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rodknock
rodknock Reader
1/6/22 2:23 p.m.

Oooh that wheel setup is going to be sick.

As far as cheap, high offset 15x7s go, that spec is probably the least desirable for 5x114.3 in the modern day. On FB Marketplace, I have seen cool 90s mesh BBS wheels in that size for next to nothing. 

maschinenbau
maschinenbau UltraDork
1/6/22 2:29 p.m.

In reply to nocones :

Thanks! I will probably have very short-travel suspension with this car, unless I go pushrods or find better coilovers. With a 4" subframe ride height, the wheels can only travel so far...

Is vSAL the same thing that VSUSP calls "FVSA length" (front-view swing arm length)? Looks like I can reduce that to 100" by dropping the UCA pivot down 1". But then at 3" bump the UCA swings like 45". Which I guess is okay, just seems like a ton of movement. 

VSUSP project

Gammaboy
Gammaboy New Reader
1/7/22 5:34 a.m.

I don't quite get why you're going to run the Honda wishbone mounts vertically and slot the mounting holes for camber adjustment - it'd be so much simpler to run the mountings horizontally and shim for camber. Then you're not relying on clamping to hold the camber adjustment, and you're not hanging a cantilever out the top of the mounting point that will be trying to twist the tube/plate that you're bolting to.

 

maschinenbau
maschinenbau UltraDork
1/9/22 6:26 p.m.

I'm ready to fab. But first, a bath.

Ah, much better. This unit is almost attractive now, but looks massive next to its future home. Everything is blocked up to the correct intended ride height. 4" from lowest point (subframe and exhaust) to ground. I would love to weigh this thing if I had the right equipment.

Starting fabrication with the forward subframe mounts. I hacked these off the Avalon shell along with the massive M14x1.5 mounting bolts before scrapping it. Only tacking for now, but the solid part of the tapped rod will be welded to the square tube then fully boxed in.

untchabl
untchabl HalfDork
1/9/22 10:06 p.m.

I ordered this the other day to weigh the chassis for my rock crawler project. Bet it would be perfect for your needs as well. I haven't used mine yet, still in the process of tearing my project apart. 

1,000lb crane scale

​​​​

maschinenbau
maschinenbau UltraDork
1/14/22 9:42 a.m.

Last minute updates to the CAD model, some printed drawings, and tube fab is underway!

maschinenbau
maschinenbau UltraDork
1/17/22 10:31 a.m.

You ever get halfway through building something, only to realize you need to completely re-think the remaining half? I made a critical error in calculating the motion ratio of the rear suspension. I assumed I could use the ratio of distance from LCA bushing for spring and wheel mounting. But that only works if the spring is mounted to the LCA! I was planning to attach the coilover directly to the knuckle where the McP strut used to be. This means motion ratio was always 1:1 (plus some angular deviation). So if I had continued building, the MR would have been 1:1 instead of the planned 2:1, resulting in a harsh ride frequency of about 3 Hz! Not good because I am shooting for 1.4-1.5 Hz. I can't fix this by simply mounting the coilover to the LCA for a few reasons: 1. the LCA is hollow stamped steel and probably not strong enough, 2. I assume the lower ball joint of a McP strut suspension was never designed to take full vehicle weight, and 3. the CV axle is in the way. The only other alternative would be to toss out the GSXR600 coilovers and try to spec the correct size spring and shock combination. I would need a 140 lb/in spring with a huge travel range that can fit 8-10" compressed, not be too wide, and cheap. I found mid-2000's Mazda 3 and Ford Focus rear springs might work. But then I need to spec a separate performance shock, which for cars is not cheap nor easy to find compared to the $25 fancy double-adjustable sportbike coilovers I was planning to use. So I burned a whole day analyzing and re-designing the rear suspension. The combined cost and time of junkyard springs and decent sports car shocks outweighed the additional $50 worth of rod-ends, flange bearings, and hardware to convert to a pushrod rocker-arm type of design. The challenge was packaging the coilover so that the external reservoirs don't hit anything, then beefing up the frame in some key places since the rocker pivot loads will be high. I also added some alternative holes in the rocker arm for a much softer ride when I want it, such as a drag launch... thanks for the tip, nocones :) 

Long story short - we're going full pushrod suspension!

I also did some actual work. The rear subframe needed brackets like this to move the rear cross-member tube to clear the sway bar mounts. 

NOHOME
NOHOME MegaDork
1/17/22 10:39 a.m.

I think you just wanted to do the more cooler pushrod suspension and the rest was all just rationalizing it to yourself and the rest of us!

 

Pete

maschinenbau
maschinenbau UltraDork
1/17/22 10:48 a.m.

Not gonna lie, it was pretty fun spending a whole day going between CAD, calculation spreadsheets, and parts sourcing. Which is basically my actual job. It's just so much more fun when you're personally invested. 

nocones
nocones UberDork
1/17/22 10:53 a.m.

In reply to maschinenbau :

What are your belcrank lengths.  Those look suspiciously close to the stock Yamaha Belcranks that I have that came with my shocks.  

If they work I can get you them.

maschinenbau
maschinenbau UltraDork
1/17/22 10:56 a.m.

In reply to nocones :

Brotus7
Brotus7 Dork
1/18/22 1:20 p.m.

Glad you realized the problem before it was all in metal, that's about when I resigned to needing pushrods.  What are you thinking for bellcrank bearings?

Shavarsh
Shavarsh Reader
1/18/22 1:31 p.m.
maschinenbau said:

Not gonna lie, it was pretty fun spending a whole day going between CAD, calculation spreadsheets, and parts sourcing. Which is basically my actual job. It's just so much more fun when you're personally invested. 

Quoted for truth

maschinenbau
maschinenbau UltraDork
1/18/22 2:03 p.m.

In reply to Brotus7 :

For now (Challenge budget) just some oil-impregnated bronze sleeve bearings like these. Eventually I'd like to machine some billet aluminum rockers and use needle bearings.

maschinenbau
maschinenbau UltraDork
1/19/22 9:24 p.m.

Got some new parts. These are 15x7 Jeep wheels, which almost kinda look like old-school Revolution wheels if you squint. I would love to find a matching set for the front, but you know, weird Lotus lug pattern and $$$. These are the backup plan is 15x8 is too wide for the amount of widebodywork I'm willing to do.

Also I deleted the A/C, power steering, and an idler pulley. The MR2 forums figured out the correct belt for this like 10 years ago, which is a Gates K060578 for Honda S2000. Or any 57.8" belt with 6 or 7 ribs. The 2GR pulleys are 7 rib, but this belt only has 6 and the internet said that's okay. Call it a 14.3% belt weight savings.

I designed a caliper adapter for downsizing my brakes (oh this is a weird project). Test fitting the paper template guided some dimensional tweaks. I'm sending this part out to a site called sendcutsend.com to see what they're like. It needs to be 3/8" thick, which I don't have on hand and don't feel like cutting. $10.90 each shipped, isn't that awesome?

More frame progress, including upper control arms and lower subframe mounted. 

Pushrod suspension conversion hardware. I'm kind of a slut for McMaster-Carr. I just love shiny obscure high-quality hardware. Right to left are rocker pivot bolts with oil-impregnated flange bearings, the pushrods which are 3/8" female rod-ends with grease fittings, and the rocker pivot housing which is 1"x1/8" wall tubing (3/4" ID matches the flange bearings). All of this plus the coilover mounting bolts was about $50 shipped. The rockers themselves are a tab-and-slot 1/8" steel design, which I'm also having cut by sendcutsend.com. Including the double-adjustable GSXR600 coilovers, this a $150 suspension. Yes I'm pro-rating what I actually use on the car, including every nut and bolt. Yes I have a nut-and-bolt spreadsheet. I dare someone to protest my budget devil

The tubing was a gamble since OD and wall were the only controlled tolerances, but sure enough the bearings fit perfectly.

Mr_Asa
Mr_Asa PowerDork
1/19/22 9:33 p.m.

I'm sure you'll love SCS, I damn sure do.  Does the steel stuff have a minimum order like the 6061 stuff does?

maschinenbau
maschinenbau UltraDork
1/19/22 9:35 p.m.

In reply to Mr_Asa :

Yeah $29. I spent $72 total on all the brake adapters and rocker arm parts. If I run out of Challenge budget, I could always fabricobble the rockers by hand. They will probably need revision anyway.

Mezzanine
Mezzanine Dork
1/19/22 10:14 p.m.

Another SCS fan. I learned to use Fusion 360 just to get stuff cut out online and I haven't looked back since. I usually check their rates against oshcut...depending on volumes and materials sometimes there's a big difference between the two outfits. 

maschinenbau
maschinenbau UltraDork
1/23/22 6:56 p.m.

More frame progress. The passenger side needs this extra arch for the upper engine mount. UCA is barely still removable.

Time for the really tricky piece. I need to convert this McPherson strut to a double-wishbone. That bracket needs to connect the knuckle to the UCA ball joint. It also needs to transfer force to the suspension. I'm thinking two 1/8" backets that bolt through the original strut mounts, which sandwich two tubes - one going up to the ball joint, the other cantilevered out to the suspension pushrod.

4 brackets all need the same bolt pattern. I really should invest in fixture tooling.

I think it's going to work. I just need to figure out the upper ball joint connection. Something that allows camber adjustment ideal, otherwise I have to slot the UCA mounting holes. I should also figure out an attachment for the stock sway bar link. Oh and the steering link...to keep it from steering....seems important.

maschinenbau
maschinenbau UltraDork
1/30/22 6:07 p.m.

If you've never used SendCutSend, I highly recommend them. These parts went from CAD to front door in 1 week for $72 shipped. Even this great deal is still a high price for Challenge car parts, but this next step just needed more precision. 

The 3/8" parts are brake caliper adapters. 

Had to raid the metric bolts kitty litter tub. When gutting the Toyota Avalon, I threw all those OEM-quality fasteners in here.

First-ever midsize Toyota 'Little Brake Kit'. I also 3D-printed a hub-centric ring for the rotor.

They even clear a set of 15x6 Tacoma steel wheels I just found listed for free. These kinda match the stock Lotus steelies, and I think it'll be fun to have a skinny-tire steelie set to cruise around on before any bodywork. They also have the same backspacing as the Jeep 15x8's, so if one clears the suspension, the other will too. This is a 27" truck tire for reference. I am fitting 22.7" front and rear.

Suspension stuff happened too. I made an upper ball joint adapter from some 1/2" bar stock. A 7 degree ball joint reamer into a 1/2" hole did the trick.

A stack of washers takes up the rest of the space under the castle nut. It'll probably be fine? Still need to connect it to the knuckle extender with some kind of camber adjustment.

The rest of that laser cut order was rocker arms. I designed in some tabs and slots so they self-fixture for welding.

I also added a grease port to the rocker bearings.

And TIG'd them up along with the caliper adapters. 

That was the easy part. The hard part now is all the hand-cut mounts for coilover, rocker pivot, pushrod-to-spindle bracket, etc. I also have to make sure the spindle/knuckle bracket doesn't collide with the rocker at full squat, due to camber gain. It'll be close.

obsolete
obsolete HalfDork
1/30/22 6:12 p.m.

Can't click the thumbs-up button enough times. It's really cool to see this coming together. Awesome stuff.

Brotus7
Brotus7 Dork
1/30/22 9:10 p.m.

Looking good! Thanks for the tip on sendcutsend, I have a couple parts to get quoted.

cruisermatt
cruisermatt Reader
1/30/22 10:49 p.m.

Very very cool

maschinenbau
maschinenbau UltraDork
2/6/22 6:45 p.m.

I kept whittling away at the Knuckle Bracket until it fit. Then I tacked, tested, cut, re-positioned the rocker pivot brackets 5 different times. I just couldn't get the rocker in a good spot that minimizes the pushrod angles without colliding with the knuckle bracket at full squat. 

Then I realized I could lengthen the cantilevered tube that comes off the bracket. So here it is, lengthened and tacked enough to bear weight. 

Yep that's daylight under the subframe!

Now just have to repeat for the other side, and add plenty of gussets. I also decided to put camber adjustment in the original, tried-and-true spot - the bolt slop at the knuckle where the struts would have gone, slotting as necessary. Essentially an articulating knuckle. 

Mr_Asa
Mr_Asa PowerDork
2/6/22 7:05 p.m.
maschinenbau said:

First-ever midsize Toyota 'Little Brake Kit'. I also 3D-printed a hub-centric ring for the rotor.

A 3D printed what now?  

Unless that is a temporary thing, send me the dimensions and I'll lathe something out for that.  I'm 90% sure I've got some stock in my pile that Dad found on the side of the road.  I'll do it at no cost.

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