22 replies to this topic

[Brandon]

I was curious if there was a compiled "interchange chart" of the parts most of us SM'ers use?

Namely control arms (what's interchangeable on front/rear, upper/lower across the years), rear uprights, axle shafts...most of the driveline bits I'm already familiar with (transmission, differential for 95+...).  Also wondering about the steering rack too (power is power is power across all years?) and column.

 

The ones available on Miata.net are helpful but not particularly thorough enough when it comes to whether they're "legal" per se (thinking track width for example).

 

Some of the areas I'm concerned with are:

Rear control arms - I know the track widths are different between the NA & NB but I don't recall whether the differences were in the control arms, subframes, or uprights.

Front control arms - Miata.net notes the upper ball joints are different (hence a spindle difference) but otherwise they're identical.

Axles?  Not certain whether 95+ axles are all identical

 

Perhaps someone already has something compiled they could share?

 

TIA!
Brandon

[Jim Drago]

I was curious if there was a compiled "interchange chart" of the parts most of us SM'ers use?

Namely control arms (what's interchangeable on front/rear, upper/lower across the years), rear uprights, axle shafts...most of the driveline bits I'm already familiar with (transmission, differential for 95+...).  Also wondering about the steering rack too (power is power is power across all years?) and column.

 

The ones available on Miata.net are helpful but not particularly thorough enough when it comes to whether they're "legal" per se (thinking track width for example).

 

Some of the areas I'm concerned with are:

Rear control arms - I know the track widths are different between the NA & NB but I don't recall whether the differences were in the control arms, subframes, or uprights.

Front control arms - Miata.net notes the upper ball joints are different (hence a spindle difference) but otherwise they're identical.

Axles?  Not certain whether 95+ axles are all identical

 

Perhaps someone already has something compiled they could share?

 

TIA!
Brandon

Some of the areas I'm concerned with are:

 

Rear control arms - They are the same, only sway bar attachments are different. track is in rear knckles

rear uprights- 90-97 are the same, 99-05 the same. 99 up slightly wider than 90-97 

axles- 90-93 same, 94-95.5 same they are two piece axles, 95.6-00 the same, 01-05 all the same... 99/00 vs 01-05 only difference is thread diameter of axle and axle nut

Front control arms upper - Miata.net notes the upper ball joints are diifferent..  upper arms all the same other than balljoint, if you have the right castle nut, they all will interchange. 

Spindles 90-93 same, 94-97 same ( i dont remember if 90-97 are all the same or not) 99-05 are all the same but different than 97 down

 

rear subframes.. all 90-05 subframes will work, difference is exhaust hangers only... By interchance 90-97 and 99/05

Front subframes 90-97 and 99-05, they will not interchange with each other.. different steering rack attachments

[davew]

Jim is about 90% right

 

rear upper control arms are all the same.

rear lower control arms are the same except for sway bar link mount. But they are interchangable, just different.

rear uprights vary depending upon with or without ABS. 90-97 all the same, 99-05 all the same. Track width difference is in the upright. They do work on any year.

Axles are different for ABS versus non ABS, but interchangable. Turbo axles have larger inboard spline and only work with a turbo diff

Front upper arms have different ball joints. Geometry is the same. Pick the same year upper and spindle and you will be fine. The ball joint holes in the arms are different sizes, so you can not just swap the joint from one year to another.

I believe 90-97 spindles are all the same except for ABS sensor holes.

rear subframes have a different looking allignment adjustment. But only cosmetic differences. Functionalty is the same

Front sub frames can be interchanged, but take some mods to mount the steering rack. If you swap the rack also, they interchange. Not legally.

[Ron Alan]

So this gives me the opportunity to ask again a question that I've yet to get an answer for. Given the rear track width is the same for all years can the NB rear upright be used on the NA car now(legally)?? 

[Jim Drago]

So this gives me the opportunity to ask again a question that I've yet to get an answer for. Given the rear track width is the same for all years can the NB rear upright be used on the NA car now(legally)?? 

No it can not.  Not unless they change the rule

[davew]

So this gives me the opportunity to ask again a question that I've yet to get an answer for. Given the rear track width is the same for all years can the NB rear upright be used on the NA car now(legally)?? 

 

It should be legal, but it is not.

[Ron Alan]

It should be legal, but it is not.

 

Who wants to write the letter??  There cant possible be any reason why this wouldn't be allowed...lets make this simple!!

[davew]

This would be the slippery slope towards allowing suspension updating. This would be easily allowed if the vocal minority would have allowed updating to all NB suspension components many years ago.

 

Makes total sense to me.

[Brandon]

When you say "vary depending upon ABS", are you referring to merely the sensor mounting holes on the uprights and the addition of the Hall effect rings on the axles or are there really practical (weight, axle housing longer) differences?

 

Speaking of the difference in uprights, is there a visual cue you can use to tell the difference?

Jim is about 90% right

 

rear upper control arms are all the same.

rear lower control arms are the same except for sway bar link mount. But they are interchangable, just different.

rear uprights vary depending upon with or without ABS. 90-97 all the same, 99-05 all the same. Track width difference is in the upright. They do work on any year.

Axles are different for ABS versus non ABS, but interchangable. Turbo axles have larger inboard spline and only work with a turbo diff

Front upper arms have different ball joints. Geometry is the same. Pick the same year upper and spindle and you will be fine. The ball joint holes in the arms are different sizes, so you can not just swap the joint from one year to another.

I believe 90-97 spindles are all the same except for ABS sensor holes.

rear subframes have a different looking allignment adjustment. But only cosmetic differences. Functionalty is the same

Front sub frames can be interchanged, but take some mods to mount the steering rack. If you swap the rack also, they interchange. Not legally.

[Ron Alan]

When you say "vary depending upon ABS", are you referring to merely the sensor mounting holes on the uprights and the addition of the Hall effect rings on the axles or are there really practical (weight, axle housing longer) differences?

 

Speaking of the difference in uprights, is there a visual cue you can use to tell the difference?

NB uprights have the raised letters "NC"on the back lower side. Front spindles on the NB car are also stamped "NC"

 

And dont ask me why the letter choice...

 

NA uprights and spindle have nothing other than L and R on the front spindles.

[davew]

Rear axles and front wheel bearings from/for ABS cars have the reluctor wheels. They are easily removable. Otherwise ABS and non ABS are interchangable. The front hubs I sell are actually ABS versions. They are $30 cheaper than the non-abs version.

 

1.6 uprights, both front and rear, do not have the boss for the ABS sensor. NA 1.8 versions have the boss. If the part is for ABS, the sensor hole is drilled and the mounting bolt hole is drilled and tapped into the boss. Outside of that all NA uprights are interchangable.

 

99-05 rear uprights, what we normally refer to as NB cars, have the letters NC cast into the upright. The letters are below the wheel bearing on the inside of the casting. Hard to see with the upright installed, but very easy to see when removed. The letters are about 1 inch tall and raised up significantly from the main casting. The hub(what actually spins), the bearing and hardware are the same for all 1.8 cars. The rear hub on a 1.6 have the smaller wheel stud holes, but are the same in all other dimensions.

 

NB front uprights have a thicker upper ball joint flange than their NA versions. It is noticably thicker by 1/4" (guess) Maybe I can get a caliper on a set this afternoon.

 

When the SMAC came up with the current track width rule, I made a zig zag bar to measure from inside of one wheel, to outside of the opposite side wheel. I only had 20 cars in the shop back then, now I have 45. I calculated average track width based on wheel offset and that info was used to make the rule. A small fudge factor was built into the number. We based our spec on a 25mm offset wheel with a couple mm fudge factor. The 24mm wheels are probably right at our intended absolute, fudge factor included measurement.

 

Dave

[davew]

had to go measure something else, so I measured the upper ball joint flange.

 

NA= just over 1/2 inch 0.55 to be precise

NB= 3/4 of an inch almost exactly

[Brandon]

Thanks for the confirmation on the ABS stuff - I had presumed they were identical in measurements with the ring being the only difference.

 

Last question: axles between NB & NAs (that use the same style) - are they longer in the NBs to account for the wider track or did they just use up some of  the "bellows expansion" space from the CV boots to accommodate?

[davew]

To quote Mr. Drago from above

 

axles- 90-93 same, 94-95.5 same they are two piece axles, 95.6-00 the same, 01-05 all the same... 99/00 vs 01-05 only difference is thread diameter of axle and axle nut

 

 

I will add that the 94-95.5 2 piece axles will interchange with the 95.6+ axles as long as you use the stub axle.

 

Mazdaspeed turbo axles will not fit anything except a Mazdaspeed Turbo diff.

[RazerX]

I would add, not sure of the exact year, but the older rear subframes, do not have a tabs with the threaded studs, on them for the cross braces that at least the 99+ have.   Some use those use the braces others do not.  

[davew]

Rear subframes are 4 designs, all have the same geometry

 

Early NA (not sure of the exact cutoff) without bracket tabs

Mid NA with only 2 bracket tabs

Late NA with 4 bracket tabs

NB with 4 slightly different bracket tabs for the NB version of the brace.

 

Note that NB2 cars (VVT motor) come from the factory with additional chassis braces under the seats. By rules these must be removed.

 

Dave

[RazerX]

Hi Dave,

 

Where is the rules on that so I can be clear.  

 

I have seen a lot of 'bars' under the NB's ones on the rear of the front subframe, ones on the front and rear of the rear subframe, and then latter type frame that is down the PTF, betweeen the two subframes.

 

Thanks

[Brandon]

The component identified as #9 is the piece that must be removed on VVT ('01+) cars.

http://quadesl.com/m...ont_diagram.gif

[Bench Racer]

   , you don't really mean part #9.

[RazerX]

Bench, is that not correct?  I don't ever recall seeing on of those.  

 

But i have seen something that was coined, "butterfly" brace.  And the ladder brace that connects the two subframes (heavy).