New lower shock mount

I need to raise it 13mm. This is my idea. T6 aluminum plate, but 13 mm thick ,17mm thick, or 19mm thick.  See drawings please.thank you. 3rd and 5th photo will give idea on oem  lower shock location 

If I understand what you want to do.......you're proposing to bolt the plate to one side of the A-arm using the ball joint bolts.. then I'm not comfortable. You state you need to raise the mount by 13mm, yet the bolts are 12mm and this leaves little or no meat between the holes. The bottom of the shock will also be offset by the thickness of the plate and will be cantilevered on a bolt through that aluminum plate. I think the bolt will distort the hole in the aluminum pretty quickly. I'd propose welding extensions to both halves of the arm and put the shock mount bolt through there with a spacer between the two halves of the arm. Use two bolts in the normal holes to secure the ball joint. Why the need to raise the suspension in the first place?

deadskunk, perhaps this will give you better idea.been working  too much,so some of the measurements are not perfect right now

 Will update after 1830 pat

Why t6,aluminum? Finding steel plate that thick is difficult,and I have no interest  in buying a  40+ dollar  plate of steel for 2 small parts.

Alfaromeoguy said:

I need to raise it 13mm. This is my idea. T6 aluminum plate, but 13 mm thick ,17mm thick, or 19mm thick.  See drawings please.thank you. 3rd and 5th photo will give idea on oem  lower shock location 

 Look at photo 1 , part no 7 and 8. As you can see welding that area to togeather would not be the best idea

I'm not suggesting welding the two parts of the arm to each other. I would weld a chunk of steel to each of them ,right above the shock mount hole and drill a new mounting hole above the stock one.

Here are some examples of aluminum bolt on shock mounts. The top one is for a corvette 

Any other voices,out there?

Maybe I missed the reasoning for this mod, but it seems like extending the top mount downward would be easier, and also result in a bit less unsprung weight.

I used an upside down tophat for similar hackery once.  Just another angle to consider. 

I'm only worried about the hole distortion DeadSkunk mentioned, if the upper shock mount is perfectly in line with the arc that the lower shock mount moves through it might work as-is, but if there's any lateral deflection at all you should have a spherical bearing of some kind (even a bushing could work, that's what most cars use) for the hole where the new lower shock mount bracket bolts to the A-arm.

Edit: Or maybe I'm misunderstanding. If the new bracket bolts to 2 holes on the lower A-arm and the remaining one connects to the bottom of the shock, it should work fine as-is.

The lower 2 holes would mount onto the lower A arm, yes 

Alfaromeoguy said:

According to this illustration with a 60mm height, you will be raising the lower mounting point by more than 13mm.  Assuming at least 1D edge margin, you'd be raising the mounting point by 21mm, but would have less than 1D (a mere 8mm) of meat between the holes. To increase the material between the holes, will only serve to raise the mounting point that much further. In order to raise the mounting point by only 13mm, while using 13mm holes, the holes would contact each other.  Is there a reason you're trying to lift the car by this amount in this manner? 

So durring  compression, my qa1s don't bottom out, they don't make them for my car, so I must get ones close to what I need. The are a bit short for my car. That's why need to raise the lower mount. I need 13 mm to avoid a hard hit ,under full drop, to my very expensive qa1's.. and as for perfect measiurments,these are just idea for moment, too  busy to get perfect  numbers

DeadSkunk said:

I'm not suggesting welding the two parts of the arm to each other. I would weld a chunk of steel to each of them ,right above the shock mount hole and drill a new mounting hole above the stock one.

Alternatively, it could be separate pieces, similar to that being discussed, but bolted to both sides and the shock mounting between them.

Alfaromeoguy said:

So durring  compression, my qa1s don't bottom out, they don't make them for my car, so I must get ones close to what I need. The are a bit short for my car. That's why need to raise the lower mount. I need 13 mm to avoid a hard hit ,under full drop, to my very expensive qa1's.. and as for perfect measiurments,these are just idea for moment, too  busy to get perfect  numbers

An exact design is not needed to see that the numbers you are stating are incompatible with the design you show. Why not just modify the droop limiter to engage 13mm sooner? 

Driven5 said:

DeadSkunk said:

I'm not suggesting welding the two parts of the arm to each other. I would weld a chunk of steel to each of them ,right above the shock mount hole and drill a new mounting hole above the stock one.

Alternatively, it could be separate pieces, similar to that being discussed, but bolted to both sides and the shock mounting between them.

Yes, that puts the bolt in two supports and should eliminate my concern about wallowing out the hole.

Just out of curiosity, since you are doing this work to change to a specific shock absorber, are you also altering the suspension geometry to fix it's flaw?

And I'm not talking about the GTA change, but lowering the bottom mount.

The cheap way of doing it is to take a 105 upright (not the 115 you have) and mount the ball joint pointing up instead of down.  That does require some welding and drilling of the upright, or you need to get a really good heim joint that can take a lot of lateral load (they do exist).  That drops the car a nice amount, and really improves the geometry of the front.  At the same time, you can work on fabricating a coil over for the front.   One nice feature for this mod is that the brake slave holes are different, so you can use lighter aluminum brakes from a Milano.

Or you can buy a new upright fabricated by Orion Motorsports (if they still exist)- that's who made the one on my GTV race car, and it looks like a cast piece.

If you don't do that, getting a super high end shock is going to be very muted in terms of it's benefit.

At the same time, the rear can really use a panahard rod or a watts link set up- as the trunion arm is placed in a pretty bad spot.  It's not bad, but with modern tires, a Watts or Panahard will prevent the right inside wheel lift- which is REALLY bad.  So bad that you will constantly be going through LSD clutch plates.  I've driven a panhard set up car- and it drives really nice- much more like a Miata in terms of the rear end behavior.  

Alfadriver, I am getting a panhard system for my Alfa Romeo spider, next. Have basic design set up in paper,.next to make cardboard cut out for main mount of panhard system. And as for that 'miata 'quip.. shame on you. I drive  with my top down " mann, if the folks on the Alfa Romeo bb. Heard you say that....chills

Miata are nice cars. But Alfa Romeo is Passion

Alfaromeoguy said:

Alfadriver, I am getting a panhard system for my Alfa Romeo spider, next. Have basic design set up in paper,.next to make cardboard cut out for main mount of panhard system. And as for that 'miata 'quip.. shame on you. I drive  with my top down " mann, if the folks on the Alfa Romeo bb. Heard you say that....chills

 

 

So it seems like you've never driven a 105/115 Alfa at it's limit, and then a Miata at it's limit.  If you had, you would know what I'm talking about.  And you would want to address it, and accept that Miatas are fast for a reason.  I used to be on the Alfabb, back when it started...  On the racing thread, they would be fine with the comment, since they know what I'm talking about.

Good luck.

Perhaps, the joke did not go over well. I never berated the miata, I see them at Sears point,and thunderbolt raceways, all the time. And I have also Seen 115 cars also on the track.as you know ,getting parts ( aftermarket products) like panhard systems, bigger brakes, shocks, pretty much, only konis, so my choice  to use qa1 double adjustable shocks, for the front and rear, can be a challange, look at there catalog, no mention  for a 84 spider.on my new brakes, I had to design the mounts for my Porsche booster bermbos, front mounts were easy, the rears were very harf,as I was determined to keep my oem parking brake, this is a street car.. my miata friends tease me about my pasta rocket, and I tease them about there cute cars, no harm done. We exchange  ideas  and help work on each other's car,if asked. Sorry you took it so bad. Take care.

Well, if this is just going to be a street car, then none of what I mentioned will ever really be noticed. 

And the joke got old a long time ago.  I've put way, way more miles on my Miata than I have my GTV, and without a doubt in my mind, the Miata is a superior car.  So if you really want to be fast, copying how a Miata drives isn't a bad thing.

Found a small peice of 13 mm steel plate. Will assemble  per photo.