Supercharged Blackjack Avion

[andrewc]

Hello,

We changed email addresses a month or so ago which hopefully explains my not replying - I'm not normally rude!

On the ignition timing topic, I've been looking at options for boost-retard as the ideal solution, rather than just retarding. The options I've looked at are

micro dynamics boost retard module - 1980s unit that provides an amount of retard per 1000rpm above a certain manifold absolute pressure (MAP). Hard to get hold of, and micro dynamics aren't sure it will work well with wasted spark. Start at about £50 when they come up on eBay

1-2 spark - Dutch chap who sells a programmable electronic ignition with boost retard function. Requires a MAP sensor, and a crank position sensor, picking up a flag welded to the flywheel. Can be found by googling 1-2 spark, or I can send an email if you're struggling. He uses the ignition himself on his Smart turboed 2cv. About £200 I think

Mega spark / mega jolt / emerald - all programmable ignition systems, quite complicated to a mechanical engineer like me, and not a common 2cv solution, although if you google it I think a Finn is supercharging a 2cv with an aisin amr300 using mega spark, but he's also fuel injecting - too complicated for me. Cost seems to start at around £350

Another option seemed to be 123ignition, as the evo unit seems to give some retarded curves. I sent them an email, asking about boost retard, and they told me they were developing a unit with that function. I sent a cheeky email, offering my services as a test mule, and after further discussions I hopefully receive a development unit in the next couple of weeks. It appears to be fitted like a 123 unit, will need a MAP sensor, and will apparently be programmable via Bluetooth. No mention of a crank angle sensor yet. I don't know about costs yet either

By then I should have the carb connected and the crankcase breather etc. sorted. Biggest snag at the moment is the exhaust manifold to supercharger inlet clearance, which is a bit tight.

Hope this helps - Hopefully I'll have some good feedback to give in a month or so

Andrew

[Geoff Ryall-Harvey]

You need to move the exhaust manifold out from the supercharger - changing the angle of that run. Cut it in the middle of the first long straight section and also about an inch above the manifold flange. Insert a section (maybe 2“) in the straight and tack it all back together. Then get it tigged.

[andrewc]

Some more progress in the last month.

I've come up with a "lets see if it all works before doing anything drastic" solution for the carb to supercharger / exhaust clearance issue using some wire reinforced flexible ducting which is supposedly good for 300deg.C combined with heatshield wrapping the offending manifold. This should be good enough to see if it all works well enough to make it worthwhile doing something better.

The prototype 123ignition unit has arrived and I've fitted it in place of the normal ignition, and after discussion with Frank at 123ignition regarding primary resistances I've gone for a yellow super coil. Next big job is wiring changes for coil, ignition unit and alternator with internal voltage regulator. I'm definitely a mechanical engineer by training and inclination, but luckily my dad (builder of the red and white "flying pig" 2cv trike often seen on the 10000ft run) is an electrical engineer.

The 38HIF SU carb has had a new sealkit, and after using the Mintylamb website I've gone for a AAU needle on the basis that the one thing I don't want to be when I fire it up for the first time is too lean. The carb originally had an AAT fitted, which seems very similar in profile to an ABC or ABB. The AAU is richer all the way from needle stations 4 to 15.

Brackets are 95% complete and have been painted, I just need to silver solder a crankcase breather and oil filler solution onto the stub pipe visible on the main combined supercharger and alternator bracket.

Couple of photo's below, one shows the complete parts kit and fabricated brackets, less the yellow super coil. The other one shows the 123ignition unit installed. You can just see the MAP pressure tapping at the lower left quadrant. This is a truly multinational project - the supercharger came from Japanese ebay, the idler/vee pulleys and neat plasma cut curved bracket from Australia, the coil is American, the ignition is Dutch and the carb from the UK - I'm not sure it would have all been possible without the internet.

So once the wirings complete I should just need to bolt it all back together.

My initial aim was to make the April Harewood Hillclimb school, as the driver behind the project was attending the school twice last year and the thirst for a bit more power. I think the car will be back together by then, but unfortunately work means I'll miss the April school day, so it'll be the next school in June before I can try and beat my 2014 best of about 94 secs. There are a couple of video's of last years attempts at the link below, in case anyone is foolish enough to be tempted to think about having a go themselves.

https://www.youtube.com/channel/UCDRP5O ... nJIkrKva1A

[andrewc]

Here's a sentence I didn't think I'd be writing when I bought the Avion just short of 12 months ago

Today I have successfully paired my IPad to the 123 electronic ignition unit via Bluetooth

[Geoff Ryall-Harvey]

Cool beans.... Can you now create your own ignition curve??

[andrewc]

Thats the idea - you can create a normal advance curve, and then a MAP adjusted curve. There are various theories/values for how much you need to retard for 1psi of boost, I'm going to start by using 1.5 degrees as the multiplier (David Vizard rekon 1.1deg. and Alan Allard reckons on 1 to 2 deg.)

But I'm a couple of weeks away from that yet - this was just to see if it connected OK. It did, and on the IPad app "virtual dashboard" the MAP pressure sensor read atmospheric pressure and the voltmeter measured volts - it all seems to work OK so far.

[andrewc]

Nearly there - taking longer than I thought but as a wise man once said "its the first 90% that takes nearly 100% of the time and the last 10% that takes the other 100%"

Or something like that - I'm fairly sure that's what Burt Levy's lead character Buddy Palumbo say's with regard to a car project in one of his Last Open Road series of books. Set in 1950's America about a small time New Jersey car mechanic who gets involved in SCCA racing and eventually gets involved in La Carrera Panamerica, Sebring 12 hours etc. they name check Phil Hill, Briggs Cunnigham, John Fitch, Stirling Moss, Fangio etc.. I'd recommend them as light reading for any petrol head (he even runs at Bonneville in one book Geoff - right up your street I would have thought with your liking for rods)

[Geoff Ryall-Harvey]

Incredible job of packaging it all in that tiny space. Well done - I'd like to see this running.

I agree about the 90% taking 10% and vice versa.... That the big problem with hot rod building.

[hutchii]

Andrew,
Regarding the 123 Tune + unit shown in your pics. Is this the "test mule" item you mentioned in an earlier post, or is it now, "readily" available? As soon as I've got my Solo on the road, I intend turning all my attention to the the spare engine/box, and it's supercharged development. I haven't been able to resist doing some of the preparatory work! The HIF 4 to charger mount is pretty much done, and I've mocked up the charger mounting in ply. Unfortunately I'm rarely satisfied with my prototypes, or the thinking behind them, so I invariably make a number of re-thinks before I'm satisfied. Wood mock-ups are so much quicker and easy to make and then refine. I can measure, mark out, and make a bracket from ply (which is plenty strong enough for checking clearances and alignments) in a few minutes using my old Burgess bandsaw. A friend can then create DXF files pretty quickly to enable the real ones to be Laser cut.
On the subject of Laser cutting, I've just had some 12mm stainless plate cut to replace the Citroen steering arms (the bit with the ball end) so that I can use rose joints. When they're finished I'll get my computer guru to show me how to post some pictures. The reason for this mod is primarily to lower the track rods so that I don't have to put clearance slots in the lower edge of the bonnet.

[andrewc]

The 123igntion is still the test mule at the moment - still some desnagging on-going

I appreciate the comment on the packaging, but I'll probably appreciate it more when the things running again!