The car torque steers and generally feels very unsettled and wandery, so I ordered a bunch of rear suspension bushings from Vintage Import and set to changing them. My first issue was actually getting the lower arms OUT: of course I had to cut the front bolt out and the rear stud looked a little like this:



Clearly this couldn't go back in my car as it might only take 1 or 2 dupuis' before I snap it off, and I didn't want it to happen while driving, so I need to build something. First step, whip up a little jig!



After I was done prancing around the garage like a drunken sailor, I built this out of scrap pieces. A jig doesn't have to be pretty...



Maybe I WAS a drunken sailor after all? BLURRY PHOTO!



I had a nice pair of 240 torque rods with poly bushings laying around, so I chopped off one bushing and happily it looks like it'll do the job.



With much burly 5/8" grade 8 bolts, we will recreate the stud. But how do I fill this hole?



Another blurry photo, this time of the bushing to be used.



Wrap around stud:



And weld up the holes.



Drill plug holes in torque rod, and weld in place



Big buttery weld. A bit crude, but this one's not coming apart. I have a TIG and I'm sure with a practiced hand, these could have been made a bit more elegantly, but I TIG weld like a monkey on crack so I'd rather trust my "inferior" MIG to this job.



After a bit of grinding on the weld, slide on a big fat 1" washer, and clamp the whole mess in the jig.



Two and done, ready for a little POR-15 touch-up. I'm not spending a bunch of time on cosmetics right now, the underside of this car needs some attention and the arms will get tidied up then.



New Volvo stock bushings. I love Olof!





I do have some IPD poly for this location, I'm not sure if I'll use them though.

After the weekend, the upper arms get done and the front suspension gets some attention.

Beauty Matt! Well done!

Atta boy - that looks like it will do the trick.

The car ran super - sure it's cornering on the door handles, that's what 122's do.

Well that was fun! Streetwheelers was a blast, the autox was a riot, and after a Sunday thrash session I have my new steering and front suspension. Thank goodness, I need it and Craig needed it gone.

I leaned that the car needs some things if I'm ever going to do this again, but there are some early rules (which may get re-written later):

- I must keep this car reasonably stock and ready to sell.
- I must spend my time and effort making the GT the way I want it.
- I must not use parts on this car that are marked for the GT.

I have a set of VPD lowering / performance springs that will not be used on the GT, but using them here may make this car too ... something. This weekend the springs would have taken me out of the class that included a 911 and put me into one with a C7 Corvette. Not a deal breaker 'cause the 911 is way out of my league already. I have a set of IPD bars too but for now, at least the rear is meant for the GT (maybe the front).

I need to address front end grip and the chaulk tells me I'm rolling over down to the Continental lettering on my sidewalls, so static camber will be helpful and I may mod the crossmember like I did for Dale (but not as extreme). That mod gives more camber gain under roll, and raises the roll center a little.

The driver rear tire is hitting the upper spring perch upon roll, and the axle isn't quite centered. I need to make an adjustable panhard rod and possibly space the wheels a touch.

The rear axle is on the limiting straps in the corners, and trying to accelerate produces axle hop. Less roll would help, so that front bar might make it's way in here. The rear bar would just lift the inside tire some more, and if I can get more front camber I'll have more front grip to balance load against. Less roll will give me more front grip as well, and will reduce rubbing in the rear. Less roll is less like 122 behavior, not sure I want to give up the completely stock claim.

I have a diff from a 123GT that is going unused (the GT is getting a 240 axle) and this would solve the axle hop problem by reducing inside wheelspin. It could be a selling feature as well.

All that roll and you still look like your not getting air under the tires....all are still gripping (loosely used here)
That is a good thing. What are you running for tires ? they can make a huge difference in times. Did you play with the pressures, especially the front where it seems to be very much on the sidewalls ?
If you want to run stock you are fairly limited in what you can do. Used to be that they awarded points to mods which then could be lessened by adding a fire extinguisher or such to bring you back into class. not sure anymore since they seem to run the scca rules these days and I run in mod ( which is a free for all really, except for slicks which requires a roll bar...really in a Volvo ???) so I cant really say about the stocky classes. My thoughts Matt, just keep it the way it is and have fun. Its hard to be the fastest these days, technology has moved on and cars are much more capable right off the showroom floor, you will have more fun at 10/10ths than those who have it easier. Just think, you will be the coolest Guy probably in the oldest car running at a normal event ( believe it or not my 82 is usually the oldest at our events except for the sprite) and it will be a workout. Years ago in Saskatoon (25-6 yrs ago maybe more) there was a guy who regularly ran a 60 something Shelby 350 mustang white with blue stripe (his son had it out at an ssis event 7-8 yrs ago and it still looks great) boy was that car fun to watch ! way to much power on stock brakes and armstrong steering...it was lots of fun to watch him maneuver that around the cones quickly, and he always came in with a smile on his face, and very sweaty !!

Haha, Alex - I'm not at all serious about winning, I just want it to feel better and to use up some parts. I'm not trying to compete with the 911, in fact it got it's ass handed to it by a guy in a 90's FWD Escort. I will do it to be a better driver, but I also can't leave things alone...

Tires are 205/55R16 Continental DWS, an all-season tire, on 7" rims. The front suspension bushings are shot, and the alignment is whatever it currently is (probably 1/2 degree positive camber, i.e. stock). Adding air would just put more load on the outer shoulder, not really the right idea in my mind. The inside rear tire has almost no load on it, it can be spun at part throttle 2nd gear. That is the biggest vice I see - I can't accelerate out of a corner. Limit the roll and I can keep the rear end off the limiting straps, or put in an LSD and I can at least put some power to the outside tire.

Anyway, while installing this new front end I must either swap out the front springs for stockers, or swap out the rear springs for the ones to match the front. I think I'll do the latter to see how it rides and if it feels a bunch better, I'll keep them. If not, stockers can go back in and I try something else.

You're right: I'd rather have fun than go fast.

Good stuff Matt, sorry I had to miss the weekend, looks like fun.

It was, Jim. Right up until the wind blew us off the runway. Craig and I got shorted two runs, but that's okay because I'd learned about me and my car.

Back it up a week or two: I installed my new front suspension and monkeyed with the alignment at home. All the shims came out of the subframe, so caster got maxed out (I'm not sure what the number is). I scrounged all my shims and stacked some thick ones in the dogbones, and got an even 1.5 degrees negative. The VPD springs stayed in the front, which meant the matching springs needed to go in the rear. Billys stayed put. Oh, and I made an adjustable panhard bar (which turned out to be just what I needed as neither tire rubbed last weekend).

I drove it like that for a day or two, and it felt a lot more responsive but it's pretty jiggly. The rear end is STIFF, those rear shocks are pretty firm. Some of the lean was gone but much of the lean remained. While I was tuning up the car for last weekend's practice session I installed the front IPD sway bar. I didn't get to drive it until I hit the highway.

With the added neg camber and reduced roll I now feel like adding air is a good move, so I pumped them up to 40 all around. The first few laps showed me that the car is a lot more responsive and it has a lot better turn-in, and it can now put a little power down in the corners. Transitions are really sloppy, with a tendency towards oversteer, but it has heavy understeer in the long turns. The first few runs showed the front tires were still rolling under a bit, so I brought them up 5 psi. The rears were fine where they were. The final two runs gave me more even chaulk rubs, a bit better handling on the transition but a bit more push on the pinwheels.

More in a bit.

Here's where we start to geek out on the suspension a little. First, some definitions for those who aren't 100% up on this stuff:

Roll center: An imaginary point at which a suspension rolls about. Old cars had quite low roll centers in the front, more modern cars have higher roll centers to control roll without stiff springs or sways. The roll center is complicated to describe, but if you draw a line between the center of the tire's contact patch through the instant center of the suspension, for each side of the car, the roll center will be where those lines cross each other. It can be above or below the ground, and it can be to the left or to the right of the center of the car. Ideally it shouldn't move around too much in relation to the body's center of gravity.

Roll couple: The distance between the roll center and the body's center of gravity, creating a roll moment. Increase cornering force or weight, or increase the distance between the center of gravity and the roll center, and the car will generate more roll moment.

Roll axis: A line drawn between the front and rear roll centers. Front suspension roll centers are usually much lower than those in the rear on live axle cars, a bit more level on independent suspension cars.

Camber gain: The tendency for a suspension to gain (or lose) negative camber upon compression. A good front suspension will have this feature tailored to keep the tire planted at all times.

Instant center: This is an imaginary point in space where lines drawn through the upper and lower suspension pivot points meet. Extend a line through the upper balljoint and upper inner pivot, and another line through the lower balljoint and lower inner pivot, and where those lines meet is the instant center.

Swing arm length: In a 1:1 relationship with camber gain, the swing arm length is the distance between the instant center and the wheel. Shorter swing arm lengths mean more camber gain, but too short can also cause handling issues.

Front Lateral Load Distribution: The FLLD is analogous to the relative roll stiffness of the front suspension, compared to the total roll stiffness of the car. This takes into account roll couples at each end plus the stiffness of the front & rear springs & sways.

---------------------------------

Stock, at rest, the front suspension roll center of a 122 is at ground level due to the arms being parallel and horizontal. Since the arms are parallel, camber gain is zero and the swing arm is infinite. When you lower the car on lowering springs, the roll center drops below ground by approximately the same distance that the car's been lowered: 1.5" lowered car means the RC is 1.5" below grade, and this is good because it maintains the same roll couple as at stock height. The net result is that the center of gravity is lowered so it won't put as much load on the outside tire, but with the same roll couple the car will roll as much as it did before (minus the effect of stiffer springs, if present). Since the control arms on a 122 are so long (relative to the width of the car) there isn't much camber gain, and all the roll you get in corners (no matter the height of the body) puts more positive camber into the outside tire, which ruins handling. There IS slightly more camber gain at this new lowered position, but not much.

The rear roll center is where the panhard rod crosses the body centerline - that's the way it is with beam axles - and when you lower the car 1" the roll center drops 1/2". The roll couple in the rear reduces a little, so the rear end doesn't generate as much roll moment. Since the front roll center has dropped more than the rear, the roll axis gets steeper. This means that the car is rolling less on a horizontal axis, if you can picture it, and this causes some handling traits that could be considered "old fashioned".

So what does this all mean in my car? Well, the low front roll center and the stiff springs & stiff front sway combine to give me an FLLD of 70%, according to the suspension analysis program I'm running. In theory the FLLD should be about 5%, numerically, than the front weight distribution. On a car with 52%/48% F/R distribution, AND with everything else squared away nicely, the FLLD will be in the neighborhood of 57%. 70% suggests that I've got a TON of understeer, and this is exactly what I found in steady state cornering. Additionally, I've got a compromised camber condition: I know the car rolls more than 1.5 degrees, so in hard cornering my outside tire has lost all of it's static negative camber and is going into positive camber, and the high tire pressure in the front (needed to try and help the edges of the tire survive) reduces grip even further due to reduced rubber on the road.

Analyzing the front suspension, and building on past experience, I believe I will try lowering the front inner pivots (the "dogbones") by 1" this winter. Doing this does two things: first of all, it raises the roll center from 1.5" below grade to 1" above grade and will reduce the roll couple by quite a margin. This will make the FLLD a little worse, though, but changing the dogbone position also gives me a lot more camber gain so it will help keep the outside tire vertical and should give me more front end grip right there. My program tells me that the camber gain is currently 0.38 degrees per inch of travel, and it will change to 1 degree per inch with the new setup. If I keep the current 1.5 degrees of static camber, the car will be able to roll more than 2.5 degrees before the tire goes positive camber. That's good. I would also like to get the FLLD a little closer to correct, which means I'll have to put the rear sway bar in and possibly replace the IPD front bar with a stock one. With the reduced roll couple that much bar might not be needed anymore to control the roll.

(by "past experience" I mean on Dale's car, where we lowered the dogbone by 2" and that created some other issues. The swing arm length got really short, and at his lowered stance the negative camber was pretty extreme. There were some bump steer issues too. The car did go around corners well, though!)

The loose transition could be down to a couple things. First, the tires. They're sooper squishy, with full depth all season treads, and are tuned by Continental more for all season performance and good ride/quietness rather than sharp handling. I chose them for these qualities, but I think the tradeoff is that I'll have to drive it a little more carefully to let the loads build up more gradually than when I spasmodically hack away at the wheel in the slaloms. Another problem could be the shocks: They're Bilstiens from VPD, but I don't believe they're the revalved VPD version. The rears are mighty stiff compared to the fronts, and could be resisting a lot of roll on the transition (but not in steady state cornering like a sway bar would). I have some KYB rears that I will try, to see what they do. I will also consider taking out the two polyurethane donut bushings under the axle and replace them with rubber: the stiffness of the poly in this location WILL affect the articulation of the axle. I will also remove the limiting straps, as they're no longer needed to keep the car from falling over and on transitions they might be stretching out and yanking a wheel off the ground, temporarily upsetting the car. We ran Dale's car without straps and it didn't explode, so I think I'll be fine.

For what it's worth, my best, worst, and average times were about 2 seconds slower than Craig's, but unlike at Streetwheelers it was on a 60+ second run so it seems like I'm catching up. I know that I was losing a TON of time on the two 270 degree pinwheels, I was loose on entry and very very tight on exit. I still couldn't power out of them either, so I know a limited slip would help and I might install one this winter too.

Again, the goals must be maintained: the car must handle well but must not be brutal or uncomfortable, and I'm not in it to win it, I just want to improve myself and my car.

I measured up some stock stuff today:

Front coils
.572" wire diameter
4.75" OD
6.5 active coils
11.875" free length
325 lb/in spring rate
91 lb/in wheel rate

Rear coils
.468" wire diameter
4.5" OD
8.5 active coils
15.25" free length
125 lb/in spring and wheel rates

Currently I am running VPD springs all around. The fronts are said to be 250-500 lb/in variable and the rears are 145 lb/in linear. At VPD they claim the actual stock front spring rate is closer to 250 lb/in. I suspect that measurement is taken from the free length position, which uses all 8 or so coils: I only counted coils that showed no signs of having rubbed up against another coil, i.e. 'active' coils. With that in mind, the VPD lowering spring might actually be stiffer than 250 lb/in going down the road, it's tough to say. I'm not sure how much they lower the car but it's 1-1.5" in the rear and around 2-2.5" in the front, but Craig had cut them a little to get the stance he wanted. The fronts are 5" diameter which are also said to be the same as some R-sport springs that were available way back in the day. It's tough to calculate the wheel rate from this at ride height, but the motion ratio is 53% so the wheel rates are 70-140 lb/in if the published spring rates are accurate.

I have on order a pair of 5" x 10.5" 400 lb/in springs and a pair of 5" x 9.5" 550 lb/in springs. The 400 lb-in springs should bring the front up about 1" from where it is now, the 550s should bring it up about 1/2". The 400s give 112 lb/in wheel rate and the 550s will give 154 lb/in.

More Data:



These numbers are calculated with the assumption that my car weighs roughly 2400 lbs, with a 52/48 balance, and with 110 lbs unsprung on each front wheel & 139 lbs unsprung on each rear wheel. I've made fairly educated guesses in most of these departments, combining actual measurements with some common knowledge.

And more info:

Ride Frequencies are a subjective thing, but the guidelines here are pretty simple. For comfort, you want a ride frequency of about 1hz, maybe slightly less, but less than about 0.8hz is a pretty wallowy ride. A very light, very sporty car will have a ride frequency of about 2hz. More than this is considered too harsh for street use (unless you're 21 years old or have <6% body fat). To achieve 2hz or higher you need limited wheel travel or to have some other means of keeping the springs from being unseated at high amplitude wheel travel. For instance, my 550 lb-in spring will compress less than 2" from full free length, any higher spring rate than this and I risk having them flop around at full droop.

So why am I going through all this bother? Simply put, I don't like that much variability in the spring rate. It might be a compromise between ride and handling, but I think both parts suffer more than either part gains. The greatest benefit to a spring like this is that you can lower the car more and not risk bottoming out as easily. Since I don't need/want the car LOW, I would prefer a linear rate spring.

A spring will compress a certain amount with a given load. Remove a given load, the spring will extend. A stiffer spring will compress or extend less for a given load difference than a softer spring. It's pretty easy to see this happening when you load a car up: add weight, the suspension compresses; but you don't often think about what happens when you remove load. The softer spring will extend further, the car will gain more height.

In a corner, load transfers from the inner wheel to the outer wheel due to the height of the center of gravity and the track width. With a CG at around 18" and a track width of 52", a 0.8G corner will take about 315 lbs of load from the inside wheels of my car and put them onto the outside wheels. The outside suspension must absorb this extra load and will compress, while the inside suspension will extend upon release of this load. Stiff springs travel less, so the outside wheel compresses less and the inside wheel extends less.

But a variable rate spring will do something funny: With added load it will compress a certain amount but will then stiffen up and stop moving. When relieved of the same amount of load it will extend further than it will compress when that load is added. So when going around a corner, the outside wheel will compress a little while the inside wheel will extend a lot. This means that in addition to the car rolling "more" (more than it would with a pair of linear springs equal to the stiff part of the variable springs), the car rises up, which raises the center of gravity, which adds load transfer, which adds load, which adds roll, etc.

Similar issues occur when it hits a bump. Imagine a 2" bump: The wheels compressing the suspension increases the load on the springs. This load is then released, which converts into body momentum travelling upwards. If the compressed position puts the springs into their "stiff" zone, they will store and release much more energy in a short distance, and will release it more quickly. This moves the body faster, and as it goes back into the lightly sprung range the body will keep moving further because the lighter springs lose load more slowly. A stiff linear spring would compress the same amount and would store the same energy, but would lose it more quickly and would "bounce" not as high as the variable rate spring. On small bumps the ride is similar to stock, but that makes the big bumps all the more surprising when the nose heads to the sky.

So what you really get with variable rate springs is a spring that uses both heavy coils on big city street bumps, but only one heavy coil in a corner. I'd rather have linear springs that produce the same effect in corners but ride better on the street, or springs that ride the same on the street but work better in the corners. Savvy?

The 400# spring is stiffer in proportion to stock in the same general amount as the VPD rear springs are to stock, which was my first choice of things to try. The idea with the 550# springs is to try something about as stiff as the "stiff" position of the VPD variables and to bring the ride rates and balance more into the sports car range. For reference, a similarly "old" guy as myself just installed 300 lb/in springs in the front of his 242 and that gives a ride frequency in the 2.0 hz range, and he doesn't think it's TOO harsh, so my 550s might be just fine.

More to report when the springs arrive.

Just read the whole thread - awesome as usual.

Any updates on spring arrival or how the car is doing as a DD?

I also need to rekindle the working in the garage fire - seeing all this progress in such a short time was just so damn impressive!

Rabin

I just got the 400 lb/in front springs installed tonight. I may have miscalculated something... the front end came up nearly 2", or pretty much back to stock ride height. I expected it to come up about half that, maybe a little more. Also, it turns out that 5" diameter springs really aren't what we're looking for: the stockers are closer to 4.75-4.875". The 5" springs don't quite get all the way down into the pocket of the lower control arm, but they might make their way down there given enough time and road hammering. Maybe they need to be chamfered with a grinder before installation, I'm not sure.

That's the bad news.

The good news is that the ride has improved, in my opinion. It's stiffer on small bumps but softer on the big ones, it goes over speed bumps without that sudden jolt at full compression, and the balance feels pretty much like stock (just stiffer). I should really put the Bilstiens back in the rear, or KYBs in the front, because now it feels a bit soft back there. I would consider these to be an excellent rough-road spring when matched up with something equally stiff and tall in the rear (maybe an overload of some sort).

I ran the VPD and these 400 lb/in springs through my calculator and came up with much higher numbers than what I expected, so either my calculator is messed up or I'm not using it right. In order to get these 400 lb/in springs to actually calculate at 400 lb/in, I need to claim one more "active" coil than I would expect. Adjusting the VPD and stock springs down to match, the stockers and the VPDs both approached the claims posted on the VPD website, which frankly, I believe to be true. So ignore my 325 lb/in "stock" spring measurement, it's likely closer to 225 lb/in.

I'll run these for the next couple weeks and will probably pull the car off the road before I absolutely need to, so that I can start hitting this long list I have for the winter. The 550s will go in when I reassemble the car, I just wanted to see what the 400s would be like before I put it to bed.

In all honesty...that was one of the worst aspects of these springs. They'd give you that coil bind jolt and after a week or two you wouldn't be loving it anymore. So I'm glad that's gone. I think if I'd known more back when I had them, I would have swapped them out and done something about it. On the track, they were fine as the surface is smooth and in the corners it felt stable and was really much better than on the street.