Daily Archives: April 3, 2017

Clean sheet of paper

How would I be doing the Mid-Bucket if I wasn’t trying to save sunk costs on parts already bought? What if I had a clean sheet of paper to go with the free engine and transmission? Those are the two most powerful words in engineering, What If…?

Well I would be doing pretty much the same thing I’m doing now behind the body, a de Dion truss and fabricated uprights with Metric e-brake calipers from that kit I linked to a while back. The main difference would be all the links would be straight aluminum tubes swedged to thread 5/8” heim joints, and the coilover would bolt to the upright, instead of to the top bar of the 4-link.
This is a sunk cost that I had to protect in the current design.

The middle would also be very similar to what I have on paper now, I see no need to make any changes just because I have that the way I want it. I really don’t need to change anything to make it work with any changes I make up front. Seriously it will work as it is with anything I put up front.

If it wasn’t for the weight I would use this spindle and brake kit . I’m thinking I might just buy another front bearing set for the donor vehicle and fabricate a light front upright for a lightweight IFS and maybe take a few pounds of unsprung weight. I would lose a bit of the camber control the tube axle would bring but counter with adjustability and limiting travel to keep everything lined up and pointed in the right direction. Also by using the driven hub I could go AWD in the future should that particular bug bite me. Right now I don’t see it as AWD would add about 200 pounds to the Mid-Bucket for only marginal gains in dry weather. That’s going from 1575 to about 1800. Now if that free engine and transmission came from an AWD Pacifica instead of a ’96 Town and Country… with the 305 HP tune from the Ram 1500… which might get me slightly ahead of what I have now. So, not worth the cost and time to install.

Anyway getting back to the RWD Mid-Bucket, I might be able to get down to 1550 pounds with the cast iron block 3.8 V6 by ditching the tube axle and redesigning the front clip for IFS. But that would be pushing the limits very hard, risking breakage on potholes and such. More realistically for a street car I could get down to 1560 from 1575 by changing from the tube front axle to an IFS and starting from a clean sheet of paper using the lightest components I could reasonably get. Subtract another 85 pounds from that for swapping in the Pentastar V6 so 1475 would be the lightest Mid-Bucket that could survive on the street.

And I’m ready to take my walk now, Opus the fat but still Unkillable