Seeking Mysterian (M2) setup advice

[nhill40]

I'm wondering if someone could help me out with a setup question.

I have been running a Mysterian M2 and have noted that, relative to a couple other M2s I've been around, my uprights shown in the photo here look noticeably narrower on my car.

I did a measurement between the middle of the two bolts circled in red in the photo and got right about 11.5" (this was unloaded). I'm wondering if I'm running a bit narrow here. Could anyone advise me on this?

[Steve Davis]

That distance will vary, based on the rating and length of your spring. It WILL change the suspension ratio a tad but it will do that anyway when you hit a bump. That distance needs to have those uprights APPROX vertical (and balanced L/R) and that's all you really need.. however, you need to make sure that your spring can't go into 'coil bind' if you jump on the back with all your weight. If is does... .or the frame bottoms out.. you need to install a stiffer spring to support the rear.
Steve, FV80

I should add, that the camber limiter below the spring also plays a BIG PART in the handling of a Vee. Generally, the limiter should have a bit of preload keeping the axles from going more positive at rest. The 'value' of the rubber (MUST be 'some kind' and not a 'hard stop') is an adjusting tool to help you get the feel you want from the car.

[FVRacer21]

This could end up as an interesting thread

Years ago, I was taught to adjust camber with the spring perch, not the push rods.
That was when we were running 5 - 6 degrees negative.

Now we are running in the 3.5 - 4.5 degree range and changing the original geometry.

I believe most people today are setting their rocker geometry by measuring the loaded spring length, then adjusting the camber/ride height with the push rods. Yours look like they are extended quite a bit, which might imply you rockers should lean out just a bit.

This is what I got from Fred Clark (Caracal Cars). The rockers on the Mysterian are similar to the Caracal.

"Here's the trick with the rods, it again is affected by the shock and now the SPRING.Step 1 install spring on the shock and tighten it until the free play is gone and then add 1 one-inch preload, this creates the true value of the spring you have chosen
Install the shock and adjust the bars to give you the -3 degrees of camber on each rear wheel, (that would give 6 total, adjust for what you are running)
Remember whatever you do to one bar you have to do to the other to keep them the same length, you can start the bars almost anywhere you can install them easily
The above must be done with the driver's weight, body weight and 1/2 tank of fuel weight mentioned in the other e-mail .
This process creates the rocker angle with no problem, at least on the cars I have worked on.
All for now.
Fred"

If Fred's trick does not work and the rockers lean in too much - you might have a collapsing spring....

On cars with short rockers, like the Citation, this could affect if you have a rising rate or decreasing rate suspension - not sure how critical it is unless you try to redesign the original system. They put a lot of work into the original geometry.

with apologies to Paul Simon

"Still crazy (and learning) after all these years."

ChrisZ

PS - re Steve's comments on the droop rod. At Thompson this weekend I tried a new design on my Caracal (similar to Mysterian) thinking that I was doing something different - only to find everyone else has already done it! Moving the drop rod to above the shock. Should have taken pictures of all the different systems, but PM me with your email and I will dig some up.

This is how most other (Citation, Protoform etc.) do it and it seems to be less harsh. There was a discussion in another thread about if you need a rubber stop at all, (people in the past have used cables or just rods) but I think the quality of tracks makes the rubber necessary.

[BLS]

I don't know if there is any particular information to be found regarding your question, but there is a lot of discussions about FV suspensions available here:

https://www.formulavee.org/viewforum...c212fbed216cde

If you have not been there it is very useful and can answer many questions with searches.

[FVRacer21]

Duplicate

[Hardingfv32]

I'm wondering if I'm running a bit narrow here. Could anyone advise me on this?

It makes no difference at all assuming no mechanical issues. After 50 years of zero roll, why hasn't the class settled on a setup or design for the rear spring.... because it makes no deference. Someone is going to bring up how spring rate will vary with different angles, etc., so what? This is not a typical rear race car suspension. it does NOT load up, hunker down, etc. in the turns. It raises or jacks up in the turns. That is why the droop setting is your MOST important adjustment at the rear. Everything else is a distant second.

I have built and experiment with more types of rear suspension designs that anyone in FV that I know of. This gives me first hand experience. Each new design is just as fast as the last one, but no better. I love experimenting so I keep changing, hoping to unlock some secret. Most adjustments of the rear suspension on my car are driver adjustable so the driver can get immediate feedback within the same session to a change. Not chasing tire or track variables.

Brian

[Hardingfv32]

This could end up as an interesting thread


At Thompson this weekend I tried a new design on my Caracal (similar to Mysterian) thinking that I was doing something different - only to find everyone else has already done it! Moving the drop rod to above the shock.

Yes, it could be an interesting thread IF people are willing to ignore the mythes that have been generated over the last 50 years and accept what the science of this subject really indicates.

Droop rods, rubbers, etc., why no consensus after 50 years??

FACT: the only thing that matters is the droop setting you end up with. The droop setting is the rear camber setting when the car is in the turn, as such it represents the grip you will get at the rear.

How you come to a stop on this setting has NO importance. FACT: I have used metal to metal bump stops for 20-30 years. Data showing the travel of the rear shock NEVER has indicated ANY bounce when hitting the limit. FACT: the rear shock is in rebound on the way to the droop limit, It has only the jacking force and rear spring to control. There is nothing violent about this motion, all well controlled by the shock.

You stated your change seemed less harsh. How and when is the harshness being perceived? You put some effort out to implement the change, ANY chance of driver bias to some kind of expected change?

Brian

[Ed Womer]

I'm wondering if someone could help me out with a setup question.

I have been running a Mysterian M2 and have noted that, relative to a couple other M2s I've been around, my uprights shown in the photo here look noticeably narrower on my car.

I did a measurement between the middle of the two bolts circled in red in the photo and got right about 11.5" (this was unloaded). I'm wondering if I'm running a bit narrow here. Could anyone advise me on this?

This would be MY opinion, but I see a few things I would change, based on experience of the 40 years of doing this. First, the large aluminum rockers are not centered. So shorten the left push rod so they are the same distance from center of the chassis, which a quick way to check is the center split of the tranny case. Note this is assuming your chassis is square and not bent. Your spring does not seemed to be collapsed but that is judging by the picture. You might have to run the nut on the spring in to get yourself back to your preferred ride height. You can also get spacers to put on the spring if needed.

As a note, when I went with the zero roll design I bought from a friend of Bob Tupper which was used on early Zink chassis, it would bend the bracket if I had an off road experience. So after making a new for the third time I decided to look at it and noticed the chassis could not bottom out on the ground before the shock did. Well guess what? Because the shock could travel no further, the bracket would bend.

So I figure out that the distance between my rockers need to be further apart. So I ended up with moving the pivot points to 12" instead of the 10" the design called for. That is for the rockers. Presto! problem solved. I also realized that in order to keep things working without the rockers going over center, that the ride height needed to be with the shock bolts at a minimum distance of 12 3/4" apart center to center.

I have never changed the design since then. As a note, the P1 Protoform was a direct copy of my car and used the exact rockers and bracket.

Just keep in mind that design differences developed over the years, are do to packaging requirements and not always due to a better idea. The zero roll was a big change from the other options and has worked ever since then.

If you want to go another direction you could contact Brad Bunting who has developed a 4 shock system that some people think might be better. You need to decide on your own.

Ed