front end around, wanna make somethin'
> of it? :^) )

> So what does YOUR suspension weigh?

> Doug Dawson
> dawson@physics.utexas.edu
The same except I have the motorsport springs-2 drop,I guess I'll have to tear them out to give you the weight of those,
I'll get right on it:^)
 
#3 ·
Re: And ride height too!!

> The same except I have the motorsport
> springs-2 drop

Two inch drop!! What's your current ride height? I have the ST springs on mine right now, and my ground clearance is running at 3.8 inches, with no occupants or cargo and a mostly empty tank of gas. With a driver and passenger, and a full tank, it's running closer to 3.5 inches, which was the height of the BRE 510 in Honsewetz, and which Honsewetz claimed was unstreetable ( of course you and I know otherwise. )

Doug Dawson
dawson@physics.utexas.edu
 
#4 ·
I didn't know MS made 2" drop springs....

2 inches, are you sure?

How much did the MS springs cost you? I heard that the MS springs are crap, do you like them?

> The same except I have the motorsport
> springs-2 drop,I guess I'll have to
> tear them out to give you the weight of
> those,
> I'll get right on it:^)
 
#5 ·
Re: I didn't know MS made 2" drop springs....

> 2 inches, are you sure?

> How much did the MS springs cost you? I
> heard that the MS springs are crap, do you
> like them?
The guy before me put them in,
and it is lowww,he gave me all the reciepts for the car, I'll have to see if there is a P/N on these or if he cut them besides the advertised drop, it's streetable but I grit my teeth when I go over serious speed bumps at grocery stores.-- have lost a little paint from the under side until I got used to it. Drives great and about as stiff as my old Trans Am with the ws6 suspension.
 
#6 ·
Re: I didn't know MS made 2" drop springs....

> The guy before me put them in,
> and it is lowww,

Could you measure how low it is? All you need is a tape measure. One amusing thing about the 280ZX is that most of the underbody is at pretty much exactly the same altitude, as you'll see, so it's not critical exactly where you measure. Let's say the bottom of the rear swaybar brackets.

> he gave me all the reciepts
> for the car, I'll have to see if there is a
> P/N on these or if he cut them besides the
> advertised drop, it's streetable but I grit
> my teeth when I go over serious speed bumps
> at grocery stores.

YOU GO OVER SPEED BUMPS?!? At a normal ride height of just over 3.5 inches, I never approach a speed bump without stopping the car, getting out and physically measuring its height. People usually stop and stare, but that's their problem. Whoever puts up a speed bump that is too high, they deserve to lose the patronage of discerning people like us. Fie!!!

>-- have lost a little
> paint from the under side until I got used
> to it. Drives great and about as stiff as my
> old Trans Am with the ws6 suspension.

The improvement in handling just from lowering the car, and that alone, doing nothing else, is what makes it all worthwhile. Unbelievable!! Every little thing matters.

Doug Dawson
dawson@physics.utexas.edu
 
#7 ·
Re: I didn't know MS made 2" drop springs....

> Could you measure how low it is? All you
> need is a tape measure. One amusing thing
> about the 280ZX is that most of the
> underbody is at pretty much exactly the same
> altitude, as you'll see, so it's not
> critical exactly where you measure. Let's
> say the bottom of the rear swaybar brackets.

> YOU GO OVER SPEED BUMPS?!? At a normal ride
> height of just over 3.5 inches, I never
> approach a speed bump without stopping the
> car, getting out and physically measuring
> its height. People usually stop and stare,
> but that's their problem. Whoever puts up a
> speed bump that is too high, they deserve to
> lose the patronage of discerning people like
> us. Fie!!!

> The improvement in handling just from
> lowering the car, and that alone, doing
> nothing else, is what makes it all
> worthwhile. Unbelievable!! Every little
> thing matters.

> Doug Dawson
> dawson@physics.utexas.edu
 
#8 ·
Re: I didn't know MS made 2" drop springs....

As to every little thing matters,I will say this to everyone, if you are going low, keep in mind that once you go over 1 1/4 you run out of camber adjustment,great on turns
lousy on tires. has anyone come over this problem besides me?
 
#9 ·
Re: I didn't know MS made 2" drop springs....

Are you saying that you run out of camber adjustment using a Camber Bushing kit or are you saying that you need the camber bushing kit after you lower the car past 1 1/4. Also , what size tires are you running. I want to put 245's on my rear with a 2 drop, what do you guys think?

> As to every little thing matters,I will say
> this to everyone, if you are going low, keep
> in mind that once you go over 1 1/4
> you run out of camber adjustment,great on
> turns
> lousy on tires. has anyone come over this
> problem besides me?
 
#10 ·
Re: I didn't know MS made 2" drop springs....

> As to every little thing matters,I will say
> this to everyone, if you are going low, keep
> in mind that once you go over 1 1/4
> you run out of camber adjustment,great on
> turns
> lousy on tires. has anyone come over this
> problem besides me?

The rule of thumb on the 82-83 280ZX is that every inch of lowering from stock _in_the_suspension_ results in roughly a 2 degree increase in negative camber in the rear. I'm not sure to what extent you can say the same thing about the earlier-model-year 280ZX's, because the geometry of the rear end was a little different -- they made some changes in the mounting points of the rear suspension arms, among other things.

OTOH, any lowering you can do _by_the_tires_ is completely free, i.e. the suspension geometry is unchanged as far as the above stuff goes. So if a 280ZX owner wanted to lower their car, I would say definitely to DO SO BY THE TIRES _FIRST_, by going to a lower profile.

In my own case, the first inch of lowering was by going to a lower profile tire, and the rest was by the springs lowering the car a further inch or so, and at this point I'm running a bit over 2 degrees of negative rear camber, as opposed to the stock zero degrees.

You're right, this is rough on the tires. The tires I'm using are not cheap, so I'm keenly aware of it. OTOH, that's one price you pay for lowering the car and not making any other modifications. It's basically an autocross camber setting. It DOES pay dividends in handling, in that extreme cornering is more predictable on this car with the camber set like that.

The rear camber _can_ be changed back to a more normal setting, and that's one of the things I'm considering doing over the next few months. There are several ways of doing it.

How are you adjusting yours?

Doug Dawson
dawson@physics.utexas.edu
 
#12 ·
Re: I didn't know MS made 2" drop springs....

> The rule of thumb on the 82-83 280ZX is that
> every inch of lowering from stock
> _in_the_suspension_ results in roughly a 2
> degree increase in negative camber in the
> rear. I'm not sure to what extent you can
> say the same thing about the
> earlier-model-year 280ZX's, because the
> geometry of the rear end was a little
> different -- they made some changes in the
> mounting points of the rear suspension arms,
> among other things.

> OTOH, any lowering you can do _by_the_tires_
> is completely free, i.e. the suspension
> geometry is unchanged as far as the above
> stuff goes. So if a 280ZX owner wanted to
> lower their car, I would say definitely to
> DO SO BY THE TIRES _FIRST_, by going to a
> lower profile.

> In my own case, the first inch of lowering
> was by going to a lower profile tire, and
> the rest was by the springs lowering the car
> a further inch or so, and at this point I'm
> running a bit over 2 degrees of negative
> rear camber, as opposed to the stock zero
> degrees.

> You're right, this is rough on the tires.
> The tires I'm using are not cheap, so I'm
> keenly aware of it. OTOH, that's one price
> you pay for lowering the car and not making
> any other modifications. It's basically an
> autocross camber setting. It DOES pay
> dividends in handling, in that extreme
> cornering is more predictable on this car
> with the camber set like that.

> The rear camber _can_ be changed back to a
> more normal setting, and that's
> one of the things I'm considering doing over
> the next few months. There are several ways
> of doing it.

> How are you adjusting yours?

> Doug Dawson
> dawson@physics.utexas.edu

Doug,

You mentioned that the suspension arms had different mounting locations on early 280ZX.
I was contemplating rebuilding / modifying suspension from my 81ZX parts car, then swapping into my 83ZX,less downtime on 83.
Now you got me wondering about fit. Any problems with this idea?

Gleaned lots of info from this discussion. Keep up the good work guys!
 
#13 ·
Re: I didn't know MS made 2" drop springs....

> You mentioned that the suspension arms had
> different mounting locations on early 280ZX.
> I was contemplating rebuilding / modifying
> suspension from my 81ZX parts car, then
> swapping into my 83ZX,less downtime on 83.
> Now you got me wondering about fit. Any
> problems with this idea?

The _easiest_ way to get an idea of which parts are or aren't interchangeable is to look them up in the Motorsport Auto catalog and see if that part from your 83 has the same part number as for the 81. :^) I don't think you could do a direct swap. The part numbers on the rear cross-member and arms are different, so I suspect you'd have to replace the cross-member as a matched set with your arms. The front strut assemblies were also different, even from option to option and month to month. I'm not sure what's going on with that, perhaps some variation for which steering system was used on the car?

The two sets of suspensions I have for my '83 are both from the same model and month of production, so there's not much doubt that they're compatible. This is the ideal situation.

Doug Dawson
dawson@physics.utexas.edu
 
#14 ·
Re: I didn't know MS made 2" drop springs....

re. transferring a rebuilt 81 suspension into an 83 to save on downtime, I'd written,

> The _easiest_ way to get an idea of which
> parts are or aren't interchangeable is to
> look them up in the Motorsport Auto catalog
> and see if that part from your 83 has the
> same part number as for the 81. :^) I don't
> think you could do a direct swap. The part
> numbers on the rear cross-member and arms
> are different, so I suspect you'd have to
> replace the cross-member as a matched set
> with your arms. The front strut assemblies
> were also different, even from option to
> option and month to month. I'm not sure
> what's going on with that, perhaps some
> variation for which steering system was used
> on the car?

> The two sets of suspensions I have for my
> '83 are both from the same model and month
> of production, so there's not much doubt
> that they're compatible. This is the ideal
> situation.

You know, one thing you _might_ be able to do is the following. Provided you were willing to R&R the rear suspension member as well as the rest of the rear suspension, you could simply take the rear end out of your 83, and then transfer the rear end of your 81 ( including the 81 suspension member ( the big mounting cross-piece ) ) into your 83. It _might_ fit without trouble, of course you'd have to check that. THEN, just rebuild the 83 rear end while it's out, and once you've done that, swap the rebuilt 83 rear end back into the car. This way you'd have to R&R the rear end _twice_, but OTOH, the modifications that Nissan made to the 280ZX over the years were supposed to be in the nature of _improvements_, so...

You might, after some checking and measuring, be able to do the same thing with the front end. It's not clear to me what were the changes in the front strut assembly over those years, they're definitely different parts. You'd have to check it carefully, e.g. to ensure that the steering geometry didn't get screwed up.

Swapping out the entire suspension assemblies isn't difficult, it shouldn't take you any more than a day to complete the R&R on both ends, if you work carefully.

Doug Dawson
dawson@physics.utexas.edu
 
#15 ·
Re: I didn't know MS made 2" drop springs....

> re. transferring a rebuilt 81 suspension
> into an 83 to save on downtime, I'd written,

> You know, one thing you _might_ be able to
> do is the following. Provided you were
> willing to R&R the rear suspension member as
> well as the rest of the rear suspension, you
> could simply take the rear end out of your
> 83, and then transfer the rear end of your
> 81 ( including the 81 suspension member (
> the big mounting cross-piece ) ) into your
> 83. It _might_ fit without trouble, of
> course you'd have to check that. THEN, just
> rebuild the 83 rear end while it's out, and
> once you've done that, swap the rebuilt 83
> rear end back into the car. This way you'd
> have to R&R the rear end _twice_, but OTOH,
> the modifications that Nissan made to the
> 280ZX over the years were supposed to be in
> the nature of _improvements_, so...

> You might, after some checking and
> measuring, be able to do the same thing with
> the front end. It's not clear to me what
> were the changes in the front strut assembly
> over those years, they're definitely
> different parts. You'd have to check it
> carefully, e.g. to ensure that the steering
> geometry didn't get screwed up.

> Swapping out the entire suspension
> assemblies isn't difficult, it shouldn't
> take you any more than a day to complete the
> R&R on both ends, if you work carefully.

> Doug Dawson
> dawson@physics.utexas.edu
Thanks for info guys, some where down the road, it sounds like I should put in Eibach, heard they have 1 1/4 set, then go to different tire combo, Best parking lots out here are Fred Meyer, only two speed bumps not much higher than the yellow paint that covers them. worst, Q.F.C. guranteed scrapers. personally boycott those so and so's..
 
#16 ·
Re: I didn't know MS made 2" drop springs....

> Thanks for info guys, some where down the
> road, it sounds like I should put in Eibach,
> heard they have 1 1/4 set, then go to
> different tire combo

IMO you'll have better luck getting your suspension tuned to your satisfaction if you choose a non-progressive spring. The Eibach's are progressives, and they have some strange properties, and IMO are more difficult to work with, even though they look good on paper and in the advertising blurbs.

Doug Dawson
dawson@physics.utexas.edu
 
#17 ·
Re: I didn't know MS made 2" drop springs....

> Are you saying that you run out of camber
> adjustment using a Camber Bushing kit or are
> you saying that you need the camber bushing
> kit after you lower the car past 1
> 1/4. Also , what size tires are you
> running. I want to put 245's on my rear with
> a 2 drop, what do you guys think?

It would also matter what size rim you're using, on a 16 rim you'de need a 245/45, a pretty pricey tire.

I think that would be a waste. There will be some people who will disagree with me on this, but putting wider tires on any car does not increase grip. On a skidpad it won't make a difference at all. Anything past a 215 or 225 would be a waste of money.

What wider does affect is turn in response, but again I don't think you'll notice much of a difference from a 215 to a 245. I don't think the sacrifice in ride quality is worth it.

If you do it be sure to let us know how it works out for you,
Good Luck.
 
#18 ·
Re: I didn't know MS made 2" drop springs....

> IMO you'll have better luck getting your
> suspension tuned to your satisfaction if you
> choose a non-progressive spring. The
> Eibach's are progressives, and they have
> some strange properties, and IMO are more
> difficult to work with, even though they
> look good on paper and in the advertising
> blurbs.

> Doug Dawson
> dawson@physics.utexas.edu
 
#19 ·
Re: I didn't know MS made 2" drop springs....

> IMO you'll have better luck
getting your
> suspension tuned to your
satisfaction if you
> choose a non-progressive
spring. The
> Eibach's are progressives, and
they have
> some strange properties, and
IMO are more
> difficult to work with, even
though they
> look good on paper and in the
advertising
> blurbs.

> Doug Dawson
> dawson@physics.utexas.edu
I've got to quit scrolling so fast, second time i've posted before I wrote.DUH! Thanks for the tip on Eibach.
 
#20 ·
Re: I didn't know MS made 2" drop springs....

> re. transferring a rebuilt 81 suspension
> into an 83 to save on downtime, I'd written,

> You know, one thing you _might_ be able to
> do is the following. Provided you were
> willing to R&R the rear suspension member as
> well as the rest of the rear suspension, you
> could simply take the rear end out of your
> 83, and then transfer the rear end of your
> 81 ( including the 81 suspension member (
> the big mounting cross-piece ) ) into your
> 83. It _might_ fit without trouble, of
> course you'd have to check that. THEN, just
> rebuild the 83 rear end while it's out, and
> once you've done that, swap the rebuilt 83
> rear end back into the car. This way you'd
> have to R&R the rear end _twice_, but OTOH,
> the modifications that Nissan made to the
> 280ZX over the years were supposed to be in
> the nature of _improvements_, so...

> You might, after some checking and
> measuring, be able to do the same thing with
> the front end. It's not clear to me what
> were the changes in the front strut assembly
> over those years, they're definitely
> different parts. You'd have to check it
> carefully, e.g. to ensure that the steering
> geometry didn't get screwed up.

> Swapping out the entire suspension
> assemblies isn't difficult, it shouldn't
> take you any more than a day to complete the
> R&R on both ends, if you work carefully.

> Doug Dawson
> dawson@physics.utexas.edu

Sorry Jeff, didn't mean to interupt. You guys got visions of great handling dancing in my head reading your posts. Anxious to get started! Thanks Doug, I'm going to pull out the catalog and crawl under the cars this weekend with tape in hand and do some measuring.
 
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