Announcement

**Rattmandu** · 07-13-2020, 12:42 PM

Engine mounts and transmission mount are finished.

Driver:

Passenger:

Trans:

And I've started mocking up the new transmission tunnel. I'll also be mounting the hydro hand brake to this, and hopefully adding a couple cup holders. I think I'll go one inch narrower in the rear of the tunnel than this mock-up. Also keep in mind it needs to slide slightly further forward than pictured but I have to dig more insulation off the firewall piece by piece till I can get it in there.

**scweet14** · 07-20-2020, 07:25 PM

this thing is fucking rad!

**Rattmandu** · 07-23-2020, 04:10 PM

Originally posted by scweet14 View Post

this thing is fucking rad!

Thanks!

**Rattmandu** · 07-23-2020, 04:37 PM

Over the last couple weeks, I've gotten the trans tunnel cut out of 16 gauge, and folded it up on a finger brake at work. I ended up making the end cap a separate piece, and also altered the design versus the cardboard mock-up. It's now the same width at the base, but tapers to an inch narrower at the top.

End cap welded on and ground smooth.

Then came the arduous task of getting it to fit the floor and firewall. I had to totally strip everything off the dash to get enough access to the firewall, then spent about two and a half days trimming and heating and beating to get everything to meet up properly. It's fully seam welded along the entire perimeter inside the cab.

It was then etch primed.

And I gooped up the underside with seam sealer.

Finally the fan, heater core, and AC evaporator went back in. I had to remove everything that allowed air to be directed at my feet, but that's no big deal.

And now for some big changes, I've been designing my own front suspension. I'm starting with the knuckles from a 2012 2WD Silverado, so that the stud pattern matches the Tahoe rear axle. Also they're cheap, and not super tall like a Tacoma knuckle, and they're front steer which is important for engine clearance. The knuckles have been modified to use a 1" Uni-ball joint instead of the standard ball joint. Note in the below pictures I have it mocked up with a Heim joint, which isn't what I'm going to be using in the final design.

This will be a double A-arm design, which is currently designed to have 40% anti-dive, and an instantaneous roll center about 30% of the way up to the CG. These are subject to change because I'm making some educated guess about where the CG is. I'm also planning on moving the front wheels about 2" further forward, this will get me some more traction on the rear wheels, and also give me more tire clearance to the foot-well. Up front I only have to worry about running into a fiberglass fender and a bumper I haven't made yet.

I've designed it to have about 6 inches of bump and 4 inches of droop. Bump steer going up is pretty good, as it sags down I get like a half degree of toe-in.

This would be with a 6.5" stroke shock and a 500-550 lb/in spring, which results in around a 1.6 hz natural frequency. Again, these numbers will change a bit once I get the truck on some wheel scales and get true numbers for sprung and un-sprung weight.

And here's a shot of the basic design of the A-arms. These will be cnc plasma cut 10 guage plates that will tab and slot together to self jig into the right shape. Those inboard plates that the A-arms connect to is designed to be welded to the outside of the frame rails so I can actually position the arms correctly in space. You can also see what the uni-ball joints look like.

**Rattmandu** · 08-03-2020, 06:05 PM

Spent the weekend turning the A-Arms into a real sheet metal design that tab and slots together. This is primarily 10 gauge cold rolled sheet, with the threaded bungs for the heims being welded into 1.5" OD, 0.25" wall DOM tubing.

The upper arm should be right at 10 pounds for the weldment, plus a little bit more for the uniball bearing and the ball of the heim joints. Upper arm design:

Exploded view:

The lower arm is right around 15 pounds. Lower arm:

Exploded:

And I also ran a little FEA simulation on a simplified model of the lower arm. The test shown here is at 2000 pounds force at the shock mount, but peak force at end of travel will be something close to 3200 pounds.