Vsusp question

[Djboston]

Hello,

I'm getting ready to build my own chassis and want to start from the wheel/tire setup and work inward. The car will have 16" wire wheels and about a 90" wheel base. I have a fiberglass body I picked up from the UK, for a formosa 236. Any advice on vsusp? I'm not expecting a lot of suspension travel, 1.5-2" max on bump.
Is what is shown in vsusp below ok? What is best? Rear roll center is above front roll center. https://vsusp.com/?tool=2d#0.8%26projec ... enter.y%7D

[Miatav8,MstrASE,A&P,F]

Needs work. Plenty of info here: https://www.locostusa.com/forums/viewtopic.php?t=13928

Where is your build project?

[Djboston]

I live in SW Florida. Thanks not sure why that thread did not show up in my search.

IMG_20250214_170921.jpg

here is the car on the soon to be replaced Triumph Herald chassis with small tires.

[anduril3018]

That's a great looking body! Do you plan on using a Locost based frame design, or something else?

You might find some inspiration here @Locost 11 R1

https://www.locostusa.com/forums/viewtopic.php?t=3386

[Miatav8,MstrASE,A&P,F]

Very nice! I meant where is your build topic going to be? I'd like to follow your progress.

I've not seen a herald in a very long time but plenty of spitfires floating around. Hard to beat the unsprung weight of using the triumph uprights and brakes. Keeping it all herald? If so, you won't need to redesign the suspension. It looks like you could just add a little structure to the herald frame with a backbone around the transmission (like a TVR) to replace the body as a structural component, to prevent cracking the fiberglass.

If you don't want to use the original chassis at all, you can still use that as a starting point in vsusp. I will help you tweak the vsusp once you've had a chance to review and update. I can compare your upright dimensions to my spitfire uprights. The tire size shown in vsusp is much too large and won't fit the wire wheels. I expect you will need a 155 to 175 70 to 80 series 13 inch or similar size tire if using the wire wheels.

[Miatav8,MstrASE,A&P,F]

I looked only at the front vsusp. I tweaked it a bit for 175-70-13 tires, 7/8" offset wheels, corrected the triumph upright dims, lengthened the upper control arm one inch to 7.5, changed the chassis attachment points, but left the trunnion uprights and lower control arm as-is.


The actual scrub is half what is shown due to having trunnions instead of lower ball joints but it is still a lot of scrub by comparison. A lower ball joint conversion doesn't fix that.

The roll center is high by comparison but the triumph swingaxle has a much higher roll center.

Given the limitations, I think this makes the most out of a weekend touring build but it is just a rough tweak in the right direction from where it was in your first vsusp version.

When fitting the steering rack to your custom frame, I suggest moving it an inch or two rearward relative to the uprights as clearance allows for easier low speed steering/ackermann. If you are using the herald frame, none of this matters.

formosa236 tweak 02182025

[Djboston]

Thanks for the replies. I'm going to ditch the herald chassis and build a variation on the book chassis to fit within the body.

The body is designed for larger wheels than the 13" on the Herald so I have 16" wires and will use the longer hub adapter. I'm liking the look of the rx8 hub assemblies for the front.

As for the engine etc I'm torn between a cyclone or duratec v6. I think numbers wise the mustang/cyclone v6 is a more flexible option due to the transmission options. I don't want a v8 before anyone suggests that .

The Herald running gear and mechanicals will go into a second car that will hopefully look like a Lotus IX (9). I will be creating a suspension template from the chassis and then scrapping the chassis. I bought the car in the UK and have the paperwork associated with it and will have to work out which car will be registered as a Herald and which is the component built car when I go to the FL tax office. If you have a suggestion for the herald based suspension and 13" wheels, that will also be appreciated. The car has drum brakes and a factory rebuilt 948cc engine that last ran in may of 24.

Thanks

Dan

[Miatav8,MstrASE,A&P,F]

The link in my last post titled "formosa236 tweak 02182025" is for the herald with 13 inch wheels.

The primary limiting factor is the bonnet/hood clearance. The choices to fit will be short but the torque output more compatible with your wheels and axle. The herald hubs are not the primary limiting factor.

Determine the ground clearance to the bottom of the hood, subtract 5 or so inches, a 1/2 inch for hood clearance, then find an engine that will fit.