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Discussion Starter #1 (Edited)
Post #1

First of all, I want to thank Wile E Coyote Jr. for getting me interested in this project.

Second, I want to stress that there is NOTHING wrong with generic KYB/Gabriel replacement shocks on Vogtland springs... you just won't get the same level of performance (at the sacrifice of comfort) as you would with proper performance parts.

Third, and MOST IMPORTANTLY, I want to state right now that this mod is NOT for the feint of heart or unskilled of hand.

OK, now that all that is out of the way, on to the nitty-gritty.

42398


This is a "Street Basis Z" kit from TEIN for the Nissan 350Z from 03-08. The spring rates are 9 kg/mm (504 in/lbs) both sides. It can be made to fit our cars, with the exception of the rear springs (unless you really want to hack into the body). I planned to use my rear Vogtlands anyways, since the spring rate for those is 530-650 and therefore stiffer than the Z springs. I purchased my kit from Redline360 for 550 USD, and their service and shipping is top-notch.

Aside from the various sockets (such as 12mm, 14mm, 15mm, 18mm, 19mm, 21mm), you'll need to find a 17/32 drill bit, a hammer, jack and stands, and probably a pair of medium crescent wrenches. This job WILL require cutting and welding to do properly. It will also require a rotary tool such as a Dremel, and I'd recommend a straight cut burr such as this one.
42399

Never mind those drill bits, totally unnecessary.

First thing I did was tackle the rear end... and I'll admit I got lazy with this, but I really just wanted to get rid of the KYB shocks as they just weren't cutting it for me. I first checked out how to mount the top end of the TEIN shocks, and that was honestly fairly easy... transfer over the mounting hardware plus one extra washer and good enough for me.
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The UGLY part, where I absolutely positively got lazy and chucked caution to the wind, is on the lower mount....... I just hacked off one side of it. The spacer was necessary to take up the extra slack, and that came from the front lower shock bushing I replaced last year (just ripped it out of the rubber and cut it in half).
42403

I got lazy.

Couple ugga-duggas, cinch down the top with the wrenches in the trunk, job done. WONDERFUL upgrade in the control and predictability of the rear end, and pairs extremely well with a swaybar upgrade. Remember, I have Vogtland 3/4" drop springs in the rear.

ON TO THE FRONT!!!

Now, you will need to re-use the large cupped washer from the top of your shock assembly, unless you can find a pair that isn't already attached to your car. I would also recommend a new pair of upper mounts, that way you don't have to play chicken with an angry spring to re-use the ones in the car now. I cleaned mine up and painted them black.
42404

Innit pretty?

How did I get that to fit, you ask? It's not as hard as it seems. For starters, it's necessary for the spring to sit centered in the mount, so I whipped out ye olde burr and hogged off about 1/2 of the inner lip.
42405

About this much, all the way around, both mounts... it's hard to see, I know, but that's the best one I could get. You can see that the edge has a bevel, so as long as you ride the top of that you'll get it done and the spring will happily sit centered.
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Fat side on the mount, skinny side on the shock.

Now the new shock rod fits smoothly and perfectly into the top mount, but there's a snapring in groove that keeps the rod from flopping about that needs to sit at the correct depth.
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Pictured is the 350Z's bushing, which has a recessed lip to hold the snapring seen sitting on the top mount. You won't be needing this bushing, but it illustrates just how you'll need to proceed.

Continued in Post #2
 

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Discussion Starter #2 (Edited)
Post #2

"But DJ, what or how do I drill that step?"
VERY VERY CAREFULLY. Gack this part up, you'll be needing to replace the upper mount. You have to machine a lip similar to the bushing into the underside of the top mount. Use the 17/32 drill bit to bore a nice, even lip.
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This side, not the top side.

This needs to about 9/16" deep (or 14mm), give or take a mil. You'll check if you have it right when you go to assemble the unit, as the top of the shock rod has flats milled to hold with a wrench and you want to make sure the nut threads down past these (with the washer in place). Refer to post #1 image of assembled top end.

Once you get the lip machined right, you can assemble the top part. I'd recommend adjusting the unit to the lowest ride height setting, as this allows it to assemble without fighting the spring. If your nut doesn't clear the flats by at LEAST one thread, take it apart and take a little more out with the drill bit (you barely need to touch it, gently).

On to the bottom!

Now, to get this to fit the car you need to take the 17/32 drill bit and run it through the shackle holes. Nice and straight now, ya hear?
42409


I'm honestly going to say that you probably need a 9/16 bit for that hole, as I had to burr it gently to get the factory bolt to go through it.

This next part gets risky... and permanent.

Once you get the hole sized correctly, you need to grind off about 3/8" of the material from both sides of each lower shock mount on the control arm. This is honestly a pain to do, and my grinder actually got loose and bit me, took a small chunk off me finger (don't worry though, not the first time and not that bad).

[I didn't take a picture of it, on the count of me finger]

The reason you need to grind off material is because the TEIN shackle is narrower than this bushing. Take a little off at a time and keep testing, you want it to slide on effortlessly but not loosely. Keep it straight.

At this point you can now bolt them into the car... HOWEVER!!!! As I discovered, the TEIN is longer than the factory unit, and the car ends up being higher than stock in the front (I checked, my sister has a stock 97).

/ / / / PROCEED TO THE NEXT SECTION AT YOUR OWN RISK ! ! \ \ \ \

Continued in Post #3
 

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Discussion Starter #3
Post #3

/ / / / WARNING ! ! ! MESSING UP HERE WILL BE EXPENSIVE ! ! ! \ \ \ \

So this is the most risky, demanding, and nerve-wracking part.... you need to cut out some of the extension material from the bottom of the coilover.

I used a caliper to score out how much material to take off the extensions... now I took off 1.75 inches, but that was honestly too much as at the lowest setting the car actually was resting on the jack. I'd recommend 1.25 inches, max 1.50 if you want it to go lower. If you look carefully, you'll see that the extension has a straight part (bottom) and taper (top) go from the taper downwards for your mark.
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You now have to cut the extension twice... AND MAKE SURE IT'S STRAIGHT, FOR THE LOVE OF FORD. Also, don't mix up which shackle goes to which coilover.
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Next, you have to start getting it ready to weld back together....

Now I don't have to tell you guys that adding a ton of heat to a gas-charged, oil-filled tube is a bad, bad idea. I filled up a 5-gallon bucket with water and constantly quenched the shock every time I did anything that added heat... if you can't comfortably hold it in your palm for 10 seconds without thinking (this is kinda warm), it's too much heat.

The extension is solid mild steel, so you'll have to bevel the ends before welding them back together. You want to bevel about half the diameter off, maybe a hair more... You should also make sure the cut ends are flat, but don't go hogging off a bunch of material. Use a caliper to make sure both shackles are the same "height" from underside to top of cut.

To tack them back together, I bolted the pieces onto the car and used a jack to lift it up to where they just touch together with very little pressure and squared them up.
42412

DO NOT ground to the bolt, it will incinerate the threads! I ground off some of the paint to get to bare metal.


Tack one side, quench with a wet rag until it's cool to the touch. Tack the other side, quench, then remove carefully.

Be VERY careful as you weld up the parts back together... I used a 6011 rod at about 100 amps to do the job, welding less than a dime-wide at a time then IMMEDIATELY dunking the hot side into the bucket until cold. Use a wire brush (I used a wire cup on a drill) to clean it between each go. Repeat until root pass is complete.

Once the root pass is done and the weld looks solid, dress it carefully with a flap disk and clean it again. You now have to "cap" the weld and blend it back to the original diameter (or as close as you can get). Remember to do maybe a pinky-width welding at a time, and immediately quench in the bucket... if that thing gets too hot, it WILL blow. Clean and dress between each segment until the "cap" is complete and the weld is back to the original diameter.

Use your flap disk again to blend out any high spots, then paint.
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Love me some wrinkle black, but it takes like 3 damn days to cure above 70°F.
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If you've done it right, you'll have yourself some coilovers that give you full ride height adjustability (albeit only semi-adjustable as the spring preload increases as you raise the ride height).... and if you're a good welder, it'll last forever.
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Are these better than the QA1 option? Hard to say.... The QA1 do offer adjustable valving, so for some that's a deal breaker... but TEIN at $550 delivered, I was willing to make that sacrifice compared to roughly $1000 per axle for QA1.

How do they ride? Firm, but not hard. Control, response, and predictability are exponentially better, however - full disclosure - bad bumps or potholes will get you in the gut... good thing you can swerve around them now though, eh?

Brake dive is also vastly diminished, and rear squat is hardly noticeable now (it's still there, but the car doesn't feel like you backed off a cliff now) and there's no more "road humping" going on if you take off suddenly but don't commit.

I'm very happy with the TEINs, they ride and perform very well on the MN12 platform even if you gotta do some work... they also make ripping fat, rowdy drifts a cinch.

Cheers, and good luck to you brave souls who want to do this mod.
 

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1) I'm impressed you cut and welded a filled shock without any drama. Since you survived without getting a squirt of some hot hydraulic fluid in your eye, that's great.
2) I'm still a little concerned about you taking out one of the two ears for the lower mount of the rear dampener. That changes the angle of the force applied when the spring compresses dramatically. Instead of having two ears to distribute the force and push downwards on the LCA, it will want to fold up like a taco over time.

I'm sure it will work... until it doesnt. Its probably better that its the rear that will collapse before the front though.

-g
 

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What? They don't have Carolina Squat vehicles in Canatucky or Canatexas?

Hahaha not that I've seen. I'm just concerned that regardless of how clean his welds look, the coilovers have been structurally compromised. The goal would be to have a complete drop in set with no modification no?
 

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Hahaha not that I've seen. I'm just concerned that regardless of how clean his welds look, the coilovers have been structurally compromised. The goal would be to have a complete drop in set with no modification no?
Personally, I think the bilstein insert option is better for the front and rear.
 

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Those rear shock lower mounts should be fine .. They are not likely to fold up .. The vehicle weight is still supported by the Vogtlands.

On the front end .. I would have ground the original weld off the lower mount and cut then stem shorter for a socket weld rather than a filler. Also dont grind the welds to make it look "smooth" .. It reduces the strength of the weld, and the metal surrounding is already fatigued by the heat process ( weld and quench ) .. If it breaks its not going to be slightly past the weld.
Looks fine to me otherwise. I have known hot rodders to cut a mn12 spindle shorter by arc welding on cast.
 

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One of you more handy people with welders need to make the top and bottom pieces for the QA1 set-up that Bill sells. There's maybe $10 of material in that and a couple hours time. Sell them for $150 and the purchaser can put the rest together based on their ways/needs.
 

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One of you more handy people with welders need to make the top and bottom pieces for the QA1 set-up that Bill sells. There's maybe $10 of material in that and a couple hours time. Sell them for $150 and the purchaser can put the rest together based on their ways/needs.
Do you have any specs, measurements, diagrams ?? The last time i custom fabricated a set of mounts for the front end of a Tbird was for an air suspension setup that used an airbag / shock combo. This was about 2001, 20 years ago .. 😬 the guys with the fancy pants setup used a custom machined aluminum lower mount - actually the owner of SIC Motorsports contacted me for my measurements. 😂
 

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I bet with the right dimensions, a product could be made from someone cutting out the pieces and leaving it for the customer to weld themselves. That'd be cheaper to mfg and less liability for the mfg (I'm selling you a set of plates -- how good you weld them into an actual suspension mount is on you). Maybe worth it if someone wants to proto it and sell a few extra pieces.
 

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Do you have any specs, measurements, diagrams ?? The last time i custom fabricated a set of mounts for the front end of a Tbird was for an air suspension setup that used an airbag / shock combo. This was about 2001, 20 years ago .. 😬 the guys with the fancy pants setup used a custom machined aluminum lower mount - actually the owner of SIC Motorsports contacted me for my measurements. 😂
I don't have any measurements and I don't need a front setup right now as I have a set of Bilstein inserts ready to go in. I would think that looking at Bills design and measuring my car while I have it apart, then back together with Vogtlands for length, one could come up with a good design.
That'd be cheaper to mfg and less liability for the mfg (I'm selling you a set of plates -- how good you weld them into an actual suspension mount is on you). Maybe worth it if someone wants to proto it and sell a few extra pieces.
This is a great idea. Someone like me would need to pay to get it welded, but I'd be willing to do so, if I needed a set.
 

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Well, here's part of the solution. Cut a round plate to bolt to the shock tower and weld these in.

42880


Don't laugh at me.... Would welding these or something similar to the LCA ruin the metallurgy of said arms if you quenched between welds?
 

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Don't laugh at me.... Would welding these or something similar to the LCA ruin the metallurgy of said arms if you quenched between welds?
You wouldnt need to quench between tack welds .. Also you cant get a good root to form without the keyhole opening up. 🤔

The quenching is to prevent the shock oil from boiling .. Its just as important if not more so to quench while grinding also. I quench brass valves when I solder and braze in critical areas where I dont want heat transfer to destroy seals. It just draws the heat off as long as you keep a wet rag wrapped around during the weld process .. Quenching after applying heat is more likely to distort the metallurgy.

Otherwise the differences between mild steel and cast LCAs can be made up by using the correct welding rod.

I remember Scott from baggedbirds front suspension setup was built with a pair of shock mounting tabs welded to the body to act as a stabilizing point for a 2500 airbag mounted between the upper shock tower / bolted to the perch - swing arm to the body / and mounted to the lower control arm. This was to stabilize the assembly .. A standard shock was also mounted off to the side. Hard to describe, i would need to dig for pictures ..
 
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