Volvo P1800ES...kinda

In reply to JoeTR6 :

I think I will be going pretty much as high as they go and still have some droop left.

Pete

So....we got the Hella-Stanced thing going on here. This is with the collars screwed up to the top limits. The thing is off the bumpstop by about 1/4"

Not loving the upwards angle of the lower control arm...Need to get the a-arm at least level with the ground

I am guessing that I need to go up substantially in spring rate to get the lower a-arm at least horizontal to the ground.  Looking at the prose on the spring, is there any way to tell what the baseline spring rate is?

Pete

You're at that ride height with the bottom of the coil as HIGH as it will go?  (This is with the collars screwed up to the top limits.)  If so, the issue has virtually nothing to do with spring rate.  If you're a 1/4" off the stops with the spring as high as it will go, you need a MUCH longer shock/spring combo.  Spring rate set by what balance of wheel-tire control/stiffness/ride comfort you're trying to achieve.  Jack the car to the height that levels your control arm/steering arm and then measure between control arm and upper mounting point.  That should set the length of the coil over laden.  Perfect world -- the shock sits in the middle of its travel when the car is at the desired ride height so you've got about half of your travel on each side - rebound/compression.

What's the front spring height unladen?  I'm running 12" springs in front and 14" in back for decent (but still lowered) street ride height on the 240.  Jack body up in front/center until you've got your level control arms and see where the ride height hits...go from there.

If I remember correctly that's one of the FM V-Maxx kits right?  I'm amazed that it sits that low with them adjusted all the way up, I guess the Volvo body must have added some heft!

EDIT:  I went back and looked at the post where you weighed it, and something is berkeleyed up here.  It's not that much heavier than a Miata.  The markings on the spring you posted match the photos on FM's page, so I'm stumped.

Any chance you can borrow some scales? It sounds like you need that number (plus probably about another 300 lbs for glass, HVAC and interior bits still to be installed) and then contact Keith.  Otherwise you run the risk of chasing springs via guess-work, which might get expensive (and annoying).

Pete, 

I went out and took some rough measurements of the suspension on my Challenge Miata. It's on the stock sport Bilsteins with Ebay coilover springs and collars. At full droop the distance from the lip of the tophat to the center of the A-arm pivot bolt is 9.5", tophat to top of shock body is 4", tophat to spring perch is 5.5". Is the point where your tophat bolts in the original Miata, or something you've fabricated ?

This how it sits on the ground...

In reply to DeadSkunk :

What confuses me is that the a arm is past level with the ground.I can’t see where that would ever be the case with a spring in the  500 lb/in range that I believe these to be. Regardless of the body length.

weight as measured is 600 lbs per front tire.

Pete

I'm wondering if the area where the tophat bolts to the body is too far from the A-arms. Compare your photo on the previous page to this....

Long shot question.......you do have the longer pair of shocks on the front of the car, right? 

In reply to DeadSkunk :

yup. And the right springs on the right shock bodies.

Nex step is to use the stock Bilsteins that I have kicking around. I have a set of springs for the front that I bought from Monster Miata and the stock front springs go on the back.  The front sat a LOT higher in front with the stock springs.

Another option is to get rid of the rattle spring and replace with a piece of tubing as a spacer.

cant help but think I am missing something. This was supposed to be the easy part of the project.

The only pictures that show the perches show the collars threaded down as far as they can go. I assume its not as simple as the spring perches at the bottom end of adjustment instead of the top? :-) 

In reply to MrJoshua :

I wish.

You could get a miata suspension raise kit.  They have spacers for between the shock tower and shock upper mount. Assuming there's nothing else wrong and it's just the suspension all being too short. 

Can you take a picture of the shock in the setup where it was sitting so low?

The two  ASSUMPTIONS that I am working under  are:

1- the track cars that use this suspension do not have  lower a-arms that point upwards from the inner pivots as shown in this picture. My understanding is that lowering a car to the point where the a-arm is past level with the ground is not good for handling.

2-600 lbs per wheel is not too far off what a stock miata would weigh per corner.

Options at this point are

1- put the bilsteins in with the front springs in the rear and the Monster Miata springs in the front. 

Pro- Solution proven by Monster Miata . Cheap since I have the Monster Miata springs on the shelf.

Con- shocks look new(is), but are used and of unknown provenance and no damping adjustability or knowledge of how they will like the stiffer springs

2-Find a different spring set for the V-Max

Pro- Get to keep the V-Max adjustable damping. 

Con- since the math does not seem to be working, ( or I am doing bad math)  guessing game on springs until I find the ones that work.   Cost and delivery time.  I am ASSUMING that other spring rates are available.

3- Build a tube spacer with a flange that replaces the helper spring. Most of the compression achieved by  moving the spring perch up goes into compressing the helper spring with very little change to the main spring, so eliminating the lost travel of the helper might do the job. 

Pro- cheap.

Con- Seems bogus

4- Order new coil overs with adjustable bodies as used sold by V8 Roadsters

Pro- Proven solution designed for a V8 swap. Adjustable shock bodies so ride height can be adjusted independent of spring preload. 

Con- Cost and delivery time. 

Pete

Get us and keith a picture of the installed coilover.  This is very odd. Even though the drivetrain weighs more, its not 1k lbs more on just the front axle. 

I'm pretty sure that you got sent wrong parts. 

Pete, 

Checked my spring length and it's 5.75". Old notes for cross weights on my NA SpecMiata showed 622# LF, 582# RF with me (200#) sitting in the seat. That would have been set with the pinch welds on the rocker area at 5.25" from the ground. A-arms were not sloping upward like yours. Shocks were Bilsteins with a coilover kit, and 700# springs. 

On the Challenge Miata I have room to jack up the suspension quite a bit yet.

There's definitely something wrong with a dimension some place. How much difference is there in length between the Bilsteins and V-Maxx shocks? Check your rocker panel to floor measurement against my race height. Are all the suspension pick up points still stock Miata? You haven't  fabricated the upper shock mount , have you? 

This points at having the wrong length of shock, as Dusterbd13 suggested. If that's the case then I don't know who would want a Miata this low, aside from the stance crowd.

Edit: You built the subframe. Is the lower inboard pivot point the same distance from the bottom of the chassis rail as a stock Miata?

If need be, I could come up for the day and bring a set of nearly new NB  Bilsteins and stock springs, tophats, and perches for a test fit. Not sure what the customs folks would say about parts though.

Another thought.....if this is all a result of the shock body being shorter than the Bilsteins you might be able to rectify it by eliminating the helper springs and utilizing a longer main spring with the same rate as the kit springs. Less chance of coil bind happening and it would move the spring perch lower on the shock body. Which V-Maxx kit is this?  

On Flyin' Miatas site they state that V8 cars should use the extended springs. Is that what you ordered and got?

Mentioned before -- I don't think this has anything to do with spring rate.  It's to do with the overall spring/shock HEIGHT and, as mentioned above, where the control arm pivot sits (heightwise) relative to the new frame rail (as compared to a stock Miata set up).  If that pivot point is in a different location than stock, then you're going to need a different length coilover to get back to stock geometry/roll centers.  The way it's sitting impacts the front roll center - impacts cornering AND rear traction.  Once you get the geometry sorted out, you still need to be sure your damper is sitting close to mid-stroke at desired ride height -- and that there's a match between shock full travel and spring travel.

edit - I recall, with some head scratching, questions being asked about geometry many, many pages ago when initial subframe fab was occurring.  But I think it fell into a sort of 'well, it's not a race car' black hole.  Could be that it's now time to cross that bridge.

The entire chassis is stock Miata. The only geometry in question would have been the ackerman due to adding 7" to the wheelbase.

I took some pictures of the mounted coil-over. The hub is bolted to my "Wheel emulator" that I used to set the ride height when  I built the car. It is equal to the radius of the wheels I am using.

Looking from the front of the car, here is a picture of the a-arm at the angle where I expected the car to sit. Based on my understanding, it would never be a good idea to run a Miata with the lower a-arm past level with the ground. With that though process, I ASSUMED that the V-max extremes, despite being a race car shock body, would not have the car operating with an  a-arm sloping upwards towards the wheel. That might very well be my mistake and in fact race cars do slope the a-arm upwards.

With the a-arm at ride height, I have 2" of compression and 1" of droop. Not going to run Baja, but workable maybe.

With the car still on the wheel emulator and at the car still supported by a jack under the crossmember to set the ride height, this is the view from the side:

The helper spring is essentially a spacer at this point

The main spring ( rate unknown) has only compressed 3/4 of an inch. So I can see where if it is, say 500 lbs/in, it has a ways to go before it picks up the front of the car. ( Might have been a good idea to drop the car off the jack just to do the fully compressed image)

Total shock travel is 3" for these shocks, so if the a-arm is level it would be pretty close to the 50-50 point of the travel. Giving up the 1.5" of travel by going to the shorter shock bodies ( did not see that one coming) would be lack of due diligence on my part.

The solution, as long as I can live with the suspension travel, of a race shock, should be to just find a set of longer springs and get rid of the helper springs since they don't seem to be doing anything in the first place.

Some random measurements:

Total amount of shock shaft exposed 3"

Free length of main spring 5 1/2"

Length of main spring with collars at top of travel 5"

Free length of helper spring 3 3/4"

Length of  helper with collars at top of travel 1 1/2"

Length of main spring at ride hight 4 7/8" A-arm just before level as in picture)

Length of helper spring 1 1/4 ( fully collapsed and coil bound)

I should probably at this point contact FM to see what spring options they have that would fit these shocks.

Pete

Another solution may be to use the Paco Motorsport lift kit that Flyin' Miata sells, or just weld tabs to your A-arms to accomplish the same thing. This would allow you to set the shocks close to mid-travel.  A longer spring would allow you to raise it ,but at the expense of some droop. 

Just my 2 cents, but you've put so much effort into this build that I wouldn't compromise. Sell this stuff to the stance crowd, take your lumps and put in something closer to stock geometry. The Bilsteins and Monster Miata springs would be where I'd start. A coilover kit on them and you can try a variety of spring rates until you're happy with the ride/handling.

I'm not sure what's in my spring inventory, but several choices in the 250-700 range and you're welcome to try any or all.

Spring rates for the various V-Maxx kits are all listed on the FM site, so you can find where you currently are. 

Get Keith's input on this. He can do this stuff in his sleep.

In reply to DeadSkunk :

Agreed that the first step is to follow the Monster Miata formula. I have everything in house. Can't say as I understand what you mean by coil over kits for the Bilsteins; do you actually somehow convert the stock Bilsteins so that the spring  can be preloaded?

Also agreed that I might have to take the hit and blow these out the door to the stance crowd. The problem I have with that is that as they are, I have proven that they  wont work on a stock Miata with a corner weight of aprox 600 lbs, and I don't want to be dealing with some pissed-off Kajiji buyer who buys them  and then cant drive his car after doing  the work to install them. Lets find out if there is another spring option that might solve the problem; I think springs are cheap.

Keep in mind that I am a tin basher, this is my first foray into suspension, so there is going to be a learning curve. Pretty sure that at the end of it all I will have a better understanding of  what I should have done in the first place!

Pete

edit...did not someone drive the challenge on like 3 or 4 bump-stops?

Coilover kit in my vocabulary is just the collars and perches that I used on my Challenge Miata. I had to remove the stock aluminum perches and then slip the collars on. It's the stuff that's in my suspension picture. The advantage is you have the height adjustment and an unlimited choice of spring lengths and rates. I used them on my SpecMiata and ITB GTI ,too. The shock in the picture is just the standard sport suspension unit that was on the car when I bought it. Removing the stock aluminum perch is a PITA without a press because they're on there tight. I heated the aluminum with a heat gun and then hammered them off.

....and, I don't think your problem has anything to do with your corner weight. Spring rates are double the stock value and the car is only slightly heavier than what my race car weighed.

Do you know exactly which V-maxx kit you bought? It would be helpful to know which springs you currently have.