IFS Suspension HELP Needed...Warning - Volvo Content Inside.

[Coburn_Performance]

OK - I'm getting hopelessly lost in the world of suspension geometry and appeal to the collective wisdom of this board for a little assistance. My project car is a 1966 Volvo Canadian (Amazon/122s whatever you want to call it). I've had the car for 7 years and it has undergone a number of simple revisions and some rather more complicated additions. Like the rest of you, I take this car out to track days (surprise a lot of people) and the rest of the time it's a vigorously driven street car. Before everyone starts to laugh - it's making 160 hp out of 2L and I've converted the front brakes to Wilwood FSL's and have a disk brake rear with LSD. It's only 2400 lbs and generally handles well with 28mm front sway and 20mm rear. Spring rates are variable (250 - 500 lbs/in) up front and 150 lbs/in in the rear with Bilsteins doing damping duty.

After rebuilding everything, I'd like to equip the car with rack and pinion steering, get some suspension travel at the stance that I like and am not shy with the plasma cutter and welder (all processes). As a Volvo performance guy, I have to home-brew just about everything - so don't hold back if you've got a crazy idea. I like crazy.

Here's the patient:

https://static1.pt-content.com/images/pt/2012/04/canuck1-1.jpg

Here's what I know:
- I set up the suspension for the current ride height and the centre of the hub is located 11 7/8" from a level surface.
- Track (wheel mount face to wheel mount face is 55 1/2"
- The frame rails are 24.25" inside and 28.625" outside
- LCA is 16" from pivot to ball joint.
- UCA is 10.5" from pivot to ball joint.
- LCA pivot is 7.1875" from the centre of the crossmember.
- UCA pivot is 10.75" from the centre of the crossmember.
- LCA is set at 5.5 degrees (ball joint is higher than the pivot).
- UCA is set at 2.5 degrees.
- Camber is -0.5 degrees
- Caster is 0 (as far as I can determine).

It's a narrow car and I'm just about sitting on the bump stops right now (one inch of travel).

https://static1.pt-content.com/images/noimg.gif

The original design is good for its intended purpose, but not for what I do with the car.

I'm thinking that I'm going to have to chop off the front of the car and build a new front suspension. My problem is that I'm not sure what I should be looking for - there is a bunch of Mustang II stuff that would work - but what should I do to calculated what I've got now and what do does good look like for geometry?

[67zo6Camaro]

Very cool project. Love the idea of something different. So, looking at the last picture with the lower A-arm looking level. It appears that you still have suspension travel (if you reduce older rubber bump stop for smaller urathane style).

If your first intention is just to improve steering with a Rack and Pinion set-up, then try some type of manual rack set-up from your area. Here in the States (Cali) the ford mustang or thunderbird style seams to be the most plentiful. So, try to find a common rack you have access to. You will probably only need a manual due to the weight of the car. Also this will aid in the simplicity of the application.

So, first. do just as you did. Lower car to the desired ride height. If the above picture is true to that, then it appears your lower A-arm is at an acceptable level angel.

Then measure the distance between the mounting points of the lower a-arms at the frame craddle area. This number will help you search for a rack & pinion that has a similar "pivioting width". Try to find a rack with the bendeing portion of the stearing arms having a similar distance in the middle of the rack to match the distance of the lower a-arms mounting points. That way the lower a-arms and rack have a similar motion arc.

Now, if you have found that rack, then try to visualize and/or mock up to package it in the front or rear of the wheel axis. The closer it is to the same plain as the motion of the lower a-arms the better. However, there are work-arounds for this.

You may need to modify the frame and/or engine oil pan... or even pulley accesories to get some clearance.

This is a good starting point. If you get this far... then it's possible you will not need to build a front clip.

If you make it past this fitment and size issue.... you will need to start planing steering arm sizing and steering arm angles along with access for a steering wheel shaft to make it down from the steering column.

Now I know there is alot more we could talk about to get this thing to handle more aggressively. For example... from the pictures it looks like you could stuff wider tires, or even lower car more with stiffer spring rates and/or sway bars.
Do all of the above. Rack, lower, wider tires, stiffer springs and sway bars..... and lighten the car up as much as possible.

Im totally interested.
Post more info and pics.

cheers

[67zo6Camaro]

:nopity: lol, I went back and read your post again.....

Not sure how I got on the rack and pinion conversations. Just as a side note, Im sitting home today with a cold in front of a computer. Obviously not a good combination. :rolleyes:

Ok lets try a quick version. I think there are a few more things you could do before jumping to a custom front clip. Although a custom front clip and rear suspension would be way cool.

Old school, just remount suspension higher in frame and/or body of car. Requires some cutting and clearance modifications but will net ability to put suspension in geometry sweet spot and lower roll center, center of gravity ect. Lots of other things can be done after this mod that will bring a more racing inspired handling car.

Example: Wider rear end width and wider custom front A arms with wider tires at all 4 corners. Stiffer spring rates and changing to a coil-over. Mounting coil-overs out and at an angle to the wider suspension.... Will need to add body flaring.

Anyway. I'll leave the first post up even if it's off topic a little.

[Coburn_Performance]

Thanks guys - I was needing some encouragement to figure a few things out. Here's the list from today. First up, I created a wooden model of my suspension geometry (2D) and discovered that my instant centres are 132" long (see photo). All those geometric examples where the UCA/LCA intersect within the chasis...what an eye opener!

https://static1.pt-content.com/images/pt/2012/04/suspension_geometry-1.jpg

So AFAIK that means that I get a lot of camber gain (positive or negative) with suspension movemen or body roll. This makes sense as the usual solution for these cars it to lower the car just a little, but equip it with big antiroll bars (28 mm front and 20mm rear (remember 2400 lb. car)) and stiff springs to try to limit body roll and suspension travel - after I got my wooden model built, I tried it out and it makes total sense. It shows dramatic movement of the hub with body roll or bump.

I can't fit a rack as the pivots for the LCA are only 14.75" apart! I'd need 16" to fit a mustang rack (I think). I've emailed several manufacturers and they all say no due to bump steer.

The C-notch is really narrow (8" wide) so if I just wanted to drop it, I could make it taller, but I dont' really care to lower the body on the frame, I want to have suspension travel. Now I suppose if I did that I could raise the suspension, which would give me more travel (or cut my bumps) - but I really think that instant centre is my issue (as raising the suspension makes the instant centre longer!). This geometry makes sense when you consider that it was designed for tall sidewall tires and lower speeds with no caster to make manual steering tollerable. I have looked at (but not measured directly) what would happen to my roll centre and it would be migrating like a lost Irish imagrant (sorry - not a cultural slur...just family history:lol:).

I think a custom clip is the only answer for real handling. I've already installed a wider track rear end (2") with a custom 4 link that I fabricated...helped a bit, but the rear roll centre is fixed with the 4 link to the centre of the diff (where the panhard rod crosses). I'm going to be converting the rear to a Supra IRS (not a drag car!).

So I'm now thinking that a Welder's series crossmember (reinforced as things like the LCA mount look dangerously weak) with Mustang bits would be a giant step forward (start the M2 Flame wars!:getout:).

[GrayRaceCat]

I'm a fellow Volvo 122s owner (1964 120 4dr), and I'm wondering if you have anything to update the thread.
Thanks, Brian

[Coburn_Performance]

I'm a fellow Volvo 122s owner (1964 120 4dr), and I'm wondering if you have anything to update the thread.
Thanks, Brian

So...it's been about forever since I even checked this thread. Sorry about that. I've moved the information about this build over to a YouTube Channel (Throttle Stop Garage - www.youtube.com/throttlestopgarage).

By way of updating...I installed a hot rod company's front suspension (Corvette C4 based) and couldn't get their cross member to square - because it was not made square. I designed my own version using their pick up points. Welded that into my car...then checked the dynamics and discovered that it was way out. Now I'm redesigning that suspension system and have to redo everything.

I've also made most of the body panels in carbon fibre (complete front end, doors, and trunk). That was a lot of work - cool process though.

Anyway - it's all a bit pear-shaped at the moment and giving scope-creep a bad name. The car is getting done.

[raustinss]

im sorry im not very helpful but i do need to add that throttle stop garage is awesome ..