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Volvo 122S Build Thread: Scope-creep the Sequel

Thank you for telling us your way Craig.

I tryed to do some modifying and building my own suspension too. And the more i did learn, the more stupid I did feel.
In the past I did try and error, a lot of error.
Card and ribbon "design". Worked pretty well, in 2D ;-)
I started to test suspesnion programms and wasn't happy. the ceap ones are not really better than the card and ribbon design, the expensive ones: expensive!
I didn't and won't have the cash to buy this programms.

Your build is way of what I will do. Too much at the same time. Next step would be to build your own body. And to build a body out of scratch is waaaaaaay more easy than building a suspension out of scratch.
I'm really impressed of your way and your motivation.
I don't have the time and the money to build something like this, for bad luck.

with the help of Ron it will be a success. Without it will be sucking, I'm shure.

My experience with shocks and springs was a hard way of learning. In the end we found a very good working suspension even with a living axle.
The "perefct" shocks we got wth the help of the bilstein guys, in half a day, instead of weeks and weeks.....try and error, error, error

good luck, the follow on youtube is more difficult to me, lame w-lan access and not my natural language.
(and your workshop remembers me all time at the waste and chaos in mine, I would like to find a few weeks to build storage components and clear the s h i t)

regards, Kay
 
Craig, the vid from EE was the first I found and I liked it because it cleared up in my head at least how the anti dive is calculated. The simple diagram showing how it can be adjusted by % from 0% to 100% was simple. Maybe a bit too simple to actually design around, but clear enough to get me in the ball park.

Any thoughts on my quadrilateral theory? Have you ever moved the spindle up and down without the shock/spring attached and tracked the spindle travel? Does it move freely without binding? Does the tip of the spindle track an arc or does it move slightly fore or aft through it's range of motion? Just curious;-)
 
Craig, the vid from EE was the first I found and I liked it because it cleared up in my head at least how the anti dive is calculated. The simple diagram showing how it can be adjusted by % from 0% to 100% was simple. Maybe a bit too simple to actually design around, but clear enough to get me in the ball park.

Any thoughts on my quadrilateral theory? Have you ever moved the spindle up and down without the shock/spring attached and tracked the spindle travel? Does it move freely without binding? Does the tip of the spindle track an arc or does it move slightly fore or aft through it's range of motion? Just curious;-)



I'm not sure it makes sense. If we define the quadrilateral as the intersection of the pivots, then they don't move...and the length of the links doesn't move. So there is no change in the volume described by the links and the ball joints/spindle. That doesn't mean the the shape that holds the volume is constant - it won't be.

I've moved it up and down a lot - it doesn't "bind" - by design it moves in an arc (camber/caster are dynamic). I've got computer simulated camber curves and will plot them when it's all welded in to validate that we've got it right.

In the lecture, the professor defined anti dive geometry as changing the direction of the force vector through the link formed by the virtual pivot for the suspension. This change from an initial horizontal plane necessarily has a vertical component. So it's this vertical component that resists the deceleration force. I'll elaborate a little.

I thought of it this way - if both arms are parallel to the ground then under braking, the force vector remains parallel as the instant centre of the suspension in the side view is infinite and the only thing preventing this from having the virtual car slam into the ground is the spring. The spring has to counter act the change in weight seen at the wheel.

If there is an angle to the links that cause these points to intersect and create a shorter virtual arm (it therefore pivots instead of going straight up and down), then the acceleration force acts on the pivot through a moment arm created by the contact patch and pivot. This change in the direction of the force vector creates a vertical force resisting the rotating force of the car.

Not clear enough to engage in arguments or finger-wagging on the internet...but clear enough that I think I understand what's going on.
 
OK, what I left out of my hair brained quadrilateral theory is the fact that the ball joints allow the spindle arm to rotate with (follow) the arcs created by the UCA & LCA. Duh, I'm still crawling out of the muck with this stuff! Thanx for taking the time to address it though. In the future I'll try not to take you away from more important matters.:lol:
 
Beautiful work Craig.

As far as the C4 front short/long arm wishbone suspension, I'm certain GM spent 6 figures + getting the geometry right for performance caster & camber. Are you duplicating what they designed, or modifying it for your vehicle weight and loads?

I'm looking forward to seeing & hearing that whiteblock purr...... or has that been shelved for other power?
 
Beautiful work Craig.

As far as the C4 front short/long arm wishbone suspension, I'm certain GM spent 6 figures + getting the geometry right for performance caster & camber. Are you duplicating what they designed, or modifying it for your vehicle weight and loads?

I'm looking forward to seeing & hearing that whiteblock purr...... or has that been shelved for other power?

Well, I have evolved what GM did with the changes...in some respects it's more or less what those with serious competition C4's run. I've been able to make some changes that they can't on a stock subframe without a lot of work.

It had better work!

Power is going to be whiteblock. Never waivered on that. Just sorting out those details in the background right now. The engine will go off to the machine shop in a few months. I really don't need it for a while...I have a mock up block.
 
Well, I have evolved what GM did with the changes...in some respects it's more or less what those with serious competition C4's run. I've been able to make some changes that they can't on a stock subframe without a lot of work.

Power is going to be whiteblock.

What were the C4 factory specs for caster & camber? I'll presume you are bumping both slightly larger.... no time to watch your Youtube vids....

I built a "Pro Touring" suspension (nearly all bolt on, nothing like your work) for my 70 Chevelle. I chuckled when I read the Howe Tall Ball Joints (NASCAR Origins I think)... I have those on the Malibu. GM camber curves were a disaster back in the stone age, as the stock suspension traveled the curves went negative! :wtf: The tall BJs fixed that, along with adjustable UCAs which let me build in some caster (I think I am right at 4*)..... it tracks down the interstate like a cruise missile.

I'm with you on the whiteblock power..... got my 92K mile engine on the dolly, small bore B5244T5 which I understand tolerates boost quite well. Johann "The Man" in the Netherlands says several of his friends run these making 350 ~ 500 lb.ft. at the crank with stock internals....my plan is to keep them stock. Waiting to see what type of exhaust mani you build for the 5 cylinder.

Keep it up! Fun to watch your progress.
 
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What were the C4 factory specs for caster & camber? I'll presume you are bumping both slightly larger.... no time to watch your Youtube vids....

I built a "Pro Touring" suspension (nearly all bolt on, nothing like your work) for my 70 Chevelle. I chuckled when I read the Howe Tall Ball Joints (NASCAR Origins I think)... I have those on the Malibu. GM camber curves were a disaster back in the stone age, as the stock suspension traveled the curves went negative! :wtf: The tall BJs fixed that, along with adjustable UCAs which let me build in some caster (I think I am right at 4*)..... it tracks down the interstate like a cruise missile.

I'm with you on the whiteblock power..... got my 92K mile engine on the dolly, small bore B5244T5 which I understand tolerates boost quite well. Johann "The Man" in the Netherlands says several of his friends run these making 350 ~ 500 lb.ft. at the crank with stock internals....my plan is to keep them stock. Waiting to see what type of exhaust mani you build for the 5 cylinder.

Keep it up! Fun to watch your progress.


It's an interesting progression over the years. The early cars had a narrower track so my car's parts came from a 1986 (Z51...not that it matters) - they originally were 59.6" (wider later) and we've reduced that to 56".

Here's the caster progression.

1984 1985 1986
+3.0? +3.8? +6.0?

Camber -1.0?
Caster +3.0?
Toe -0.110

1988-1996

Camber -1.0?
Caster +6?
Toe 0.00


So here's what I have.

First we changed the geometry of the UCA mount by moving it back from the axle centre line 1" and lowering the front pivot point 0.25" (rear pivot didn't change) - I may have reported this value as something else before. I'm now looking at the report, so will get the details correct.

Using the Howe 1/2" longer ball joints as noted.

Camber -0.6?
Caster +8.2?
Toe 0.125 (total toe)

Why is this a good thing?? Well, the increase in caster allows you to run less camber and optimize the tire contact patch when turning. The camber gain with a steering angle of 25? and 1" dive/ roll 2.5? yields an additional 0.6? of camber for 1.2? from my set point. I may need more depending on the tire I'm running.

Where I'm positioning the steering rack will place the Ackermann at 99.9% in this condition. The anti dive % would be 54.5% which is excellent.

Total roll centre height movement is from 3 7/8" to 2 3/8" and is one of the benefits of the longer ball joints. This is considered excellent.

Other interesting stats. Roll centre migration is 2.7" - not bad.

The virtual swing arm length is 109" which is also good.

With 1" of dive, the caster gain will be 1.2? - depending on how the car feels, we can back the caster off a bit.


The idea with the whiteblock (like all my engines) is to change out the rods for H-Beams and remove that fuse. I've gone with the 147 mm length rod and will have Wiseco knock me out some pistons to suit when the time comes. I'm pinning the block and will be running a Borg-Warner EFR turbo (still debating the end size). The manifold will be 321 stainless and some of that is already under design.
 
For fun. Here are some numbers I found online.

Stock C7

Front
Roll center height 3.272"
Camber gain .818? per deg of roll
Camber gain -0.460? per inch of bump
Caster 5.726?


Stock C5
Roll Centre height 2.595"
RC height (in roll) with +/-3deg of roll = - .025" in RC height change
RC width (in roll) with +/- 3deg of roll = +/-.733" in RC width change
Camber gain (ride) - about -0.46 ? per inch of bump travel
Camber gain (roll) - about +0.774? per degree for outside tire
Caster 6.358?
 
OK - Time for an update. Honestly, I'm hammering on this thing like a drunken blacksmith but it just doesn't look like I'm making progress. One of the problems is that I keep running into little snags related to how much time has passed between purchasing and installing parts. I started writing a separate build journal for all the details several years ago, but most of this predates that (or precipitated) effort.

Exhibit A - The Case of the Buggered Steering Rack.

40386269964_d20efa606f_b.jpg


In one of the videos I mentioned the surreal experience of talking to Tony Woodward of Woodward Precision Power Steering. Great products but you'd better be ready for the oddest conversation. Maybe all steering guys are like this? So I called on the 15th of Feb, 2012 with the need for a custom power steering rack as I wanted to get the rack lower so the engine would sit down in the chassis. The old rack was up around the crank and an inch really was going to matter. So with some string, I "measured" where the rack pivots should go (he'd need this measurement, and I try not to waste people's time.)...picked up my phone and credit card...and made the decision to buy this rack. The Canadian Peso was riding high, so buy it now and "save" later. So I get the boss (Tony) on the phone. I try to have a conversation where he would educate me on my options. He's on the shop floor working on things...we have about a 15 second discussion. It goes sort of like this:

Me: Hello. I'm building a Volvo with a Corvette C4 suspension...
Tony: Yes, I know exactly what you need. What are your pivot dimensions.
Me: What sort of rack do you think would be best?..oh and 21".
Tony: You don't want to steer too quickly for a street car - 2.36 turns lock to lock is fine.
Me: Interesting. What kind of servo or parts and things will I need to put this together?
Tony: Great, I'll pass you back to the billing people.

That's about how it all went. Parts come in. Look fantastic. I don't need them for years. Sit in the basement parts stash collecting dust.

Scroll back to the picture of the bill - decoding the part number is critical...GLM is the style of rack, 236 is the turns lock to lock...C is the cylinder, 2700 is the pivot to pivot in inches, 950 is the servo.

I noticed this about 3 months ago when I was trying to look up the mount details and spoke to Tony on the phone again. I was wondering if the online instructions that required 3/8" plate for the mount was required. It is. I asked Tony about the rack as it wasn't supposed to be 27" pivot to pivot. He had no clue...I told him that I measured it and it was 21 - he reply's with "Well, it's 21" then!"

This is what causes stress people.

Alone on an island with bad paperwork and not enough knowledge.

So I just put the rack on the bracket and tacked it on the frame.

Well, after I scribed a few layout lines.

40386270024_b29395d790_b.jpg


41052570662_d704d9a243_b.jpg


40386269564_3f650d463f_b.jpg


I was very careful with these fits...in fact the parts only go in one way as I didn't square up the laser kerf. You have to tap it together when installed.

I'll cover the how's and why's on a future video.

Then it was back to the string to check the pivot positioning and a little test of centre with the square.

It should be 2" from the frame rail to the pivot. Yup...that'll do.

40386269704_08fef40472_b.jpg


40386269704_08fef40472_b.jpg


Now it's on to the coil over mount check. The design says 15? inclination.

41052570282_fb7fc23a81_b.jpg


That also...will do.

So that was where we were at about a week ago. I've spent the last week working out the suspension dynamics to buy anti roll bars and coil overs. I have stumbled and fumbled around with this as I'm working through it long hand, don't like witchcraft, and need to be able to understand what I'm doing (I'm not a software monkey - I'm a scientist dammit). So that's taken some time.

I may post the method when I understand it - but also understand that it's pretty niche market on the who cares scale.

So now you're caught up.
 
Craig, Here's a short version of how I did mine, see if you agree. After pulling a string on both sides between the center line of the UCA & LCA inboard pivots I calculated that the center of the steering knuckle tie rod end ball was 4" (IIRC) above the center of the lower ball joint ball. I then transferred this dimension (4") to both strings above the LCA pivot. Then measured between the strings at this dimension and came up with 17" (IIRC). This meant I needed a rack with 17" between the centers of it's pivot balls that would be mounted 4" above the LCA pivots. By doing this I will have the steering link between the rack ball and the steering tie rod that is parallel to the LCA so that they move in conjunction without causing a bind (bump steer) What say you? That Woodward fab stuff is beautiful but they use too many gold parts for my pocketbook!
 
Craig, Here's a short version of how I did mine, see if you agree. After pulling a string on both sides between the center line of the UCA & LCA inboard pivots I calculated that the center of the steering knuckle tie rod end ball was 4" (IIRC) above the center of the lower ball joint ball. I then transferred this dimension (4") to both strings above the LCA pivot. Then measured between the strings at this dimension and came up with 17" (IIRC). This meant I needed a rack with 17" between the centers of it's pivot balls that would be mounted 4" above the LCA pivots. By doing this I will have the steering link between the rack ball and the steering tie rod that is parallel to the LCA so that they move in conjunction without causing a bind (bump steer) What say you? That Woodward fab stuff is beautiful but they use too many gold parts for my pocketbook!


That's exactly how I did it. The end location was verified in a 3D suspension analysis program where Ackermann and bump steer measurements were conducted.

Trust me, when I got the bill...I almost died. I paid more for the steering rack than I did for the car :omg::omg:. Not kidding even a little bit.
 
Using the stock cross member prevented me from moving the rack rearward enough to get the Ackerman correct. That's where you and I differ, I was like, well fork, let's just see how this works. It works OK by me, I don't notice anything wifty! I verified all the geometry by cutting up manila folders to represent all the suspension components and pinning the UCA and LCA to a board, using small nutz and bolts for pivots and doing some I guess that will work analysis!;-)
 
Hey ya', Craig, I love cruisin' around on U toob. Found this from Pedantic Publishing. They have some pretty good suspension tutorials.

Here's an interesting concept:

<iframe width="560" height="315" src="https://www.youtube.com/embed/38fHEoEBd1k" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>
 
Hey ya', Craig, I love cruisin' around on U toob. Found this from Pedantic Publishing. They have some pretty good suspension tutorials.

Here's an interesting concept:

<iframe width="560" height="315" src="https://www.youtube.com/embed/38fHEoEBd1k" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>

That's very cool for a rear steer set up. I'm tuning into their channel to see if there is some pithy advice for setting up an anti roll bar rate.

I can't believe I've spent a week working on suspension dynamics. And I wonder why I get stalled every once in a while!

I'll get a few more parts sorted out this week and just get the frame tossed under the car for a bit. Then I've got some sheet metal work to do on the pedal box/false floor part of the build... that can happen while I wait for the ARB parts to come in.
 
<iframe width="560" height="315" src="https://www.youtube.com/embed/xFMawUWaSbs" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>
 
Sorry for the delay...work (the paying kind) needed doing so I had to slow up on the video production. This one's short...more content to follow.

<iframe width="560" height="315" src="https://www.youtube.com/embed/zI5NBgcSR20" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>
 
Back rolling on the video production. This week's installment - the front frame is getting some love.

<iframe width="560" height="315" src="https://www.youtube.com/embed/QQbCkJuvfrk" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>
 
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