Popcorn

[Stoffregen Motorsports]

Not a bad idea. One slip of the saw and you toast a blade though.

[Satisaii]

I picked up some cutoff disks, flapper disks, and sawzall blades.  Hopefully I will have the time to do some cutting this weekend.

[thisismatt]

6 minutes ago, Satisaii said:

I picked up some cutoff disks, flapper disks, and sawzall blades.  Hopefully I will have the time to do some cutting this weekend.

 

That or collect some catalytic converters

[Satisaii]

Would this thread be better served in Project Datto rather than 521?  I did not consider that when I started it.  If it would be better there, can a mod move it or would I need to start over?

 

On to progress.  Got all the OEM suspension mounts cut and ground off over the weekend.  Thanks for the suggestions to use cut-off wheels and flappers.  Made quick work of it.  I may have bought too many though.  Add it to the plasma cutter (which I will probably put for sale once I get past cutting the floor out.)

 

Upside down frame:

 

 

We decided to push the subframes as far up into the truck as we could.  We cut the round cross member out and will weld in the subframe in to replace it.  Still won't hit my suspension geometry targets at the desired ride height (4.5" frame to ground) but it is close.  Right now it is supported by pieces of aluminum bolted to the bed mounts and zip ties.  Going to have to do some serious cutting and reinforcing of the frame to get upper control arm clearance.

 

 

 

Some SW snapshots for reference only.  Turned out that all my fancy scans are slightly off and I don't want to take the time to straighten them out.  They are not watertight anyways, so I can't use them for FEA.

 

 

 

Can't turn on shaded with edges.  Computer gets very unhappy with the number of triangles.  SW is not great for scanned stuff.

[datzenmike]

A couple of buttons pushed and I can move it anywhere.

[Satisaii]

If you don't mind, please move it.

 

Thanks.

[Stoffregen Motorsports]

On 9/15/2022 at 8:35 AM, Satisaii said:

Would this thread be better served in Project Datto rather than 521?  I did not consider that when I started it.  If it would be better there, can a mod move it or would I need to start over?

 

On to progress.  Got all the OEM suspension mounts cut and ground off over the weekend.  Thanks for the suggestions to use cut-off wheels and flappers.  Made quick work of it.  I may have bought too many though.  Add it to the plasma cutter (which I will probably put for sale once I get past cutting the floor out.)

 

Upside down frame:

 

 

We decided to push the subframes as far up into the truck as we could.  We cut the round cross member out and will weld in the subframe in to replace it.  Still won't hit my suspension geometry targets at the desired ride height (4.5" frame to ground) but it is close.  Right now it is supported by pieces of aluminum bolted to the bed mounts and zip ties.  Going to have to do some serious cutting and reinforcing of the frame to get upper control arm clearance.

 

 

 

Some SW snapshots for reference only.  Turned out that all my fancy scans are slightly off and I don't want to take the time to straighten them out.  They are not watertight anyways, so I can't use them for FEA.

 

 

 

Can't turn on shaded with edges.  Computer gets very unhappy with the number of triangles.  SW is not great for scanned stuff.

What about kicking the frame up to gain that clearance? Then you'd have body issues. How about sectioning the body/raising the floor to stuff the frame up in there?

[Satisaii]

I will be close enough to matching the Miata frame to ground clearance and the subframes will be higher up in the vehicle than in a Miata.  They could be higher relative to the frame, but it is not worth the hassle of pushing the subframe up into the bed.  I might have to tub the bed for tire clearance, but it will still be flat between the wheel wells.

 

I thought about channeling the cab and bed for looks, but I think I will do side skirts, possibly as part of a flat bottom.

[Satisaii]

It is time to take the leap and start cutting the frame.  After lots of careful measuring and marking, I started cutting.

 

 

 

 

My cutting looks like something from a slasher movie.  There is a lot going on inside the frame right where I cut, which has made it much more difficult.

Test fit the subframe with all the suspension bits thrown in for good measure.

 

 

 

 

This is higher than the static ride height I was shooting for, and the upper control arms are hitting the frame.  So I pulled it all out and cut some more.  At this point I started to worry about the frame strength where I had cut so I decided to go ahead with welding in some support before going any further.

 

Maybe I should mention that I have never welded anything before.  But a couple of coworkers can and I have some contacts who can do even better, so we decided to have a little get together to teach me how to weld.  To put it nicely, I sucked at it.  So they took over and told me to practice a bunch before trying the real deal.  Just as we were really getting going, we ran out of gas.  And that is where we are as of today.  Gas is getting refilled and I hope to be back at this weekend.

[Icehouse]

Did you draw up the suspension points and put them into solidworks to find the roll center?  If I remember right the roll center doesn't change much with dual A arms but anti squat does and your roll center to CG seem like it would be cool to know.   I agree solidworks sucks for point clouds.  

[Satisaii]

I had not really thought to do that, just going off of 12 years of working for a company that designs race suspensions for Miatas.  I have been thinking of the truck as a tall, long Miata in terms of CG.

 

We like to measure the ride height of a Miata at the "pinch weld" - the part of the car that we would jack up.  Stock is about 6" from the weld to the ground, and we have run our race cars as low as 3.5".  We know that when you lower the cars like this, the roll center moves below ground but the CG does not drop much, giving the CG leverage over the roll center.  To counter this, we use springs that are up to 5x the stock rate.  By lowering the frame relative to the subframes I am going to raise the roll center, lower the CG, and won't have to run such stiff springs.

 

It may be fun to model it, but it would be some WAG on the CG of the truck.  Miata info is easy to find.  The scans were some we had paid to be done years ago and delivered to us as shown here.  Ones I have done recently have turned out more useful and smaller.  Guessing the software has improved.

[Icehouse]

I don't think the CG goes below ground level.  If it was a strut car yes but that's the beauty of double wish bone.  I vote you draw it up to prove me wrong.  

[Stoffregen Motorsports]

Try doing a google search for link suspension calculator. You will definitely find the software used for off-road link suspensions, but I know I've seen an online version of a upper/lower control arm independent suspension too.

[Satisaii]

I said the roll center can go below ground, not the CG.  I never researched that myself, just something I learned from people who have been doing this longer than I have.  Maybe I will set it up to see.  It would be fun to prove them wrong after all.

 

Flipped the frame over to clean up my horrible cutting job and increase the articulation on the upper control arms.

 

 

 

Now I need to focus on adding some strength back into the frame.  That was a lot of material removed.

[Icehouse]

Sorry yeah I meant roll center.  

[Satisaii]

Cut as much as I dared out of the frame for upper control arm movement and started welding some support back in.

 

Full bump:

 

 

Static:

 

 

Full droop:

 

 

~4" frame to ground at static:

 

 

And 2" at full bump:

 

 

Close enough to move onto the front.  I need to get it rolling around again before I go back and box in all the cut areas.

[Icehouse]

You aren't going to clearance it anymore?  I mean you are there, if you change anything later (like bigger wheels and tires) or find out you need more travel it will be hard to add later.  I would make it so the frame touches the ground.  truck guys C notch the frame all the time.  Ain't no thing.  

[Satisaii]

I will run into the same problem on the front if I lower it much more.  With side skirts it is going to look lower than it seems now.

 

I don't have any experience modifying trucks.  Last time I had a modified truck was in the early 80's (1956 Ford.)  I thought about doing a tube frame in the back, then I would have to do the same in the front, and then I might as well do the middle too.  Project creep, I need to keep it simpler.  Already planning on paying for a half cage and would rather spend the money on other parts.  We don't have the tools to do that kind of work.

 

My sacrificial Miata tub comes in tomorrow.  Need the shock mounts, floor, and firewall from it.  I don't have a place to store it so I will be quite busy this weekend.

[Stoffregen Motorsports]

Yes, you did cut a lot out for control arm clearance, but you're welding in the Miata crossmembers, right? Just welding them in will give a lot of strength to the cut areas.

[thisismatt]

Just call that the crumple zone. And done.

[Satisaii]

Not much of an update.  Last weekend I took this:

 

 

To this:

 

 

And this:

 

 

Probably not much truck action this weekend either.  I am trying to get my 91 Miata ready to sell.  Somehow I have about $20k worth of parts in it at street value.  I have been avoiding looking at what I spent on it over the last 10 years. 4 engines, 3 different FI systems... yikes.

[Satisaii]

After seriously questioning my life choices for a couple of months, I am back on this project.

 

Reality was a little bit of house work (expand master bedroom by removing a load bearing wall), generate some extra income (part out long term Miata project) to fund this build,  and deal with HOA over fence (deal with SO stressing out about other people telling her what she can and can't do with our yard.)  Tons of fun instead of doing what I want to.

 

Also gave me time to think about how to deal with the front subframe and how to place it in the truck frame.  I have my Solidworks model to give me the general idea, and then I just eyeballed it to get my cuts close.

 

 

Then I really wanted to know if my model was even close to being correct.  I needed a way to figure out relationship between the suspension mounting points on a standard Miata.  I ended up using a laser range finder, a table that could be leveled, and a yardstick hanging from the alignment eccentrics while the car was on the lift.

 

 

I measured 25mm difference between the front and rear subframes.  I entered that into Solidworks and figured that was probably all accounted for in measuring error since I could not get the car, table, and laser range finder perfectly level.  They were all within 0.5° degree, and that 25mm is 0.86° across the length of the car.  I decided that all the alignment eccentrics are all on the same plane.  Time to recreate that in the truck.

 

This time I attached the range finder to the frame.  The lift is 0.01° from being level.  The frame is about 0.3° from being level.  The range finder is +/- 0.1°

 

 

And the I set the eccentrics to the same level.  But 0.1° is about 5mm measured at the front subframe.  It ended up way higher (+10mm) on the frame than I was expecting in Solidworks.

 

Now I need to decide if I trust my Solidworks model more than I do my IRL measurements.

 

I also discovered that I put the rear subframe 10mm too far forward in the vehicle.  At least I haven't welded it in yet.  Measure 5 times, cut twice.  At least it isn't still too short.

[Satisaii]

On 2/11/2023 at 2:04 PM, Satisaii said:

Forum software is fighting me.

 

Edited March 4, 2023 by Satisaii

[Satisaii]

This project has now gone sideways into a crowd of bystanders...

 

 

Ok, it was hit by a Hyundai, based on the bits and pieces found in the trunk. No innocent bystanders were hurt in the filming of this thread.

I mostly bought it for this:

 

 

2.3L, turbo, 310hp/350 ft/lbs with TONS of aftermarket support. Stuff you would never want to put into your car. Amazing what sales numbers can do for a platform.

 

This is a 2015. I kinda bought it spur of the moment, and maybe should have done a bit more research first. I wanted an auto transmission (easier since I don't have to worry about where the shifter goes) and Sync 3 (gets Android Auto). I got a 6 speed auto and Sync 2... with no Android auto. That is now an $800 upgrade. Boooo. Should have gone for the 2018+ with a 10 speed and Sync 3 included. The prices on Copart did not change much until the 2020 model anyways. If I could only sell this for about what I have in it (i.e. small loss) I would redo it.

 

FWIW, this is cheaper than doing a K24Z3 swap with a BMW DCT once you add in the cost of getting the K24 up to 300hp and the associated electronics. I will use just about all of the electronics from this in my project. I can't wait to see what the wiring harness weighs.

 

Anyways, I spent months agonizing over how to do the front subframe install. I had put the subframes so far up into the stock frame that I was looking at having to split the frame to get it to work. I then had the idea of ditching the rear FLCA mounting point from the subframe and recreating it inside the Datsun frame. I am now working on that with a local fabricator, and hopefully we will have it rolling again this month. Then I am going to get Renderos Racing to do the roll cage / chassis stiffening. While it is in his care, I will work on parting out the Mustang. I am really hoping to have a running vehicle this year. Maybe not on the road again, but close.

 

I did a burnout in the parking lot. There were no bystanders to witness this event.

[paradime]

Satisaii: You fought well sir Pony, but we must continue on our quest for The Holy 521.

 

Mustang: What? This is just a flesh wound, none shall pass!

 

Satisaii: Cut out his ecoboost popcorn popper and let's go.

 

Me: Dang, I'm watching the rest of this movie.