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Slow updates with it being silly season for farming, so nothing really new picture wise, just been working on refining the mapping after switching over from alpha-n as we were struggling with throttle response (inlet tract is longer than I'd like) - and investigating a few sensor errors on the crank/cam sensors - work on masking the windows helped out but I suspect we might have a duff cam sensor, so awaiting a replacement unit.
Dash back out to tidy/clip up all the connectors and drill holes for the dash control button and launch control dial too, which means I've got to make connectors for all the switches now everything is working, so they can be unplugged easily rather than having 4-7 pins per switch to keep track of.
Hah, yes, he used to love his time down at the workshop, he was rather attracted to shiny parts though, every time you turned around your socket and spanners would have gone missing - they'd usually turn up outside in a pile with a grinning dog sat by them, like a dragon with a gold shortage.
Unfortunately he's since passed away, so he didn't get a ride
Well, been a little while since an update, not a lot done really, we were waiting for the fiddle brake frame and few other brackets and mounts to come back from the platers, so I decided to update the dash firmware and change the screens around, that didn't go well:
Anyway, after a chat reverted to a slightly older version of the firmware that worked but still had some improvements over the old version we had on the dash. Great. Then tried uploading the new config....
Yeah, that didn't go great either, maybe I should have left it alone whilst it was working...anyway, gave up on that for the moment (it's being sorted out), and bolted the shiny bits on that came back from plating, tweaked a few things for easier servicing such as having the power cable on bulkhead attachments rather than straight through - made out of the same polyurethane as the exhaust mounts in the other thread, as a bit of flex reduces fatigue in the cable and it's pretty resistant to chemicals and heat.
Also in the servicing improvements, we tweaked the corners on the fan cowlings and ducting so now they can come straight out as a since unit instead of splitting them, same for some of the rear heatshielding over the exhaust and water pipes.
Just tidying work really.
Then decided that was all far too sensible. You know how I said we always have to make things three times? I lied.
Front suspension/uprights version 4 is in progress, ditching the link pin and sliding setup that it inherited from Volkswagen, and switching over to an upright using some large sealed spherical bearings instead - that allows us a much wider area of camber change without binding, much less friction, and because the original link pin requires some play to work correctly, we can get rid of that too, so we cut down massively on play/slop in the front suspension.
It'll also allow me to ditch some of the poor geometery around the scrub radius and castor gain in the original VW setup:
This won't be the actual upright, just a quick model to tweak clearances and geometery for the moment, design work on the proper one is in the 'stare at the front end and scratch head' stage at the minute. It's a bit more complicated than it looks as the current clearances between the front coilover and arms is tiny, and they already use 99% of the travel available on their bearings, and the steering tie rod currently clears the frame at full droop by about half a ciggerette paper.
And we've moved the spindle down 3" on the new uprights so it's screwed all the mounting points up.
Oh, and of course, being spherical bearings instead of a circular kingpin, the steering angles are limited, even with inserts to let the joints move further....so they need a bit more work yet. Good fun.
It may yet be a 9" angle grinder to the front bulkhead...
Well, no shiny pictures again, sorry - slow work on the uprights, everything at the front is pretty critical in terms of spacing - we're already using every millimetre of travel on every joint, etc, we have and things are rather tight, so we're slowly iterating the new front hubs with bits of scrap to see just what we can get away with - it's very tight for getting enough steering lock - we end up with the joints actually over centre at full lock at the minute.
Anyway it's getting closer, then once we have something that's close need to work back and see how far from the model we are geometry wise and tweak things again.
It's going to take a while so that's gone on the back burner as a slow project and back to the usual build-up stuff like new canister mounts for the dampers, spanner checks, the driveshafts and CV joints are built up and on, I just need to strip the rear dampers and drain the oil now so I can make some valving changes and machine a new droop spacer to go on the rod - that's tommorows work, along with priming everything and turn the key....
Well, after I finish drilling holes in a flywheel anyway...
So, we've had it running, why isn't it outside yet?
Well, been hunting down some issues with the engine for mapping (turned out to be an intermittent air leak on gasket but took ages to hunt it down), and we're still having some problems with the dash that are being worked on atm.
And, whilst we were putting the front suspension back together....well, the front fell off. I know it's not supposed to fall off but....
Anyway, the old front arms were a little worn so we tacked together a new set, and decided to narrow the front beam tubes slight as the tyres rub in full lock if we have the wider options on....which lead to tacking up new arms to suit....and then we decided if we're doing all that, it might be time to ditch the VW uprights as well.
For those unfamiliar with the old Beetles, the front uprights are a link and kingpin setup - basically there's a big Kingpin vertically that sits inside needle bearings, which allows the steering to happen. Then on the end of the front arms, two pins stick out horizontally into some bronze bushes for the upright to pivot on when the suspension cycles up and down.
Now, that's a relatively robust setup, as it's basically just some huge hardened steel pins taking the loads, but it also means you have to deliberately leave the pins loose to allow the suspension to cycle, which means even in perfect condition there's always some slop in the system, and also as the loads change and things flex, the friction in the front suspension jumps up and down as the bronze bushes get pinched and wear.
The steering effort also changes massively as the kingpin runs against a hardened steel washer - so the friction there changes massively with load - if you look back through the old photo's you'll see I replaced it with a bronze+acetal thrust washer when I rebuilt them the last time to help it out.
Anyway, after a lot of trial and effort get get the required angles and clearances, we've managed to get just about get enough room to switch out to a new upright using a pair of spherical bearings instead, which means everything can be bolted up tight, camber can be adjusted easily by just shimming behind the upright, and friction should be a bit more consistant as all the loads are taken through the bearing surfaces with no pinching/rocking effects like the old link pins had.
Whilst we were at it I took the opportunity to correct some of the VW front geometery at the same time - so we have less castor gain, less mechanical trail for the same castor angles, and I've corrected a lot of the scrub offset issues the Kingpin setup had
We've also shifted the axle down to the lower arm point - this lifts the arms further out of the muck if running in deep, soft mud/peat, etc, and also means we can have a bit more travel up front (as we were only limited by arm angles in droop)
Anyway, just waiting for the parts back from the laser cutters and it can go together:
....just when you thought it was nearly ready
Oh, yes, instead of altering the beam to narrow it, the whole lot just met Mr. Angle Grinder instead. Whoops. Lets us ditch some of the old plates up front from the original car build and save a few kilos.
Yes, I've just being trying to get all the parts for this and some customer car bits out for the laser cutters so it's all back before christmas, then it can all go back together and off for mapping
And if need be, the old front end can get tacked back on just for mapping if we have to.